Science.gov

Sample records for air water sediment

  1. Gas exchange rates across the sediment-water and air-water interfaces in south San Francisco Bay

    USGS Publications Warehouse

    Hartman, Blayne; Hammond, Douglas E.

    1984-01-01

    Radon 222 concentrations in the water and sedimentary columns and radon exchange rates across the sediment-water and air-water interfaces have been measured in a section of south San Francisco Bay. Two independent methods have been used to determine sediment-water exchange rates, and the annual averages of these methods agree within the uncertainty of the determinations, about 20%. The annual average of benthic fluxes from shoal areas is nearly a factor of 2 greater than fluxes from the channel areas. Fluxes from the shoal and channel areas exceed those expected from simple molecular diffusion by factors of 4 and 2, respectively, apparently due to macrofaunal irrigation. Values of the gas transfer coefficient for radon exchange across the air-water interface were determined by constructing a radon mass balance for the water column and by direct measurement using floating chambers. The chamber method appears to yield results which are too high. Transfer coefficients computed using the mass balance method range from 0.4 m/day to 1.8 m/day, with a 6-year average of 1.0 m/day. Gas exchange is linearly dependent upon wind speed over a wind speed range of 3.2–6.4 m/s, but shows no dependence upon current velocity. Gas transfer coefficients predicted from an empirical relationship between gas exchange rates and wind speed observed in lakes and the oceans are within 30% of the coefficients determined from the radon mass balance and are considerably more accurate than coefficients predicted from theoretical gas exchange models.

  2. Reliable quantification of phthalates in environmental matrices (air, water, sludge, sediment and soil): a review.

    PubMed

    Net, Sopheak; Delmont, Anne; Sempéré, Richard; Paluselli, Andrea; Ouddane, Baghdad

    2015-05-15

    Because of their widespread application, phthalates or phthalic acid esters (PAEs) are ubiquitous in the environment. Their presence has attracted considerable attention due to their potential impacts on ecosystem functioning and on public health, so their quantification has become a necessity. Various extraction procedures as well as gas/liquid chromatography and mass spectrometry detection techniques are found as suitable for reliable detection of such compounds. However, PAEs are ubiquitous in the laboratory environment including ambient air, reagents, sampling equipment, and various analytical devices, that induces difficult analysis of real samples with a low PAE background. Therefore, accurate PAE analysis in environmental matrices is a challenging task. This paper reviews the extensive literature data on the techniques for PAE quantification in natural media. Sampling, sample extraction/pretreatment and detection for quantifying PAEs in different environmental matrices (air, water, sludge, sediment and soil) have been reviewed and compared. The concept of "green analytical chemistry" for PAE determination is also discussed. Moreover useful information about the material preparation and the procedures of quality control and quality assurance are presented to overcome the problem of sample contamination and these encountered due to matrix effects in order to avoid overestimating PAE concentrations in the environment. PMID:25723871

  3. Treatment of drinking water residuals: comparing sedimentation and dissolved air flotation performance with optimal cation ratios.

    PubMed

    Bourgeois, J C; Walsh, M E; Gagnon, G A

    2004-03-01

    Spent filter backwash water (SFBW) and clarifier sludge generally comprise the majority of the waste residual volume generated and in relative terms, these can be collectively referred to as combined filter backwash water (CFBW). CFBW is essentially a low-solids wastewater with metal hydroxide flocs that are typically light and slow to settle. This study evaluates the impact of adding calcium and magnesium carbonates to CFBW in terms of assessing the impacts on the sedimentation and DAF separation processes. Representative CFBW samples were collected from two surface water treatment plants (WTP): Lake Major WTP (Dartmouth, Nova Scotia, Canada) and Victoria Park WTP (Truro, Nova Scotia, Canada). Bench-scale results indicated that improvements in the CFBW settled water quality could be achieved through the addition of the divalent cations, thereby adjusting the monovalent to divalent (M:D) ratios of the wastewater. In general, the DAF process required slightly higher M:D ratios than the sedimentation process. The optimum M:D ratios for DAF and sedimentation were determined to be 1:1 and 0.33:1, respectively. It was concluded that the optimisation of the cation balance between monovalent cations (e.g., Na(+), K(+)) and added divalent cations (i.e., Ca(2+), Mg(2+)) aided in the settling mechanism through charge neutralisation-precipitation. The increase in divalent cation concentrations within the waste residual stream promoted destabilisation of the negatively charged colour molecules within the CFBW, thereby causing the colloidal content to become more hydrophobic. PMID:14975650

  4. Results of soil, ground-water, surface-water, and streambed-sediment sampling at Air Force Plane 85, Columbus, Ohio, 1996

    USGS Publications Warehouse

    Parnell, J.M.

    1997-01-01

    The U.S. Geological Survey (USGS), in cooperation with Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, prepared the Surface- and Ground- Water Monitoring Work Plan for Air Force Plant 85 (AFP 85 or Plant), Columbus, Ohio, under the Air Force Installation Restoration Program to characterize any ground-water, surface-water, and soil contamination that may exist at AFP 85. The USGS began the study in November 1996. The Plant was divided into nine sampling areas, which included some previously investi gated study sites. The investigation activities included the collection and presentation of data taken during drilling and water-quality sampling. Data collection focused on the saturated and unsatur ated zones and surface water. Twenty-three soil borings were completed. Ten monitoring wells (six existing wells and four newly constructed monitoring wells) were selected for water-quality sam pling. Surface-water and streambed-sediment sampling locations were chosen to monitor flow onto and off of the Plant. Seven sites were sampled for both surface-water and streambed-sediment quality. This report presents data on the selected inorganic and organic constituents in soil, ground water, surface water, and streambed sediments at AFP 85. The methods of data collection and anal ysis also are included. Knowledge of the geologic and hydrologic setting could aid Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, and its governing regulatory agencies in future remediation studies.

  5. PAH and PCB in the Baltic -- A budget approach including fluxes, occurrence and concentration variability in air, suspended and settling particulates in water, surface sediments and river water

    SciTech Connect

    Broman, D.; Axelman, J.; Bandh, C.; Ishaq, R.; Naef, C.; Pettersen, H.; Zebuehr, Y.

    1995-12-31

    In order to study the fate and occurrence of two groups of hydrophobic compounds in the Baltic aquatic environment a large number of samples were collected from the southern Baltic proper to the northern Bothnian Bay for the analyses of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). The following sample matrices were collected; bottom surface sediments (0--1 cm, collected with gravity corer), settling particulate matter (collected with sediment traps), open water samples and over water samples (suspended particulates and dissolved fraction sampled by filtration) and air samples (aerosols and vapor phase sampled by filtration). All samples (except over water and air) were collected at open sea in the Baltic. The analyses results have been used to make a model approach on the whole Baltic and to elucidate different aspects of the behavior of PAHs and PCBs in the Baltic, such as the occurrence of the compounds in water and sediment, the total content as well as the concentration variabilities over such a large geographical area, Further, the data on settling particulate matter as well as the air concentration data were used to estimate the total fluxes of PAHs and PCBs to the bottoms of the Baltic and t o the total water area of the Baltic, respectively. Further, data on the PAH and PCB content in river water from four major rivers provides rough estimates of the riverine input to the Baltic. The dynamics of PAHs and PCBs within the water mass have also been studied in terms of settling velocities and residence times in the water mass for these type of compounds in the open Baltic.

  6. Are the ratios of the two concentrations at steady state in the medium pairs of air-water, air-soil, water-soil, water-sediment, and soil-sediment?

    PubMed

    Kim, Hee Seok; Kim, Seung-Kyu; Kim, Jong-Guk; Lee, Dong Soo

    2016-05-15

    For optimization and evaluation of a steady state multimedia model, concurrent multimedia monitoring data of steady state are necessary. In the lack of emission rate information, the primary aim of the present work was to assess if five concentration ratios (CRs) (Cwater/Cair, Csoil/Cair, Csediment/Csoil, Cwater/Csoil, and Csediment/Cwater) of chemical compounds are at steady state in South Korea. A total of 16,676 CRs values were calculated using 74,641 concurrent multimedia (air, water, soil and sediment) monitoring data from 96 areas for 45 semi-volatile organic compounds (polychlorinated dibenzo-p-dioxins/furans, polybrominated diphenyl ethers, phthalates, and polycyclic aromatic hydrocarbons). Test of steady state indicated that CR is statistically at steady state with an overall occurrence rate of 70% of the 223 tested cases while the rates of individual chemical groups were 94.5%, 88%, 82.5%, and 37.6% for polycyclic aromatic hydrocarbons, phthalates, polybrominated diphenyl ethers, and polychlorinated dibenzo-p-dioxins/furans, respectively. About 83% of the steady state CRs resulted from scattering of two concentrations in each of the medium pairs without a certain temporal trend while the rest due to closely co-varying two concentrations. Analysis of the 95% confidence interval of the fugacity ratio indicated that CRs at steady state may occur in equilibrium state with higher chances than CRs at unsteady state. A total of 156 point values representing the CRs at steady state were determined that can be used for optimization and evaluation of steady state one-box multimedia models. However, potential influences of the uncertainties of the values arisen from the scattering of the concentration data should quantitatively be assessed in the model optimization and evaluation. PMID:26901802

  7. Air emissions from exposed contaminated sediments and dredged material

    SciTech Connect

    Valsaraj, K.T.; Ravikrishna, R.; Reible, D.D.; Thibodeaux, L.J.; Choy, B.; Price, C.B.; Brannon, J.M.; Myers, T.E.; Yost, S.

    1999-01-01

    The sediment-to-air fluxes of two polycyclic aromatic hydrocarbons (phenanthrene and pyrene) and a heterocyclic aromatic hydrocarbon (dibenzofuran) from a laboratory-contaminated sediment and those of three polycyclic aromatic hydrocarbons (naphthalene, phenanthrene, and pyrene) from three field sediments were investigated in experimental microcosms. The flux was dependent on the sediment moisture content, air-filled porosity, and the relative humidity of the air flowing over the sediment surface. The mathematical model predictions of flux from the laboratory-spiked sediment agreed with observed values. The fluxes of compounds with higher hydrophobicity were more air-side resistance controlled. Conspicuous differences were observed between the fluxes from the laboratory-spiked and two of the three field sediments. Two field sediments showed dramatic increases in mass-transfer resistances with increasing exposure time and had significant fractions of oil and grease. The proposed mathematical model was inadequate for predicting the flux from the latter field sediments. Sediment reworking enhanced the fluxes from the field sediments due to exposure of fresh solids to the air. Variations in flux from the lab-spiked sediment as a result of change in air relative humidity were due to differences in retardation of chemicals on a dry or wet surface sediment. High moisture in the air over the dry sediment increased the competition for sorption sites between water and contaminant and increased the contaminant flux.

  8. Water- and air-quality and surficial bed-sediment monitoring of the Sweetwater Reservoir watershed, San Diego County, California, 2003-09

    USGS Publications Warehouse

    Mendez, Gregory O.; Majewski, Michael S.; Foreman, William T.; Morita, Andrew Y.

    2015-01-01

    Sampling results show concentrations of the gasoline oxygenate methyl tert-butyl ether in water and air samples declined after it was phased out by the State of California in January 2004. The largest concentrations of gasoline hydrocarbons benzene and toluene in water were detected at or near the surface of the SWR. Isophorone and phenol were the two most frequently detected BNA compounds in water. Diuron, prometon, and simazine were the most frequently detected pesticide compounds in water. Concentrations of benzene and toluene in air samples were highest during the cooler months and had a consistent seasonal pattern over time. Ten PAH compounds were detected frequently in air samples. Twelve pesticide compounds were also detected in air samples. Surficial bed-sediment samples were analyzed for 53 PAHs; 22 of the compounds had one or more detections. Surficial bed-sediment samples were analyzed for 22 organic compounds; only 6 compounds had one or more detections. Surficial bed-sediment samples were analyzed for 37 metals.

  9. Scour hole ('wielen') sediments as historical archive of floods, vegetation, and air and water quality in lowlands

    NASA Astrophysics Data System (ADS)

    Cremer, Holger; van Hoof, Thomas; Bunnik, Frans; Donders, Timme

    2010-05-01

    The sediment record from a maximum 18 m deep scour hole lake (Haarsteegse Wiel) near the embanked Meuse River in the Netherlands was studied for past changes in flooding frequency, water quality, and landscape change using a combined geochemical, geobiological and historical approach. The results are highly significant for determining long-term trends of river flood frequency, eutrophication, atmospheric pollution, and vegetation development. Haarsteegse Wiel consists of two basins connected by a shallow sill. The first flooding event is indicated in the sediment at AD 1610 when the 8 m deep southern basin of the lake was created by flood water masses bursting through the embankment. In AD 1740 embankments burst again and resulted in the formation of the northern basin of Haarsteegse Wiel. This part of the lake was originally 21 m deep and was filled up with a 3.50 m thick sediment layer since then. The sediment was dated by combining 137Cs activity measurements, biostratigraphical ages of pollen, microtephra, and historically documented floods indicated by the magnetic susceptibility of the sediment. The resulting chronology is highly accurate and shows that sedimentation rates decrease sharply with the widespread change from cereal cultivation to pasture land from around AD 1875 (agricultural crisis) as a direct result of falling wheat prices and intensified cattle farming. Water quality (total phosphorus concentration) was reconstructed using a diatom-based transfer function. Results show that the currently nutrient enriched lake has mostly been in a mesotrophic state prior to AD 1920, with the exception of several sharp eutrophication events that are generally coeval with river floods. After 1920, eutrophication of Haarsteegse Wiel is clearly documented and generally caused by the increased population, enhanced use of fertilizers and settlement of dairy industry in the region. Industrial development in both the vicinity and the hinterland of Haarsteegse Wiel

  10. Ballast water sediment elemental analysis.

    PubMed

    Maglić, Lovro; Zec, Damir; Frančić, Vlado

    2016-02-15

    Sediment samples from the ballast water tanks of ships calling at the port of Rijeka in the Northern Adriatic were analysed using X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) using caesium, argon and oxygen ion beams. The research was carried out in order to determine the sediment composition and relative abundance of the dominant elements. The results indicate that the sediment samples mostly consisted of compounds that originated from the deterioration of tank plates, tank coating residues and ballast operations such as clay, silt, sand and organic materials. No significant heavy metals or highly toxic elements were found. The research revealed some advantages and significant drawbacks of using XPS and SIMS for the routine analysis of sediment composition as a decision supporting tool for ballast water and sediment management. PMID:26763315

  11. Air/Water Purification

    NASA Technical Reports Server (NTRS)

    1992-01-01

    After 18 years of research into air/water pollution at Stennis Space Center, Dr. B. C. Wolverton formed his own company, Wolverton Environmental Services, Inc., to provide technology and consultation in air and water treatment. Common houseplants are used to absorb potentially harmful materials from bathrooms and kitchens. The plants are fertilized, air is purified, and wastewater is converted to clean water. More than 100 U.S. communities have adopted Wolverton's earlier water hyacinth and artificial marsh applications. Catfish farmers are currently evaluating the artificial marsh technology as a purification system.

  12. Storm-water characterization and lagoon sediment analysis, Grand Forks Air Force Base, North Dakota. Final report

    SciTech Connect

    Garland, J.G.; Vaughn, R.W.; Scott, P.T.

    1990-08-01

    Sampling was conducted in the wastewater treatment lagoons and stormwater runoff at Grand Forks AFB. The base was concerned about whether the unlined lagoons were creating a potential groundwater contamination problem and whether their stormwater runoff met North Dakota state stream standards. Lagoon sediment did not contain Extraction Procedure hazardous chemicals. Stormwater runoff exceeded state standards for boron, phosphates, and phenols and contained trace levels of methylene chloride. Characterization of lagoon influent showed it to be generally representative of domestic sewage, but also contained trace levels of boron, phenols, toluene, cyanide, chloroform, methylene chloride and ethyl benzene.

  13. Nitrogen Species in Soil, Sediment, and Ground Water at a Former Sewage-Treatment Wastewater Lagoon: Naval Air Station Whidbey Island, Island County, Washington

    USGS Publications Warehouse

    Cox, S.E.; Dinicola, R.S.; Huffman, R.L.

    2007-01-01

    The potential for contamination of ground water from remnant sewage sludge in re-graded sediments of a deconstructed sewage-treatment lagoon was evaluated. Ground-water levels were measured in temporary drive-point wells, and ground-water samples were collected and analyzed for nutrients and other water-quality characteristics. Composite soil and sediment samples were collected and analyzed for organic carbon and nitrogen species. Multiple lines of evidence, including lack of appreciable organic matter in sediments of the former lagoon, agronomic analysis of nitrogen, the sequestration of nitrogen in the developing soils at the former lagoon, and likely occurrence of peat deposits within the aquifer material, suggest that the potential for substantial additions of nitrogen to ground water beneath the former sewage lagoon resulting from remnant sewage sludge not removed from the former lagoon are small. Concentrations of nitrogen species measured in ground-water samples were small and did not exceed the established U.S. Environmental Protection Agency's maximum contaminant levels for nitrate (10 milligrams per liter). Concentrations of nitrate in ground-water samples were less than the laboratory reporting limit of 0.06 milligram per liter. Seventy to 90 percent of the total nitrogen present in ground water was in the ammonia form with a maximum concentration of 7.67 milligrams per liter. Concentrations of total nitrogen in ground water beneath the site, which is the sum of all forms of nitrogen including nitrate, nitrite, ammonia, and organic nitrogen, ranged from 1.15 to 8.44 milligrams per liter. Thus, even if all forms of nitrogen measured in ground water were converted to nitrate, the combined mass would be less than the maximum contaminant level. Oxidation-reduction conditions in ground water beneath the former sewage lagoon were reducing. Given the abundant supply of ambient organic carbon in the subsurface and in ground water at the former lagoon, any

  14. Integration of air and water quality issues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The environmental sustainability of dairy farms is dependent upon a number of air and water quality issues. Atmospheric emissions include hazardous compounds such as ammonia and hydrogen sulfide along with greenhouse gases and their implications with global climate change. Runoff of sediment, phosph...

  15. AMBIENT WATER, POREWATER, AND SEDIMENT

    EPA Science Inventory

    Sediment assessments may be performed for a variety of purposes; these include: dredging and dredged sediment disposal, for evaluations of sediments as a capping material, to determine sediment quality, to assess biological impairment and to assess the status of environment monit...

  16. Thermaikos Gulf Coastal System, NW Aegean Sea: an overview of water/sediment fluxes in relation to air land ocean interactions and human activities

    NASA Astrophysics Data System (ADS)

    Poulos, S. E.; Chronis, G. Th; Collins, M. B.; Lykousis, V.

    2000-04-01

    This study presents an overview of the Holocene formation and evolution of the coastal system of Thermaikos Gulf (NW Aegean Sea). The system is divided into the terrestrial sub-system and the oceanic sub-system; the former represents 90%, while the latter includes only 10% of the total area. This particular coastal zone includes the second most important socio-economic area of Greece and in the southern Balkans, the Thessaloniki region; this is in terms of population concentration (>1 million people), industry, agriculture, aquaculture, trade and services. The geomorphology of the coastal zone is controlled by sediment inputs, nearshore water circulation, and the level of wave activity. The large quantities of sediments (with yields >500 tonnes/km 2 per year), delivered annually by the main rivers (Axios, Aliakmon, Pinios, and Gallikos) and other seasonal streams are responsible for the general progradation of the coastline and the formation of the Holocene sedimentary cover over the seabed of the Gulf. Changes to the coastline can be identified on macro- and meso-time scales; the former include the evolution of the deltaic plains (at >1 km 2/year), while the latter incorporates seasonal changes along sections of the coastline (e.g. sandy spits), mostly due to the anthropogenic activities. The overall water circulation pattern in Thermaikos Gulf is characterised by northerly water movement, from the central and eastern part of the Gulf; this is compensated by southerly movement along its western part. The prevailing climate (winds and pressure systems) appears to control the surface water circulation, while near-bed current measurements reveal a general moderate (<15 cm/s) southerly flow, i.e. offshore, towards the deep water Sporades Basin. Waves approaching from southerly directions play also a role in controlling the shoreline configuration. Various human activities within the coastal system place considerable pressure on the natural evolution of the coastal

  17. CONTAMINANTS IN WATER AND SEDIMENT

    EPA Science Inventory

    The Detroit River has experienced over a century of heavy contaminant discharges from industry and municipalities. The sources of contaminants vary, and include non-point sources, combined sewer overflows, point sources, tributaries, sediments, and upstream inputs. ---
    Demonst...

  18. Volatilization of contaminants from suspended sediment in a water column during dredging.

    PubMed

    Ravikrishna, Raghunathan; Valsaraj, Kalliat T; Thibodeaux, Louis J; Price, Cynthia B; Brannon, James M; Yost, Sally

    2002-10-01

    Remedial dredging of contaminated bed sediments in rivers and lakes results in the suspension of sediment solids in the water column, which can potentially be a source for evaporation of hydrophobic organic compounds (HOCs) associated with the sediment solids. Laboratory experiments were conducted in an oscillating grid chamber to simulate the suspension of contaminated sediments and flux to air from the surface of the water column. A contaminated field sediment from Indiana Harbor Canal (IHC) and a laboratory-inoculated University Lake (UL) sediment, Baton Rouge, LA, were used in the experiments, where water and solids concentration and particle size distribution were measured in addition to contaminant fluxes to air. A transient model that takes into account contaminant desorption from sediment to water and evaporation from the water column was used to simulate water and sediment concentrations and air fluxes from the solids suspension. In experiments with both sediments, the total suspended solids (TSS) concentration and the average particle diameter of the suspended solids decreased with time. As expected, the evaporative losses were higher for compounds with higher vapor pressure and lower hydrophobicity. For the laboratory-inoculated sediment (UL), the water concentrations and air fluxes were high initially and decreased steadily implying that contaminant release to the water column from the suspended solids was rapid, followed by evaporative decay. For the field sediments (IHC), the fluxes and water concentrations increased initially and subsequently decreased steadily. This implied that the initial desorption to water was slow and that perhaps the presence of oil and grease and aging influenced the contaminant release. Comparison of the model and experimental data suggested that a realistic determination of the TSS concentration that can be input into the model was the most critical parameter for predicting air emission rates. PMID:12418732

  19. Par Pond Fish, Water, and Sediment Chemistry

    SciTech Connect

    Paller, M.H.; Wike, L.D.

    1996-06-01

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond.

  20. "ITM" (INLAND WATERS SEDIMENT TESTING MANUAL)

    EPA Science Inventory

    EPA public web site providing the national sediment testing manual for dredged material proposed for discharge in waters of the U.S. Description from site: "The "Evaluation of Dredged Material Proposed for Dischage in Waters of the U.S. - Testing Manual", commonly referred to as...

  1. Geochemical characterization of seaplane lagoon sediments, Alameda Naval Air Station

    SciTech Connect

    Bono, A; Carroll, S; Esser, B; Luther, G W; O'Day, P; Randall, S

    1999-08-16

    Our objective in the characterization of sediments from Seaplane Lagoon at the Alameda Naval Air Station (NAS) was to determine the geochemical interactions that control the partitioning of cadmium, chromium, cobalt, copper, lead, mercury, nickel, and zinc between the sediments and the porewaters. Our approach was to collect several cores at the east outfall location of the Seaplane Lagoon. We determined the porewater chemistry by (1) making in situ micro-electrode measurements, (2) extracting porewaters, and (3) modeling geochemical reactions. We determined the sediment chemistry by measuring (1) elemental abundance, (2) mineralogy, and (3) trace-element speciation. This information should help the US Navy determine the long-term hazard of the sediments if they are left in place and the short-term hazard if they are dredged. We did not fully examine the geochemistry of sediments from the West Beach Landfill Wetlands site, because these sediments were distinct from the Seaplane Lagoon sediments. Our initial motivation for studying the Landfill Wetlands site was to determine the trace-element geochemistry in Seaplane Lagoon sediments that had been dredged and then disposed in the Landfill Wetlands. Unfortunately, the location of these dredged sediments is unknown. The cores we sampled were not from the Seaplane Lagoon.

  2. Subsurface sediment contamination during borehole drilling with an air-actuated down-hole hammer.

    PubMed

    Malard, Florian; Datry, Thibault; Gibert, Janine

    2005-10-01

    Drilling methods can severely alter physical, chemical, and biological properties of aquifers, thereby influencing the reliability of water samples collected from groundwater monitoring wells. Because of their fast drilling rate, air-actuated hammers are increasingly used for the installation of groundwater monitoring wells in unconsolidated sediments. However, oil entrained in the air stream to lubricate the hammer-actuating device can contaminate subsurface sediments. Concentrations of total hydrocarbons, heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd), and nutrients (particulate organic carbon, nitrogen, and phosphorus) were measured in continuous sediment cores recovered during the completion of a 26-m deep borehole drilled with a down-hole hammer in glaciofluvial deposits. Total hydrocarbons, Cu, Ni, Cr and particulate organic carbon (POC) were all measured at concentrations far exceeding background levels in most sediment cores. Hydrocarbon concentration averaged 124 +/- 118 mg kg(-1) dry sediment (n = 78 samples) with peaks at depths of 8, 14, and 20 m below the soil surface (maximum concentration: 606 mg kg(-1)). The concentrations of hydrocarbons, Cu, Ni, Cr, and POC were positively correlated and exhibited a highly irregular vertical pattern, that probably reflected variations in air loss within glaciofluvial deposits during drilling. Because the penetration of contaminated air into the formation is unpreventable, the representativeness of groundwater samples collected may be questioned. It is concluded that air percussion drilling has strong limitations for well installation in groundwater quality monitoring surveys. PMID:16091299

  3. Subsurface sediment contamination during borehole drilling with an air-actuated down-hole hammer

    NASA Astrophysics Data System (ADS)

    Malard, Florian; Datry, Thibault; Gibert, Janine

    2005-10-01

    Drilling methods can severely alter physical, chemical, and biological properties of aquifers, thereby influencing the reliability of water samples collected from groundwater monitoring wells. Because of their fast drilling rate, air-actuated hammers are increasingly used for the installation of groundwater monitoring wells in unconsolidated sediments. However, oil entrained in the air stream to lubricate the hammer-actuating device can contaminate subsurface sediments. Concentrations of total hydrocarbons, heavy metals (Cu, Ni, Cr, Zn, Pb, and Cd), and nutrients (particulate organic carbon, nitrogen, and phosphorus) were measured in continuous sediment cores recovered during the completion of a 26-m deep borehole drilled with a down-hole hammer in glaciofluvial deposits. Total hydrocarbons, Cu, Ni, Cr and particulate organic carbon (POC) were all measured at concentrations far exceeding background levels in most sediment cores. Hydrocarbon concentration averaged 124 ± 118 mg kg - 1 dry sediment ( n = 78 samples) with peaks at depths of 8, 14, and 20 m below the soil surface (maximum concentration: 606 mg kg - 1 ). The concentrations of hydrocarbons, Cu, Ni, Cr, and POC were positively correlated and exhibited a highly irregular vertical pattern, that probably reflected variations in air loss within glaciofluvial deposits during drilling. Because the penetration of contaminated air into the formation is unpreventable, the representativeness of groundwater samples collected may be questioned. It is concluded that air percussion drilling has strong limitations for well installation in groundwater quality monitoring surveys.

  4. A vacuum-operated pore-water extractor for estuarine and freshwater sediments

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.

    1991-01-01

    A vacuum-operated pore-water extractor for estuarine and freshwater sediments was developed and constructed from a fused-glass air stone attached with aquarium airline tubing to a 30 or 60 cc polypropylene syringe. Pore water is extracted by inserting the air stone into the sediment and creating a vacuum by retracting and bracing the syringe plunger. A hand-operated vacuum pump attached to a filtration flask was also evaluated as an alternative vacuum source. The volume and time to extract pore water varies with the number of devices and the sediment particle size. Extraction time is longer for fine sediments than for sandy sediments. Four liters of sediment generally yield between 500 and 1,500 mL of pore water. The sediment that surrounds and accumulates on the air stone acts as a filter, and, except for the first few milliliters, the collected pore water is clear. Because there is no exposure to air or avenue for escape, volatile compounds andin situ characteristics are retained in the extracted pore water.

  5. A probe for sampling interstitial waters of stream sediments and bog soils

    USGS Publications Warehouse

    Nowlan, G.A.; Carollo, C.

    1974-01-01

    A probe for sampling interstitial waters of stream sediments and bog soils is described. Samples can be obtained within a stratigraphic interval of 2-3 cm, to a depth of 60-80 cm, and with little or no contamination of the samples by sediment or air. ?? 1974.

  6. Temporal variability of CO₂ fluxes at the sediment-air interface in mangroves (New Caledonia).

    PubMed

    Leopold, Audrey; Marchand, Cyril; Deborde, Jonathan; Allenbach, Michel

    2015-01-01

    Carbon budgets in mangrove forests are uncertain mainly due to the lack of data concerning carbon export in dissolved and gaseous forms. Temporal variability of in situ CO2 fluxes was investigated at the sediment-air interface in different seasons in different mangrove stands in a semi-arid climate. Fluxes were measured using dynamic closed incubation chambers (transparent and opaque) connected to an infra-red gas analyzer. Microclimatic conditions and chl-a contents of surface sediments were determined. Over all mangrove stands, CO2 fluxes on intact sediments were relatively low, ranging from -3.93 to 8.85 mmolCO₂·m(-2)·h(-1) in the light and in the dark, respectively. Changes in the fluxes over time appeared to depend to a great extent on the development of the biofilm at the sediment surface. We suggest that in intact sediments and in the dark, CO2 fluxes measured at the sediment-air interface rather reflect the metabolism of benthic organisms than sediment respiration (heterotrophic and autotrophic). However, without the biofilm, sediment water content and air temperature were main drivers of seasonal differences in CO2 fluxes, and their influence differed depending on the intertidal location of the stand. After removal of the biofilm, Q10 values in the Avicennia and the Rhizophora stands were 1.84 and 2.1, respectively, revealing the sensitivity of mangrove sediments to an increase in temperature. This study provides evidence that, if the influence of the biofilm is not taken into account, the in situ CO2 emission data currently used to calculate the budget will lead to underestimation of CO2 production linked to heterotrophic respiration fueled by organic matter detritus from the mangrove. PMID:25302449

  7. Air-water centrifugal convection

    NASA Astrophysics Data System (ADS)

    Herrada, Miguel; Shtern, Vladimir

    2014-07-01

    A sealed cylindrical container is filled with air and water. The container rotation and the axial gradient of temperature induce the steady axisymmetric meridional circulation of both fluids due to the thermal buoyancy and surface-tension (Marangoni) effects. If the temperature gradient is small, the water circulation is one-cellular while the air circulation can be one- or two-cellular depending on water fraction Wf. The numerical simulations are performed for the cylinder length-to-radius ratio l = 1 and l = 4. The l = 4 results and the analytical solution for l → ∞ agree in the cylinder's middle part. As the temperature gradient increases, the water circulation becomes one-, two-, or three-cellular depending on Wf. The results are of fundamental interest and can be applied for bioreactors.

  8. Numerical simulation of sediment related processes in water quality model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sediment is a major nonpoint-source pollutant, and the exchange of materials between water and sediment is an important component of the lake eutrophication process. Suspended sediment increases water surface reflectivity and light attenuation in the water column. Nutrients can be absorbed to sedime...

  9. Emergence and fate of cyclic volatile polydimethylsiloxanes (D4, D5) in municipal waste streams: release mechanisms, partitioning and persistence in air, water, soil and sediments.

    PubMed

    Surita, Sharon C; Tansel, Berrin

    2014-01-15

    Siloxane use in consumer products (i.e., fabrics, paper, concrete, wood, adhesive surfaces) has significantly increased in recent years due to their excellent water repelling and antimicrobial characteristics. The objectives of this study were to evaluate the release mechanisms of two siloxane compounds, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5), which have been detected both at landfills and wastewater treatment plants, estimate persistence times in different media, and project release quantities over time in relation to their increasing use. Analyses were conducted based on fate and transport mechanisms after siloxanes enter waste streams. Due to their high volatility, the majority of D4 and D5 end up in the biogas during decomposition. D5 is about ten times more likely to partition into the solid phase (i.e., soil, biosolids). D5 concentrations in the wastewater influent and biogas are about 16 times and 18 times higher respectively, in comparison to the detected levels of D4. PMID:24012894

  10. Chemical data for bottom sediment, lake water, bottom-sediment pore water, and fish in Mountain Creek Lake, Dallas, Texas, 1994-96

    USGS Publications Warehouse

    Jones, S.A.; Van Metre, P.C.; Moring, J.B.; Braun, C.L.; Wilson, J.T.; Mahler, B.J.

    1997-01-01

    Mountain Creek Lake is a reservoir adjacent to two U.S. Department of the Navy facilities, the Naval Weapons Industrial Reserve Plant and the Naval Air Station in Dallas, Texas. A Resource Conservation and Recovery Act Facility Investigation found ground-water plumes containing chlorinated solvents on both facilities. These findings led to a U.S. Geological Survey study of Mountain Creek Lake adjacent to both facilities between June 1994 and August 1996. Bottom sediments, lake water, bottom-sediment pore water, and fish were collected for chemical analysis.

  11. Air-Seawater Exchange of Organochlorine Pesticides along the Sediment Plume of a Large Contaminated River.

    PubMed

    Lin, Tian; Guo, Zhigang; Li, Yuanyuan; Nizzetto, Luca; Ma, Chuanliang; Chen, Yingjun

    2015-05-01

    Gaseous exchange fluxes of organochlorine pesticides (OCPs) across the air-water interface of the coastal East China Sea were determined in order to assess whether the contaminated plume of the Yangtze River could be an important regional source of OCPs to the atmosphere. Hexachlorocyclohexanes (HCHs), chlordane compounds (CHLs), and dichlorodiphenyltrichloroethanes (DDTs) were the most frequently detected OCPs in air and water. Air-water exchange was mainly characterized by net volatilization for all measured OCPs. The net gaseous exchange flux ranged 10-240 ng/(m2·day) for γ-HCH, 60-370 ng/(m2·day) for trans-CHL, 97-410 ng/(m2·day) for cis-CHL, and ∼0 (e.g., equilibrium) to 490 ng/(m2·day) for p,p'-DDE. We found that the plume of the large contaminated river can serve as a significant regional secondary atmospheric source of legacy contaminants released in the catchment. In particular, the sediment plume represented the relevant source of DDT compounds (especially p,p'-DDE) sustaining net degassing when clean air masses from the open ocean reached the plume area. In contrast, a mass balance showed that, for HCHs, contaminated river discharge (water and sediment) plumes were capable of sustaining volatilization throughout the year. These results demonstrate the inconsistencies in the fate of HCHs and DDTs in this large estuarine system with declining primary sources. PMID:25827140

  12. The lipid geochemistry of interstitial waters of recent marine sediments

    SciTech Connect

    Saliot, A.; Brault, M.; Boussuge, C. )

    1988-04-01

    To elucidate the nature of biogeochemical processes occurring at the water-sediment interface, the authors have analyzed fatty acids, n-alkanes and sterols contained in interstitial waters collected from oxic and anoxic marine sediments in the eastern and western intertropical Atlantic Ocean and in the Arabian Sea. Lipid concentrations in interstitial waters vary widely and are generally much higher than concentrations encountered in the overlying sea water. Higher concentrations in interstitial water are observed in environments favorable for organic input and preservation of the organic matter in the water column and in the surficial sediment. The analysis of biogeochemical markers in the various media of occurrence of the organic matter such as sea water, suspended particles, settling particles and sediment is discussed in terms of differences existing between these media and bio-transformations of the organic matter at the water-sediment interface.

  13. Sediment tracers in water erosion studies: Current approaches and challenges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interest in the use of sediment tracers as a complementary tool to traditional water soil erosion or deposition measurements or assessment has increased due to the additional information they may provide such as sediment source identification and tracking of sediment movement over the landscape ...

  14. DEVELOPING WATER QUALITY CRITERIA FOR SUSPENDED AND BEDDED SEDIMENTS

    EPA Science Inventory

    The U.S. EPA’s Framework for Developing Suspended and Bedded Sediments (SABS) Water Quality Criteria (SABS Framework) is a nationally-consistent process for developing ambient sediment quality criteria for surface waters. The SABS Framework accommodates natural variation among wa...

  15. TOXICITY EVALUATION OF LOWER FOX RIVER WATER AND SEDIMENTS

    EPA Science Inventory

    Many persistent, xenobiotic compounds have been identified from Lower Fox River water, biota, sediment, and effluent discharges; some of which are suspected of causing adverse effects to aquatic organisms. Water and sediment were collected as grab samples from the Lower Fox River...

  16. Pore Water PAH Transport in Amended Sediment Caps

    NASA Astrophysics Data System (ADS)

    Gidley, P. T.; Kwon, S.; Ghosh, U.

    2009-05-01

    Capping is a common remediation strategy for contaminated sediments that creates a physical barrier between contaminated sediments and the water column. Diffusive flux of contaminants through a sediment cap is small. However, under certain hydrodynamic conditions such as groundwater potential and tidal pumping, groundwater advection can accelerate contaminant transport. Hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) could be transported through the cap under advective conditions. To better understand PAH migration under these conditions, physical models of sediment caps were evaluated in the laboratory through direct measurement of pore water using solid phase micro-extraction with gas chromatography and mass spectrometry. Contaminated sediment and capping material was obtained from an existing Superfund site that was capped at Eagle Harbor, Washington. A PAH dissolution model linked to an advection-dispersion equation with retardation using published organic carbon-water partitioning coefficients (Koc) was compared to measured PAHs in the sediment and cap porewater of the physical model.

  17. Dispersal of fine sediment in nearshore coastal waters

    USGS Publications Warehouse

    Warrick, Jonathan A.

    2013-01-01

    Fine sediment (silt and clay) plays an important role in the physical, ecological, and environmental conditions of coastal systems, yet little is known about the dispersal and fate of fine sediment across coastal margin settings outside of river mouths. Here I provide simple physical scaling and detailed monitoring of a beach nourishment project near Imperial Beach, California, with a high portion of fines (40% silt and clay by weight). These results provide insights into the pathways and residence times of fine sediment transport across a wave-dominated coastal margin. Monitoring of the project used physical, optical, acoustic, and remote sensing techniques to track the fine portion of the nourishment sediment. The initial transport of fine sediment from the beach was influenced strongly by longshore currents of the surf zone that were established in response to the approach angles of the waves. The mean residence time of fine sediment in the surf zone—once it was suspended—was approximately 1 hour, and rapid decreases in surf zone fine sediment concentrations along the beach resulted from mixing and offshore transport in turbid rip heads. For example, during a day with oblique wave directions and surf zone longshore currents of approximately 25 cm/s, the offshore losses of fine sediment in rips resulted in a 95% reduction in alongshore surf zone fine sediment flux within 1 km of the nourishment site. However, because of the direct placement of nourishment sediment on the beach, fine suspended-sediment concentrations in the swash zone remained elevated for several days after nourishment, while fine sediment was winnowed from the beach. Once offshore of the surf zone, fine sediment settled downward in the water column and was observed to transport along and across the inner shelf. Vertically sheared currents influenced the directions and rates of fine sediment transport on the shelf. Sedimentation of fine sediment was greatest on the seafloor directly offshore

  18. Mathematical Simulation of Sediment and Radionuclide Transport in Surface Waters

    SciTech Connect

    ,

    1981-04-01

    The study objective of "The Mathematical Simulation of Sediment and Radionuclide Transport in Surface Waters" is to synthesize and test radionuclide transport models capable of realistically assessing radionuclide transport in various types of surface water bodies by including the sediment-radionuclide interactions. These interactions include radionuclide adsorption by sediment; desorption from sediment into water; and transport, deposition, and resuspension of sorbed radionuclides controlled by the sediment movements. During FY-1979, the modification of sediment and contaminant (radionuclide) transport model, FETRA, was completed to make it applicable to coastal waters. The model is an unsteady, two-dimensional (longitudinal and lateral) model that consists of three submodels (for sediment, dissolved-contaminant, and particulate-contaminant transport), coupled to include the sediment-contaminant interactions. In estuaries, flow phenomena and consequent sediment and radionuclide migration are often three-dimensional in nature mainly because of nonuniform channel cross-sections, salinity intrusion, and lateral-flow circulation. Thus, an unsteady, three-dimensional radionuclide transport model for estuaries is also being synthesized by combining and modifying a PNL unsteady hydrothermal model and FETRA. These two radionuclide transport models for coastal waters and estuaries will be applied to actual sites to examine the validity of the codes.

  19. Environmental Chemistry: Air and Water Pollution.

    ERIC Educational Resources Information Center

    Stoker, H. Stephen; Seager, Spencer L.

    This is a book about air and water pollution whose chapters cover the topics of air pollution--general considerations, carbon monoxide, oxides of nitrogen, hydrocarbons and photochemical oxidants, sulfur oxides, particulates, temperature inversions and the greenhouse effect; and water pollution--general considerations, mercury, lead, detergents,…

  20. Water gun vs air gun: A comparison

    USGS Publications Warehouse

    Hutchinson, D.R.; Detrick, R. S.

    1984-01-01

    The water gun is a relatively new marine seismic sound source that produces an acoustic signal by an implosive rather than explosive mechanism. A comparison of the source characteristics of two different-sized water guns with those of conventional air guns shows the the water gun signature is cleaner and much shorter than that of a comparable-sized air gun: about 60-100 milliseconds (ms) for an 80-in3. (1.31-liter (I)) water gun compared with several hundred ms for an 80-in3. (1.31-1) air gun. The source spectra of water guns are richer in high frequencies (>200 Hz) than are those of air guns, but they also have less energy than those of air guns at low frequencies. A comparison between water gun and air gun reflection profiles in both shallow (Long Island Sound)-and deep (western Bermuda Rise)-water settings suggests that the water gun offers a good compromise between very high resolution, limited penetration systems (e.g. 3.5-kHz profilers and sparkers) and the large volume air guns and tuned air gun arrays generally used where significant penetration is required. ?? 1984 D. Reidel Publishing Company.

  1. Influence of wave and current flow on sediment-carrying capacity and sediment flux at the water-sediment interface.

    PubMed

    Zheng, Jun; Li, Ruijie; Yu, Yonghai; Suo, Anning

    2014-01-01

    In nearshore waters, spatial and temporal scales of waves, tidal currents, and circulation patterns vary greatly. It is, therefore, difficult to combine these factors' effects when trying to predict sediment transport processes. This paper proposes the concept of significant wave velocity, which combines the effects of waves, tides, and ocean currents using the horizontal kinetic energy superposition principle. Through a comparison of the relationship between shear stress at the water-sediment interface and sediment-carrying capacity, assuming equilibrium sediment flux, a new formula for sediment-carrying capacity, which incorporates the concept of significant wave velocities, is derived. Sediment-carrying capacity is a function of the critical velocity, which increases with water depth and decreases with increasing relative roughness of the sea bed. Finally, data from field observation stations and simulations are used to test the proposed formula. The results show that the new formula is in good agreement with both field and simulation data. This new formula for sediment-carrying capacity can be used to simulate nearshore sediment transport. PMID:25259499

  2. Multi-Elements in Waters and Sediments of Shallow Lakes: Relationships with Water, Sediment, and Watershed Characteristics

    PubMed Central

    Jacob, Donna L.; Hanson, Mark A.; Herwig, Brian R.; Bowe, Shane E.; Otte, Marinus L.

    2015-01-01

    We measured concentrations of multiple elements, including rare earth elements, in waters and sediments of 38 shallow lakes of varying turbidity and macrophyte cover in the Prairie Parkland (PP) and Laurentian Mixed Forest (LMF) provinces of Minnesota. PP shallow lakes had higher element concentrations in waters and sediments compared to LMF sites. Redundancy analysis indicated that a combination of site- and watershed-scale features explained a large proportion of among-lake variability in element concentrations in lake water and sediments. Percent woodland cover in watersheds, turbidity, open water area, and macrophyte cover collectively explained 65.2 % of variation in element concentrations in lake waters. Sediment fraction smaller than 63 µm, percent woodland in watersheds, open water area, and sediment organic matter collectively explained 64.2 % of variation in element concentrations in lake sediments. In contrast to earlier work on shallow lakes, our results showed the extent to which multiple elements in shallow lake waters and sediments were influenced by a combination of variables including sediment characteristics, lake morphology, and percent land cover in watersheds. These results are informative because they help illustrate the extent of functional connectivity between shallow lakes and adjacent lands within these lake watersheds. PMID:26074657

  3. Benthic invertebrate bioassays with toxic sediment and pore water

    USGS Publications Warehouse

    Giesy, John P.; Rosiu, Cornell J.; Graney, Robert L.; Henry, Mary G.

    1990-01-01

    The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods of making the sample dilutions required to generate dose-response relationships were compared. The assays studied were: (a) Microtox®, a 15-min assay ofPhotobacterium phosphoreum bioluminescence inhibition by pore water; (b) 48-h Daphnia magnalethality test in pore water; (c) 10-d subchronic assay of lethality to and reduction of weight gain by Chironomus tentans performed in either whole sediment or pore water; (d) 168-h acute lethality assay of Hexagenia limbata in either whole sediment or pore water. The three methods of diluting sediments were: (a) extracting pore water from the toxic location and dilution with pore water from the control station; (b) diluting whole sediment from the toxic location with control whole sediment from a reference location, then extracting pore water; and (c) diluting toxic, whole sediment with whole sediment from a reference location, then using the whole sediment in bioassays. Based on lethality, H. limbata was the most sensitive organism to the toxicity of Detroit River sediment. Lethality of D. magna in pore water was similar to that of H. limbata in whole sediment and can be used to predict effects of whole sediment toxicity to H. limbata. The concentration required to cause a 50% reduction in C. tentans growth (10-d EC50) was approximately that which caused 50% lethality of D. magna (48-h LC50) and was similar to the toxicity that restricts benthic invertebrate colonization of contaminated sediments. While the three dilution techniques gave similar results with some assays, they gave very different results in other assays. The dose-response relationships determined by the three dilution techniques would be expected to vary with sediment, toxicant and bioassay type, and the dose-response relationship derived from each technique needs to be interpreted accordingly.

  4. Comparing Sediment and Pore-water Measurements as Predictors of PCB Uptake by Oligochaetes from Sediments

    EPA Science Inventory

    There is an increasing amount of chemical and biological evidence that using sediment concentrations and commonly applied Koc values frequently overpredicts interstitial water concentrations of HOCs, and thereby overestimates uptake and/or effects of those chemicals on exposed or...

  5. Toxicity of silicon carbide nanowires to sediment-dwelling invertebrates in water or sediment exposures

    USGS Publications Warehouse

    Mwangi, Joseph N.; Wang, Ning; Ritts, Andrew; Kunz, James L.; Ingersoll, Christopher G.; Li, Hao; Deng, Baolin

    2011-01-01

    Silicon carbide nanowires (SiCNW) are insoluble in water. When released into an aquatic environment, SiCNW would likely accumulate in sediment. The objective of this study was to assess the toxicity of SiCNW to four freshwater sediment-dwelling organisms: amphipods (Hyalella azteca), midges (Chironomus dilutus), oligochaetes (Lumbriculus variegatus), and mussels (Lampsilis siliquoidea). Amphipods were exposed to either sonicated or nonsonicated SiCNW in water (1.0 g/L) for 48 h. Midges, mussels, and oligochaetes were exposed only to sonicated SiCNW in water for 96 h. In addition, amphipods were exposed to sonicated SiCNW in whole sediment for 10 d (44% SiCNW on dry wt basis). Mean 48-h survival of amphipods exposed to nonsonicated SiCNW in water was not significantly different from the control, whereas mean survival of amphipods exposed to sonicated SiCNW in two 48-h exposures (0 or 15% survival) was significantly different from the control (90 or 98% survival). In contrast, no effect of sonicated SiCNW was observed on survival of midges, mussels, or oligochaetes. Survival of amphipods was not significantly reduced in 10-d exposures to sonicated SiCNW either mixed in the sediment or layered on the sediment surface. However, significant reduction in amphipod biomass was observed with the SiCNW either mixed in sediment or layered on the sediment surface, and the reduction was more pronounced for SiCNW layered on the sediment. These results indicated that, under the experimental conditions, nonsonicated SiCNW in water were not acutely toxic to amphipods, sonicated SiCNW in water were acutely toxic to the amphipods, but not to other organisms tested, and sonicated SiCNW in sediment affected the growth but not the survival of amphipods.

  6. DISTRIBUTION OF ORGANIC WASTEWATER CONTAMINANTS BETWEEN WATER AND SEDIMENT IN SURFACE WATERS OF THE UNITED STATES

    EPA Science Inventory

    Trace concentrations of pharmaceuticals and other organic wastewater contaminants have been determined in the surface waters of Europe and the United States. A preliminary report of substantially higher concentrations of pharmaceuticals in sediment suggests that bottom sediment ...

  7. Nitrogen cycling in different types of sediments from Danish waters

    SciTech Connect

    Blackburn, T.H.; Henridsen, K.

    1983-05-01

    Variations in sediment N:C ratios were correlated with water depth and season. /sup 14/NH/sub 4//sup +/ was used to measure the rates of NH/sub 4//sup +/ production (d) and incorporation into bacterial cells (i) in sediments from different stations, at different seasons. The validity of the rates d and i was indicated by the predicted correlation of d:i ratios with N:C ratios of the sediment, and the predicted N:C ratio at which net NH/sub 4//sup +/; pore water NH/sub 4//sup +/, flux of NH/sub 4//sup +/ from sediment, and flux of NH/sub 4//sup +/ into exchangeable pool. The NO/sub 3//sup -/ flux from sediment was correlated with nitrification rate and with season. Benthic infauna increased the flux of NH/sub 4//sup +/ from the sediment by 50%. The rates of transfer of nitrogen (NO/sub 3//sup -/, NH/sub 4//sup +/, N/sub 2/) from sediment to water were 44-66% of the net rates of organic nitrogen mineralization (d-i). Flux of NO/sub 3//sup -/ + NH/sub 4//sup +/ from the sediment could supply 30-82% of the nitrogen requirement of the planktonic primary producers.

  8. Sediment Transport and Water Quality Model of Cedar Lake, Indiana

    NASA Astrophysics Data System (ADS)

    James, S. C.; Jones, C. A.; Roberts, J. D.; Ahlmann, M.; Bucaro, D. A.

    2006-12-01

    The EPA-supported Environmental Fluid Dynamics Code, EFDC, is used to model hydrodynamics, sediment transport, and water quality in coastal regions, estuaries, rivers, and lakes. However, the empirical formulations used for sediment transport are not always adequate to accurately characterize cohesive sediment erosion and transport. New sediment transport subroutines have been incorporated into EFDC and the new model is called SNL-EFDC. The updated model provides an improved, coupled hydrodynamics, sediment transport, and water quality framework. The newly incorporated sediment transport subroutines facilitate direct use of measured erosion rate data from the Sediment Erosion with Depth Flume (SEDflume). Erosion rates are included as functions of both depth within the sediment bed and applied shear stresses. This bypasses problems associated with empirical erosion formulations often based on disaggregated particle size. Restoration alternatives are under consideration for Cedar Lake in Indiana and SNL-EFDC models its hydrodynamics, sediment transport, and water quality. The water quality model as implemented on Cedar Lake tracks algae, oxygen, temperature, carbon, phosphorous, and nitrogen kinetics, as well as, sediment bed diagenesis. Environmental conditions, wind, temperature, rainfall, and sunlight, were based on data collected in 2005. Tributary loading was modeled using L-THIA and provided influxes of water, nutrients (phosphorous, nitrogen, etc.), and sediments. The calibrated model was used to simulate a nine month period from March to November 2005. Results suggest that the model simulates sediments transport and associated water quality correctly. The calibrated model is being used to evaluate several restoration measures throughout the lake and watershed and their effect on water quality. Because Cedar Lake is a nitrogen limited lake, changes in the level of eutrophication from each measure are being tracked by calculating the Carlson trophic state index

  9. Cleaning verification by air/water impingement

    NASA Technical Reports Server (NTRS)

    Jones, Lisa L.; Littlefield, Maria D.; Melton, Gregory S.; Caimi, Raoul E. B.; Thaxton, Eric A.

    1995-01-01

    This paper will discuss how the Kennedy Space Center intends to perform precision cleaning verification by Air/Water Impingement in lieu of chlorofluorocarbon-113 gravimetric nonvolatile residue analysis (NVR). Test results will be given that demonstrate the effectiveness of the Air/Water system. A brief discussion of the Total Carbon method via the use of a high temperature combustion analyzer will also be given. The necessary equipment for impingement will be shown along with other possible applications of this technology.

  10. Mid frequency shallow water fine-grained sediment attenuation measurements.

    PubMed

    Holland, Charles W; Dosso, Stan E

    2013-07-01

    Attenuation is perhaps the most difficult sediment acoustic property to measure, but arguably one of the most important for predicting passive and active sonar performance. Measurement techniques can be separated into "direct" measurements (e.g., via sediment probes, sediment cores, and laboratory studies on "ideal" sediments) which are typically at high frequencies, O(10(4)-10(5)) Hz, and "indirect" measurements where attenuation is inferred from long-range propagation or reflection data, generally O(10(2)-10(3)) Hz. A frequency gap in measurements exists in the 600-4000 Hz band and also a general acknowledgement that much of the historical measurements on fine-grained sediments have been biased due to a non-negligible silt and sand component. A shallow water measurement technique using long range reverberation is critically explored. An approximate solution derived using energy flux theory shows that the reverberation is very sensitive to depth-integrated attenuation in a fine-grained sediment layer and separable from most other unknown geoacoustic parameters. Simulation using Bayesian methods confirms the theory. Reverberation measurements across a 10 m fine-grained sediment layer yield an attenuation of 0.009 dB/m/kHz with 95% confidence bounds of 0.006-0.013 dB/m/kHz. This is among the lowest values for sediment attenuation reported in shallow water. PMID:23862792

  11. Lessons learned from water/sediment-testing of pharmaceuticals.

    PubMed

    Radke, Michael; Maier, Michael P

    2014-05-15

    Previous studies revealed large differences in the transformation of pharmaceuticals in rivers with similar characteristics. The present work aimed at answering the question whether these differences are related to the transformation capacity of the specific river sediments. More generally, we also aimed at evaluating the overall diagnostic power of water/sediment tests. Incubation experiments with 9 pharmaceuticals were carried out with sediments sampled from three rivers. All compounds expect carbamazepine were removed at dissipation half-lives between 2.5 and 56 days; biotransformation was identified as the major removal process. Interestingly, sediment from river Roter Main was more efficient in removing pharmaceuticals than sediment from river Gründlach, while the opposite pattern was observed in previous field studies. Obviously, the physical boundary conditions are governing the actual elimination of pharmaceuticals and not the transformation potential of the specific sediments. In a separate experiment, an immediate onset of transformation was observed after introducing oxygen to an anoxic water/sediment system. Transformation rates in sediments sampled from several sites within one river varied up to a factor of 2.5. This considerable in-stream variability is a critical factor for environmental risk assessment where single cutoff values are being used for evaluating a compound's persistence. PMID:24602861

  12. An updated Quantitative Water Air Sediment Interaction (QWASI) model for evaluating chemical fate and input parameter sensitivities in aquatic systems: application to D5 (decamethylcyclopentasiloxane) and PCB-180 in two lakes.

    PubMed

    Mackay, Donald; Hughes, Lauren; Powell, David E; Kim, Jaeshin

    2014-09-01

    The QWASI fugacity mass balance model has been widely used since 1983 for both scientific and regulatory purposes to estimate the concentrations of organic chemicals in water and sediment, given an assumed rate of chemical emission, advective inflow in water or deposition from the atmosphere. It has become apparent that an updated version is required, especially to incorporate improved methods of obtaining input parameters such as partition coefficients. Accordingly, the model has been revised and it is now available in spreadsheet format. Changes to the model are described and the new version is applied to two chemicals, D5 (decamethylcyclopentasiloxane) and PCB-180, in two lakes, Lake Pepin (MN, USA) and Lake Ontario, showing the model's capability of illustrating both the chemical to chemical differences and lake to lake differences. Since there are now increased regulatory demands for rigorous sensitivity and uncertainty analyses, these aspects are discussed and two approaches are illustrated. It is concluded that the new QWASI water quality model can be of value for both evaluative and simulation purposes, thus providing a tool for obtaining an improved understanding of chemical mass balances in lakes, as a contribution to the assessment of fate and exposure and as a step towards the assessment of risk. PMID:24997940

  13. Effects of a nearshore wastewater discharge: Water column and sediment pore water toxicity

    SciTech Connect

    Krause, P.R.; Carr, R.S.

    1995-12-31

    The relationship between water column and sediment pore water toxicity was investigated near a municipal-industrial wastewater discharge in southern Texas. Toxicity associated with effluent distributions in the water column are known to vary in both time and space. Toxicity of sediment, however, is often more stable over time. Sediment can serve as a long-term integrator of toxicity in areas subject to chronic exposure of effluents. This study addressed the relationship between water column toxicity and that found in the sediments on both spatial and temporal scales. Four 2 Km transacts were established around a nearshore wastewater outfall. Eight stations along each transact were sampled for both surface waters and sediment pore water toxicity. Toxicity was determined using a modified sea urchin fertilization test. Surface waters were sampled and tested for eight consecutive months, while sediment pore waters were sampled on three occasions over the length of this study. Results have shown that toxicity in receiving waters was a good indicator to trace movements of the highly variable effluent plume. The distribution of effluent in the water column, and hence water column toxicity, was primarily driven by local wind conditions. Toxicity in sediment porewater was, much less variable and more evenly distributed over the study site. Sediment pore water toxicity was also a good predictor of the distribution of benthic infaunal invertebrates over much of the study site.

  14. Antifouling biocides in water and sediments from California marinas.

    PubMed

    Sapozhnikova, Yelena; Wirth, Edward; Schiff, Kenneth; Fulton, Michael

    2013-04-15

    Irgarol 1051 is a common antifouling biocide and is highly toxic to non-target plant species at low ng/L concentrations. We measured up to 254 ng/L Irgarol in water and up to 9 ng/g dry weight Irgarol in sediments from Southern California recreational marinas. Irgarol's metabolite, M1, concentrations were up to 62 ng/L in water and 5 ng/g dry weight in sediments. Another antifouling biocide, diuron, reached up to 68 ng/L in water and 4 ng/g dry weight in sediments. The maximum Irgarol concentrations in water were greater than the Irgarol concentration recommended as the plant toxicity benchmark (136 ng/L), suggesting that Irgarol concentrations may be high enough to cause changes in phytoplankton communities in the sampled marinas. Irgarol concentrations measured in sediments were greater than calculated Environmental Risk Limits (ERLs) for Irgarol in sediments (1.4 ng/g). Antifouling pesticide accumulation in sediments may present a potential undetermined risk for benthic organisms. PMID:23453818

  15. Water and suspended sediment division at a stratified tidal junction

    NASA Astrophysics Data System (ADS)

    Buschman, F. A.; Vegt, M.; Hoitink, A. J. F.; Hoekstra, P.

    2013-03-01

    Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper presents observations of water, salt and sediment transports in three channels that connect at a stratified tidal junction. Flow variation in one channel was found to lag behind flow variation in a connected channel by more than 1 h, which is largely attributed to channel length differences from the junction to the sea. The water columns in the three channels were periodically stratified during spring tide, whereas the salinity structure represented a salt wedge during neap tide. Salinity differences between the three channels were substantial. The channels contain water bodies of different salinity and act largely independently. Flow velocities in the upper and lower layers differed substantially. Flow in the lower layer was generally in the direction of acceleration produced by the baroclinic pressure gradient. Interestingly, baroclinic pressure gradients were sometimes directed landward, indicating the presence of saltier water at the land side of the estuary. In sharp channel bends close to the junction, secondary flow was strongest at the highest axial flow velocity during spring tide. In one channel bend, these circulations steered the suspended sediment toward the inner bend, which affected the suspended sediment division.

  16. Air and water cooled modulator

    DOEpatents

    Birx, Daniel L.; Arnold, Phillip A.; Ball, Don G.; Cook, Edward G.

    1995-01-01

    A compact high power magnetic compression apparatus and method for delivering high voltage pulses of short duration at a high repetition rate and high peak power output which does not require the use of environmentally unacceptable fluids such as chlorofluorocarbons either as a dielectric or as a coolant, and which discharges very little waste heat into the surrounding air. A first magnetic switch has cooling channels formed therethrough to facilitate the removal of excess heat. The first magnetic switch is mounted on a printed circuit board. A pulse transformer comprised of a plurality of discrete electrically insulated and magnetically coupled units is also mounted on said printed board and is electrically coupled to the first magnetic switch. The pulse transformer also has cooling means attached thereto for removing heat from the pulse transformer. A second magnetic switch also having cooling means for removing excess heat is electrically coupled to the pulse transformer. Thus, the present invention is able to provide high voltage pulses of short duration at a high repetition rate and high peak power output without the use of environmentally unacceptable fluids and without discharging significant waste heat into the surrounding air.

  17. Air and water cooled modulator

    DOEpatents

    Birx, D.L.; Arnold, P.A.; Ball, D.G.; Cook, E.G.

    1995-09-05

    A compact high power magnetic compression apparatus and method are disclosed for delivering high voltage pulses of short duration at a high repetition rate and high peak power output which does not require the use of environmentally unacceptable fluids such as chlorofluorocarbons either as a dielectric or as a coolant, and which discharges very little waste heat into the surrounding air. A first magnetic switch has cooling channels formed therethrough to facilitate the removal of excess heat. The first magnetic switch is mounted on a printed circuit board. A pulse transformer comprised of a plurality of discrete electrically insulated and magnetically coupled units is also mounted on said printed board and is electrically coupled to the first magnetic switch. The pulse transformer also has cooling means attached thereto for removing heat from the pulse transformer. A second magnetic switch also having cooling means for removing excess heat is electrically coupled to the pulse transformer. Thus, the present invention is able to provide high voltage pulses of short duration at a high repetition rate and high peak power output without the use of environmentally unacceptable fluids and without discharging significant waste heat into the surrounding air. 9 figs.

  18. Sediment tracers in water erosion studies: Current approaches and challenges

    NASA Astrophysics Data System (ADS)

    Guzmán, Gema; Quinton, John N.; Nearing, Mark A.; Mabit, Lionel; Giráldez, Juan V.; Gómez, José A.

    2013-04-01

    The quest for alternative methods of soil losses assessment, due to water erosion to complement and enhance existing methods has directed attention to the use of tracing approaches because of the additional information they provide, such as sediment source identification, tracking of sediment movement across the landscape at various temporal and spatial scales and soil erosion rates. For these reasons, the utility and robustness of sediment tracing approaches using a wide range of substances and soil properties have been evaluated in numerous studies. A comprehensive literature review on tracing approaches used in water erosion studies was carried out in June 2011 using the Web of Science database and as search terms in the title or as keywords: "erosion AND tracer" OR "sediment AND tracer" OR "sediment AND tracking". The search excluded reviews and tillage and/or wind erosion studies. Only studies that used tracers to make a determination of water erosion or sedimentation rates, or in some cases relative erosion contribution, were considered in this study, and were further refined by manually checking that the articles corresponded to experiments involving sediment studies using tracers, as defined within the context of this review. Five distinct groups of tracing approaches were identified: fallout radionuclides, rare earth elements, soil magnetism and magnetic substances, other tracers, and sediment fingerprinting techniques. This abstract presents a synthesis of the current approaches of each of the tracing techniques identified in assessing soil erosion and sediment redistribution and a summary with the commonalities and differences between the approaches and identifying research gaps and future trends.

  19. Spectroscopic analyses of pollutants in water, sediment and fish

    NASA Astrophysics Data System (ADS)

    Abdel-Gawad, Fagr Kh.; Ibrahim, Hanan S.; Ammar, Nabila S.; Ibrahim, Medhat

    2012-11-01

    Water ways in Egypt is suffering from continual discharge without adequate treatment especially in the Delta and greater Cairo area. Accordingly water, sediments and catfishes were collected from El Mouheet El Youmna drain in Giza. Cd, Cr, Pb and Zn were determined furthermore the molecular structure of sediment and catfish were conducted with FTIR spectroscopy. Although studied metals were lower in water, higher values are recorded in sediment and catfish samples. FTIR shows possible interaction among metals and organic structures mainly proteins. The bioaccumulation of Pb and Cd proportion was significantly increased in the liver tissues of catfish. A correlation coefficient among sediment and fish liver metals accumulation exist. This infers that the waste assimilation capacity for the drain is high, a phenomena that could be ascribed to dilution, sedimentation and continual water exchange. Furthermore, the genotoxicity affect in catfish genomic corroborates the genus diagnostic markers which attributed to long pollution. This is an indication that agriculture and industrial wastes discharged into the drain has badly a significant effect on the ecological balance.

  20. Response of crayfish to hyporheic water availability and excess sedimentation

    USGS Publications Warehouse

    Dyer, Joseph J.; Worthington, Thomas A.; Brewer, Shannon K.

    2015-01-01

    Crayfish in many headwater streams regularly cope with seasonal drought. However, it is unclear how landscape changes affect the long-term persistence of crayfish populations. We designed two laboratory experiments to investigate the acute effects of common landscape stressors on crayfish: water withdrawal and sedimentation. The first experiment tested the interaction among water withdrawals (four 24-h water reductions of 0, 15, 30, or 45 cm) and two substrate treatments (pebble and cobble) on the burrowing depth of crayfish. The second experiment evaluated the effects of excess fine sediment (three treatments of 0, 45, and 90% sediment) and substrate type (cobble and pebble) on crayfish burrowing depth. Crayfish were able to burrow deeper into the simulated hyporheic zone in cobble substrate when compared to pebble. Crayfish subjected to greater water withdrawals in the pebble treatment were not able to reach the simulated hyporheic zone. Excess fine sediment reduced the depth that crayfish burrowed, regardless of substrate type. Results from this study suggest excess fine sediment may reduce crayfish persistence, particularly when seeking refuge during prolonged dry conditions.

  1. Penguin vision in air and water.

    PubMed

    Howland, H C; Sivak, J G

    1984-01-01

    Refractive states measured by retinoscopy and photorefraction indicate that rockhopper (Eudyptes crestatus), Magellanic (Spheniscus magellanicus) and gentoo (Pygoscelis papua) penguins are approximately emmetropic in air and water. Extensive myopia in air, as predicted by early authors, is nonexistent. Photorefractive measurements of refractive state in water indicate that rockhopper, gentoo, Magellanic and king (Aptenodytes patagonica) penguins can accommodate sufficiently to make up for the loss of refractive power of the cornea. Corneas of rockhopper and Megellanic penguins are flattened relative to the overall size of the eye. This feature minimizes the optical effect of submergence. PMID:6534014

  2. Combined air and water pollution control system

    NASA Technical Reports Server (NTRS)

    Wolverton, Billy C. (Inventor); Jarrell, Lamont (Inventor)

    1990-01-01

    A bioaquatic air pollution control system for controlling both water and atmospheric pollution is disclosed. The pollution control system includes an exhaust for directing polluted gases out of a furnace and a fluid circulating system which circulates fluid, such as waste water, from a source, past the furnace where the fluid flow entrains the pollutants from the furnace. The combined fluid and pollutants are then directed through a rock/plant/microbial filtering system. A suction pump pumps the treated waste water from the filter system past the exhaust to again entrain more pollutants from the furnace where they are combined with the fluid (waste water) and directed to the filter system.

  3. Seasonal variations in pore water and sediment geochemistry of littoral lake sediments (Asylum Lake, MI, USA)

    PubMed Central

    Koretsky, Carla M; Haas, Johnson R; Miller, Douglas; Ndenga, Noah T

    2006-01-01

    Background Seasonal changes in pore water and sediment redox geochemistry have been observed in many near-surface sediments. Such changes have the potential to strongly influence trace metal distribution and thus create seasonal fluctuations in metal mobility and bioavailability. Results Seasonal trends in pore water and sediment geochemistry are assessed in the upper 50 cm of littoral kettle lake sediments. Pore waters are always redox stratified, with the least compressed redox stratification observed during fall and the most compressed redox stratification observed during summer. A 2-step sequential sediment extraction yields much more Fe in the first step, targeted at amorphous Fe(III) (hydr)oxides (AEF), then in the second step, which targets Fe(II) monosulfides. Fe extracted in the second step is relatively invariant with depth or season. In contrast, AEF decreases with sediment depth, and is seasonally variable, in agreement with changes in redox stratification inferred from pore water profiles. A 5-step Tessier extraction scheme was used to assess metal association with operationally-defined exchangeable, carbonate, iron and manganese oxide (FMO), organic/sulfide and microwave-digestible residual fractions in cores collected during winter and spring. Distribution of metals in these two seasons is similar. Co, As, Cd, and U concentrations approach detection limits. Fe, Cu and Pb are mostly associated with the organics/sulfides fraction. Cr and Zn are mostly associated with FMO. Mn is primarily associated with carbonates, and Co is nearly equally distributed between the FMO and organics/sulfide fractions. Conclusion This study clearly demonstrates that near-surface lake sediment pore water redox stratification and associated solid phase geochemistry vary significantly with season. This has important ramifications for seasonal changes in the bioavailability and mobility of trace elements. Without rate measurements, it is not possible to quantify the

  4. 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.

  5. Bacterial Mercury Methylation At The Sediment-Water Interface Of Mercury Contaminated Sediments

    EPA Science Inventory

    Bench scale experiments were conducted to improve our understanding of bacterial mediation of mercury transformation (methylation), specifically those factors which govern the production of methyl mercury (MeHg) at the sediment-water interface. The greatest cause for concern re...

  6. Contaminated marine sediments: Water column and interstitial toxic effects

    SciTech Connect

    Burgess, R.M.; McKinney, R.A. ); Schweitzer, K.A. ); Phelps, D.K. )

    1993-01-01

    The toxicity that contaminated sediments may introduce into the water column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated marine sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentration of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. Water column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial water toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in water column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial water did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.

  7. Contaminated marine sediments: Water column and interstitial toxic effects

    SciTech Connect

    Burgess, R.M.; Schweitzer, K.A.; McKinney, R.A.; Phelps, D.K.

    1993-01-01

    The toxicity that contaminated sediments may introduce into the water column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated marine sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentrations of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. Water column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial water toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in water column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial waters did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.

  8. Designing open water disposal for dredged muddy sediments

    NASA Astrophysics Data System (ADS)

    McAnally, William H.; Adamec, Stephen A.

    1987-11-01

    Open water disposal of muddy sediments in the estuarine environment is practiced to minimize dredging costs and to preserve contained disposal site capacity. Open water sites are usually either dispersive or retentive. Dispersive sites are used in the expectation that disposed sediments will not remain there, but will be transported out of the site, leaving room for additional disposal. Retentive sites are designed to ensure that disposed sediments mostly remain within the site. Choice of one of these approaches depends on the site character, sediment character, and disposal quantities. Design of disposal management plans for both site types is accomplished by use of field observations, laboratory tests, and numerical modeling. Three disposal site studies illustrate the methods used. At the Alcatraz site in San Francisco Bay, a dispersive condition is maintained by use of constraints on dredged mud characteristics that were developed from laboratory tests on erosion rates and from numerical modeling of the dump process. Field experiments were designed to evaluate the management procedure. In Corpus Christi Bay a numerical model was used to determine how much disposed sediment returns to the navigation channel, and to devise a location for disposal that will minimize that return. In Puget Sound a model has been used to ensure that most of the disposed material remains in the site. New techniques, including a piped disposal through 60 m of water, were investigated.

  9. Quenching using air-water mixtures

    SciTech Connect

    Wallis, R.A.; Garwood, R.; Ward, J.; Xia, Q.

    1996-12-31

    With the current trend toward reduced manufacturing cycle time there is considerable interest in minimizing heat treatment related distortion and the residual stresses that are present in components. There is therefore a need to optimize the quenching process for a particular part such that the desired cooling rate, and hence mechanical properties, are obtained while minimizing distortion. This paper describes work aimed at developing a system to provide heat transfer rates between those obtained for oil quenching and fan cooling. Tests are described in which quenching was carried out by spraying water into the stream of air exiting a fan cooling system. Data are also presented for air mist quenching using atomizing nozzles. Comparison of computer predicted cooling rates and residual stress levels in components are presented for oil quenching, fan cooling, fan plus water injection cooling and air-mist cooling.

  10. Timber Harvest Effects on Sediment and Water Yields and Analysis of Sediment Load Calculation Methods in the Interior Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Elverson, C.; Karwan, D. L.

    2015-12-01

    Timber harvest practices have a long-standing association with changes in water and sediment yields. We quantify the trends in water and sediment yields in the Mica Creek Experimental Watershed (MCEW) in relation to management practices with linear regression and analysis of covariance (ANCOVA). From 1991 to 2013, an increase in water yield resulted from both clearcutting and thinning treatments, with monthly water yield rate increases of 13-57% and annual water yield increases up to 210 mm (40%) in the clearcut watershed. Following treatment, annual sediment yields increased in the clearcut watershed by 40-131% and the thinned watershed by 33-163%, both relative to the control watershed, with statistically-significant monthly load increases in the year immediately following treatment. Water and sediment yield changes do not follow the same post-treatment patterns. Water yields increased immediately following treatment and, over time, gradually dropped towards pre-harvest levels. Annual sediment yields increased in some years after the harvest, but in some cases the increase was years after treatment. Monthly sediment yields increased in the first year following the clearcut harvest, but elevated monthly loads following the partial cut harvest came years later. Hence, we investigate the changes in sediment yield through an examination of water yield and sediment concentration and in response to events. We test the sensitivity of our results to different methods for computing sediment yields based on total suspended solids concentration and continuous discharge measurements. Flow-weighted sediment yield averaged 24% higher than sediment yield computed from linear-interpolated total suspended solids concentration values. During typical summer and fall conditions, flow-weighting was found to overweight storm measurements and produce large sediment yield estimates. Further work is suggested to test methods of calculating monthly sediment yields with irregularly

  11. Sediment Mobilization From Reservoirs Can Cause Short Term Oxygen Depletion In Downstream Receiving Waters

    NASA Astrophysics Data System (ADS)

    Anderson, C.; Schenk, L.; Bragg, H.; Singer, M.; Hume, N.

    2013-12-01

    Reservoir management can cause incidences of short-term sediment mobilization, e.g. during dam removal or drawdown for maintenance or habitat purposes. Much of the associated planning focuses on predicting, quantifying, and mitigating the physical impacts of sediment mobilization, transport, and deposition. Sediment pulses can cause multiple regulatory and management concerns, such as turbidity or suspended sediment concentrations that may exceed State standards, geomorphic change and effects on property or infrastructure, or wildlife impacts such as stress to fish via gill abrasion or burial of critical habitat. Water-quality issues associated with sediment mobilization, including nutrient and contaminant transport, are often given less attention, presumably because their effects are less immediate or because of resource constraints. Recent experience with large pulses of sediment from several western reservoirs involving dam removals and temporary drawdowns indicates that oxygen demand, leading to depletion of downstream dissolved oxygen (DO), can also be a significant short-term concern. During the October 2011 Condit Dam removal on the White Salmon River in Washington, DO in receiving waters about 4.5 km downstream of the dam dropped to less than 1 mg/L within 2 hours of the demolition; in response, salmonids were observed to be in distress, apparently gulping for air at the water surface. DO remained low for at least 24 hours in this reach, and dead fish were observed. In December 2012, during a drawdown designed to aid juvenile-salmonid migration through Fall Creek Reservoir in Oregon, DO dropped precipitously about 1.5 km downstream as turbidity peaked, and a muted DO decrease was also observed approximately 14 miles further downstream despite a large dilution from unaffected sources. Laboratory experiments and modeling using sediments from reservoirs proposed for removal on the Klamath River, California, demonstrated the likelihood for downstream DO

  12. Ethylene-air detonation in water spray

    NASA Astrophysics Data System (ADS)

    Jarsalé, G.; Virot, F.; Chinnayya, A.

    2016-07-01

    Detonation experiments are conducted in a 52 mm square channel with an ethylene-air gaseous mixture with dispersed liquid water droplets. The tests were conducted with a fuel-air equivalence ratio ranging from 0.9 to 1.1 at atmospheric pressure. An ultrasonic atomizer generates a polydisperse liquid water spray with droplet diameters of 8.5-12 μm, yielding an effective density of 100-120 g/m3 . Pressure signals from seven transducers and cellular structure are recorded for each test. The detonation structure in the two-phase mixture exhibits a gaseous-like behaviour. The pressure profile in the expansion fan is not affected by the addition of water. A small detonation velocity deficit of up to 5 % was measured. However, the investigation highlights a dramatic increase in the cell size (λ ) associated with the increase in the liquid water mass fraction in the two-phase mixture. The detonation structure evolves from a multi-cell to a half-cell mode. The analysis of the decay of the post-shock pressure fluctuations reveals that the ratio of the hydrodynamic thickness over the cell size (x_{{HT}}/{λ } ) remains quite constant, between 5 and 7. A slight decrease of this ratio is observed as the liquid water mass fraction is increased, or the ethylene-air mixture is made leaner.

  13. 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...

  14. 19. EMPTY SEDIMENTATION TANKS. TOP LAYER OF WATER FLOWS OVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. EMPTY SEDIMENTATION TANKS. TOP LAYER OF WATER FLOWS OVER TRIANGULATED CHANNELS AND OUT THE RAISED DUCTS TO FILTRATION PLANT. MOVEABLE BOARDS ON BOTTOM ASSIST IN REMOVING SLUDGE. VIEW LOOKING NORTHEAST. FILTER CONTROL BUILDING AT REAR. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

  15. Magnetic Characterization of Stream-Sediments From Buenos Aires Province, Argentina, Affected by Pollution

    NASA Astrophysics Data System (ADS)

    Chaparro, M. A.; Sinito, A. M.; Bidegain, J. C.; Gogorza, C. S.; Jurado, S.

    2001-12-01

    A wide urban area from Northeast of Buenos Aires Province is exposed to an important anthropogenic influence, mainly due to industrial activity. In this two water streams were chosen: one of them (Del Gato stream, G) next to La Plata City and the another one (El Pescado stream, P) on the outskirts of the city. Both streams have similar characteristics, although the first one (G) has a higher input of pollutants (fluvial effluents, fly ashes, solid wastes, etc.) than the last one (P). Sediments analyzed in this work are limes from continental origin of PostPampeano (Holocene). Although, some cores were affected by sandy-limy sediments with mollusc valves from Querandino Sea (Pleistocene - later Holocene) and limy sediments of chestnut color with calcareous concretions from the Ensenadense. Magnetic measurements and geochemical studies were carried out on the samples. Among the magnetic parameters, specific susceptibility (X), X frequency-dependence (Xfd%), X temperature-dependence, Natural Remanent Magnetization (NRM), Isothermal Remanent Magnetization (IRM), Saturation IRM (SIRM), coercivity of remanence (Bcr), S ratio and SIRM/X ratio, Anhysteric Remanent Magnetization (ARM), Magnetic and Thermal Demagnetization were studied. The magnetic characteristics for both sites indicate the predominance of magnetically soft minerals on G site and relatively hard minerals on P site. Magnetite is the main magnetic carrier, Pseudo Single Domain and Single Domain grains were found. Chemical studies show (in some cases) a high concentration for some heavy metals (Pb, Cu, Zn, Ni and Fe) on the upper 22-cm. Contents of heavy metals and ARM were correlated. Very good correlation (R> 0.81) is found for Cu, Zn, Ni, Fe and the sum (of Pb, Cu, Zn and Ni), and a weaker correlation for Pb.

  16. Extraction and concentration of phenolic compounds from water and sediment

    USGS Publications Warehouse

    Goldberg, M.C.; Weiner, Eugene R.

    1980-01-01

    Continuous liquid-liquid extractors are used to concentrate phenols at the ??g l-1 level from water into dichloromethane; this is followed by Kuderna-Danish evaporative concentration and gas chromatography. The procedure requires 5 h for 18 l of sample water. Overall concentration factors around 1000 are obtained. Overall concentration efficiencies vary from 23.1 to 87.1%. Concentration efficiencies determined by a batch method suitable for sediments range from 18.9 to 73.8%. ?? 1980.

  17. Chemical quality of water, sediment, and fish in Mountain Creek Lake, Dallas, Texas, 1994-97

    USGS Publications Warehouse

    Van Metre, Peter C.; Jones, S.A.; Moring, J. Bruce; Mahler, B.J.; Wilson, Jennifer T.

    2003-01-01

    The occurrence, trends, and sources of numerous inorganic and organic contaminants were evaluated in Mountain Creek Lake, a reservoir in Dallas, Texas. The study, done in cooperation with the Southern Division Naval Facilities Engineering Command, was prompted by the Navy?s concern for potential off-site migration of contaminants from two facilities on the shore of Mountain Creek Lake, the Naval Air Station Dallas and the Naval Weapons Industrial Reserve Plant. Sampling of stormwater (including suspended sediment), lake water, bottom sediment (including streambed sediment), and fish was primarily in Mountain Creek Lake but also was in stormwater outfalls from the Navy facilities, nearby urban streams, and small streams draining the Air Station. Volatile organic compounds, predominantly solvents from the Reserve Plant and fuel-related compounds from the Air Station, were detected in stormwater from both Navy facilities. Fuel-related compounds also were detected in Mountain Creek Lake at two locations, one near the Air Station inlet where stormwater from a part of the Air Station enters the lake and one at the center of the lake. Concentrations of volatile organic compounds at the two lake sites were small, all less than 5 micrograms per liter. Elevated concentrations of cadmium, chromium, copper, lead, mercury, nickel, silver, and zinc, from 2 to 4 times concentrations at background sites and urban reference sites, were detected in surficial bottom sediments in Cottonwood Bay, near stormwater outfalls from the Reserve Plant. Elevated concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls, compared to background and urban reference sites, were detected in surficial sediments in Cottonwood Bay. Elevated concentrations of polycyclic aromatic hydrocarbons, indicative of urban sources, also were detected in Cottonwood Creek, which drains an urbanized area apart from the Navy facilities. Elevated concentrations of polychlorinated biphenyls were

  18. Numerical simulation of suspended sediment transport merging with satellite derived data in coastal waters

    NASA Astrophysics Data System (ADS)

    Yang, Xuefei; Mao, Zhihua; Huang, Haiqing; Wang, Tianyu; Liu, Dong

    2014-11-01

    The distribution and transport of suspended sediment in the coastal areas has attracted more and more attention. Monitoring and modeling of the distribution and transport of suspended sediment is significant. The mutual promotion of remote sensing and numerical simulation plays an important role on the coastal water quality study. In this study, a method of coupling derived suspended sediment concentration (SSC) images with numerical model, based on GOCI and COHERENS (COupled Hydrodynamical-Ecological model for REgioNal and Shelf seas) model, is proposed to monitor the suspended sediment dynamics in the East China Sea. The retrieved SSC were extracted from GOCI images, to set as initial condition and employed to calibrate the parameters and validation for the hydrodynamic modeling and sediment transport modeling, respectively. The model is forced by considering tidal surface elevation at open sea boundary, river discharges, surface stress as a function of wind speed, air temperature, relative humidity and cloud coverage, bottom roughness and heat flux through sea surface. The model results are in accord with the in situ measurements. The results show that: (1) Numerical model which initialized with satellite-derived SSC data can quickly response to the changes of sediment concentration in real sense. (2) Remote sensing is helpful to calibrate and validate the model for simulating the suspended sediment concentration distribution. (3)The proposed approach can obtain reasonable simulated results in the East China Sea. (4) It is of great significance to combine remote sensing and numerical simulation together to study the water quality in the coastal areas.

  19. Brevetoxin persistence in sediments and seagrass epiphytes of east Florida coastal waters

    PubMed Central

    Hitchcock, Gary L.; Fourqurean, James W.; Drake, Jeana L.; Mead, Ralph N.; Heil, Cynthia A.

    2012-01-01

    A bloom of Karenia brevis Davis developed in September 2007 near Jacksonville, Florida and subsequently progressed south through east Florida coastal waters and the Atlantic Intracoastal Waterway (ICW). Maximum cell abundances exceeded 106 cells L−1 through October in the northern ICW between Jacksonville and the Indian River Lagoon. The bloom progressed further south during November, and terminated in December 2007 at densities of 104 cells L−1 in the ICW south of Jupiter Inlet, Florida. Brevetoxins were subsequently sampled in sediments and seagrass epiphytes in July and August 2008 in the ICW. Sediment brevetoxins occurred at concentrations of 11–15 ng PbTx-3 equivalents (g dry wt sediment)−1 in three of five basins in the northern ICW during summer 2008. Seagrass beds occur south of the Mosquito Lagoon in the ICW. Brevetoxins were detected in six of the nine seagrass beds sampled between the Mosquito Lagoon and Jupiter Inlet at concentrations of 6–18 ng (g dry wt epiphytes)−1. The highest brevetoxins concentrations were found in sediments near Patrick Air Force Base at 89 ng (g dry wt sediment)−1. In general, brevetoxins occurred in either seagrass epiphytes or sediments. Blades of the resident seagrass species have a maximum life span of less than six months, so it is postulated that brevetoxins could be transferred between epibenthic communities of individual blades in seagrass beds. The occurrence of brevetoxins in east Florida coast sediments and seagrass epiphytes up to eight months after bloom termination supports observations from the Florida west coast that brevetoxins can persist in marine ecosystems in the absence of sustained blooms. Furthermore, our observations show that brevetoxins can persist in sediments where seagrass communities are absent. PMID:23762030

  20. Brevetoxin persistence in sediments and seagrass epiphytes of east Florida coastal waters.

    PubMed

    Hitchcock, Gary L; Fourqurean, James W; Drake, Jeana L; Mead, Ralph N; Heil, Cynthia A

    2012-01-01

    A bloom of Karenia brevis Davis developed in September 2007 near Jacksonville, Florida and subsequently progressed south through east Florida coastal waters and the Atlantic Intracoastal Waterway (ICW). Maximum cell abundances exceeded 10(6) cells L(-1) through October in the northern ICW between Jacksonville and the Indian River Lagoon. The bloom progressed further south during November, and terminated in December 2007 at densities of 10(4) cells L(-1) in the ICW south of Jupiter Inlet, Florida. Brevetoxins were subsequently sampled in sediments and seagrass epiphytes in July and August 2008 in the ICW. Sediment brevetoxins occurred at concentrations of 11-15 ng PbTx-3 equivalents (g dry wt sediment)(-1) in three of five basins in the northern ICW during summer 2008. Seagrass beds occur south of the Mosquito Lagoon in the ICW. Brevetoxins were detected in six of the nine seagrass beds sampled between the Mosquito Lagoon and Jupiter Inlet at concentrations of 6-18 ng (g dry wt epiphytes)(-1). The highest brevetoxins concentrations were found in sediments near Patrick Air Force Base at 89 ng (g dry wt sediment)(-1). In general, brevetoxins occurred in either seagrass epiphytes or sediments. Blades of the resident seagrass species have a maximum life span of less than six months, so it is postulated that brevetoxins could be transferred between epibenthic communities of individual blades in seagrass beds. The occurrence of brevetoxins in east Florida coast sediments and seagrass epiphytes up to eight months after bloom termination supports observations from the Florida west coast that brevetoxins can persist in marine ecosystems in the absence of sustained blooms. Furthermore, our observations show that brevetoxins can persist in sediments where seagrass communities are absent. PMID:23762030

  1. Sediment dispersal and accumulation off the present Huanghe (Yellow River) delta as impacted by the Water-Sediment Regulation Scheme

    NASA Astrophysics Data System (ADS)

    Wu, Xiao; Bi, Naishuang; Yuan, Ping; Li, Song; Wang, Houjie

    2015-12-01

    Surface sediment samples from 15 stations around the present Huanghe (Yellow River) river mouth were collected before, during and after the Water-Sediment Regulation Scheme (WSRS) in 2010 for grain size analysis. Hydrographic surveys conducted simultaneously at stations along three transects off the river mouth during the WSRS in 2013 were used to investigate the dispersal and accumulation of the Huanghe sediment off the present Huanghe subaqueous delta. During the WSRS period, the diluted water from the river covered all over the study area within the surface layer, whereas high-concentrated sediment was found in the bottom layers and to be limited in nearshore area shallower than 12 m, indicating that the buoyant river plume was the main sediment dispersal pattern during the WSRS. At the early stage of the WSRS when large amount of clear water was released from the Xiaolangdi Reservoir, sediment eroded from the downstream riverbed in the lower reaches increased the median grain size of surface sediment at the river mouth. During the second stage when water discharge was reduced but sediment discharge was dramatically increased, the fine-grained sediment derived from the Xiaolangdi Reservoir mixed with the previously deposited coarser surface sediment, leading to the decreasing median grain size of surface sediment that approached to be poorly sorted. After the physical sorting from winter storms, the surface sediment was redistributed and varied regularly with water depth. As the median grain size of suspended sediment discharge to the sea has been significantly increased due to the WSRS, the river-delivered sediment mostly accumulated in the nearshore area, which effectively extended the subaerial delta and steepened the subaqueous slope off the present river mouth.

  2. Relative role of pore water versus ingested sediment in bioavailability of organic contaminants in marine sediments

    SciTech Connect

    Forbes, T.L.; Hansen, R.; Kure, L.K.; Forbes, V.E.; Giessing, A. |

    1998-12-01

    Experimental data for fluoranthene and feeding selectivity in combination with reaction-diffusion modeling suggest that ingestion of contaminated sediment may often be the dominant uptake pathway for deposit-feeding invertebrates in sediments. A dietary absorption efficiency of 56% and accompanying forage ratio of 2.4 were measured using natural sediment that had been dual-labeled ({sup 14}C:{sup 51}Cr) with fluoranthene and fed to the marine deposit-feeding polychaete Capitella species I. Only 3 to 4% of the total absorption could be accounted for by desorption during gut passage. These data were then used as input into a reaction-diffusion model to calculate the importance of uptake from ingested sediment relative to pore-water exposure. The calculations predict a fluoranthene dietary uptake flux that is 20 to 30 times greater than that due to pore water. Factors that act to modify or control the formation of local chemical gradients, boundary layers, or dietary absorption rates including particle selection or burrow construction will be important in determining the relative importance of potential exposure pathways. From a chemical perspective, the kinetics of the adsorption and desorption process are especially important as they will strongly influence the boundary layer immediately surrounding burrowing animals or irrigated tubes. The most important biological factors likely include irrigation behavior and burrow density and size.

  3. Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001

    USGS Publications Warehouse

    Fisher, Lawrence H.; Wood, Tamara M.

    2004-01-01

    Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. Aerial release rates for a stable sediment/water interface that is representative of the sediment surface area to water column volume ratio (1:3) observed in the lake and volumetric release rates for resuspended sediment events were determined at three different pH values (8.1, 9.2, 10.2). Ambient water column pH (8.1) was maintained by sparging study columns with atmospheric air. Elevation of the water column pH to 9.2 was achieved through the removal of dissolved carbon dioxide by sparging with carbon dioxide-reduced air, partially simulating water chemistry changes that occur during algal photosynthesis. Further elevation of the pH to 10.2 was achieved by the addition of sodium hydroxide, which doubled average alkalinities in the study columns from about 1 to 2 milliequivalents per liter. Upper Klamath Lake sediments collected from the lake bottom and then placed in contact with lake water, either at a stable sediment/water interface or by resuspension, exhibited an initial capacity to take up soluble reactive phosphorus (SRP) from the water column rather than release phosphorus to the water column. At a higher pH this initial uptake of phosphorus is slowed, but not stopped. This initial phase was followed by a reversal in which the sediments began to release SRP back into the water column. The release rate of phosphorus 30 to 40 days after suspension of sediments in the columns was 0.5 mg/L/day (micrograms per liter per day) at pH 8, and 0.9 mg/L/day at pH 10, indicating that the higher pH increased the rate of phosphorus release by a factor of about two. The highest determined rate of release was approximately 10% (percent) of the rate required to explain the annual internal loading to Upper Klamath Lake from the sediments as calculated from a lake-wide mass balance

  4. Sedimentation in lagoon waters (Case study on Segara Anakan Lagoon)

    NASA Astrophysics Data System (ADS)

    Sari, Lilik Kartika; Adrianto, Luky; Soewardi, Kadarwan; Atmadipoera, Agus S.; Hilmi, Endang

    2016-05-01

    This study aims to demonstrate the effect of sedimentation on waters area that serves as an advocate for life. It is included in the category to be wary considering these conditions will reduce the quality of life and threaten the life and survival of endemic biota. Observations rate of sedimentation since April 2014 until March 2015 performed at 6 stations that are considered to represent the condition of the lagoon. The observations for rate of sedimentation was conducted twice in a month for one year. Oceanographic parameters was taken by CTD (Conductivity, Temperature, and Depth) sensor in two seasons, at the height of the rainy season, March 2014 and August 2014. Results showed that the aquatic area more narrow characterized by changes in the outside line of the island visible on the image observation for two decades.

  5. IMPORTANCE OF INTERSTITIAL, OVERLYING WATER AND WHOLE SEDIMENT EXPOSURES TO BIOACCUMUALTION BY MARINE BIVALVES

    EPA Science Inventory

    During the performance of contaminated sediment studies using nonpolar pollutants, like polyclorinated biphenyls (PCBs), with marine organisms, the routes of exposure can include whole sediment, overlying waters and interstitial waters (assuming no feeding). These routes can be f...

  6. PCB in the air during landfilling of a contaminated lake sediment

    NASA Astrophysics Data System (ADS)

    Bremle, G.; Larsson, P.

    We studied PCB concentration in the air during the build-up of a landfill of PCB-contaminated sediment. A small lake was remediated and the sediment (150 000 m 3 containing about 400 kg PCB) deposited in a nearby landfill. PCB concentration in the air was elevated during landfilling and the extent was determined by the amount of sediment handled and the temperature. The air was enriched in more volatile PCB congeners compared to the deposited sediment, suggesting volatilization as the major transport process in addition to particle transport. The PCB concentration in air showed an exponential decline with distance from the centre of the landfill, with a one order of magnitude decrease 350 m from the centre. At a distance of 850 m from the centre about 5% of the elevated PCB level remained, which was significantly higher when compared to the reference concentration (15 km from the landfill). The PCB congener pattern changed gradually from the landfill centre to the reference. After the landfill was closed and the contaminated, dewatered sediment covered by uncontaminated soil, PCB levels and pattern were similar to that of the reference.

  7. Occurrence and significance of polychlorinated biphenyls in water, sediment pore water and surface sediments of Umgeni River, KwaZulu-Natal, South Africa.

    PubMed

    Gakuba, Emmanuel; Moodley, Brenda; Ndungu, Patrick; Birungi, Grace

    2015-09-01

    The Umgeni River is one of the main sources of water in KwaZulu-Natal, South Africa; however; there is currently a lack of information on the presence and distribution of polychlorinated biphenyls (PCBs) in its sediment, sediment pore water and surface water. This study aims to determine the occurrence and significance of selected PCBs in the surface water, sediment pore water and surface sediment samples from the Umgeni River. Liquid-liquid and soxhlet extractions were used for water or pore water, and sediments, respectively. Extracts were cleaned up using a florisil column and analysed by gas chromatography-mass spectrometry. The total concentrations of eight polychlorinated biphenyls were 6.91-21.69 ng/mL, 40.67-252.30 ng/mL and 102.60-427.80 ng/g (dry weight), in unfiltered surface water, unfiltered sediment pore water and surface sediments, respectively. The percentage contributions of various matrices were 4, 36 and 60 % for unfiltered surface water, unfiltered pore water and sediment, respectively. The highest concentrations of PCBs were found in water, pore water and sediment collected from sampling sites close to the Northern Wastewater Treatment Works. The highest chlorinated biphenyl, PCB 180, was the most abundant at almost all sampling sites. To our knowledge, this is the first report on occurrence of polychlorinated biphenyls in the Umgeni River water, pore water and sediment system and our results provide valuable information regarding the partitioning of the PCBs between the water and sediment systems as well as the organic chemical quality of the water. PMID:26266899

  8. Estimating mercury concentrations and fluxes in the water column and sediment of Lake Ontario with HERMES model.

    PubMed

    Ethier, Adrienne L M; Atkinson, Joseph F; Depinto, Joseph V; Lean, David R S

    2012-02-01

    The HERMES model-predicted Hg concentrations and fluxes in Lake Ontario were based on twelve lake and drainage basin variables (i.e., water temperature, precipitation rate, air Hg, surface area, mean depth, water volume, water inflow rate, inflow water Hg, inflow and lake suspended particulate matter, air-water and water-air mass transfer coefficients, and sedimentation rate). The HERMES model-predicted Hg water and surface sediment concentrations were found to be significantly correlated (±20%) with measured values (r(2) = 0.94, p < 0.0001, n = 13) and mechanistic model predictions (LOTOX2-Hg, r(2) = 0.95, p < 0.0001, n = 10). The predictive capacity of HERMES was previously tested on smaller (≤1 km(2)) lakes in Nova Scotia and Ontario, Canada (i.e., water and sediment Hg concentrations were ±15% of measured data). Results suggest that HERMES could be applicable to a broad range of lake sizes. Uncertainty analyses on HERMES model input variables indicated a larger atmospheric Hg contribution for Lake Ontario when compared to previous predictions for smaller lakes. PMID:21726924

  9. Draix multidisciplinary observatory for water and sediment processes

    NASA Astrophysics Data System (ADS)

    Le Bouteiller, C.; Mathys, N.; Liébault, F.; Klotz, S.

    2013-12-01

    Over the last decades, much progress has been done in the modeling and conceptualizing of surface processes. Testing theories and models requires field data, and possibly long-term time series. Here we present a 30-year old field observatory dedicated to water and sediment fluxes in the French Alps. Draix observatory is located in a badland area of the French Alps (shale lithology), and includes several subcatchments which differ in size (0.001 to 1 km2) and vegetation coverage (bare soil or forest). Climate is mountainous and Mediterranean, characterized with summer storm-induced floods and winter frost. Data collected includes climatic data (rainfall, temperature) and water and sediment fluxes (discharge at the outlet of each subcatchment, suspended load and bedload fluxes). High frequency monitoring (minute/hour) is used to capture flood dynamics. Some soil hydraulic and geophysical properties, lidar scans and vegetation maps are also available. The combination of an erodible badland morphology and tough climatic conditions induces very high erosion rates and sediment yield (up to 70 tons/ha/yr). Observed erosion processes include landslides, small-scale debris flows, gully formation, weathering on the slopes and in the riverbeds, hyperconcentrated flows and in-transport sediment abrasion. The sediment response is highly non-linear with a strong seasonal pattern of storage and scour in the bed. Current research on Draix observatory is multidisciplinary and involves hydraulic engineers, hydrologists, geomorphologists, soil scientists and restoration ecologists. Fast rates of geomorphic changes, well-constrained sediment budgets and long data series are some of the advantages of this site for the study of earth surface processes. Our data is available for the community and we welcome everyone who is interested in collaborating on it.

  10. Evaluation of petroleum-degrading potential of bacteria from water and sediment.

    PubMed Central

    Walker, J D; Colwell, R R; Petrakis, L

    1975-01-01

    Bacteria from water and sediment of an oil-polluted harbor were examined for ability to degrade petroleum. Water samples contained a greater variety of bacterial species capable of degrading petroleum than sediment. Cultures from both water and sediment contained Pseudomonas and Acinetobacter spp. Bacteria present in the water samples produced significantly greater degradation of 2-,3-,4-, and 5-ring cycloalkanes and mono-, di-, tri-, tetra-, and pentaaromatics compared with bacteria in sediment samples. PMID:1211932

  11. A case study of dissolved air flotation for seasonal high turbidity water in Korea.

    PubMed

    Kwon, S B; Ahn, H W; Ahn, C J; Wang, C K

    2004-01-01

    A DAF (Dissolved-Air-Flotation) process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when freshwater algae blooms occur or raw water turbidity becomes high. Pre-sedimentation is operated in case when the raw water turbidity is very high due to rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of the raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than the conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while the removal of them by sedimentation is more difficult. One of the main concerns for DAF operation is a high raw water turbidity. DAF is not adequate for raw water, which is more turbid than 100 NTU. In order to avoid this problem, pre-sedimentation basins are installed in the DAF plant to decrease the turbidity of the DAF inflow. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, it is suggested that pre-sedimentation with optimum coagulation prior to DAF is the appropriate treatment scheme. PMID:15686028

  12. A new conceptual framework for water and sediment connectivity

    NASA Astrophysics Data System (ADS)

    Keesstra, Saskia; Cerdà, Artemi; Parsons, Tony; Nunes, Joao Pedro; Saco, Patricia

    2016-04-01

    For many years scientists have tried to understand, describe and quantify sediment transport on multiple scales; from the geomorphological work triggered by a single thunderstorm to the geological time scale land scape evolution, and from particles and soil aggregates up to the continental scale. In the last two decades, a new concept called connectivity (Baartman et al., 2013; Bracken et al., 2013, 2015; Parsons et al., 2015) has been used by the scientific community to describe the connection between the different scales at which the sediment redistribution research along the watershed are being studied: pedon, slope tram, slope, watersheds, and basins. This concept is seen as a means to describe and quantify the results of processes influencing the transport of sediment on all these scales. Therefore the concept of connectivity and the way scales are used in the design of a measurement and monitoring scheme are interconnected (Cerdà et al., 2012), which shows that connectivity is not only a tool for process understanding, but also a tool to measure processes on multiple scales. This research aims to describe catchment system dynamics from a connectivity point of view. This conceptual framework can be helpful to look at catchment systems and synthesize which data are necessary to take into account when measuring or modelling water and sediment transfer in catchment systems, Identifying common patterns and generalities will help discover physical reasons for differences in responses and interaction between these processes. We describe a conceptual framework which is meant to bring a better understanding of the system dynamics of a catchment in terms of water and sediment transfer by breaking apart the system dynamics in stocks (the system state at a given moment) and flows (the system fluxes). Breaking apart the internal system dynamics that determine the behaviour of the catchment system is in our opinion a way to bring a better insight into the concepts of

  13. 30 CFR 77.216-4 - Water, sediment or slurry impoundments and impounding structures; reporting requirements...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Water, sediment or slurry impoundments and....216-4 Water, sediment or slurry impoundments and impounding structures; reporting requirements... of the initial plan approval, the person owning, operating, or controlling a water, sediment,...

  14. 30 CFR 77.216-4 - Water, sediment or slurry impoundments and impounding structures; reporting requirements...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Water, sediment or slurry impoundments and....216-4 Water, sediment or slurry impoundments and impounding structures; reporting requirements... of the initial plan approval, the person owning, operating, or controlling a water, sediment,...

  15. 30 CFR 77.216 - Water, sediment, or slurry impoundments and impounding structures; general.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Water, sediment, or slurry impoundments and... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216 Water, sediment, or slurry... structures which impound water, sediment, or slurry shall be required if such an existing or...

  16. 30 CFR 77.216 - Water, sediment, or slurry impoundments and impounding structures; general.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Water, sediment, or slurry impoundments and... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216 Water, sediment, or slurry... structures which impound water, sediment, or slurry shall be required if such an existing or...

  17. 30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Water, sediment, or slurry impoundments and... COAL MINES Surface Installations § 77.216-3 Water, sediment, or slurry impoundments and impounding structures; inspection requirements; correction of hazards; program requirements. (a) All water, sediment,...

  18. 30 CFR 77.216 - Water, sediment, or slurry impoundments and impounding structures; general.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Water, sediment, or slurry impoundments and... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216 Water, sediment, or slurry... structures which impound water, sediment, or slurry shall be required if such an existing or...

  19. 30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Water, sediment, or slurry impoundments and... COAL MINES Surface Installations § 77.216-3 Water, sediment, or slurry impoundments and impounding structures; inspection requirements; correction of hazards; program requirements. (a) All water, sediment,...

  20. 30 CFR 77.216 - Water, sediment, or slurry impoundments and impounding structures; general.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Water, sediment, or slurry impoundments and... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216 Water, sediment, or slurry... structures which impound water, sediment, or slurry shall be required if such an existing or...

  1. 30 CFR 77.216 - Water, sediment, or slurry impoundments and impounding structures; general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Water, sediment, or slurry impoundments and... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216 Water, sediment, or slurry... structures which impound water, sediment, or slurry shall be required if such an existing or...

  2. 30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Water, sediment, or slurry impoundments and... COAL MINES Surface Installations § 77.216-3 Water, sediment, or slurry impoundments and impounding structures; inspection requirements; correction of hazards; program requirements. (a) All water, sediment,...

  3. 30 CFR 77.216-4 - Water, sediment or slurry impoundments and impounding structures; reporting requirements...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Water, sediment or slurry impoundments and....216-4 Water, sediment or slurry impoundments and impounding structures; reporting requirements... of the initial plan approval, the person owning, operating, or controlling a water, sediment,...

  4. 30 CFR 77.216-4 - Water, sediment or slurry impoundments and impounding structures; reporting requirements...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Water, sediment or slurry impoundments and....216-4 Water, sediment or slurry impoundments and impounding structures; reporting requirements... of the initial plan approval, the person owning, operating, or controlling a water, sediment,...

  5. 30 CFR 77.216-4 - Water, sediment or slurry impoundments and impounding structures; reporting requirements...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Water, sediment or slurry impoundments and....216-4 Water, sediment or slurry impoundments and impounding structures; reporting requirements... of the initial plan approval, the person owning, operating, or controlling a water, sediment,...

  6. 30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Water, sediment, or slurry impoundments and... COAL MINES Surface Installations § 77.216-3 Water, sediment, or slurry impoundments and impounding structures; inspection requirements; correction of hazards; program requirements. (a) All water, sediment,...

  7. Remote Sensing of Suspended Sediments and Shallow Coastal Waters

    NASA Technical Reports Server (NTRS)

    Li, Rong-Rong; Kaufman, Yoram J.; Gao, Bo-Cai; Davis, Curtiss O.

    2002-01-01

    Ocean color sensors were designed mainly for remote sensing of chlorophyll concentrations over the clear open oceanic areas (case 1 water) using channels between 0.4 and 0.86 micrometers. The Moderate Resolution Imaging Spectroradiometer (MODIS) launched on the NASA Terra and Aqua Spacecrafts is equipped with narrow channels located within a wider wavelength range between 0.4 and 2.5 micrometers for a variety of remote sensing applications. The wide spectral range can provide improved capabilities for remote sensing of the more complex and turbid coastal waters (case 2 water) and for improved atmospheric corrections for Ocean scenes. In this article, we describe an empirical algorithm that uses this wide spectral range to identifying areas with suspended sediments in turbid waters and shallow waters with bottom reflections. The algorithm takes advantage of the strong water absorption at wavelengths longer than 1 micrometer that does not allow illumination of sediments in the water or a shallow ocean floor. MODIS data acquired over the east coast of China, west coast of Africa, Arabian Sea, Mississippi Delta, and west coast of Florida are used in this study.

  8. Influence of colloids on sediment-water partition coefficients of polychlorobiphenyl congeners in natural waters

    SciTech Connect

    Baker, J.E.; Capel, P.D.; Eisenreich, S.J.

    1986-11-01

    Measurements of sediment-water partitioning of polychlorobiphenyl (PCB) congeners in Lake Superior provide some of the first field evidence demonstrating the importance of colloids to the fates of highly hydrophobic organic pollutants. Laboratory-derived correlations between sediment-water distribution coefficients and properties of both the contaminant (octanol-water partition coefficient) and the suspended solids (organic carbon content, concentration) do not accurately predict PCB speciation in Lake Superior. This failure can be explained by the presence of colloidal matter with which contaminants may associate and the very low solids concentrations in oligotrophic surface waters. A surprising consequence of such colloid associations is that the observed sediment-water distribution coefficients are independent of properties of highly hydrophobic compounds. A three-phase model including nonfilterable microparticles and macromolecular organic matter shows that colloidal-associated contaminants may be the dominant species in most surface waters. Colloidal associations are therefore likely to significantly impact the geochemistry of hydrophobic pollutants.

  9. 14 CFR 1260.34 - Clean air and water.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Clean air and water. 1260.34 Section 1260... AGREEMENTS General Provisions § 1260.34 Clean air and water. Clean Air and Water October 2000 (Applicable... the Clean Air Act (42 U.S.C. 1857c-8(c)(1) or the Federal Water Pollution Control Act (33 U.S.C....

  10. 14 CFR 1260.34 - Clean air and water.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Clean air and water. 1260.34 Section 1260... AGREEMENTS General Provisions § 1260.34 Clean air and water. Clean Air and Water October 2000 (Applicable... the Clean Air Act (42 U.S.C. 1857c-8(c)(1) or the Federal Water Pollution Control Act (33 U.S.C....

  11. 14 CFR 1260.34 - Clean air and water.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Clean air and water. 1260.34 Section 1260... AGREEMENTS General Provisions § 1260.34 Clean air and water. Clean Air and Water October 2000 (Applicable... the Clean Air Act (42 U.S.C. 1857c-8(c)(1) or the Federal Water Pollution Control Act (33 U.S.C....

  12. 14 CFR § 1260.34 - Clean air and water.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Clean air and water. § 1260.34 Section Â... AGREEMENTS General Provisions § 1260.34 Clean air and water. Clean Air and Water October 2000 (Applicable... the Clean Air Act (42 U.S.C. 1857c-8(c)(1) or the Federal Water Pollution Control Act (33 U.S.C....

  13. Report on water quality, sediment and water chemistry data for water and sediment samples collected from source areas to Melton Hill and Watts Bar reservoirs

    SciTech Connect

    Tomaszewski, T.M.; Bruggink, D.J.; Nunn, D.L.

    1995-08-18

    Contamination of surface water and sediments in the Clinch River and Watts Bar Reservoir (CR/WBR) system as a result of past and present activities by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR) and also activities by non-ORR facilities are being studied by the Clinch River Environmental Restoration Program (CR-ERP). Previous studies have documented the presence of heavy metals, organics, and radionuclides in the sediments of reservoirs in the vicinity. In support of the CR-ERP, during the summer of 1991, TVA collected and evaluated water and sediment samples from swimming areas and municipal water intakes on Watts Bar Reservoir, Melton Hill Reservoir and Norris Reservoir, which was considered a source of less-contaminated reference or background data. Despite the numerous studies, until the current work documented by this report, relatively few sediment or water samples had been collected by the CR-ERP in the immediate vicinity of contaminant point sources. This work focused on water and sediment samples taken from points immediately downstream from suspected effluent point sources both on and off the ORR. In August and September, 1994, TVA sampled surface water and sediment at twelve locations in melton Hill and Watts Bar Reservoirs.

  14. Agriculture as a source of Aeolian sediment affecting air quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aeolian processes on agricultural lands have been examined for the past several decades on nearly every continent and has led to a better understanding of detachment, entrainment, transport, and deposition. Relatively little is known concerning the effect of these processes on air quality. In fact, ...

  15. Can control of soil erosion mitigate water pollution by sediments?

    PubMed

    Rickson, R J

    2014-01-15

    The detrimental impact of sediment and associated pollutants on water quality is widely acknowledged, with many watercourses in the UK failing to meet the standard of 'good ecological status'. Catchment sediment budgets show that hill slope erosion processes can be significant sources of waterborne sediment, with rates of erosion likely to increase given predicted future weather patterns. However, linking on-site erosion rates with off-site impacts is complicated because of the limited data on soil erosion rates in the UK and the dynamic nature of the source-pathway-receptor continuum over space and time. Even so, soil erosion control measures are designed to reduce sediment production (source) and mobilisation/transport (pathway) on hill slopes, with consequent mitigation of pollution incidents in watercourses (receptors). The purpose of this paper is to review the scientific evidence of the effectiveness of erosion control measures used in the UK to reduce sediment loads of hill slope origin in watercourses. Although over 73 soil erosion mitigation measures have been identified from the literature, empirical data on erosion control effectiveness are limited. Baseline comparisons for the 18 measures where data do exist reveal erosion control effectiveness is highly variable over time and between study locations. Given the limitations of the evidence base in terms of geographical coverage and duration of monitoring, performance of the different measures cannot be extrapolated to other areas. This uncertainty in effectiveness has implications for implementing erosion/sediment risk reduction policies, where quantified targets are stipulated, as is the case in the EU Freshwater Fish and draft Soil Framework Directives. Also, demonstrating technical effectiveness of erosion control measures alone will not encourage uptake by land managers: quantifying the costs and benefits of adopting erosion mitigation is equally important, but these are uncertain and difficult to

  16. Extraction of tricyclazole from soil and sediment with subcritical water.

    PubMed

    Krieger, M S; Cook, W L; Kennard, L M

    2000-06-01

    The use of subcritical water to extract tricyclazole from soils and sediments was examined. Extraction efficiency and kinetics were determined as a function of temperature, sample age, sample matrix, sample size, and flow rate. Extraction temperature was the most influential experimental factor affecting extraction efficiency and kinetics, with increasing temperature (up to 150 degrees C) yielding faster and higher efficiency extractions. Higher extraction temperatures were also important for quantitative recovery of tricyclazole from aged samples. Extraction at 50 degrees C yielded 97% recoveries from samples aged 1 day but only 30% recoveries for samples aged 202 days, whereas extraction at 150 degrees C yielded recoveries of 85-100% that were independent of incubation time and sample matrix, with the exception of one sediment that contained a large amount of organic matter. Sample extracts from subcritical water extraction were generally a pale yellow color, contrasted with a dark brown color from organic solvent extractions of the same matrixes. Less sample cleanup was therefore required prior to analysis, with the total time for the extraction and analysis of a single sample being approximately 2 h. Subcritical water extraction is an effective technique for the rapid and quantitative extraction of tricyclazole from soils and sediments. PMID:10888518

  17. A sediment resuspension and water quality model of Lake Okeechobee

    USGS Publications Warehouse

    James, R.T.; Martin, J.; Wool, T.; Wang, P.-F.

    1997-01-01

    The influence of sediment resuspension on the water quality of shallow lakes is well documented. However, a search of the literature reveals no deterministic mass-balance eutrophication models that explicitly include resuspension. We modified the Lake Okeeehobee water quality model - which uses the Water Analysis Simulation Package (WASP) to simulate algal dynamics and phosphorus, nitrogen, and oxygen cycles - to include inorganic suspended solids and algorithms that: (1) define changes in depth with changes in volume; (2) compute sediment resuspension based on bottom shear stress; (3) compute partition coefficients for ammonia and ortho-phosphorus to solids; and (4) relate light attenuation to solids concentrations. The model calibration and validation were successful with the exception of dissolved inorganic nitrogen species which did not correspond well to observed data in the validation phase. This could be attributed to an inaccurate formulation of algal nitrogen preference and/or the absence of nitrogen fixation in the model. The model correctly predicted that the lake is lightlimited from resuspended solids, and algae are primarily nitrogen limited. The model simulation suggested that biological fluxes greatly exceed external loads of dissolved nutrients; and sedimentwater interactions of organic nitrogen and phosphorus far exceed external loads. A sensitivity analysis demonstrated that parameters affecting resuspension, settling, sediment nutrient and solids concentrations, mineralization, algal productivity, and algal stoichiometry are factors requiring further study to improve our understanding of the Lake Okeechobee ecosystem.

  18. Numerical Simulation of Sediment-Associated Water Quality Processes for a Mississippi Delta Lake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three major sediment-associated processes were presented to describe the effects of sediment on lake water quality processes: the effect of suspended sediment on the light intensity for the growth of phytoplankton (PHYTO), the adsorption–desorption of nutrients by sediment, and the release of nutrie...

  19. High resolution microprofiling, fractionation and speciation at sediment water interfaces

    NASA Astrophysics Data System (ADS)

    Fabricius, Anne-Lena; Duester, Lars; Ecker, Dennis; Ternes, Thomas A.

    2016-04-01

    Within aquatic environments, the exchange between the sediment and the overlaying water is often driven by steep gradients of, e.g., the oxygen concentration, the redox potential or the pH value at the sediment water interface (SWI). Important transport processes at the SWI are sedimentation and resuspension of particulate matter and diffusional fluxes of dissolved substances. To gain a better understanding of the key factors and processes determining the fate of substances at the SWI, methods with a spatial high resolution are required that enable the investigation of several sediment parameters in parallel to different analytes of interest in the sediment pore water. Moreover, beside the total content, questions concerning the speciation and fractionation are of concern in studying the different (transport) processes. Due to the availability of numerous micro-sensors and -electrodes (e.g., O2, redox potential, pH value, H2S, N2O) and the development of methods for pore water sampling [1], the toolbox to study the heterogeneous and often dynamic conditions at the SWI at a sub-millimetre scale were considerably improved. Nevertheless, the methods available for pore water sampling often require the installation of the sampling devices at the sampling site and/or intensive preparation procedures that may influence the conditions at the area studied and/or the characteristics of the samples taken. By combination of a micro profiling system with a new micro filtration probe head connected to a pump and a fraction collector, a micro profiling and micro sampling system ("missy") was developed that enables for the first time a direct, automate and low invasive sampling of small volumes (<500 μL) at a spatial high resolution of a few millimetres to sub-millimetres [2]. Via the application of different sample preparation procedures followed by inductively plasma-mass spectrometry analyses, it was possible to address not only the total content of metal(loid)s, but also

  20. Photodetoxification and purification of water and air

    SciTech Connect

    Anderson, M.; Blake, D.M.

    1996-09-01

    The scope of interest in this section is basic research in photochemistry that can remove barriers to the development of photochemical technologies for the removal of hazardous chemicals from contaminated air or water (photodetoxification). Photochemistry is be broadly interpreted to include direct photochemistry, indirect photochemistry (sensitized and photocatalytic), photochemistry of species adsorbed on inert surfaces, and complementary effects of high energy radiation photons and particles. These may occur in either homogeneous or heterogeneous media. The photon source may span the range from ionizing radiation to the near infrared.

  1. Stable Encapsulated Air Nanobubbles in Water.

    PubMed

    Wang, Yu; Liu, Guojun; Hu, Heng; Li, Terry Yantian; Johri, Amer M; Li, Xiaoyu; Wang, Jian

    2015-11-23

    The dispersion into water of nanocapsules bearing a highly hydrophobic fluorinated internal lining yielded encapsulated air nanobubbles. These bubbles, like their micrometer-sized counterparts (microbubbles), effectively reflected ultrasound. More importantly, the nanobubbles survived under ultrasonication 100-times longer than a commercial microbubble sample that is currently in clinical use. We justify this unprecedented stability theoretically. These nanobubbles, owing to their small size and potential ability to permeate the capillary networks of tissues, may expand the applications of microbubbles in diagnostic ultrasonography and find new applications in ultrasound-regulated drug delivery. PMID:26439669

  2. Removal of sediment and bacteria from water using green chemistry.

    PubMed

    Buttice, Audrey L; Stroot, Joyce M; Lim, Daniel V; Stroot, Peter G; Alcantar, Norma A

    2010-05-01

    Although nearly all newly derived water purification methods have improved the water quality in developing countries, few have been accepted and maintained for long-term use. Field studies indicate that the most beneficial methods use indigenous resources, as they are both accessible and accepted by communities they help. In an effort to implement a material that will meet community needs, two fractions of mucilage gum were extracted from the Opuntia ficus-indica cactus and tested as flocculation agents against sediment and bacterial contamination. As diatomic ions are known to affect both mucilage and promote cell aggregation, CaCl(2) was studied in conjunction and compared with mucilage as a bacteria removal method. To evaluate performance, ion-rich waters that mimic natural water bodies were prepared. Column tests containing suspensions of the sediment kaolin exhibited particle flocculation and settling rates up to 13.2 cm/min with mucilage versus control settling rates of 0.5 cm/min. Bacillus cereus tests displayed flocculation and improved settling times with mucilage concentrations lower than 5 ppm and removal rates between 97 and 98% were observed for high bacteria concentration tests (>10(8) cells/ml). This natural material not only displays water purification abilities, but it is also affordable, renewable and readily available. PMID:20369814

  3. NBC detection in air and water

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T.; Smith, Steven J.; McMurtry, Gary M.

    2003-01-01

    Participating in a Navy STTR project to develop a system capable of the 'real-time' detection and quanitification of nuclear, biological and chemical (NBC) warfare agents, and of related industrial chemicals including NBC agent synthesis by-products in water and in air immediately above the water's surface. This project uses JPL's Soft Ionization Membrane (SIM) technology which totally ionizes molecules without fragmentation (a process that can markedly improve the sensitivity and specificity of molecule compostition identification), and JPL's Rotating Field Mass Spectrometer (RFMS) technology which has large enough dynamic mass range to enable detection of nuclear materials as well as biological and chemical agents. This Navy project integrates these JPL Environmental Monitoring UnitS (REMUS) an autonomous underwater vehicle (AUV). It is anticipated that the REMUS AUV will be capable of 'real-time' detection and quantification of NBC warefare agents.

  4. Interaction of Ammonia Gas with Sediments and Pore Water and Induced Uranium Immobilization under Vadose Zone Conditions

    NASA Astrophysics Data System (ADS)

    Zhong, L.; Szecsody, J. E.; Truex, M. J.

    2014-12-01

    Preliminary studies have demonstrated the potential of ammonia gas (NH3) treatment on contaminated sediment as a vadose zone uranium remediation approach. In this work, we conducted batch, column, and flow wedge experiments to study the ammonia gas transport and interaction with sediments and pore water. The uranium immobilization effectiveness of the ammonia gas treatment technology was also evaluated. Ammonia gas quickly partitions into sediment pore water and significantly increases the pH (up to ~13.2) and the electrical conductivity (EC). The rate and range of the increase in both pH and EC are dependent on the ammonia concentration in the gas and the pore water content and chemistry. The pH and EC changes follow a similar pattern. During an ammonia gas injection into a heterogeneous system, it was observed that the NH3 front proceeded faster in layers of lower water content compared to the same sediment layers of higher water content. Elevated pH values (11 to 13.2) initially resulted from the NH3 gas partitioning into the pore water was buffered down to ~ 9 after 7 months of sediment exposure to the air. The rate of NH3 diffusion in sediment is a function of the water content in the sediment. Higher cation/anion concentrations during the ammonia gas treatment indicated mineral dissolution due to pH increase, while lower ionic concentrations after the pH buffering revealed significant mineral precipitation. This precipitation incorporates uranium into mineral structures or provides a coating to uranium minerals, therefore achieving uranium immobilization. Treatment with 5% v/v NH3 gas for one week followed by three weeks buffering resulted in a 75% reduction in the mobile uranium mass. After 2 to 12 months of treatment, the immobile phase of uranium mass increased by up to 2.3 times.

  5. 30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., sediment, or slurry impoundment and impounding structure which meets the requirements of 30 CFR 77.216(a... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-5 Water, sediment...

  6. A novel tracer technique for the assessment of fine sediment dynamics in urban water management systems.

    PubMed

    Spencer, K L; Droppo, I G; He, C; Grapentine, L; Exall, K

    2011-04-01

    Urban storm water run off can reduce the quality of receiving waters due to high sediment load and associated sediment-bound contaminants. Consequently, urban water management systems, such as detention ponds, that both modify water quantity through storage and improve water quality through sediment retention are frequently-used best management practices. To manage such systems effectively and to improve their efficiency, there is a need to understand the dynamics (transport and settling) of sediment, and in particular the fine sediment fraction (<63 μm) and its associated contaminants within urban storm water management systems. This can be difficult to achieve, as modelling the transport behaviour of fine-grained and cohesive sediment is problematic and field-based measurements can be costly, time-consuming and unrepresentative. The aim of this study was to test the application of a novel cohesive sediment tracer and to determine fine sediment transport dynamics within a storm water detention pond. The cohesive sediment tracer used was a holmium labelled montmorillonite clay which flocculated and had similar size and settling velocity to the natural pond sediment it was intended to mimic. The tracer demonstrated that fine sediment was deposited across the entire pond, with the presence of reed beds and water depth being important factors for maximising sediment retention. The results of the sediment tracer experiment were in good agreement with those of a mathematical sediment transport model. Here, the deposited sediment tracer was sampled by collecting and analysing surface pond sediments for holmium. However, analysis and sampling of the three dimensional suspended tracer 'cloud' may provide more accurate information regarding internal pond sediment dynamics. PMID:21420140

  7. Survey of the Mutagenicity of Surface Water, Sediments, and Drinking Water from the Penobscot Indian Nation.

    EPA Science Inventory

    Survey of the Mutagenicity of Surface Water, Sediments, andDrinking Water from the Penobscot Indian NationSarah H. Warren, Larry D. Claxton,1, Thomas J. Hughes,*, Adam Swank,Janet Diliberto, Valerie Marshall, Daniel H. Kusnierz, Robert Hillger, David M. DeMariniNational Health a...

  8. Field Evaluation Of Arsenic Speciation In Sediments At The Ground Water/Surface Water Interface

    EPA Science Inventory

    The speciation and mineralogy of sediments contaminated with arsenic at the ground water/surface water interface of the Ft. Devens Super Fund Site in Ft. Devens, MA were determined using X-ray absorption fine structure and X-ray diffraction spectroscopy. Speciation and mineralog...

  9. Remediation of muddy tidal flat sediments using hot air-dried crushed oyster shells.

    PubMed

    Yamamoto, Tamiji; Kondo, Shunsuke; Kim, Kyung-Hoi; Asaoka, Satoshi; Yamamoto, Hironori; Tokuoka, Makoto; Hibino, Tadashi

    2012-11-01

    In order to prove that hot air-dried crushed oyster shells (HACOS) are effective in reducing hydrogen sulfide in muddy tidal flat sediments and increasing the biomass, field experiments were carried out. The concentration of hydrogen sulfide in the interstitial water, which was 16 mg SL(-1) before the application of HACOS, decreased sharply and maintained almost zero in the experimental sites (HACOS application sites) for one year, whereas it was remained at ca. 5 mg SL(-1) in the control sites. The number of macrobenthos individuals increased to 2-4.5 times higher than that in the control site. Using a simple numerical model, the effective periods for suppression of hydrogen sulfide were estimated to be 3.2-7.6 and 6.4-15.2 years for the experimental sites with 4 and 8 tons per 10 × 10 × 0.2m area, respectively. From these results, it is concluded that HACOS is an effective material to remediate muddy tidal flats. PMID:23017947

  10. THE RELATIONSHIP OF BIOACCUMULATIVE CHEMICALS IN WATER AND SEDIMENT TO RESIDUES IN FISH: A VISUALIZATION APPROACH

    EPA Science Inventory

    A visualization approach is developed and presented for depicting and interpreting bioaccumulation relationships and data, i.e., bioaccumulation factors (BAFs), biota-sediment accumulation factors (BSAFs) and chemical residues in fish, using water-sediment chemical concentration ...

  11. 21 CFR 874.1800 - Air or water caloric stimulator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Air or water caloric stimulator. 874.1800 Section 874.1800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1800 Air or water caloric stimulator. (a) Identification. An air or...

  12. 14 CFR 1260.34 - Clean air and water.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Clean air and water. 1260.34 Section 1260.34... Provisions § 1260.34 Clean air and water. Clean Air and Water October 2000 (Applicable only if the award... (42 U.S.C. 1857c-8(c)(1) or the Federal Water Pollution Control Act (33 U.S.C. 1319(c)), and is...

  13. Assessing the fate of dredged sediments placed in open-water sites, Northern Chesapeake Bay

    USGS Publications Warehouse

    Halka, Jeffrey; Panageotou, William; Sanford, Lawrence; Yu-Chou, Shenn

    1994-01-01

    An integrated series of field studies and experiments have been carried out on dredged sediments placed in open water sites in Northern Chesapeake Bay. The studies include: (1) examination of the potential for fluidized sediment flow, (2) quantifying the volumetric changes that the sediments undergo during dredging process and subsequent to deposition, (3) estimating parameters for cohesive sediment erosion models from field data on currents and suspended sediment concentrations, and (4) incorporating the erosion model parameters and sediment transport equation into a 3-D hydrodynamic model for the upper Chesapeake Bay to predict transport directions and setting sites of eroded sediments under a variety of seasonal weather and river flow conditions.

  14. Evaluation of toxicity: Whole-sediment versus overlying-water exposures with amphipod Hyalella azteca

    USGS Publications Warehouse

    Ingersoll, C.G.; Ivey, C.D.; Brunson, E.L.; Hardesty, D.K.; Kemble, N.E.

    2000-01-01

    A laboratory study was conducted to evaluate the toxicity of whole-sediment versus overlying-water exposures to the amphipod Hyalella azteca using field-collected sediments. Severe toxic effects (5-63% survival) were observed with amphipods exposed for 10 d in direct contact with sediment. In contrast, amphipods exposed only to overlying water in these sediment exposures did not exhibit any toxic effects.

  15. Speciation and Fate of Trace Metals in Estuarine Sediments Under Reduced and Oxidized Conditions, Seaplane Lagoon, Alameda Naval Air Station

    SciTech Connect

    Carroll, S A; Day, P A; Esser, B; Randall, S

    2002-10-18

    We have identified important chemical reactions that control the fate of metal-contaminated estuarine sediments if they are left undisturbed (in situ) or if they are dredged. We combined information on the molecular bonding of metals in solids from X-ray absorption spectroscopy (XAS) with thermodynamic and kinetic driving forces obtained from dissolved metal concentrations to deduce the dominant reactions under reduced and oxidized conditions. We evaluated the in situ geochemistry of metals (cadmium, chromium, iron, lead, manganese and zinc) as a function of sediment depth (to 100 cm) from a 60-year record of contamination at the Alameda Naval Air Station, California. Results from XAS and thermodynamic modeling of porewaters show that cadmium and most of the zinc form stable sulfide phases, and that lead and chromium are associated with stable carbonate, phosphate, phyllosilicate, or oxide minerals. Therefore, there is minimal risk associated with the release of these trace metals from the deeper sediments contaminated prior to the Clean Water Act (1975) as long as reducing conditions are maintained. Increased concentrations of dissolved metals with depth were indicative of the formation of metal HS- complexes. The sediments also contain zinc, chromium, and manganese associated with detrital iron-rich phyllosilicates and/or oxides. These phases are recalcitrant at near-neutral pH and do not undergo reductive dissolution within the 60-year depositional history of sediments at this site. The fate of these metals during dredging was evaluated by comparing in situ geochemistry with that of sediments oxidized by seawater in laboratory experiments. Cadmium and zinc pose the greatest hazard from dredging because their sulfides were highly reactive in seawater. However, their dissolved concentrations under oxic conditions were limited eventually by sorption to or co-precipitation with an iron (oxy)hydroxide. About 50% of the reacted CdS and 80% of the reacted ZnS were

  16. Concentrations of Elements in Sediments and Selective Fractions of Sediments, and in Natural Waters in Contact with Sediments from Lake Roosevelt, Washington, September 2004

    USGS Publications Warehouse

    Paulson, Anthony J.; Wagner, Richard J.; Sanzolone, Richard F.; Cox, Steven E.

    2006-01-01

    Twenty-eight composite and replicate sediment samples from 8 Lake Roosevelt sites were collected and analyzed for 10 alkali and alkaline earth elements, 2 non-metals, 20 metals, and 4 lanthanide and actinide elements. All elements were detected in all sediment samples except for silver (95 percent of the elements detected for 1,008 analyses), which was detected only in 4 samples. Sequential selective extraction procedures were performed on single composite samples from the eight sites. The percentage of detections for the 31 elements analyzed ranged from 76 percent for the first extraction fraction using a weak extractant to 93 percent for the four-acid dissolution of the sediments remaining after the third sequential selective extraction. Water samples in various degrees of contact with the sediment were analyzed for 10 alkali and alkaline earth elements, 5 non-metals, 25 metals, and 16 lanthanide and actinide elements. The filtered water samples included 10 samples from the reservoir water column at 8 sites, 32 samples of porewater, 55 samples from reservoir water overlying sediments in 8 cores from the site incubated in a field laboratory, and 24 water samples that were filtered after being tumbled with sediments from 8 sites. Overall, the concentrations of only 37 percent of the 6,776 analyses of the 121 water samples were greater than the reporting limit. Selenium, bismuth, chromium, niobium, silver, and zirconium were not detected in any water samples. The percentage of concentrations for the water samples that were above the reporting limit ranged from 14 percent for the lanthanide and actinide elements to 77 percent for the alkali and alkaline earth elements. Concentrations were greater than reporting limits in only 23 percent of the analyses of reservoir water and 29 percent of the analyses of reservoir water overlying incubation cores. In contrast, 47 and 48 percent of the concentrations of porewater and water samples tumbled with sediments, respectively

  17. Correlation of Dynamic Surface Tension with Sedimentation of PTFE Particles and Water Penetration in Powders.

    PubMed

    Shah, Vidhi; Bharatiya, Bhavesh; Shah, Dinesh O; Mukherjee, Tulsi

    2015-12-29

    The dynamic surface tension of aqueous poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) [(PEO-PPO-PEO)]-type polymeric surfactant (P103, P105, F108, P123, and F127) solutions were correlated with water penetration in packed Teflon powders, the sedimentation of Teflon suspensions in these solutions, foamability, and contact angle measurements on a Teflon surface. The DST trend with bubble lifetime indicated that the overall slowdown in the diffusion process in aqueous solutions is a function of a higher poly(ethylene oxide) (PEO) molecular weight for a given series of block copolymers containing equal PPO molecular weights, favoring slower diffusion kinetics to the air-water interface caused by preferential partitioning in bulk water. The wettability of poly(tetrafluoroethylene) (PTFE) powder illustrates better water penetration for polymers with low molecular weight and lower HLB values. The wettability of F127 solutions decreases with corresponding increases in concentration resulting from higher viscosity, which restrains the diffusion kinetics at the PTFE-water interface. The foamability decreases drastically with higher PEO molecular weight as attributed by slower diffusion kinetics, leading to a decrease in the effective concentration of molecules at the foam interface. The contact angle on glass and the PTFE surface are in good agreement with assumptions made by other analytical techniques showing a lower value of the contact angle with a lower HLB of the Pluronic, which relates to the higher adsorption of molecules at the interface. It is concluded that the adsorption of molecules at the PTFE-water interface decreases in aqueous Pluronic solutions with corresponding increases in the hydrophilic lipophilic balance (HLB), which is consistent with foaming, water penetration in a packed powder of PTFE, the rate of sedimentation, and DST data. A PTFE dispersion containing P123 showed the maximum wettability and lowest sedimentation among the series

  18. Laboratory Study of Chemical Speciation of Mercury in Lake Sediment and Water under Aerobic and Anaerobic Conditions

    PubMed Central

    Regnell, Olof; Tunlid, Anders

    1991-01-01

    Chemical speciation and partitioning of radiolabeled HgCl2 were studied in model aquatic systems consisting of undisturbed eutrophic lake sediment and water in plastic cylinders. The cylinders were either gradually made anaerobic by a gentle flow of N2-CO2 or kept aerobic by air flow. The proportion of methylated 203Hg was significantly higher, in both water and sediment, in the anaerobic systems than in the aerobic systems. The composition and total concentration of fatty acids originating from bacterial phospholipids, as well as the concentration of vitamin B12, including related cobalamins, were similar in sediments from the anaerobic and aerobic systems. Bacterial cell numbers were, on average, 3.6 times higher in the anaerobic water columns than in the aerobic ones. Volatilization of 203Hg occurred in all systems except in an autoclaved control and was of similar magnitudes in the anaerobic and aerobic systems. Incorporation of 203Hg into the sediment was significantly faster in the aerobic systems than in the anaerobic systems. These results suggest that episodes of anoxia in bottom waters and sediment cause an increase in net mercury methylation and, hence, an increase in bioavailable mercury. PMID:16348444

  19. Food-Growing, Air- And Water-Cleaning Module

    NASA Technical Reports Server (NTRS)

    Sauer, R. L.; Scheld, H. W.; Mafnuson, J. W.

    1988-01-01

    Apparatus produces fresh vegetables and removes pollutants from air. Hydroponic apparatus performs dual function of growing fresh vegetables and purifying air and water. Leafy vegetables rooted in granular growth medium grow in light of fluorescent lamps. Air flowing over leaves supplies carbon dioxide and receives fresh oxygen from them. Adaptable to production of food and cleaning of air and water in closed environments as in underwater research stations and submarines.

  20. Summary report on water quality, sediment and water chemistry data for water and sediment samples collected from source areas to Melton Hill and Watts Bar reservoirs

    SciTech Connect

    Tomaszewski, T.M.; Bruggink, D.J.; Nunn, D.L.

    1995-08-01

    Contamination of surface water and sediments in the Clinch River and Watts Bar Reservoir (CR/WBR) system as a result of past and present activities by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR) and also activities by non-ORR facilities are being studied by the Clinch River Environmental Restoration Program (CR-ERP). Previous studies have documented the presence of heavy metals, organics, and radionuclides in the sediments of reservoirs in the vicinity. In support of the CR-ERP, during the summer of 1991, TVA collected and evaluated water and sediment samples from swimming areas and municipal water intakes on Watts Bar Reservoir, Melton Hill Reservoir (which is considered part of the Clinch River and Watts Bar Reservoir System), and Norris Reservoir, which was considered a source of less-contaminated reference or background data. Results of this study indicated that the levels of contamination in the samples from the Watts Bar and Melton Hill Reservoir sites did not pose a threat to human health. Despite the numerous studies, until the current work documented by this report, relatively few sediment or water samples had been collected by the CR-ERP in the immediate vicinity of contaminant point sources. This work focused on water and sediment samples taken from points immediately downstream from suspected effluent point sources both on and off the ORR. In August and September, 1994, TVA sampled surface water and sediment at twelve locations in Melton Hill and Watts Bar Reservoirs. Eleven of the sampling sites were selected based on existence of pollutant discharge permits, known locations of hazardous waste sites, and knowledge of past practices. The twelfth sample site was selected as a relatively less contaminated reference site for comparison purposes.

  1. Revisiting Atmospheric Lead in NYC - Comparison of Archived Air Filters to Urban Park Sediments and Soils

    NASA Astrophysics Data System (ADS)

    Chillrud, S. N.; Ross, J. M.; Yan, B.; Bopp, R.

    2015-12-01

    Urban lake sediments have the potential to be used for reconstructing history of aerosols, providing data before the start of urban air quality monitoring. In a previous study, the similarity between radionuclide and excess Pb inventories (57 g/m^2) in Central Park Lake (CPL) sediments and those same parameters in Central Park soils (CPS) was interpreted to indicate that urban lake sediment cores from CPL represent deposition of atmospheric aerosols over the history of the park, which was constructed in the 1860s. Furthermore, metal ratios and metal chronologies indicated that incineration was the major source of Pb to the NYC atmosphere over the 20th century. In this report, we compare the lake chronologies for metals to a set of archived air filters collected by the Department of Energy's Environmental Measurement Lab (EML). These weekly filters of total suspended particulates (TSP) were collected by a high volume sampler located in lower Manhattan for radionuclides as part of the program focused on documenting radioactive fallout from nuclear weapons testing. Metal concentrations measured in subsamples of the EML filters collected between the 1970s to 1990s showed Pb decreasing more slowly than the records of Pb added to gasoline. Metal ratios in the filters were similar to the ratios measured in CPL sediments; the Pb to Sn ratios were roughly 20:1 and the Pb to Zn ratios were in close to 1. The similarity of the ratios provides additional solid support that the CP Lake sediment cores reflect atmospheric inputs. The enrichment of Pb in the large aerosol particle fraction (TSP), relative to fine PM2.5 fraction, demonstrates that the resuspended NYC soils and their historical contaminant burden, are the primary, current source of Pb to NYC air.

  2. Investigation of the mechanism of contaminant release through the sediment-overlying water interface

    NASA Astrophysics Data System (ADS)

    Guo, Jia-Hong; Zheng, Shu-Jun; Wang, Dao-Zeng; Environment Fluid Dynamics Collaboration

    2013-11-01

    After the external pollutant discharge has been reduced, the release of the contaminant from the sediment to the overlying water may cause the river and lake be contaminated again. On the condition that the overlying water flow does not lead to sediment suspension, numerical and experimental researches are carried out for the contaminant release mechanism through the sediment-overlying water interface. In the numerical simulation, the overlying water flow is calculated as turbulent flow. The sediment is regarded as isotropic homogeneous porous medium, therefore the seepage field in the porous sediment layer is obtained by solving Darcy's equations. Several coupled two dimensional steady and unsteady flows of the overlying water and the pore water in the sediment are calculated. Based on the flow fields obtained, the unsteady contaminant solute transportation process in the sediment and the overlying water is numerically simulated, as the shapes of the sediment-overlying water interface are flat or periodic triangular respectively. The numerical results agree with the experimental results quite well. The results show that the exchange of the pore water and the overlying water is an important factor which decides the release flux of the contaminant from the sediment to the overlying water. Project supported by the National Natural Science Foundation of China (Grant No. 11032007) and Shanghai Program for Innovative Research Team in Universities.

  3. Long Series Multi-objectives Optimal Operation of Water And Sediment Regulation

    NASA Astrophysics Data System (ADS)

    Bai, T.; Jin, W.

    2015-12-01

    Secondary suspended river in Inner Mongolia reaches have formed and the security of reach and ecological health of the river are threatened. Therefore, researches on water-sediment regulation by cascade reservoirs are urgent and necessary. Under this emergency background, multi-objectives water and sediment regulation are studied in this paper. Firstly, multi-objective optimal operation models of Longyangxia and Liujiaxia cascade reservoirs are established. Secondly, based on constraints handling and feasible search space techniques, the Non-dominated Sorting Genetic Algorithm (NSGA-II) is greatly improved to solve the model. Thirdly, four different scenarios are set. It is demonstrated that: (1) scatter diagrams of perato front are obtained to show optimal solutions of power generation maximization, sediment maximization and the global equilibrium solutions between the two; (2) the potentiality of water-sediment regulation by Longyangxia and Liujiaxia cascade reservoirs are analyzed; (3) with the increasing water supply in future, conflict between water supply and water-sediment regulation occurred, and the sustainability of water and sediment regulation will confront with negative influences for decreasing transferable water in cascade reservoirs; (4) the transfer project has less benefit for water-sediment regulation. The research results have an important practical significance and application on water-sediment regulation by cascade reservoirs in the Upper Yellow River, to construct water and sediment control system in the whole Yellow River basin.

  4. Metabolism of niclosamide in sediment and water systems

    USGS Publications Warehouse

    Graebing, P.W.; Chib, J.S.; Hubert, T.D.; Gingerich, W.H.

    2004-01-01

    A series of experiments analyzed the kinetics and mechanisms of [ 14C]niclosamide degradation. The aerobic aquatic metabolism of [ 14C]niclosamide was studied in nonsterile river water/sediment mixtures. Test systems, maintained under aerobic conditions, were treated with niclosamide and incubated in the dark at 25.0 ?? 1.0 ??C for 30 days. Half-lives of 4.9 and 5.4 days were calculated for the chlorosalicylic acid- and chloronitroaniline-labeled test systems, respectively. From 0 to 21 days after treatment (DAT), the only metabolism product observed in either test system was aminoniclosamide. At the final sampling interval, five peaks were resolved from the chlorosalicylic acid label, and three peaks were resolved from the chloronitroaniline label test substance. By 30 DAT, sediment-bound residues represented ???70% of the observed radioactivity. For the anaerobic aquatic metabolism of [14C]niclosamide, test systems were incubated under anaerobic conditions for 365 days. Half-lives of 0.65 day for the chlorosalicylic acid label and 2.79 days for the chloronitroaniline label were calculated. From 0 to 3 DAT, niclosamide was first transformed into aminoniclosamide. Aminoniclosamide is readily formed, as it was observed in the chlorosalicylic acid label 0 DAT sampling. Several minor metabolites were observed in the water and sediment extracts. None of these metabolites were formed to a significant amount until the parent niclosamide dissipated below the detection limit. Two of the byproducts from these metabolism studies are polar unknowns eluting at 3 and 5 min by HPLC, similar to the unknowns observed in aqueous photolysis studies.

  5. 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

  6. Isolation of enteroviruses from water, suspended solids, and sediments from Galveston Bay: survival of poliovirus and rotavirus adsorbed to sediments.

    PubMed Central

    Rao, V C; Seidel, K M; Goyal, S M; Metcalf, T G; Melnick, J L

    1984-01-01

    The distribution and quantitation of enteroviruses among water, suspended solids, and compact sediments in a polluted estuary are described. Samples were collected sequentially from water, suspended solids, fluffy sediments (uppermost layer of bottom sediments), and compact sediment. A total of 103 samples were examined of which 27 (26%) were positive for virus. Polioviruses were recovered most often, followed by coxsackie B viruses and echoviruses 7 and 29. Virus was found most often attached to suspended solids: 72% of these samples were positive, whereas only 14% of water samples without solids yielded virus. Fluffy sediments yielded virus in 47% of the samples, whereas only 5% of compact bottom-sediment samples were positive. When associated with solids, poliovirus and rotavirus retained their infectious quality for 19 days. The same viruses remained infectious for only 9 days when freely suspended in seawater. Collection of suspended solids at ambient water pH appears to be very useful for the detection of virus; it has advantages over collecting and processing large volumes of water, with accompanying pH adjustment and salt addition for processing. PMID:6091548

  7. Radioactive dating: Studies on ground water and sediments. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1994-10-01

    The bibliography contains citations concerning radioactive dating of ground water and sediments. Articles discuss ground water movement and recharge; and lake, marine, and glacial sediments. Citations address dating techniques using isotopes of carbon, lead, uranium, radium, and tritium. Studies on sedimentation rate, water quality, aquifer characteristics, geological survey, and glacial history are presented. (Contains a minimum of 103 citations and includes a subject term index and title list.)

  8. Microplastics in coastal sediments from Southern Portuguese shelf waters.

    PubMed

    Frias, J P G L; Gago, J; Otero, V; Sobral, P

    2016-03-01

    Microplastics are well-documented pollutants in the marine environment that result from fragmentation of larger plastic items. Due to their long chemical chains, they can remain in the environment for long periods of time. It is estimated that the vast majority (80%) of marine litter derives from land sources and that 70% will sink and remain at the bottom of the ocean. Microplastics that result from fragmentation of larger pieces of plastic are common to be found in beaches and in the water surface. The most common microplastics are pellets, fragments and fibres. This work provides original data of the presence of microplastics in coastal sediments from Southern Portuguese shelf waters, reporting on microplastic concentration and polymer types. Microplastic particles were found in nearly 56% of sediment samples, accounting a total of 31 particles in 27 samples. The vast majority were microfibers (25), identified as rayon fibres, and fragments (6) identified as polypropylene, through infrared spectroscopy (μ-FTIR). The concentration and polymer type data is consistent with other relevant studies and reports worldwide. PMID:26748246

  9. Underwater MASW to evaluate stiffness of water-bottom sediments

    USGS Publications Warehouse

    Park, C.B.; Miller, R.D.; Xia, J.; Ivanov, J.; Sonnichsen, G.V.; Hunter, J.A.; Good, R.L.; Burns, R.A.; Christian, H.

    2005-01-01

    The multichannel analysis of surface waves (MASW) is initially intended as a land survey method to investigate the near-surface materials for their elastic properties. The acquired data are first analyzed for dispersion characteristics and, from these the shear-wave velocity is estimated using an inversion technique. Land applications show the potential of the MASW method to map 2D bedrock surface, zones of low strength, Poisson's ratio, voids, as well as to generate shear-wave profiles for various othe geotechnical problems. An overview is given of several underwater applications of the MASW method to characterize stiffness distribution of water-bottom sediments. The first application details the survey under shallow-water (1-6 m) in the Fraser River (Canada). The second application is an innovative experimental marine seismic survey in the North Atlantic Ocean near oil fields in Grand Bank offshore Newfoundland.

  10. Methylglyoxal at the Air-Water Interface

    NASA Astrophysics Data System (ADS)

    Wren, S. N.; Gordon, B. P.; McWilliams, L.; Valley, N. A.; Richmond, G.

    2014-12-01

    Recently, it has been suggested that aqueous-phase processing of atmospheric α-dicarbonyl compounds such as methylglyoxal (MG) could constitute an important source of secondary organic aerosol (SOA). The uptake of MG to aqueous particles is higher than expected due to the fact that its carbonyl moieties can hydrate to form diols, as well as the fact that MG can undergo aldol condensation reactions to form larger oligomers in solution. MG is known to be surface active but an improved description of its surface behaviour is crucial to understanding MG-SOA formation, in addition to understanding its gas-to-particle partitioning and cloud forming potential. Here, we employ a combined experimental and theoretical approach involving vibrational sum frequency generation spectroscopy (VSFS), surface tensiometry, molecular dynamics simulations, and density functional theory calculations to study MG's surface adsorption, in both the presence and absence of salts. We are particularly interested in determining MG's hydration state at the surface. Our experimental results indicate that MG slowly adsorbs to the air-water interface and strongly perturbs the water structure there. This perturbation is enhanced in the presence of NaCl. Together our experimental and theoretical results suggest that singly-hydrated MG is the dominant form of MG at the surface.

  11. Hexachlorobenzene uptake by fathead minnows and macroinvertebrates in recirculating sediment/water systems

    SciTech Connect

    Schuytema, G.S.; Krawczyk, D.F.; Griffis, W.L.; Nebeker, A.V.; Robideaux, M.L.

    1990-01-01

    Fathead minnow (Pimephales promelas), the worm, Lumbriculus variegatus, and the amphipods Hyalella azteca and Gammarus lacustris were exposed to hexachlorobenzene (HCB) in water with and without a bed of HCB-spiked sediment. Water HCB concentrations were maintained by recirculation through HCB-packed columns. Recirculating HCB-bound particulates and possibly eroded HCB particulates were an added source of HCB in addition to the sediment bed. Significant bioaccumulation of HCB in animal tissues was observed in water-only and water-sediment exposures. The presence of the HCB-spiked sediment did not result in a significant increase in the uptake of HCB by the organisms, but there was a substantial increase in sediment HCB levels over time. Higher tissue HCB levels in aquaria without sediment suggest that the sediment was a more efficient sink for HCB than the organisms.

  12. 30 CFR 77.216-1 - Water, sediment or slurry impoundments and impounding structures; identification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-1 Water, sediment or..., operating, or controlling the structure, shall be located on or immediately adjacent to each water,...

  13. 30 CFR 77.216-1 - Water, sediment or slurry impoundments and impounding structures; identification.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-1 Water, sediment or..., operating, or controlling the structure, shall be located on or immediately adjacent to each water,...

  14. 30 CFR 77.216-1 - Water, sediment or slurry impoundments and impounding structures; identification.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-1 Water, sediment or..., operating, or controlling the structure, shall be located on or immediately adjacent to each water,...

  15. 30 CFR 77.216-1 - Water, sediment or slurry impoundments and impounding structures; identification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-1 Water, sediment or..., operating, or controlling the structure, shall be located on or immediately adjacent to each water,...

  16. 30 CFR 77.216-1 - Water, sediment or slurry impoundments and impounding structures; identification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-1 Water, sediment or..., operating, or controlling the structure, shall be located on or immediately adjacent to each water,...

  17. Degradation, Fate and Bioavailability of Sulfamethazine in Pond Water and Sediment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibiotics from animal agriculture are found in surface waters and stream sediments. We investigated the degradation and fate of sulfamethazine in small pond water and sediment microcosms. Sulfamethazine [14C-phenyl] was added to the water phase directly, or in a dilute swine manure solution that s...

  18. Laboratory experiments on dam-break flow of water-sediment mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dams induce sedimentation and store significant amounts of sediment as they age; therefore, dam failures often involve the release of sediment-laden water to the downstream floodplain. In particular, tailings dams, which are constructed to impound mining wastes, can cause devastating damage when the...

  19. STAND, A DYNAMIC MODEL FOR SEDIMENT TRANSPORT AND WATER QUALITY. (R825758)

    EPA Science Inventory

    We introduce a new model–STAND (Sediment-Transport-Associated Nutrient Dynamics)–for simulating stream flow, sediment transport, and the interactions of sediment with other attributes of water quality. In contrast to other models, STAND employs a fully dynamic ba...

  20. Discharge, suspended sediment, bedload, and water quality in Clear Creek, western Nevada, water years 2010-12

    USGS Publications Warehouse

    Huntington, Jena M.; Savard, Charles S.

    2015-01-01

    During this study, total annual sediment loads ranged from 355 tons per year in 2010 to 1,768 tons per year in 2011 and were significantly lower than the previous study (water years 2004–07). Bedload represented between 29 and 38 percent of total sediment load in water years 2010–12, and between 72 and 90 percent of the total sediment load in water years 2004–07, which indicates a decrease in bedload between study periods. Annual suspended-sediment loads in water years 2010–12 indicated no significant change from water years 2004–07. Mean daily discharge was significantly lower in water years 2010–12 than in waters years 2004–07 and may be the reason for the decrease in bedload that resulted in a lower total sediment load.

  1. Resuspension and settling of helminth eggs in water: Interactions with cohesive sediments.

    PubMed

    Sengupta, Mita E; Andersen, Thorbjørn J; Dalsgaard, Anders; Olsen, Annette; Thamsborg, Stig M

    2012-08-01

    Helminth parasite eggs in low quality water represent main food safety and health hazards and are therefore important indicators used to determine whether such water can be used for irrigation. Through sedimentation helminth eggs accumulate in the sediment, however resuspension of deposited helminth eggs will lead to increased concentration of suspended eggs in the water. Our study aimed to determine the erodibility (erosion rate and erosion threshold) and settling velocity of Ascaris and Trichuris eggs as well as cohesive sediment at different time points after incorporation into the sediment. Cohesive sediment collected from a freshwater stream was used to prepare a sediment bed onto which helminth eggs were allowed to settle. The erodibility of both sediment and helminth eggs was found to decrease over time indicating that the eggs were incorporated into the surface material of the bed and that this material was stabilized through time. This interaction between eggs and bulk sediment was further manifested in an increased settling velocity of suspended eggs when sediment was present in the suspension as compared to a situation with settling in clean water. The incorporation into the sediment bed and the aggregation with sediment particles decrease the mobility of both helminth egg types. Our findings document that helminth eggs should not be viewed as single entities in water systems when modelling the distribution of eggs since both erodibility and settling velocity of eggs are determined by mobility of the sediment present in the water stream. Recalculation of the erosion threshold for helminth eggs and sediment showed that even at relatively low current velocities i.e. 0.07-0.12ms(-1) newly deposited eggs will be mobile in open irrigation channels. These environmental factors affecting resuspension must be taken into account when developing models for sedimentation of helminth eggs in different water systems. PMID:22591818

  2. 21 CFR 874.1800 - Air or water caloric stimulator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1800 Air or water caloric... or water to the ear canal at controlled rates of flow and temperature and that is intended...

  3. 21 CFR 874.1800 - Air or water caloric stimulator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1800 Air or water caloric... or water to the ear canal at controlled rates of flow and temperature and that is intended...

  4. 21 CFR 874.1800 - Air or water caloric stimulator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1800 Air or water caloric... or water to the ear canal at controlled rates of flow and temperature and that is intended...

  5. 21 CFR 874.1800 - Air or water caloric stimulator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1800 Air or water caloric... or water to the ear canal at controlled rates of flow and temperature and that is intended...

  6. Evolution of the earth's water mass and sedimentation

    SciTech Connect

    Timofeev, P.P.; Kholodov, V.N.; Zverev, V.P.

    1986-05-01

    The origin of the hydrosphere has been discussed repeatedly. It has become clear that one cannot explain the current mass of water on the earth without invoking the most modern cosmogenic hypotheses, on the one hand, and without reconstructing the processes of metamorphism, granitization, and basalt melting, on the other. As all these problems are still at the stage of scientific hypothesis, any treatment of the change in water volume through geologic time can only be a very crude approximation. Recently, it has become clear that there is a fairly complicated interaction between the different parts of the lithosphere and the ocean water. The formation of water bound in various crustal shells (basalt, granite, and sediment) is summarized. It is concluded that in the remote period (up to 2 billion years ago), shallow lake-type basins were the most abundant, while in the period from 2 billion years to 0.2 billion years, there were extensive shallow intercontinental and epicontinental seas with an average depth of 0.5-2 km; there probably were no oceans resembling modern ones at that time. The modern oceans were effectively formed at the boundary between the Mesozoic and Cenozoic, when the volume of the hydrosphere attained its maximum value, while relief contrast resulted in depressions 5-6 km deep. 15 references.

  7. Remote sensing of water clarity and suspended sediments in coastal waters

    USGS Publications Warehouse

    Stumpf, R.P.

    1992-01-01

    Processing of data for estimation of suspended sediment concentrations and water clarity in turbid coastal water requires three components: (1) correction of raw data to water reflectance; (2) establishment of appropriate general models relating reflectance characteristics to materials in the water; and (3) determination of the coefficients of the models appropriate for the area under study. This paper presents equations and procedures appropriate for this processing. It provides example coefficients and data for the NOAA advanced very high resolution radiometer, which is the most appropriate sensor for investigating larger estuaries and turbid coastal systems until the launch of an ocean color imager (SeaWiFS) in late 1993.

  8. Parameterization of biogeochemical sediment-water fluxes using in situ measurements and a diagenetic model

    NASA Astrophysics Data System (ADS)

    Laurent, A.; Fennel, K.; Wilson, R.; Lehrter, J.; Devereux, R.

    2016-01-01

    Diagenetic processes are important drivers of water column biogeochemistry in coastal areas. For example, sediment oxygen consumption can be a significant contributor to oxygen depletion in hypoxic systems, and sediment-water nutrient fluxes support primary productivity in the overlying water column. Moreover, nonlinearities develop between bottom water conditions and sediment-water fluxes due to loss of oxygen-dependent processes in the sediment as oxygen becomes depleted in bottom waters. Yet, sediment-water fluxes of chemical species are often parameterized crudely in coupled physical-biogeochemical models, using simple linear parameterizations that are only poorly constrained by observations. Diagenetic models that represent sediment biogeochemistry are available, but rarely are coupled to water column biogeochemical models because they are computationally expensive. Here, we apply a method that efficiently parameterizes sediment-water fluxes of oxygen, nitrate and ammonium by combining in situ measurements, a diagenetic model and a parameter optimization method. As a proof of concept, we apply this method to the Louisiana Shelf where high primary production, stimulated by excessive nutrient loads from the Mississippi-Atchafalaya River system, promotes the development of hypoxic bottom waters in summer. The parameterized sediment-water fluxes represent nonlinear feedbacks between water column and sediment processes at low bottom water oxygen concentrations, which may persist for long periods (weeks to months) in hypoxic systems such as the Louisiana Shelf. This method can be applied to other systems and is particularly relevant for shallow coastal and estuarine waters where the interaction between sediment and water column is strong and hypoxia is prone to occur due to land-based nutrient loads.

  9. Method and apparatus for extracting water from air

    DOEpatents

    Spletzer, Barry L.; Callow, Diane Schafer; Marron, Lisa C.; Salton, Jonathan R.

    2002-01-01

    The present invention provides a method and apparatus for extracting liquid water from moist air using minimal energy input. The method comprises compressing moist air under conditions that foster the condensation of liquid water. The air can be decompressed under conditions that do not foster the vaporization of the condensate. The decompressed, dried air can be exchanged for a fresh charge of moist air and the process repeated. The liquid condensate can be removed for use. The apparatus can comprise a compression chamber having a variable internal volume. An intake port allows moist air into the compression chamber. An exhaust port allows dried air out of the compression chamber. A condensation device fosters condensation at the desired conditions. A condensate removal port allows liquid water to be removed.

  10. Method and apparatus for extracting water from air

    DOEpatents

    Spletzer, Barry L.

    2001-01-01

    The present invention provides a method and apparatus for extracting liquid water from moist air using minimal energy input. The method comprises compressing moist air under conditions that foster the condensation of liquid water (ideally isothermal to a humidity of 1.0, then adiabatic thereafter). The air can be decompressed under conditions that do not foster the vaporization of the condensate. The decompressed, dried air can be exchanged for a fresh charge of moist air and the process repeated. The liquid condensate can be removed for use. The apparatus can comprise a compression chamber having a variable internal volume. An intake port allows moist air into the compression chamber. An exhaust port allows dried air out of the compression chamber. A condensation device fosters condensation at the desired conditions. A condensate removal port allows liquid water to be removed.

  11. Respiratory disease and particulate air pollution in Santiago Chile: contribution of erosion particles from fine sediments.

    PubMed

    Garcia-Chevesich, Pablo A; Alvarado, Sergio; Neary, Daniel G; Valdes, Rodrigo; Valdes, Juan; Aguirre, Juan José; Mena, Marcelo; Pizarro, Roberto; Jofré, Paola; Vera, Mauricio; Olivares, Claudio

    2014-04-01

    Air pollution in Santiago is a serious problem every winter, causing thousands of cases of breathing problems within the population. With more than 6 million people and almost two million vehicles, this large city receives rainfall only during winters. Depending on the frequency of storms, statistics show that every time it rains, air quality improves for a couple of days, followed by extreme levels of air pollution. Current regulations focus mostly on PM10 and PM2.5, due to its strong influence on respiratory diseases. Though more than 50% of the ambient PM10s in Santiago is represented by soil particles, most of the efforts have been focused on the remaining 50%, i.e. particulate material originating from fossil and wood fuel combustion, among others. This document emphasizes the need for the creation of erosion/sediment control regulations in Chile, to decrease respiratory diseases on Chilean polluted cities. PMID:24485904

  12. Distributions of pesticides and organic contaminants between water and suspended sediment, San Francisco Bay, California

    USGS Publications Warehouse

    Domagalski, J.L.; Kuivila, K.M.

    1993-01-01

    Suspended-sediment and water samples were collected from San Francisco Bay in 1991 during low river discharge and after spring rains. All samples were analyzed for organophosphate, carbamate, and organochlorine pesticides; petroleum hydrocarbons; biomarkers; and polynuclear aromatic hydrocarbons. The objectives were to determine the concentrations of these contaminants in water and suspended sediment during two different hydrologic conditions and to determine partition coefficients of the contaminants between water and sediment. Concentrations of hydrophobic contaminants, such as polynuclear aromatic hydrocarbons, varied with location of sample collection, riverine discharge, and tidal cycle. Concentrations of hydrophobic contaminants in suspended sediments were highest during low river discharge but became diluted as agricultural soils entered the bay after spring rains. Polynuclear aromatic hydrocarbons defined as dissolved in the water column were not detected. The concentrations sorbed on suspended sediments were variable and were dependent on sediment transport patterns in the bay. In contrast, the relatively hydrophilic organophosphate pesticides, such as chlorpyrifos and diazinon, has a more uniform concentration in suspended sediment. These pesticides were detected only after spring rains. Most of the measured diazinon, at least 98% for all samples, was in the dissolved phase. Measured partition coefficients for diazinon generally were uniform, which suggests that suspended-sediment concentrations were close to equilibrium with dissolved concentrations. The concentration of diazinon sorbed to suspended sediments, at any given sampling site, was driven primarily by the more abundant solution concentration. The concentrations of diazinon sorbed to suspended sediments, therefore, were independent of the patterns of sediment movement. ?? 1993 Estuarine Research Federation.

  13. Estimating suspended sediment concentrations in surface waters of the Amazon River wetlands from Landsat images

    SciTech Connect

    Mertes, L.A.K.; Smith, M.O.; Adams, J.B. )

    1993-03-01

    A method has been developed, based on spectral mixture analysis, to estimate the concentration of suspended sediment in surface waters of the Amazon River wetlands from Landsat MSS and TM images. Endmembers were derived from laboratory reflectance measurements of water-sediment mixtures with a range of sediment concentrations. Using these references spectra, the authors applied a linear mixture analysis to multispectral images after accounting for instrument and atmosphere gains and offsets. Sediment concentrations were estimated for individual pixels from the mixture analysis results based on a nonlinear calibration curve relating laboratory sediment concentrations and reflectance to endmember fractions. The uncertainty in the sediment concentrations derived from this analysis for three Amazon images is predicted to be within [plus minus] 20 mg/L, and the concentrations fall within a range of concentrations of suspended sediment that were measured at several times and places in the field over the past 15 years. The emphasis of their work is to use the patterns of sediment concentrations to compute the approximate volumes of sediment that are transferred between the main channel and floodplain of the Amazon River. However, the methodology can be applied universally if the optical properties of water and sediment at the site are known, and it is, therefore, useful for the study of suspended sediment concentrations in surface waters of wetlands elsewhere.

  14. Linking Air, Land, and Water Pollution for Effective Environmental Management

    EPA Science Inventory

    Since the passage of the National Environmental Policy Act in 1970, the U.S. Environmental Protection Agency, other federal agencies, and the states have made substantial progress in improving the Nation’s air and water quality. Traditionally, the air, land, and water pollution ...

  15. Effects of drainage on water, sediment and biota

    USGS Publications Warehouse

    Engberg, Richard A.; Sylvester, Marc A.; Feltz, Herman R.

    1991-01-01

    The U.S. Department of the Interior started a program in 1985 to identify effects of irrigation-induced trace constituents in water, bottom sediment and biota. The program was developed in response to concerns that contamination similar to that found in 1983 at Kesterson Reservoir in California might exist elsewhere. Studies are complete or underway for 26 sites in 15 western States. Selenium is the trace constituent most often found at elevated concentrations in all media. Maximum selenium concentrations in fish from 9 of 20 areas exceeded the threshold concentration for adverse reproductive effects. Maximum selenium concentrations in bird livers from 11 areas exceeded the level at which embryonic deformities are likely; deformed birds were observed in 5 areas. Trace constituent problems may be anticipated if geologic sources such as marine shales occur in an irrigation project area. The potential for problems is increased if closed basins or sinks are present.

  16. Environmental monitoring of chromium in air, soil, and water.

    PubMed

    Vitale, R J; Mussoline, G R; Rinehimer, K A

    1997-08-01

    Historical uses of chromium have resulted in its widespread release into the environment. In recent years, a significant amount of research has evaluated the impact of chromium on human health and the environment. Additionally, numerous analytical methods have been developed to identify and quantitate chromium in environmental media in response to various state and federal mandates such as CERCLA, RCRA, CWA, CAA, and SWDA. Due to the significant toxicity differences between trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium, it is essential that chromium be quantified in these two distinct valence states to assess the potential risks to exposure to each in environmental media. Speciation is equally important because of their marked differences in environmental behavior. As the knowledge of risks associated with each valence state has grown and regulatory requirements have evolved, methods to accurately quantitate these species at ever-decreasing concentrations within environmental media have also evolved. This paper addresses the challenges of chromium species quantitation and some of the most relevant current methods used for environmental monitoring, including ASTM Method D5281 for air, SW-846 Methods 3060A, 7196A and 7199 for soils, sediments, and waste, and U.S. EPA Method 218.6 for water. PMID:9380841

  17. Thermodynamic and transport properties of air/water mixtures

    NASA Technical Reports Server (NTRS)

    Fessler, T. E.

    1981-01-01

    Subroutine WETAIR calculates properties at nearly 1,500 K and 4,500 atmospheres. Necessary inputs are assigned values of combinations of density, pressure, temperature, and entropy. Interpolation of property tables obtains dry air and water (steam) properties, and simple mixing laws calculate properties of air/water mixture. WETAIR is used to test gas turbine engines and components operating in relatively humid air. Program is written in SFTRAN and FORTRAN.

  18. Microbial Diversity in Water and Sediment of Lake Chaka, an Athalassohaline Lake in Northwestern China

    PubMed Central

    Jiang, Hongchen; Dong, Hailiang; Zhang, Gengxin; Yu, Bingsong; Chapman, Leah R.; Fields, Matthew W.

    2006-01-01

    We employed culture-dependent and -independent techniques to study microbial diversity in Lake Chaka, a unique hypersaline lake (32.5% salinity) in northwest China. It is situated at 3,214 m above sea level in a dry climate. The average water depth is 2 to 3 cm. Halophilic isolates were obtained from the lake water, and halotolerant isolates were obtained from the shallow sediment. The isolates exhibited resistance to UV and gamma radiation. Microbial abundance in the sediments ranged from 108 cells/g at the water-sediment interface to 107 cells/g at a sediment depth of 42 cm. A major change in the bacterial community composition was observed across the interface. In the lake water, clone sequences affiliated with the Bacteroidetes were the most abundant, whereas in the sediments, sequences related to low G+C gram-positive bacteria were predominant. A similar change was also present in the archaeal community. While all archaeal clone sequences in the lake water belonged to the Halobacteriales, the majority of the sequences in the sediments were related to those previously obtained from methanogenic soils and sediments. The observed changes in the microbial community structure across the water-sediment interface were correlated with a decrease in salinity from the lake water (32.5%) to the sediments (approximately 4%). Across the interface, the redox state also changed from oxic to anoxic and may also have contributed to the observed shift in the microbial community. PMID:16751487

  19. A multilayer shallow water system for polydisperse sedimentation

    NASA Astrophysics Data System (ADS)

    Fernández-Nieto, E. D.; Koné, E. H.; Morales de Luna, T.; Bürger, R.

    2013-04-01

    This work considers the flow of a fluid containing one disperse substance consisting of small particles that belong to different species differing in size and density. The flow is modelled by combining a multilayer shallow water approach with a polydisperse sedimentation process. This technique allows one to keep information on the vertical distribution of the solid particles in the mixture, and thereby to model the segregation of the particle species from each other, and from the fluid, taking place in the vertical direction of the gravity body force only. This polydisperse sedimentation process is described by the well-known Masliyah-Lockett-Bassoon (MLB) velocity functions. The resulting multilayer sedimentation-flow model can be written as a hyperbolic system with nonconservative products. The definitions of the nonconservative products are related to the hydrostatic pressure and to the mass and momentum hydrodynamic transfer terms between the layers. For the numerical discretization a strategy of two steps is proposed, where the first one is also divided into two parts. In the first step, instead of approximating the complete model, we approximate a reduced model with a smaller number of unknowns. Then, taking advantage of the fact that the concentrations are passive scalars in the system, we approximate the concentrations of the different species by an upwind scheme related to the numerical flux of the total concentration. In the second step, the effect of the transference terms defined in terms of the MLB model is introduced. These transfer terms are approximated by using a numerical flux function used to discretize the 1D vertical polydisperse model, see Bürger et al. [ R. Bürger, A. García, K.H. Karlsen, J.D. Towers, A family of numerical schemes for kinematic flows with discontinuous flux, J. Eng. Math. 60 (2008) 387-425]. Finally, some numerical examples are presented. Numerical results suggest that the multilayer shallow water model could be adequate

  20. Suspended sediment control and water quality conservation through riparian vegetation:

    NASA Astrophysics Data System (ADS)

    Pavanelli, D.; Cavazza, C.; Correggiari, S.

    2009-04-01

    Soil erosion and Suspended Sediment River are strongly related in the Apennines catchments which are generally characterised by a clayey lithology and impermeable soils and extensive and severe erosion and slope stability problems. In fact the suspended sediment yield represents one of the most reliable tools to assess real basin soil loss (Pavanelli and Pagliarani, 2002; Pavanelli and Rigotti, 2007) from the surface rain erosive features in a mountain watershed, as rills and interrills erosion, gullies, bad-lands (calanchi basins). Suspended sediment yield is known to imply several detrimental consequences: soil losses from agricultural land, worsening of the quality of the water, clogging of water supply filters and reservoir siltation. In addition, suspended sediment yield is also one of the main vector for pollutants and nutrients: various studies have already proved how nitrogen content has been constantly rising in aquifers and surface waters [Böhlke and Denver, 1995]. Finer particles and their aggregates have been proved to be the preferential vehicle for particulate nitrogen [Droppo et al., 1997; Ongley et al., 1992]. In one research [Pavanelli and al. 2006] four Apennines torrents (Gaiana, Sillaro, Savena and Lavino) with mountain basins ranging from 8.7 to 139 Km2 were monitored via automatic sampling devices, the samples of water collected were analysed to characterise suspended solids in terms of their grain size distribution and total nitrogen with respect to the source of eroded area in the catchment. Preliminary results [Pavanelli and al. 2007] seem to show the existence of a direct relationship between nitrogen concentration and finer particle concentration (<20 μm), with the maximum nitrogen loss values being related to factors like the presence of clayey formations, their position within the catchment and the availability of suspended particles. The results seem to indicate hillsides as main sources of suspended sediment to the torrents

  1. Suspended sediment control and water quality conservation through riparian vegetation:

    NASA Astrophysics Data System (ADS)

    Pavanelli, D.; Cavazza, C.; Correggiari, S.

    2009-04-01

    Soil erosion and Suspended Sediment River are strongly related in the Apennines catchments which are generally characterised by a clayey lithology and impermeable soils and extensive and severe erosion and slope stability problems. In fact the suspended sediment yield represents one of the most reliable tools to assess real basin soil loss (Pavanelli and Pagliarani, 2002; Pavanelli and Rigotti, 2007) from the surface rain erosive features in a mountain watershed, as rills and interrills erosion, gullies, bad-lands (calanchi basins). Suspended sediment yield is known to imply several detrimental consequences: soil losses from agricultural land, worsening of the quality of the water, clogging of water supply filters and reservoir siltation. In addition, suspended sediment yield is also one of the main vector for pollutants and nutrients: various studies have already proved how nitrogen content has been constantly rising in aquifers and surface waters [Böhlke and Denver, 1995]. Finer particles and their aggregates have been proved to be the preferential vehicle for particulate nitrogen [Droppo et al., 1997; Ongley et al., 1992]. In one research [Pavanelli and al. 2006] four Apennines torrents (Gaiana, Sillaro, Savena and Lavino) with mountain basins ranging from 8.7 to 139 Km2 were monitored via automatic sampling devices, the samples of water collected were analysed to characterise suspended solids in terms of their grain size distribution and total nitrogen with respect to the source of eroded area in the catchment. Preliminary results [Pavanelli and al. 2007] seem to show the existence of a direct relationship between nitrogen concentration and finer particle concentration (<20 μm), with the maximum nitrogen loss values being related to factors like the presence of clayey formations, their position within the catchment and the availability of suspended particles. The results seem to indicate hillsides as main sources of suspended sediment to the torrents

  2. Response of coliform populations in streambed sediment and water column to changes in nutrient concentrations in water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: The focus of this work was to observe the response of water column and sediment coliform population to the change in nutrient concentrations in the water column. Methods and Results: The survival experiments were conducted in flow-through chambers containing sandy sediments. Bovine faeces wer...

  3. Bubble Shuttle: A newly discovered transport mechanism, which transfers microorganisms from the sediment into the water column

    NASA Astrophysics Data System (ADS)

    Schmale, O.; Stolle, C.; Leifer, I.; Schneider von Deimling, J.; Kiesslich, K.; Krause, S.; Frahm, A.; Treude, T.

    2013-12-01

    The diversity and abundance of methanotrophic microorganisms is well studied in the aquatic environment, indicating their importance in biogeochemical cycling of methane in the sediment and the water column. However, whether methanotrophs are distinct populations in these habitats or are exchanged between benthic and pelagic environments, remains an open question. Therefore, field studies were conducted at the 'Rostocker Seep' site (Coal Oil Point seep area, California, USA) to test our hypothesis that methane-oxidizing microorganisms can be transported by gas bubbles from the sediment into the water column. The natural methane emanating location 'Rostocker Seep' showed a strong surface water oversaturation in methane with respect to the atmospheric equilibrium. Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) analyzes were performed to determine the abundance of aerobic and anaerobic methanotrophic microorganisms. Aerobic methane oxidizing bacteria were detected in the sediment and the water column, whereas anaerobic methanotrophs were detected exclusively in the sediment. The key device of the project was the newly developed "Bubble Catcher" used to collect naturally emanating gas bubbles at the sea floor together with particles attached to the bubble surface rim. Bubble Catcher experiments were carried out directly above a natural bubble release spot and on a reference site at which artificially released gas bubbles were caught, which had no contact with the sediment. CARD-FISH analyzes showed that aerobic methane oxidizing bacteria were transported by gas bubbles from the sediment into the water column. In contrast anaerobic methanotrophs were not detected in the bubble catcher. Further results indicate that this newly discovered Bubble Shuttle transport mechanism might influence the distribution pattern of methanotrophic microorganisms in the water column and even at the air-sea interface. Methane seep areas are often characterized

  4. Sediment-water distribution of contaminants of emerging concern in a mixed use watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the occurrence and distribution of 15 contaminants of emerging concern (CEC) in stream water and sediments in the Zumbro River watershed in Minnesota and compared these with sub-watershed land uses. Sixty pairs of sediment and water samples were collected across all seasons from...

  5. Modeling sedimentation-filtration basins for urban watersheds using Soil and Water Assessment Tool

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sedimentation-filtration (SedFil) basins are one of the storm-water best management practices (BMPs) that are intended to mitigate water quality problems in urban creeks and rivers. A new physically based model of variably saturated flows was developed for simulating flow and sediment in SedFils wi...

  6. Sediment data for streams near Mount St. Helens, Washington; Volume 1, 1980 water year

    USGS Publications Warehouse

    Dinehart, Randal L.; Ritter, John R.; Knott, J.M.

    1981-01-01

    This report presents fluvial sediment data collected primarily in response to the eruption of Mount St. Helens. To monitor the sediment transported by streams in the Mount St. Helens area and the particle-size distributions of the sediment, the Water Resources Division of the U.S. Geological Survey initially established 18 fluvial sediment stations. In this report, concentrations and discharges of suspended sediment are given for 16 fluvial-sediment stations (5 are in the Toutle River basin) and for 11 miscellaneous sampling sites. Also included are particle-size distributions of suspended sediment and bed material, water discharge, and water temperature for many of the sediment samples. Daily sediment discharges for the period May 18 to September 30 were calculated for Toutle River at Highway 99 near Castle Rock and Cowlitz River at Castel Rock. Over 150 million tons of sediment are estimated to have passed the Toutle River at Highway 99 station on May 18-19, 1980. High concentrations of suspended sediment persisted at several stations throughout the spring and summer of 1980. (USGS)

  7. Trace element distribution in the water and sediments of certain storage lakes from the Jijia catchment, (Romania)

    NASA Astrophysics Data System (ADS)

    Dughila, A.; Iancu, O. G.; Romanescu, G. T.

    2012-04-01

    The present study aims at investigating the concentrations and distribution levels of a series of trace elements in water and sediment samples collected from six storage lakes located in the Jijia catchment - NE of Romania. The lakes are multi-purpose water reservoirs, three of them being mainly used as a source of municipal drinking water, or for fishing, irrigation for the farms in the area, protection against floods and the regulation of river flows. By contrast, agricultural wastes, fertilizers, raw sewage effluents and road runoff constitute the predominant anthropogenic sources, which supply the lakes in question with Cd, Cu, Pb and Zn. The present study was conducted on a series of 63 sediment samples and 18 water samples, collected from the same locations, in order to establish the distribution levels of certain trace elements from the water through sediments. Sediment cores were collected from two sections across each lake by means of a motor boat, using a system that consists of a graduated sampling tube (0.9 m in length and 72.5 mm in diameter) made of Plexiglas (Eijkelkamp sample tube guide). Prior to the analyses, the samples were air-dried, ground and homogenized using an agate mortar, oven-dried at 50 °C for 6 days and then sieved through 63 µm sieves. The sediment and water samples were subjected to a digestion technique with concentrated nitric acid using a microwave oven (Berghof type), and analyzed for the following elements: Pb, Zn, Cu, Cd, Cr and Ni. The total concentration of the elements was measured through atomic absorption spectrometry (AAS) with an RSD of < 10 % from solutions. The vertical distribution of most elements in the cores examined could be characterized as relatively uniform, with higher concentrations for those collected from the lakes which are more influenced by anthropogenic factors, compared to those situated in forested areas. The lake-water quality characteristics were below the recommended drinking water standards

  8. Occurrence of microcystins in water, bloom, sediment and fish from a public water supply.

    PubMed

    Gurbuz, Fatma; Uzunmehmetoğlu, Oğuz Y; Diler, Öznur; Metcalf, James S; Codd, Geoffrey A

    2016-08-15

    Microcystin (MC) accumulation was determined in the liver and muscle of two omnivorous fish species which are consumed and are economically important, and in a planktivorous-carnivorous fish from Lake Eğirdir, Turkey. Free extractable MCs in fish tissue samples were detected by enzyme-linked immunosorbent assay (ELISA) with confirmation by high performance liquid chromatography with photodiode array detection (HPLC-PDA). MC-LA and -YR, were detected in both liver and muscle, followed by MCs -LY, -LF, -RR and -LR respectively. The MC concentrations varied between 0.043 and 1.72μg/g dry weight in liver and muscle tissues. MCs were also determined in samples of water, sediment and a bloom sample of Microcystis aeruginosa from the lake by HPLC-PDA. MC-LY and -YR were most commonly identified in water samples, with total MC concentrations ranging from 2.9±0.05 to 13.5±2.3μg/L. Sediment analyses, showed that MC-YR was present in samples between 7.0 and 17.6μg/g dw, especially in October, November and December when no MC-YR was recorded in water, followed by MC-LW. The findings indicate that water and sediment contained MCs, and more importantly that fish were contaminated with MCs that may pose an MC-associated human health risk. PMID:27115623

  9. Sequencing Insights into Microbial Communities in the Water and Sediments of Fenghe River, China.

    PubMed

    Lu, Sidan; Sun, Yujiao; Zhao, Xuan; Wang, Lei; Ding, Aizhong; Zhao, Xiaohui

    2016-07-01

    The connection between microbial community structure and spatial variation and pollution in river waters has been widely investigated. However, water and sediments together have rarely been explored. In this study, Illumina high-throughput sequencing was performed to analyze microbes in 24 water and sediment samples from natural to anthropogenic sources and from headstream to downstream areas. These data were used to assess variability in microbial community structure and diversity along in the Fenghe River, China. The relationship between bacterial diversity and environmental parameters was statistically analyzed. An average of 1682 operational taxonomic units was obtained. Microbial diversity increased from the headstream to downstream and tended to be greater in sediment compared with water. The water samples near the headstream endured relatively low Shannon and Chao1 indices. These diversity indices and the number of observed species in the water and sediment samples increase downstream. The parameters also differ in the two river tributaries. Community structures shift based on the extent of nitrogen pollution variation in the sediment and water samples. The four most dominant genera in the water community were Escherichia, Acinetobacter, Comamonadaceae, and Pseudomonas. In the sediments, the most dominant genera were Stramenopiles, Flavobacterium, Pseudomonas, and Comamonadaceae. The number of ammonia-oxidizing archaea in the headstream water slightly differed from that in the sediment but varied considerably in the downstream sediments. Statistical analysis showed that community variation is correlated with changes in ammonia nitrogen, total nitrogen, and nitrate nitrogen. This study identified different microbial community structures in river water and sediments. Overall this study emphasized the need to elucidate spatial variations in bacterial diversity in water and sediments associated with physicochemical gradients and to show the effects of such

  10. Immobilization of phosphorus from water and sediment using zirconium-modified zeolites.

    PubMed

    Yang, Mengjuan; Lin, Jianwei; Zhan, Yanhui; Zhu, Zhiliang; Zhang, Honghua

    2015-03-01

    Adding sorbents to sediments has been suggested as an effective technology for contaminated sediment remediation. In this study, a zirconium-modified zeolite (ZrMZ) was prepared, characterized, and used as a sediment amendment to control phosphorus (P) release from eutrophic lake sediments. The efficiency of ZrMZ in immobilizing P from water and sediments was investigated through a series of experiments. The phosphate adsorption capacity for ZrMZ decreased with increasing water pH. The adsorption of phosphate on ZrMZ followed a pseudo-second-order kinetic model. The equilibrium adsorption data of phosphate on ZrMZ could be well described by the Langmuir isotherm model with a maximum monolayer adsorption capacity of 10.2 mg P/g at pH 7 and 25 °C. Sequential extraction of P from the phosphate-adsorbed ZrMZ suggested that most of P bound by ZrMZ existed as the NaOH extractable P (NaOH-P) and residual P (Res-P) and was unlikely to be released under natural pH and reducing conditions. The addition of ZrMZ into sediments reduced the inorganic P activity in the sediments by transforming bicarbonate-dithionite extractable P (BD-P) to NaOH-P and Res-P. The contents of bioavailable P such as water-soluble P (WS-P), NaHCO3 extractable P (Olsen-P), and algal available P (AAP) in sediments reduced after the sediments were mixed with ZrMZ, making P in the sediments more stable. The addition of ZrMZ into sediments significantly reduced the releasing flux of P from the sediments to the water column under different conditions. Results of this study indicate that the ZrMZ is a promising sediment amendment for controlling the internal P loading of lake sediments. PMID:25253056

  11. 9. Water Purification System and Instrument Air Receiver Tank, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Water Purification System and Instrument Air Receiver Tank, view to the south. The water purification system is visible in the right foreground of the photograph and the instrument air receiver tank is visible in the right background of the photograph. - Washington Water Power Clark Fork River Cabinet Gorge Hydroelectric Development, Powerhouse, North Bank of Clark Fork River at Cabinet Gorge, Cabinet, Bonner County, ID

  12. [Distribution Characteristics and Pollution Status Evaluation of Sediments Nutrients in a Drinking Water Reservoir].

    PubMed

    Huang, Ting-lin; Liu, Fei; Shi, Jian-chao

    2016-01-15

    The main purpose of this paper is to illustrate the influence of nutrients distribution in sediments on the eutrophication of drinking water reservoir. The sediments of three representative locations were field-sampled and analyzed in laboratory in March 2015. The distribution characteristics of TOC, TN and TP were measured, and the pollution status of sediments was evaluated by the comprehensive pollution index and the manual for sediment quality assessment. The content of TOC in sediments decreased with depth, and there was an increasing trend of the nitrogen content. The TP was enriched in surface sediment, implying the nutrients load in Zhoucun Reservoir was aggravating as the result of human activities. Regression analysis indicated that the content of TOC in sediments was positively correlated with contents of TN and TP in sediments. The TOC/TN values reflected that the vascular land plants, which contain cellulose, were the main source of organic matter in sediments. The comprehensive pollution index analysis result showed that the surface sediments in all three sampling sites were heavily polluted. The contents of TN and TP of surface sediments in three sampling sites were 3273-4870 mg x kg(-1) and 653-2969 mg x kg(-1), and the content of TOC was 45.65-83.00 mg x g(-1). According to the manual for sediment quality assessment, the TN, TP and TOC contents in sediments exceed the standard values for the lowest level of ecotoxicity, so there is a risk of eutrophication in Zhoucun Reservoir. PMID:27078954

  13. Summary of Suspended-Sediment Concentration Data, San Francisco Bay, California, Water Year 2007

    USGS Publications Warehouse

    Buchanan, Paul A.; Morgan, Tara L.

    2010-01-01

    Suspended-sediment concentration data were collected by the U.S. Geological Survey in San Francisco Bay during water year 2007 (October 1, 2006-September 30, 2007). Optical sensors and water samples were used to monitor suspended-sediment concentration at two sites in Suisun Bay, two sites in Central San Francisco Bay, and one site in South San Francisco Bay. Sensors were positioned at two depths at most sites to help define the vertical variability of suspended sediments.Water samples were collected periodically and analyzed for concentrations of suspended sediment. The results of the analyses were used to calibrate the output of the optical sensors so that a record of suspended-sediment concentrations could be derived. This report presents the data-collection methods used and summarizes, in graphs, the suspended-sediment concentration data collected from October 2006 through September 2007. Calibration curves and plots of the processed data for each sensor also are presented.

  14. Summary of suspended-sediment concentration data, San Francisco Bay, California, water year 2008

    USGS Publications Warehouse

    Buchanan, Paul A.; Morgan, Tara L.

    2011-01-01

    Suspended-sediment concentration data were collected by the U.S. Geological Survey in San Francisco Bay during water year 2008 (October 1, 2007–September 30, 2008). Optical sensors and water samples were used to monitor suspended-sediment concentration at two sites in Suisun Bay, two sites in Central San Francisco Bay, and one site in South San Francisco Bay. Sensors were positioned at two depths at most sites to help define the vertical variability of suspended sediments. Water samples were collected periodically and analyzed for concentrations of suspended sediment. The results of the analyses were used to calibrate the output of the optical sensors so that a record of suspended-sediment concentrations could be derived. This report presents the data-collection methods used and summarizes, in graphs, the suspended-sediment concentration data collected from October 2007 through September 2008. Calibration curves and plots of the processed data for each sensor also are presented.

  15. Nano-porous pottery using calcined waste sediment from tap water production as an additive.

    PubMed

    Sangsuk, Supin; Khunthon, Srichalai; Nilpairach, Siriphan

    2010-10-01

    A suspension of sediment from a lagoon in a tap water production plant was collected for this experiment. The suspension was spray dried and calcined at 700 °C for 1 h. After calcining, 30 wt.% of the sediment were mixed with pottery clay. Samples with and without calcined sediment were sintered at 900, 1000 and 1100 °C. The results show that calcined sediment can be used as an additive in pottery clay. The samples with calcined sediment show higher porosity, water absorption and flexural strength, especially for 900 and 1000 °C. At 900 °C, samples with calcined sediment show a porosity of 50% with an average pore size of 68 nm, water absorption of 31% and flexural strength of 12.61 MPa. PMID:19942644

  16. Multistate Evaluation of Microbial Water and Sediment Quality from Agricultural Recovery Basins.

    PubMed

    Partyka, Melissa L; Bond, Ronald F; Chase, Jennifer A; Kiger, Luana; Atwill, Edward R

    2016-03-01

    Agricultural recovery basins are an important conservation practice designed to provide temporary storage of sediment and water on farms before low-volume discharge. However, food safety concerns have been raised regarding redistribution of captured sediment and water to fields used for human food production. The purpose of this study was to examine the potential microbiological risk that recovery basins may contribute to nearby produce fields and to evaluate characteristics that may influence or mitigate those risks. Water and sediment samples were collected from participating farms in three states and evaluated for bacterial indicators and pathogens over several months. Overall, 45% ( = 48) of water samples and less than 15% ( = 13) of sediment samples were positive for spp. In water samples, the occurrence of was positively associated with the use of surface water as a source of irrigation compared with groundwater as well as log-scale increases in concentration. In sediment samples, was associated with basin location (region) and basin fill levels. Sediment exposed to drying during dewatering had lower concentrations of indicator and a lower proportion of positives than submerged sediment from the same pond. Surrounding landscape characteristics, including vegetative coverage, proximity to livestock operations, and evidence of wildlife, were not correlated with pathogen occurrence in either sediment or water samples, suggesting that although habitat surrounding ponds may be an attractant to wildlife, those features may not contribute to increased pathogen occurrence in agricultural recovery basins. PMID:27065413

  17. Field Observations of Hydrodynamics, Sediment Transport, and Water and Sediment Quality in the Hudson-Raritan Estuary

    NASA Astrophysics Data System (ADS)

    Bruno, M. S.; Glenn, S.; Chant, R.; Rankin, K.; Korfiatis, G.; Dimou, N.; Creed, E.; Fullerton, B.; Pence, A.; Burke, P.; Haldeman, C.; Hires, R.; Hunter, E.

    2002-12-01

    The New York-New Jersey Harbor estuary system is of enormous ecological and economic importance to the region. The presence of toxic chemicals in the water and sediments results in reduced water quality, fisheries restrictions/advisories, and general adverse impacts to the estuarine ecosystem. The Port of New York and New Jersey is central to the economy of the region. However, in recent years, problems associated with the management of contaminated dredged material, including high costs and the lack of suitable disposal/use alternatives, have threatened to impact the volume of shipping in the Harbor. Sources of contaminants include atmospheric deposition, municipal and industrial wastewater treatment facilities, combined sewer and stormwater outfalls, and rainfall-induced runoff (non-point sources). In addition, Harbor sediments can act as a continuing source as they are re-suspended and moved throughout the system by both natural and man-made means. As part of the New Jersey Toxics Reduction Workplan, Stevens Institute of Technology and Rutgers University are conducting hydrodynamic, sediment transport, and water and suspended sediment quality measurements in Newark Bay, the Arthur Kill and the Kill van Kull. The goals of the project include: (1) collection of high resolution (event-driven and long-term) hydrodynamic, sediment transport and water and suspended sediment quality measurements for use in the assessment of the dominant physics of the system and in the development of a combined hydrodynamic-sediment transport-water/sediment quality model for the region. (2) identification of those tributaries to NY-NJ Harbor that are significant sources of the chemicals of concern, and evaluation of the importance of non-point sources and existing contaminated bottom sediments as sources of the chemicals of concern. (3) identification of point discharges that represent significant sources of the chemicals of concern. Observations were obtained over a two-year period

  18. Sediment Enzyme Activities and Microbial Community Diversity in an Oligotrophic Drinking Water Reservoir, Eastern China

    PubMed Central

    Zhang, Haihan; Huang, Tinglin; Liu, Tingting

    2013-01-01

    Drinking water reservoir plays a vital role in the security of urban water supply, yet little is known about microbial community diversity harbored in the sediment of this oligotrophic freshwater environmental ecosystem. In the present study, integrating community level physiological profiles (CLPPs), nested polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and clone sequence technologies, we examined the sediment urease and protease activities, bacterial community functional diversity, genetic diversity of bacterial and fungal communities in sediments from six sampling sites of Zhou cun drinking water reservoir, eastern China. The results showed that sediment urease activity was markedly distinct along the sites, ranged from 2.48 to 11.81 mg NH3-N/(g·24h). The highest average well color development (AWCD) was found in site C, indicating the highest metabolic activity of heterotrophic bacterial community. Principal component analysis (PCA) revealed tremendous differences in the functional (metabolic) diversity patterns of the sediment bacterial communities from different sites. Meanwhile, DGGE fingerprints also indicated spatial changes of genetic diversity of sediment bacterial and fungal communities. The sequence BLAST analysis of all the sediment samples found that Comamonas sp. was the dominant bacterial species harbored in site A. Alternaria alternate, Allomyces macrogynus and Rhizophydium sp. were most commonly detected fungal species in sediments of the Zhou cun drinking water reservoir. The results from this work provide new insights about the heterogeneity of sediment microbial community metabolic activity and genetic diversity in the oligotrophic drinking water reservoir. PMID:24205265

  19. Sediment toxicity assessment through evaluation of the toxicity of interstitial water

    SciTech Connect

    Ankley, G.

    1989-01-01

    The interstitial-water-toxicity approach is a multiphase procedure for assessing sediment toxicity using interstitial (i.e., pore) water. The use of pore water for sediment toxicity assessment was based on the strong correlations between contaminant concentrations in pore water and toxicity (and/or bioaccumulation) of sediment-associated contaminants by benthic macroinvertebrates. The approach combines the quantitation of pore water toxicity with toxicity identification evaluation (TIE) procedures to identify and quantify chemical components responsible for sediment toxicity. TIE involves recently developed procedures for the identification of toxic compounds in aqueous samples containing complex mixtures of chemicals. In the interstitial water-toxicity method, TIE procedures are implemented in three phases to characterize pore-water toxicity, identify the suspected toxicant, and confirm toxicant identification.

  20. Control of water erosion and sediment in open cut coal mines in tropical areas

    SciTech Connect

    Ueda, T.; Nugraha, C.; Matsui, K.; Shimada, H.; Ichinose, M.; Gottfried, J.

    2005-07-01

    The purpose is to reduce the environmental impacts from open cut mining in tropical areas, such as Indonesia and Vietnam. Research conducted on methods for the control of water erosion and sediment from open cut coal mines is described. Data were collected on climate and weathering in tropical areas, mechanism of water erosion and sedimentation, characteristics of rocks in coal measures under wet conditions, water management at pits and haul roads and ramps, and construction of waste dumps and water management. The results will be applied to the optimum control and management of erosion and sediments in open cut mining. 6 refs., 8 figs.

  1. Ecological impacts of lead mining on Ozark streams: Toxicity of sediment and pore water

    USGS Publications Warehouse

    Besser, J.M.; Brumbaugh, W.G.; Allert, A.L.; Poulton, B.C.; Schmitt, C.J.; Ingersoll, C.G.

    2009-01-01

    We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most pore waters tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and pore waters and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.

  2. Pore water nutrient characteristics and the fluxes across the sediment in the Pearl River estuary and adjacent waters, China

    NASA Astrophysics Data System (ADS)

    Zhang, Ling; Wang, Lu; Yin, Kedong; Lü, Ying; Zhang, Derong; Yang, Yongqiang; Huang, Xiaoping

    2013-11-01

    Spatio-temporal distribution of pore water nutrients and the fluxes at the sediment-water interface (SWI) were investigated to probe into the geochemical behavior of nutrients associated with early diagenesis of organic matter (OM), and to study the accumulation and transformation processes of nutrients at the SWI, as well as to discuss the impact of riverine inputs on nutrients in the Pearl River estuary (PRE) and adjacent offshore areas. Nutrient concentrations decreased from the upper to the lower reaches of the estuary, suggesting that there was a high input of anthropogenic nutrients and the estuary was acting as a nutrient sink. Dissolved inorganic nitrogen (DIN: the sum of NH4-N, NO3-N and NO2-N) concentrations in the water column and the pore water were higher in the estuary than at offshore areas due to the riverine discharge and the high accumulation rate in the estuary. NO3-N concentration was the highest of the three forms of DIN in the overlying water and showed a sharp decrease from the surficial sediment with increasing sediment depth, indicating that there was strong denitrification at the SWI. NH4-N, mainly deriving from the anaerobic degradation of OM, was the main form of DIN in the pore water and increased with depth. Negative NO3-N fluxes (into the sediment) and positive NH4-N fluxes (from the sediment) were commonly observed from incubation experiments, indicating the denitrification occurred at the SWI. DIN flux suggested that the sediment was a sink of DIN in spring, however, the sediment was the source of DIN in summer and winter. Nutrients dominantly diffused out of the sediment, suggesting that the sediment was the source of nutrients in spring at adjacent offshore areas. The fluxes directed that PO4-P mainly diffused into the sediment while SiO4-Si mainly diffused out of the sediment.

  3. Chemistry of calcium carbonate-rich shallow water sediments in the Bahamas

    SciTech Connect

    Morse, J.W.; Zullig, J.J.; Bernstein, L.D.; Millero, F.J.; Milne, P.; Mucci, A.; Choppin, G.R.

    1985-02-01

    The geochemistry of calcium carbonate-rich sediments from a variety of environments throughout the Bahamas was investigated with particular emphasis on the factors that control the pore water chemistry. Most sediments are supersaturated with respect to aragonite, the most abundant carbonate component. Experimental studies indicate that the observed in situ calcium carbonate ion activity products can often be produced as reversible metastable equilibria between the sediments and seawater. This is interpreted as being the result of interactions between the solutions and the minor high Mg-calcite component present in these sediments. Although the overlying waters are more supersaturated than the pore waters, carbonate dissolution, not precipitation, dominates in these sediments as a result of organic matter oxidation and the resulting increase in P/sub CO/sub 2//. The carbonate sediments of the Bahamas are remarkable for their purity, with the exception of special environments such as mangrove swamps and tidal flats with algal mats. Organic matter and heavy metal content is extremely low. Only minor sulfate reduction is occurring in most sediments. Phosphate is undetectable in all pore waters, probably as a result of adsorption on carbonate mineral surfaces. Other dissolved pore water components such as ammonia and DOC are much lower than typically found in shallow water fine-grained terrigeneous sediments.

  4. 18 CFR 1316.5 - Clean Air and Water Acts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Conditions and Certifications § 1316.5 Clean Air and Water Acts. When so indicated in TVA contract documents... Acts. 1316.5 Section 1316.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY... Water Acts (a) If performance of this contract would involve the use of facilities which have given...

  5. 18 CFR 1316.5 - Clean Air and Water Acts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Conditions and Certifications § 1316.5 Clean Air and Water Acts. When so indicated in TVA contract documents... Acts. 1316.5 Section 1316.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY... Water Acts (a) If performance of this contract would involve the use of facilities which have given...

  6. Ecosystem impacts of Alpine water intakes for hydropower: the challenge of sediment management

    NASA Astrophysics Data System (ADS)

    Gabbud, Chrystelle; Lane, Stuart

    2016-04-01

    Natural Alpine flow regimes are strongly modified by anthropogenic activities, notably water abstraction or impoundment for hydroelectric power production, which impacts upon both river discharge and sediment transfer systems, and in turn upon flora and fauna downstream. These kinds of impacts are well studied where rivers are regulated by dams, with sediment retained in the associated reservoirs although occasional flushing may be required (a frequency typically of many years). Such impacts may be managed by environmental flows or e-flows, whose restoration value has been shown in a number of research publications. However, there has been less attention in relation to the e-flows needed at water intakes which in Alpine environments may be associated with serious sediment-related problems. Water intakes have a very smaller sediment storage capacity than dams and thus may need to be flushed of accumulated sediment more regularly. In an Alpine setting, because rates of erosion are naturally higher, sediment is flushed in 'purges' with a frequency that may even be sub-daily at certain times of the year. Purges feed the river with solid material, but as the means of transporting it, the water, is being abstracted, sediment transport capacity is reduced. In theory, this does not eliminate sediment connectivity, but rather reduces it: the sediment is still delivered, but it can only be transported for a reduced duration; and the results may be profound hydrogeomorphic and ecosystem impacts, including downstream aggradation. In this study, we present results from a combined study of fluvial geomorphology, hydrology and ecosystem impacts of flow abstraction at water intakes. Using hydrodynamic modelling, we show that because the duration of remobilisation of purges and the peak discharge are much shorter than under natural flows, this causes the formation of a zone of sediment aggradation that moves progressively downstream as a sediment wave, leading to sedimentation

  7. Anthropogenic effects on global riverine sediment and water discharge - a spatially explicit analysis

    NASA Astrophysics Data System (ADS)

    Cohen, S.; Kettner, A. J.; Syvitski, J. P.

    2013-12-01

    Changes in global riverine water discharge and suspended sediment flux over a 50-year period, 1960-2010 are studied, applying a new version of the WBMsed (WBMsed v.2.0) global hydrological water balance model. A new floodplain component is introduced to better represent water and sediment dynamics during periods of overbank discharge. Validated against data from 16 globally distributed stations, WBMsed v.2.0 simulation results show considerable improvement over the original model. Anthropogenic impact on sediment and water discharge is evaluated by comparing global scale simulations with and without human drivers and parameters (agricultural land use, water intake form aquifers and rivers, sediment trapping in reservoirs, and human-induced soil erosion). The results show that, on average, global riverine sediment flux is reduced by approximately 25% by anthropogenic activities (almost exclusively due to trapping in reservoirs) while water discharge is reduced by about 2%. These results correspond to previous analysis by other research groups. Substantial global and intra-basin variability is observed (see Figure 1) for the first time. In some regions an opposite anthropogenic effect on sediment and water discharge was predicted (e.g. west Mississippi Basin, Rio Grande River, Indian subcontinent). We discuss the western part of the Mississippi Basin as an example of this intriguing anthropogenic impact. Figure 1. Percent change between disturbed and pristine simulations (with and without human footprint respectively) for sediment flux (top) and water discharge (bottom).

  8. Increased Power in Sediment Microbial Fuel Cell: Facilitated Mass Transfer via a Water-Layer Anode Embedded in Sediment

    PubMed Central

    Lee, Yoo Seok; An, Junyeong; Kim, Bongkyu; Park, HyunJun; Kim, Jisu; Chang, In Seop

    2015-01-01

    We report a methodology for enhancing the mass transfer at the anode electrode of sediment microbial fuel cells (SMFCs), by employing a fabric baffle to create a separate water-layer for installing the anode electrode in sediment. The maximum power in an SMFC with the anode installed in the separate water-layer (SMFC-wFB) was improved by factor of 6.6 compared to an SMFC having the anode embedded in the sediment (SMFC-woFB). The maximum current density in the SMFC-wFB was also 3.9 times higher (220.46 mA/m2) than for the SMFC-woFB. We found that the increased performance in the SMFC-wFB was due to the improved mass transfer rate of organic matter obtained by employing the water-layer during anode installation in the sediment layer. Acetate injection tests revealed that the SMFC-wFB could be applied to natural water bodies in which there is frequent organic contamination, based on the acetate flux from the cathode to the anode. PMID:26714176

  9. Clear salt water above sediment-laden fresh water: Interfacial instabilities

    NASA Astrophysics Data System (ADS)

    Schulte, B.; Konopliv, N.; Meiburg, E.

    2016-05-01

    The stability of an interface separating less dense, clear salt water above from more dense, sediment-laden fresh water below is explored via direct numerical simulations. We find that the destabilizing effects of double diffusion and particle settling amplify each other above the diffusive interface, whereas they tend to cancel each other below. For moderate settling velocities, plumes form both above and below the interface, whereas for large settling velocities plume formation below the interface is suppressed. We identify the dimensionless parameter that determines in which regime a given flow takes place, along with the critical value at which the transition between the regimes takes place.

  10. Forced convection heat transfer to air/water vapor mixtures

    NASA Technical Reports Server (NTRS)

    Richards, D. R.; Florschuetz, L. W.

    1986-01-01

    Heat transfer coefficients were measured using both dry air and air/water vapor mixtures in the same forced convection cooling test rig (jet array impingement configurations) with mass ratios of water vapor to air up to 0.23. The primary objective was to verify by direct experiment that selected existing methods for evaluation of viscosity and thermal conductivity of air/water vapor mixtures could be used with confidence to predict heat transfer coefficients for such mixtures using as a basis heat transfer data for dry air only. The property evaluation methods deemed most appropriate require as a basis a measured property value at one mixture composition in addition to the property values for the pure components.

  11. Sediments, porewaters and diagenesis in an urban water body, Salford, UK: impacts of remediation

    NASA Astrophysics Data System (ADS)

    Taylor, Kevin G.; Boyd, Nathan A.; Boult, Stephen

    2003-07-01

    Contaminated sediments deposited within urban water bodies commonly exert a significant negative effect on overlying water quality. However, our understanding of the processes operating within such anthropogenic sediments is currently poor. This paper describes the nature of the sediment and early diagenetic reactions in a highly polluted major urban water body (the Salford Quays of the Manchester Ship Canal) that has undergone remediation focused on the water column.The style of sedimentation within Salford Quays has been significantly changed as a result of remediation of the water column. Pre-remediation sediments are composed of a range of natural detrital grains, predominantly quartz and clay, and anthropogenic detrital material dominated by industrial furnace-derived metal-rich slag grains. Post-remediation sediments are composed of predominantly autochthonous material, including siliceous algal remains and clays. At the top of the pre-remediation sediments and immediately beneath the post-remediation sediments is a layer significantly enriched in furnace-derived slag grains, input into the basin as a result of site clearance prior to water-column remediation. These grains contain a high level of metals, resulting in a significantly enhanced metal concentration in the sediments at this depth.Porewater analysis reveals the importance of both bacterial organic matter oxidation reactions and the dissolution of industrial grains upon the mobility of nutrient and chemical species within Salford Quays. Minor release of iron and manganese at shallow depths is likely to be taking place as a result of bacterial Fe(III) and Mn(IV) reduction. Petrographic analysis reveals that the abundant authigenic mineral within the sediment is manganese-rich vivianite, and thus Fe(II) and Mn(II) released by bacterial reactions may be being taken up through the precipitation of this mineral. Significant porewater peaks in iron, manganese and silicon deeper in the sediment column are

  12. Interparticle collision of natural sediment grains in water

    USGS Publications Warehouse

    Schmeeckle, M.W.; Nelson, J.M.; Pitlick, J.; Bennett, J.P.

    2001-01-01

    Elastohydrodynamic theory and measurements of particle impacts on an inclined glass plane in water are used to investigate the mechanics of interparticle collisions in sediment-transporting flows. A collision Stokes number is proposed as a measure of the momentum of an interparticle collision versus the viscous pressure force in the interstitial gap between colliding particles. The viscous pressure force opposes motion of the particles on approach and rebound. A Stokes number of between 39 and 105 is estimated as the critical range below which particle impacts are completely viscously damped and above which impacts are partially elastic. The critical Stokes number is shown to roughly coincide with the Bagnold number transition between macroviscous and grain inertial debris flows and the transition between damped and partially elastic bed load transport saltation impacts. The nonspherical nature of natural particles significantly alters the motion of the center of mass after a partially elastic collision. The normal to the point of contact between the particles does not necessarily go through the center of mass. Thus normal rebound of the center of mass may not occur. A model of particle motion after rebound for particles of arbitrary shape, conserving both linear and angular momentum, is proposed.

  13. Sudden clearing of estuarine waters upon crossing the threshold from transport to supply regulation of sediment transport as an erodible sediment pool is depleted: San Francisco Bay, 1999

    USGS Publications Warehouse

    Schoellhamer, David H.

    2011-01-01

    The quantity of suspended sediment in an estuary is regulated either by transport, where energy or time needed to suspend sediment is limiting, or by supply, where the quantity of erodible sediment is limiting. This paper presents a hypothesis that suspended-sediment concentration (SSC) in estuaries can suddenly decrease when the threshold from transport to supply regulation is crossed as an erodible sediment pool is depleted. This study was motivated by a statistically significant 36% step decrease in SSC in San Francisco Bay from water years 1991–1998 to 1999–2007. A quantitative conceptual model of an estuary with an erodible sediment pool and transport or supply regulation of sediment transport is developed. Model results confirm that, if the regulation threshold was crossed in 1999, SSC would decrease rapidly after water year 1999 as observed. Estuaries with a similar history of a depositional sediment pulse followed by erosion may experience sudden clearing.

  14. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    USGS Publications Warehouse

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  15. Specific features of aluminum nanoparticle water and wet air oxidation

    SciTech Connect

    Lozhkomoev, Aleksandr S. Glazkova, Elena A. Svarovskaya, Natalia V. Bakina, Olga V. Kazantsev, Sergey O. Lerner, Marat I.

    2015-10-27

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation.

  16. Specific features of aluminum nanoparticle water and wet air oxidation

    NASA Astrophysics Data System (ADS)

    Lozhkomoev, Aleksandr S.; Glazkova, Elena A.; Svarovskaya, Natalia V.; Bakina, Olga V.; Kazantsev, Sergey O.; Lerner, Marat I.

    2015-10-01

    The oxidation processes of the electrically exploded aluminum nanopowders in water and in wet air are examined in the paper. The morphology of the intermediate reaction products of aluminum oxidation has been studied using the transmission electron microscopy. It was shown that the aluminum nanopowder water oxidation causes the formation of the hollow spheres with mesoporous boehmite nanosheets coating. The wedge-like bayerite particles are formed during aluminum nanopowder wet air oxidation.

  17. ECO: A Generic Eutrophication Model Including Comprehensive Sediment-Water Interaction

    PubMed Central

    Smits, Johannes G. C.; van Beek, Jan K. L.

    2013-01-01

    The content and calibration of the comprehensive generic 3D eutrophication model ECO for water and sediment quality is presented. Based on a computational grid for water and sediment, ECO is used as a tool for water quality management to simulate concentrations and mass fluxes of nutrients (N, P, Si), phytoplankton species, detrital organic matter, electron acceptors and related substances. ECO combines integral simulation of water and sediment quality with sediment diagenesis and closed mass balances. Its advanced process formulations for substances in the water column and the bed sediment were developed to allow for a much more dynamic calculation of the sediment-water exchange fluxes of nutrients as resulting from steep concentration gradients across the sediment-water interface than is possible with other eutrophication models. ECO is to more accurately calculate the accumulation of organic matter and nutrients in the sediment, and to allow for more accurate prediction of phytoplankton biomass and water quality in response to mitigative measures such as nutrient load reduction. ECO was calibrated for shallow Lake Veluwe (The Netherlands). Due to restoration measures this lake underwent a transition from hypertrophic conditions to moderately eutrophic conditions, leading to the extensive colonization by submerged macrophytes. ECO reproduces observed water quality well for the transition period of ten years. The values of its process coefficients are in line with ranges derived from literature. ECO’s calculation results underline the importance of redox processes and phosphate speciation for the nutrient return fluxes. Among other things, the results suggest that authigenic formation of a stable apatite-like mineral in the sediment can contribute significantly to oligotrophication of a lake after a phosphorus load reduction. PMID:23844160

  18. Parameterization of biogeochemical sediment-water fluxes using in-situ measurements and a steady-state diagenetic model

    NASA Astrophysics Data System (ADS)

    Laurent, Arnaud; Fennel, Katja; Wilson, Robin; Lehrter, John; Devereux, Richard

    2014-05-01

    Sediment biogeochemical processes are important drivers of water column biogeochemistry in coastal areas. For example, sediment oxygen consumption can be an important driver of bottom water oxygen depletion in hypoxic systems, and sediment-water nutrient fluxes support primary productivity in the overlying water column. Yet, biogeochemical sediment-water fluxes are often parameterized crudely and only poorly constrained in coupled physical-biogeochemical models. Here, we present a method for parameterizing biogeochemical sediment-water fluxes realistically and efficiently, using in-situ measurements and a steady state diagenetic model. We apply this method to the Louisiana Shelf where high primary production induced by excess nutrient loads from the Mississippi-Atchafalaya River system promotes the development of hypoxic bottom waters in summer. The implementation of the parameterizations in a coupled circulation-biogeochemical model of the northern Gulf of Mexico results in realistic sediment-water fluxes that enable a sediment-water column feedback at low bottom oxygen concentrations.

  19. Ground-water seepage and sulfur diagenesis in acidified lake sediments

    SciTech Connect

    McIntire, P.E.

    1988-01-01

    Most sulfur diagenesis models predict that porewater SO{sub 4}{sup 2{minus}} concentrations will decrease exponentially with increasing sediment depth and will be lower than that of the overlying water throughout the sediments. Sulfate concentrations below 0.2 mM are common in Lake Anna sediments which receive acid mine drainage; however, sediment porewater containing up to 29 mM SO{sub 4}{sup 2{minus}} is also seen at about 20 cm below the sediment surface in this section of the lake. A decision tree was used to investigate the cause of the high SO{sub 4}{sup 2{minus}} concentrations at depth (HSD) in the sediment. The first hypothesis was that increased ground-water flow through Lake Anna HSD sediments, relative to the non-HSD sediments, increases groundwater advection of SO{sub 4}{sup 2{minus}} or of oxygen which would induce sulfide oxidation. Stations having HSD profiles did not have higher groundwater flow than other sites samples. Alternative explanations for the HSD profiles were that the region in which they occurred had (1) unusual sediment chemical compositions; (2) groundwater seepage containing unusually high sulfate concentrations; or (3) a lateral intrusion of high SO{sub 4}{sup 2{minus}} water from the sulfide mines which supplied SO{sub 4}{sup 2{minus}} to the HSD region before the lake was impounded.

  20. Toxicity tests of effluents with marsh plants in water and sediment

    SciTech Connect

    Walsh, G.E.; Weber, D.E.; Simon, T.L.; Brashers, L.K.

    1991-01-01

    Methods are described for toxicity testing of water and sediment with two varieties of the freshwater marsh plant Echinochloa crusgalli (Linneaus) Palisot de Beauvois (Poaceae), and complex effluents. Two tests are described: a seed germination and early seedling growth test in water, and a survival and seedling growth test in natural and synthetic sediments. Effects of effluents from a sewage treatment plant, tannery, textile mill, pulp and paper mill, coking plant and sewage treatment plant included inhibition of germination, chlorophyll synthesis and growth. The tests with rooted marsh plants were sensitive to pollutants and detected toxicity of a range of pollutants in water and sediment. Synthetic sediments similar to natural sediments allowed toxicity tests to be done under carefully controlled conditions of particle size distribution, organic content, pH, electrode potential (Eh) and cation exchange capacity (CEC).

  1. Summary of Suspended-Sediment Concentration Data, San Francisco Bay, California, Water Year 2005

    USGS Publications Warehouse

    Buchanan, Paul A.; Lionberger, Megan A.

    2007-01-01

    Suspended-sediment concentration data were collected by the U.S. Geological Survey in San Francisco Bay during water year 2005 (October 1, 2004-September 30, 2005). Optical sensors and water samples were used to monitor suspended-sediment concentration at two sites in Suisun Bay, three sites in San Pablo Bay, two sites in Central San Francisco Bay, and three sites in South San Francisco Bay. Sensors were positioned at two depths at most sites. Water samples were collected periodically and analyzed for concentrations of suspended sediment. The results of the analyses were used to calibrate the output of the optical sensors so that a record of suspended-sediment concentrations could be derived. This report presents the data-collection methods used and summarizes, in graphs, the suspended-sediment concentration data collected from October 2004 through September 2005. Calibration curves and plots of the processed data for each sensor also are presented.

  2. Assessing the occurrence and distribution of pyrethroids in water and suspended sediments

    USGS Publications Warehouse

    Hladik, M.L.; Kuivila, K.M.

    2009-01-01

    The distribution of pyrethroid insecticides in the environment was assessed by separately measuring concentrations in the dissolved and suspended sediment phases of surface water samples. Filtered water was extracted by HLB solid-phase extraction cartridges, while the sediment on the filter was sonicated and cleaned up using carbon and aluminum cartridges. Detection limits for the 13 pyrethroids analyzed by gas chromatography-tandem mass spectrometry were 0.5 to 1 ng L-1 for water and 2 to 6 ng g for the suspended sediments. Seven pyrethroids were detected in six water samples collected from either urban or agricultural creeks, with bifenthrin detected the most frequently and at the highest concentrations. In spiked water samples and field samples, the majority of the pyrethroids were associated with the suspended sediments.

  3. A multi-level pore-water sampler for permeable sediments

    USGS Publications Warehouse

    Martin, J.B.; Hartl, K.M.; Corbett, D.R.; Swarzenski, P.W.; Cable, J.E.

    2003-01-01

    The construction and operation of a multi-level piezometer (multisampler) designed to collect pore water from permeable sediments up to 230 cm below the sediment-water interface is described. Multisamplers are constructed from 1 1/2 inch schedule 80 PVC pipe. One-quarter-inch flexible PVC tubing leads from eight ports at variable depths to a 1 1/2 inch tee fitting at the top of the PVC pipe. Multisamplers are driven into the sediments using standard fence-post drivers. Water is pumped from the PVC tubing with a peristaltic pump. Field tests in Banana River Lagoon, Florida, demonstrate the utility of multisamplers. These tests include collection of multiple samples from the permeable sediments and reveal mixing between shallow pore water and overlying lagoon water.

  4. Predicting pollutant concentrations in the water column during dredging operations: Implications for sediment quality criteria.

    PubMed

    Wasserman, Julio Cesar; Wasserman, Maria Angélica V; Barrocas, Paulo Rubens G; Almeida, Aline Mansur

    2016-07-15

    The development of new dredging techniques that can reduce, or at least predict, the environmental impacts, is in high demand by governments in developing countries. In the present work, a new methodology was developed, to evaluate the level of metals contamination (i.e. cadmium, lead and zinc) of the water column, during a dredging operation. This methodology was used to evaluate the impacts of the construction of a new maritime terminal in Sepetiba Bay, Brazil. The methodology quantifies the amount of resuspended sediments and calculates the expected contaminants concentrations in the water column. The results indicated that sediment quality criteria were not compatible with water quality criteria, because the dredging of contaminated sediments does not necessarily yield contaminated water. It is suggested that the use of sediment quality criteria for dredging operations might be abandoned, and the methodology presented in this study applied to assess dredging's environmental impacts, predicting water contamination levels. PMID:27216043

  5. Bottom Topography, Recent Sedimentation and Water Volume of the Cerro Prieto Dam, NE Mexico

    NASA Astrophysics Data System (ADS)

    Yutsis, V. V.

    2012-12-01

    Cerro Prieto dam, relatively small water reservoir in the NE of Mexico, is characterized by a very high velocity of recent sedimentation, irregular bottom topography and sub-bottom seepage. Very high resolution seismic study using non-linear parametric echo sounder SES-2000 was carried out in this water reservoir, which is one of the main resources of potable water for the Monterrey, the city with a population of about four million inhabitants. A strong difference between water depth and hence the volume capacity calculated by National Commission of Water (Comision Nacional del Agua, CNA), Digital Elevation Model (DEM), and acoustic data was discovered. Very high rate of recent sedimentation due to damming is discussed. SES data interpretation shows that the thickness of recent sediments due to siltation of the reservoir reaches 3.5-4.0 m. Differences between the CNA and SES data indicate storage losses from 8-10 up to 30 million cubic meters due to sedimentation.

  6. Modelling nutrient exchange at the sediment water interface of river systems

    NASA Astrophysics Data System (ADS)

    Thouvenot, Marie; Billen, Gilles; Garnier, Josette

    2007-07-01

    SummaryIn-stream benthic processes can play a significant role on the water quality of overlying waters flowing through a river network. In order to better understand and quantify the fate of nutrients (nitrogen, phosphorus and silica) during their travel through the river continuum, a deterministic benthic sub-model was developed with the purpose of being connected to a drainage network model. This benthic sub-model resolves the differential equations representing early diagenesis in the sediment, linking the sedimentation rate of organic matter onto the sediment to the resulting flux of nutrients across the sediment-water interface. The model has been developed for conditions where sedimentation prevails as well as for situations where net erosion prevents the built-up of a significant sediment layer and where only a biofilm can develop, attached to solid substrates. The benthic model was tested independently of the main water column biological-hydrological model to which it is intended to be coupled. For this, three case studies were chosen from the literature representing various sedimentation/erosion conditions: the 8th order river Seine (France), the water storage basin of Méry s/Oise (France), and the headwater stream Orneau (Belgium). The general benthic model has been validated for ammonium, nitrate, oxygen and phosphorus fluxes across the sediment-water interface. The capability of the model to correctly predict the observed nutrients profiles within the sediment was also validated for organic carbon, ammonium and phosphorus. An uncertainty analysis showed that using two modelling objectives (observed fluxes and concentration profiles in the sediment) strongly reduces the uncertainty in parameters calibration. A sensitivity analysis illustrated the complexity of the interacting reactions driving each variable, and justifies the usefulness of the model as a tool for understanding and predicting the behaviour of the benthic compartment of river systems.

  7. IMPACT OF STORM-WATER OUTFALLS ON SEDIMENT QUALITY IN CORPUS CHRISTI BAY, TEXAS, USA

    EPA Science Inventory

    To determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm-water outfalls, but 13 other sites (i.e., industr...

  8. DEGRATION OF SELECTED HALOGENATED ETHANES IN ANOXIC SEDIMENT-WATER SYSTEMS

    EPA Science Inventory

    The degradation of selected halogenated ethanes was studied in anoxic sediment-water suspensions at 1 to 20% sediment concentrations. Batch kinetic experiments were used to quantify decay. Eh measurements of all suspensions were below -100mV (vs SHE), indicating reduced environme...

  9. AUTOMATED LONG-TERM REMOTE MONITORING OF SEDIMENT-WATER INTERFACIAL FLUX

    EPA Science Inventory

    Advective flux across the sediment-water interface is temporally and spatially heterogeneous in nature. For contaminated sediment sites, monitoring spatial as well as temporal variation of advective flux is of importance to proper risk management. This project was conducted to ...

  10. 30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., sediment, or slurry impoundment and impounding structure which meets the requirements of 30 CFR 77.216(a... ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-5 Water, sediment...

  11. A reservoir operating method for riverine ecosystem protection, reservoir sedimentation control and water supply

    NASA Astrophysics Data System (ADS)

    Yin, Xin-An; Yang, Zhi-Feng; Petts, Geoffrey E.; Kondolf, G. Mathias

    2014-05-01

    Riverine ecosystem protection requires the maintenance of natural flow and sediment regimes downstream from dams. In reservoir management schedules this requirement should be integrated with sedimentation control and human water supply. However, traditional eco-friendly reservoir operating methods have usually only considered the natural flow regime. This paper seeks to develop a reservoir operating method that accounts for both the natural flow and sediment regimes as well as optimizing the water supply allocations. Herein, reservoir water level (RWL), sediment-occupied ratio of reservoir volume (SOR) and rate of change of SOR (RCSOR) are adopted as three triggers of a drawdown-flushing-based sediment management policy. Two different groups of reservoir operating rule curves (RORCs) are designed for sediment-flushing and non-sediment-flushing years, and the three triggers, RWL, SOR and RCSOR, are used to change the “static” RORCs to “dynamic” ones. The approach is applied to the Wangkuai Reservoir, China to test its effectiveness. This shows that the approach can improve the flexibility of reservoir operators to balance the reservoir management, water supply management and the flow and sediment needs of the downstream riverine ecosystem.

  12. The transport of fine-grained sediments in shallow waters

    NASA Astrophysics Data System (ADS)

    Ziegler, Carl Kirk; Lick, Wilbert

    1988-02-01

    A numerical model of the resuspension, deposition, and transport of fine-grained, cohesive sediments has been developed and applied. An essential part of this model is an accurate and physically realistic description of the sediment bed and the resuspension of the bottom sediments due to physical processes. The description is based on data from recent experimental and field work on fine-grained sediments. Pertinent results from this work have been incorporated into the present model, and as part of the calculation, changes in the resuspension properties of the sediment bed with time due to resuspension, deposition, and compaction can be approximately determined. Vertically integrated differential equations were used to approximate the hydrodynamic and sediment transport equations. A volume integral method was used to derive finite difference equations which are second-order accurate, explicit, and locally conservative. A unique feature of the numerical model is that it can successfully treat conditions at open boundaries where both incoming and outgoing waves or disturbances may be present. The model has been applied to the resuspension, deposition, and transport of fine-grained sediments in (1) the Raisin River, a small polluted stream flowing into Lake Erie; (2) a river flowing into a lake or ocean with a cross-flow; and (3) a time-dependent flow in a simple estuary as affected by tidal currents. The formation of erosional and depositional areas under various conditions is demonstrated.

  13. Towards the development of a combined Norovirus and sediment transport model for coastal waters

    NASA Astrophysics Data System (ADS)

    Barry, K.; O'Kane, J. P. J.

    2009-04-01

    Sewage effluent in coastal waters used for oyster culture poses a risk to human health. The primary pathogen in outbreaks of gastroenteritis following consumption of raw oysters is the Norovirus or "winter vomiting bug". The Norovirus is a highly infectious RNA virus of the Caliciviridae taxonomic family. It has a long survival time in coastal waters (T90 = 30 days in winter). Oysters selectively concentrate Norovirus in their digestive ducts. The virus cannot be removed by conventional depuration. The primary goal of the research is to quantify the risk of Norovirus infection in coastal waters through physically-based high-resolution numerical modelling. Cork Harbour and Clew Bay in Ireland provide case studies for the research. The models simulate a number of complex physical, chemical and biological processes which influence the transport and decay of the virus as well as its bioaccumulation in oyster tissue. The current phase of the research is concerned with the adsorption of the virus to suspended sediment in the water column. Adsorbed viruses may be taken out of the water column when sedimentation occurs and, subsequently, be added to it with resuspension of the bed sediment. Preliminary simulations of the Norovirus-sediment model indicate that suspended sediment can influence the transport of the virus in coastal waters when a high sediment-water partitioning coefficient is used and the model is run under calm environmental conditions. In this instance a certain fraction of the adsorbed viruses are taken out of the water column by sedimentation and end up locked in the bed sediment. Subsequently, under storm conditions, a large number of viruses in the bed are released into the water column by erosion of the bed and a risk of contamination occurs at a time different to when the viruses were initially released into the body of water.

  14. Spatial and temporal variability of CO2 fluxes at the sediment-air interface in a tidal flat of a temperate lagoon (Arcachon Bay, France)

    NASA Astrophysics Data System (ADS)

    Migné, Aline; Davoult, Dominique; Spilmont, Nicolas; Ouisse, Vincent; Boucher, Guy

    2016-03-01

    This study aimed to explore the spatial and temporal variability of benthic metabolism in a temperate mesotidal lagoon. This was achieved by measuring fluxes of CO2 in static chambers during emersion, both under light and dark conditions. Three sample sites were selected according to their tidal level (upper or mid), their sediment type (sand or mud) and the presence/absence of the seagrass Zostera noltei. The three sites were investigated at three seasons (end of winter, spring and beginning of autumn). At each site and each season, three benthic chambers were used simultaneously in successive incubations over the emersion period. The sediment chlorophyll-a content varied seasonally in the upper sands (reaching 283 mg.m- 2 in spring) but not in the mid muds (averaging 142 mg m- 2 in bare muds and 186 mg m- 2 in muds covered by seagrass). The maximum sediment CO2-uptake under light was 9.89 mmol m- 2 h- 1 in the mid-bare muds, in early autumn. The maximum sediment CO2-release under darkness was 6.97 mmol m- 2 h- 1 in the mid muds covered by seagrass, in spring. Both CO2-fluxes measured in the light and in the dark increased over periods of emersion. This increase, not related to light nor temperature variations, could be explained by changes in the amount and chemistry of pore water during the air exposure of sediments. The benthic trophic state index, based on the maximum light CO2-flux versus maximum dark CO2-flux ratio, assigned to each site at each season indicated that the sediments were net autotrophic in spring in upper sands and in mid muds covered by seagrass and highly autotrophic in other cases. The most autotrophic sediments were the mid-level bare muds whatever the season. The relevance of this index is discussed compared to carbon annual budget.

  15. Cold water aquifer storage. [air conditioning

    NASA Technical Reports Server (NTRS)

    Reddell, D. L.; Davison, R. R.; Harris, W. B.

    1980-01-01

    A working prototype system is described in which water is pumped from an aquifer at 70 F in the winter time, chilled to a temperature of less than 50 F, injected into a ground-water aquifer, stored for a period of several months, pumped back to the surface in the summer time. A total of 8.1 million gallons of chilled water at an average temperature of 48 F were injected. This was followed by a storage period of 100 days. The recovery cycle was completed a year later with a total of 8.1 million gallons recovered. Approximately 20 percent of the chill energy was recovered.

  16. Spatial variability of metals in surface water and sediment in the langat river and geochemical factors that influence their water-sediment interactions.

    PubMed

    Lim, Wan Ying; Aris, Ahmad Zaharin; Zakaria, Mohamad Pauzi

    2012-01-01

    This paper determines the controlling factors that influence the metals' behavior water-sediment interaction facies and distribution of elemental content ((75)As, (111)Cd, (59)Co, (52)Cr, (60)Ni, and (208)Pb) in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals' concentration varied among stations. Metal concentrations of water ranged between 0.08-24.71 μg/L for As, <0.01-0.53 μg/L for Cd, 0.06-6.22 μg/L for Co, 0.32-4.67 μg/L for Cr, 0.80-24.72 μg/L for Ni, and <0.005-6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47-30.04 mg/kg for As, 0.02-0.18 mg/kg for Cd, 0.87-4.66 mg/kg for Co, 4.31-29.04 mg/kg for Cr, 2.33-8.25 mg/kg for Ni and 5.57-55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb) were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans. PMID:22919346

  17. Remote sensing of suspended sediment water research: principles, methods, and progress

    NASA Astrophysics Data System (ADS)

    Shen, Ping; Zhang, Jing

    2011-12-01

    In this paper, we reviewed the principle, data, methods and steps in suspended sediment research by using remote sensing, summed up some representative models and methods, and analyzes the deficiencies of existing methods. Combined with the recent progress of remote sensing theory and application in water suspended sediment research, we introduced in some data processing methods such as atmospheric correction method, adjacent effect correction, and some intelligence algorithms such as neural networks, genetic algorithms, support vector machines into the suspended sediment inversion research, combined with other geographic information, based on Bayesian theory, we improved the suspended sediment inversion precision, and aim to give references to the related researchers.

  18. Contribution of Streptomyces in sediment to earthy odor in the overlying water in Xionghe Reservoir, China.

    PubMed

    Zuo, Yanxia; Li, Lin; Zhang, Ting; Zheng, Lingling; Dai, Gongyuan; Liu, Liming; Song, Lirong

    2010-12-01

    Musty and earthy odors frequently characterize the source water and fish of the Xionghe Reservoir in China. Although odorous compounds and odor-producing cyanobacteria have been analyzed in surface water, potential odorants in sediments and their contribution to the water body have remained uninvestigated. In this study, we examined the odorous compounds and possible odor-producers in the sediments and overlying water of Xionghe Reservoir from November 2007 to October 2008. High concentrations of geosmin (up to 5280.1 ng kg(-1) dw(-1)) were detected in sediments, and eight strains of Streptomyces isolated from sediments were verified as producers of geosmin and/or 2-MIB in M liquid medium by HSPME-GC-MS. Geosmin concentrations in the overlying water were correlated with those in the sediments (r = 0.838, p < 0.05). In vitro studies showed that geosmin in the overlying water was released from the sediment, and that within 12 days the amount released from the sediment was 21.4-51.4%. Concentrations of geosmin in sediments were positively correlated with organic matter (r = 0.642, p < 0.01), total nitrogen (r = 0.606, p < 0.01) and Chl a (r = 0.674, p < 0.01), and were negatively associated with temperature (r = -0.425, p < 0.05). This study indicates that odorous compounds that are released from sediments should be taken into account when assessing the sources of these odorants in waters. PMID:20800260

  19. Oxygen consumption in the water column and sediments of the northern Gulf of Mexico hypoxic zone

    NASA Astrophysics Data System (ADS)

    McCarthy, Mark J.; Carini, Stephen A.; Liu, Zhanfei; Ostrom, Nathaniel E.; Gardner, Wayne S.

    2013-05-01

    Hypoxia is a global problem resulting from excessive nutrient inputs to coastal regions, but the biogeochemical mechanisms of hypoxia development are not well understood. The primary location of oxygen consumption (i.e., sediments versus water column) is still debated and may depend on the analytical approach used. In this study, oxygen respiration was measured using incubations combined with membrane inlet mass spectrometry in sediments, water overlying sediments, and the water column in the Gulf of Mexico hypoxic zone. Water column respiration ranged from 0.09 to 4.42 μmol O2 l-1 h-1 (mean = 0.77 ± 0.07 (standard error)) and was significantly higher shortly after two hurricanes. Overlying water respiration ranged from 0.31 to 2.46 μmol O2 l-1 h-1 (mean = 0.70 ± 0.09) and accounted for 3.7 ± 0.8% of total below-pycnocline respiration. Sediment oxygen consumption, measured using a continuous-flow incubation technique, was lowest after the two hurricanes and ranged from 408 to 1800 μmol O2 m-2 h-1 (mean = 834 ± 83.8 μmol O2 m-2 h-1). Sediments accounted for 25 ± 5.3% of total below-pycnocline respiration, and sediment oxygen consumption was related negatively to ambient bottom-water oxygen concentration. This negative relationship contradicts previous literature and suggests that high sediment oxygen consumption is driven by abundant, fresh organic material and regulates bottom-water oxygen concentration, rather than the common assumption that bottom-water oxygen concentration determines sediment oxygen consumption. The results from this study suggest that storms and mixing events may lead to conditions suitable for hypoxia redevelopment in as little as two days after disturbances, with the water column playing a critical role in system hypoxia development and maintenance.

  20. Carbon dioxide production in surface sediments of temporarily anoxic basins (Baltic Sea) and resulting sediment-water interface fluxes

    NASA Astrophysics Data System (ADS)

    Böttcher, M. E.; Al-Raei, A. M.; Winde, V.; Lenz, C.; Dellwig, O.; Leipe, T.; Segl, M.; Struck, U.

    2009-04-01

    Organic matter is mineralized in marine sediments by microbial activity using predominantly oxygen, sulfate, and metal oxides as electron acceptors. Modern euxinic basins as found in the Baltic Sea or the Black Sea are of particular importance because they may serve as type systems for anoxia in Earth's history. We present here results from biogeochemical investigations carried out in the Baltic deeps (Gotland Basin, Landsort Deep) during the first scientific cruise of RV M.S. MERIAN in 2006, additionally during RV Prof. Penck cruises in 2006 and 2007. Short sediment cores were obtained with a multi-corer and analyzed for particulate and dissolved main, minor and trace elements, pH, DIC, methane alkalinity, besides the stable carbon isotopes of dissolved inorganic carbon (DIC). Microsensors were applied to analyze steep gradients of oxygen, sulphide and sulphate. Pore water profiles are evaluated in terms of process rates and associated element fluxes using the PROFILE software (Berg et al., 1998, L&O). Gross and net anaerobic mineralization rates were additionally obtained from core incubations with 35S. Steep gradients in DIC are associated with a strong enrichment of the light stable isotope resulting in the Gotland basin from oxidized OM. Element fluxes across the sediment-water interface are compared with literature data and show for the Baltic Sea a dependence from bottom water redox conditions, and sediment compositions and formation conditions (e.g., accumulation rates). DIC in the anoxic part of the water column in the Landsort Deep and the Gotland Deep show relatively similar isotope values, close to the bottom water value, but steep gradients towards heavier values above the pelagic redoxcline. Acknowledgements: The research was supported by Leibniz IO Warnemünde, DFG (Cruise RV MSM MERIAN 01), and MPG. Thanks to B. Schneider and F. Pollehne stimulating discussions, and S. Lage and A. Schipper for technical support.

  1. Partition of nonpolar organic pollutants from water to soil and sediment organic matters

    USGS Publications Warehouse

    Chiou, C.T.

    1995-01-01

    The partition coefficients (Koc) of carbon tetrachloride and 1,2-dichlorobenzene between normal soil/sediment organic matter and water have been determined for a large set of soils, bed sediments, and suspended solids from the United States and the People's Republic of China. The Koc values for both solutes are quite invariant either for the soils or for the bed sediments; the values on bed sediments are about twice those on soils. The similarity of Koc values between normal soils and between normal bed sediments suggests that natural organic matters in soils (or sediments) of different geographic origins exhibit comparable polarities and possibly comparable compositions. The results also suggest that the process that converts eroded soils into bed sediments brings about a change in the organic matter property. The difference between soil and sediment Koc values provides a basis for identifying the source of suspended solids in river waters. The very high Koc values observed for some special soils and sediments are diagnostic of severe anthropogenic contamination.

  2. Suspended-sediment characteristics for the Johnson Creek basin, Oregon, water years 2007-10

    USGS Publications Warehouse

    Stonewall, Adam J.; Bragg, Heather M.

    2012-01-01

    Significant Findings An analysis of suspended-sediment transport in the Johnson Creek basin, Oregon, during water years 2007–10 indicated that: Streamflow characteristics for the 4 years of study were not extremely dry or wet, and represented near-average conditions. Computed average annual suspended-sediment loads were 1,890 and 4,640 tons at the Gresham and Milwaukie stations, respectively. More than 70 percent of suspended-sediment transport in the watershed occurred during the high-flow months of November, December, and January. Less than 10 percent of suspended-sediment transport in the watershed occurred during April–October. About 50 percent of all suspended-sediment load is transported during the highest 1 percent of streamflows. The January 2009 streamflow peak was the third highest in the 70-year record for Johnson Creek. About 50 percent of suspended-sediment transport in water year 2009 occurred in January. The drainage area upstream of the Gresham streamflow-gaging station constitutes about 30 percent of the drainage area at the Milwaukie station, but accounted for about 40 percent of the suspended sediment and 45 percent of the streamflow at the Milwaukie station. On an annual basis, most of the higher sediment yield at the Gresham station, relative to the Milwaukie station, can be explained by the higher streamflow yield at the Gresham station rather than by higher suspended-sediment concentration.

  3. Minimizing the water and air impacts of unconventional energy extraction

    NASA Astrophysics Data System (ADS)

    Jackson, R. B.

    2014-12-01

    Unconventional energy generates income and, done well, can reduce air pollution compared to other fossil fuels and even water use compared to fossil fuels and nuclear energy. Alternatively, it could slow the adoption of renewables and, done poorly, release toxic chemicals into water and air. Based on research to date, some primary threats to water resources come from surface spills, wastewater disposal, and drinking-water contamination through poor well integrity. For air resources, an increase in volatile organic compounds and air toxics locally is a potential health threat, but the switch from coal to natural gas for electricity generation will reduce sulfur, nitrogen, mercury, and particulate pollution regionally. Critical needs for future research include data for 1) estimated ultimate recovery (EUR) of unconventional hydrocarbons; 2) the potential for further reductions of water requirements and chemical toxicity; 3) whether unconventional resource development alters the frequency of well-integrity failures; 4) potential contamination of surface and ground waters from drilling and spills; and 5) the consequences of greenhouse gases and air pollution on ecosystems and human health.

  4. Accumulation of radium in sediments from continued disposal of produced water and hydraulic fracturing flowback water

    NASA Astrophysics Data System (ADS)

    Warner, N. R.; Menio, E. C.; Landis, J. D.; Vengosh, A.; Lauer, N.; Harkness, J.; Kondash, A.

    2014-12-01

    Recent public interest in high volume slickwater hydraulic fracturing (HVHF) has drawn increased interest in wastewater management practices by the public, researchers, industry, and regulators. The management of wastes, including both fluids and solids, poses many engineering challenges, including elevated total dissolved solids and elevated activities of naturally occurring radioactive materials (NORM). One management option for wastewater in particular, which is used in western Pennsylvania, USA, is treatment at centralized waste treatment facilities [1]. Previous studies conducted from 2010-2012 indicated that one centralized facility, the Josephine Brine Treatment facility, removed the majority of radium from produced water and hydraulic fracturing flowback fluid (HFFF) during treatment, but low activities of radium remained in treated effluent and were discharged to surface water [2]. Despite the treatment process and radium reduction, high activities (200 times higher than upstream/background) accumulated in stream sediments at the point of effluent discharge. Here we present new results from sampling conducted at two additional centralized waste treatment facilities (Franklin Brine Treatment and Hart Brine Treatment facilities) and Josephine Brine Treatment facility conducted in June 2014. Preliminary results indicate radium is released to surface water at very low (<50 pCi/L) to non-detectable activities, however; radium continues to accumulate in sediments surrounding the area of effluent release. Combined, the data indicate that 1) radium continues to be released to surface water streams in western Pennsylvania despite oil and gas operators voluntary ban on treatment and disposal of HFFF in centralized waste treatment facilities, 2) radium accumulation in sediments occurred at multiple brine treatment facilities and is not isolated to a single accidental release of contaminants or a single facility. [1] Wilson, J. M. and J. M. VanBriesen (2012). "Oil and

  5. Forced convection heat transfer to air/water vapor mixtures

    NASA Technical Reports Server (NTRS)

    Richards, D. R.; Florschuetz, L. W.

    1984-01-01

    Heat transfer coefficients were measured using both dry and humid air in the same forced convection cooling scheme and were compared using appropriate nondimensional parameters (Nusselt, Prandtl and Reynolds numbers). A forced convection scheme with a complex flow field, two dimensional arrays of circular jets with crossflow, was utilized with humidity ratios (mass ratio of water vapor to air) up to 0.23. The dynamic viscosity, thermal conductivity and specific heat of air, steam and air/steam mixtures are examined. Methods for determining gaseous mixture properties from the properties of their pure components are reviewed as well as methods for determining these properties with good confidence. The need for more experimentally determined property data for humid air is discussed. It is concluded that dimensionless forms of forced convection heat transfer data and empirical correlations based on measurements with dry air may be applied to conditions involving humid air with the same confidence as for the dry air case itself, provided that the thermophysical properties of the humid air mixtures are known with the same confidence as their dry air counterparts.

  6. An air-water interfacial area based variable tortuosity model for unsaturated sands

    SciTech Connect

    Khaleel, Raziuddin; Saripalli, Prasad

    2006-05-01

    Based on Kozeny-Carman equation for saturated media permeability, a new model is developed for the prediction of unsaturated hydraulic conductivity, K as a function of moisture content, ?. The K(???) estimates are obtained using laboratory measurements of moisture retention and saturated hydraulic conductivity, and a saturation-dependent tortuosity based on the immiscible fluid (air-water) interfacial area. Tortuosity (?a) for unsaturated media is defined as aaw/aaw,o (ratio of the specific air-water interfacial area of a real and the corresponding idealized porous medium). A correspondence between the real and idealized media is established by using the laboratory-measured soil moisture retention curve to calculate the interfacial area. The general trend in prediction of ?a as a function water saturation is in agreement with similar recent predictions based on diffusion theory. Unsaturated hydraulic conductivities measured for a number of coarse-textured, repacked Hanford sediments agree well with predictions based on the modified Kozeny-Carman relation. Because of the use of saturated hydraulic conductivity, a slight bias is apparent in measured and predicted K at low ?. While the modified Kozeny-Carman relation was found to be reasonably accurate in predicting K(??) for the repacked, sandy soils considered in this study, a further testing of the new model for undisturbed sediments and other soil textures would be useful.

  7. Fremont Lake, Wyoming--some aspects of the inflow of water and sediment

    USGS Publications Warehouse

    Emmett, W.W.; Averett, R.C.

    1989-01-01

    Fremont Lake is a large (20.6 sq km), deep lake (185 m) in western Wyoming. Average annual inflow of water is about 5.1 cu meters/sec, and this discharge is equaled or exceeded about 23% of the time. Annual instantaneous peak flows of Pine Creek usually exceed 30 cu m/sec and the 100-year flood is about 80 cu m/sec. About 800 tons of sediment are delivered to the lake annually; annual deposition of sediment in the northern lake area throughout the last 10,000 years about equals contemporary values of sediment inflow. Only small quantities of fine-gradient sediment are transported beyond the delta at the northern end of the lake. Current rates of deposition in the delta are about 1 to 3 mm/yr. Sediment in the delta generally is sand size; elsewhere in the lake, sediment generally is clay and silt size. (USGS)

  8. MONITORING OXIDATION-REDUCTION PROCESSES IN GROUND WATERS, SEDIMENTS, AND SOILS

    EPA Science Inventory

    The overall goal of this project is to develop recommendations and technical guidelines for evaluating redox processes in contaminated ground water, sediment, and soil systems. One specific goal is to evaluate existing methodologies for determining Dissolved Oxygen (DO) concentra...

  9. TOXICITY TESTS OF EFFLUENTS WITH MARSH PLANTS IN WATER AND SEDIMENT

    EPA Science Inventory

    Methods are described for toxicity testing of water and sediment with the rooted marsh plants, Echinochloa crusgalli var. crusgalli and var. zelavensis (freshwater) and Spartina alterniflora (estuarine). ive industrial effluents, a sewage treatment plant effluent and a herbicide ...

  10. METAL SPECIATION IN SOIL, SEDIMENT, AND WATER SYSTEMS VIA SYNCHROTRON RADIATION RESEARCH

    EPA Science Inventory

    Metal contaminated environmental systems (soils, sediments, and water) have challenged researchers for many years. Traditional methods of analysis have employed extraction methods to determine total metal content and define risk based on the premise that as metal concentration in...

  11. Development of a standard operating procedure for the collection of pyrethroids in water and sediment matrices

    EPA Science Inventory

    Through a Regional Applied Research Effort grant to the United States Geological Survey, Region 9 collaborated with ORD on this project to develop a standard operating procedure for collection of water and sediment samples for pyrethroid analysis.

  12. PRECISION OF DIALYSIS (PEEPER) SAMPLING OF CADMIUM IN MARINE SEDIMENT INTERSTITIAL WATER

    EPA Science Inventory

    Isolating and analyzing interstitial water (IW) during sediment toxicity tests enables researchers to relate concentrations of contaminants to responses of organisms, particularly when IW is a primary route of exposure to bioavailable contaminants by benthic dwelling organisms. W...

  13. Characterization of bottom-sediment, water, and elutriate chemistry at selected stations at Reelfoot Lake, Tennessee

    USGS Publications Warehouse

    Broshears, R.E.

    1991-01-01

    To better-understand and predict the potential effect of dredging on water quality at Reelfoot Lake, chemical analyses were conducted on samples of lake water, bottom sediment, and elutriate water. Chemical analyses were conducted on samples of lake water, bottom sediment, and elutriate water collected at five stations in the lake during November 1988. Lake water was of the calcium magnesium bicarbonate type with an average dissolved-solids concentration of 120 milligrams per liter. Trace constituents were present in bottom sediments at concentrations representative of their average relative abundance in the earth?s crust. Elutriate waters prepared by mixing bottom sediment and lake water had suspended-solids concentrations as high as 2,000 milligrams per liter which exerted significant oxygen demand Trace constituents in the unfiltered elutriate waters were elevated with respect to lake water; elevated concentrations were attributable to the increased suspended-solids concentrations. Concentrations of total-recoverable copper, lead., and zinc in many elutriate waters exceeded U.S. Environmental Protection Agency?s water-quality criteria for the protection of freshwater aquatic life. The toxicity of elutriate waters, as measured by a 48-hour bioassay with Ceriodaphnia dubia, was low.

  14. Dynamic Coupling of Iron, Manganese, and Phosphorus Behavior in Water and Sediment of Shallow Ice-Covered Eutrophic Lakes.

    PubMed

    Schroth, Andrew W; Giles, Courtney D; Isles, Peter D F; Xu, Yaoyang; Perzan, Zachary; Druschel, Gregory K

    2015-08-18

    Decreasing duration and occurrence of northern hemisphere ice cover due to recent climate warming is well-documented; however, biogeochemical dynamics underneath the ice are poorly understood. We couple time-series analyses of water column and sediment water interface (SWI) geochemistry with hydrodynamic data to develop a holistic model of iron (Fe), manganese (Mn), and phosphorus (P) behavior underneath the ice of a shallow eutrophic freshwater bay. During periods of persistent subfreezing temperatures, a highly reactive pool of dissolved and colloidal Fe, Mn, and P develops over time in surface sediments and bottom waters due to reductive dissolution of Fe/Mn(oxy)hydroxides below the SWI. Redox dynamics are driven by benthic O2 consumption, limited air-water exchange of oxygen due to ice cover, and minimal circulation. During thaw events, the concentration, distribution and size partitioning of all species changes, with the highest concentrations of P and "truly dissolved" Fe near the water column surface, and a relatively well-mixed "truly dissolved" Mn and "colloidal" Fe profile due to the influx of geochemically distinct river water and increased circulation. The partitioning and flux of trace metals and phosphorus beneath the ice is dynamic, and heavily influenced by climate-dependent physical processes that vary in both time and space. PMID:26206098

  15. Polycyclic aromatic hydrocarbons in water, sediment, soil, and plants of the Aojiang River waterway in Wenzhou, China

    PubMed Central

    Li, Jianwang; Shang, Xu; Zhao, Zhixu; Tanguay, Robert L.; Dong, Qiaoxiang; Huang, Changjiang

    2012-01-01

    The town of Shuitou was renowned as the leather capital of China because of its large-scale tanning industry, but the industry’s lack of pollution controls has caused severe damage to the local water system. This study determined 15 priority polycyclic aromatic hydrocarbons (PAHs) in water, sediment, soil, and plant samples collected from Aojiang River and its estuary. The total PAHs ranged from 910 to 1520 ng/L in water samples. The total PAH in sediments were moderate to low in comparison with other rivers and estuaries in China, but the relative proportions of PAHs per million people are high when considering the population size associated with each watershed. Ratios of fluoranthene/pyrene and PAHs with low/high molecular weight suggest a petrogenic PAH origin. The PAH composition profile in soil was similar to that in sediment with 4–6 ring PAHs being dominant. The PAHs with 2–3 rings were the dominant species in plant leaves. There were no correlations between PAHs in soils and in plants, suggesting that PAHs accumulate in plant leaves through absorption from the air. The general observation of elevated PAH concentrations in all matrix suggests a possible contribution by the local leather industry on the PAH concentrations in the Aojiang watershed. PMID:19726127

  16. Hydrothermal sediments are a source of water column Fe and Mn in the Bransfield Strait, Antarctica

    NASA Astrophysics Data System (ADS)

    Aquilina, Alfred; Homoky, William B.; Hawkes, Jeffrey A.; Lyons, Timothy W.; Mills, Rachel A.

    2014-07-01

    Short sediment cores were collected from ∼1100 m water depth at the top of Hook Ridge, a submarine volcanic edifice in the Central Basin of the Bransfield Strait, Antarctica, to assess Fe and Mn supply to the water column. Low-temperature hydrothermal fluids advect through these sediments and, in places, subsurface H2S is present at high enough concentrations to support abundant Sclerolinum sp., an infaunal tubeworm that hosts symbiotic thiotrophic bacteria. The water column is fully oxic, and oxygen penetration depths at all sites are 2-5 cmbsf. Pore water Fe and Mn content is high within the subsurface ferruginous zone (max. 565 μmol Fe L-1, >3-7 cmbsf)-14-18 times higher than values measured at a nearby, background site of equivalent water depth. Diffusion and advection of pore waters supply significant Fe and Mn to the surface sediment. Sequential extraction of the sediment demonstrates that there is a significant enrichment in a suite of reactive, authigenic Fe minerals in the upper 0-5 cm of sediment at one site characterised by weathered crusts at the seafloor. At a site with only minor authigenic mineral surface enrichment we infer that leakage of pore water Fe and Mn from the sediment leads to enriched total dissolvable Fe and Mn in bottom waters. An Eh sensor mounted on a towed package mapped a distinct Eh signature above this coring site which is dispersed over several km at the depth of Hook Ridge. We hypothesise that the main mechanism for Fe and Mn efflux from the sediment is breach of the surface oxic layer by the abundant Sclerolinum sp., along with episodic enhancements by physical mixing and resuspension of sediment in this dynamic volcanic environment. We propose that Hook Ridge sediments are an important source of Fe and Mn to the deep waters of the Central Basin in the Bransfield Strait, where concentrations are sustained by the benthic flux, and Fe is stabilised in the water column as either colloidal phases or ligand-bound dissolved

  17. Interrelationships of petiole air canal architecture, water depth and convective air flow in Nymphaea odorata (Nymphaeaceae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Premise of the study--Nymphaea odorata grows in water up to 2 m deep, producing fewer, larger leaves in deeper water. This species has a convective flow system that moves gases from younger leaves through submerged parts to older leaves, aerating submerged parts. Petiole air canals are in the conv...

  18. Determination of pentachlorophenol in water and aquifer sediments by high-performance liquid chromatography

    USGS Publications Warehouse

    Goerlitz, D.F.

    1981-01-01

    Methods for the determination of pentachlorophenol (PCP) in water and aquifer sediments are presented. Reverse-phase high-performance liquid chromotography employing ion suppression and gradient elution is used. PCP can be determined directly in water at a lower limit of detection Of 0.2 micrograms per liter. For extracts of sediment, PCP can be determined to a lower limit of 1.0 micrograms per kilogram.

  19. Utilizing air purge to reduce water contamination of lube systems

    SciTech Connect

    Sirois, H.J.

    1994-12-31

    Lubrication systems are exposed to contaminants including dirt, process dilutants and water. Water contamination of lubricating oil is commonly experienced by users of machinery such as steam and gas turbines, compressors, pumps, motors, generators and others. Poorly designed or maintained turbomachinery features such as bearing housing seals and shaft packing do not prevent moisture laden air, the primary source of water, from entering the lube system. This paper presents a case history where a mechanical drive steam turbine and boiler feed pump was experiencing severe water contamination of the lube system. Bearing and control system component failures resulted from water induced corrosion. Various systems and approaches for dealing with this contamination are reviewed. Installation of a very simple and cost effective system using low pressure air applied directly to the bearing housing oil seals proved a most effective method for eliminating measurable water contamination of the lubrication system and can be applied to machinery of all types.

  20. Plants Clean Air and Water for Indoor Environments

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Wolverton Environmental Services Inc., founded by longtime government environmental scientist B.C. "Bill" Wolverton, is an environmental consulting firm that gives customers access to the results of his decades of cutting-edge bioremediation research. Findings about how to use plants to improve indoor air quality have been published in dozens of NASA technical papers and in the book, "How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office." The book has now been translated into 12 languages and has been on the shelves of bookstores for nearly 10 years. A companion book, "Growing Clean Water: Nature's Solution to Water Pollution," explains how plants can clean waste water. Other discoveries include that the more air that is allowed to circulate through the roots of the plants, the more effective they are at cleaning polluted air; and that plants play a psychological role in welfare in that people recover from illness faster in the presence of plants. Wolverton Environmental is also working in partnership with Syracuse University, to engineer systems consisting of modular wicking filters tied into duct work and water supplies, essentially tying plant-based filters into heating, ventilation, and air conditioning (HVAC) systems. Also, the company has recently begun to assess the ability of the EcoPlanter to remove formaldehyde from interior environments. Wolverton Environmental is also in talks with designers of the new Stennis Visitor's Center, who are interested in using its designs for indoor air-quality filters

  1. The Determination of Metals in Sediment Pore Waters and in 1N HCl-Extracted Sediments by ICP-MS

    USGS Publications Warehouse

    May, T.W.; Wiedmeyer, R.H.; Brumbaugh, W.G.; Schmitt, C.J.

    1997-01-01

    Concentrations of metals in sediment interstitial water (pore water) and those extractable from sediment with weak acids can provide important information about the bioavailability and toxicological effects of such contaminants. The highly variable nature of metal concentrations in these matrices requires instrumentation with the detection limit capability of graphite furnace atomic absorption and the wide dynamic linear range capability of ICP-OES. These criteria are satisfied with ICP-MS instrumentation. We investigated the performance of ICP-MS in the determination of certain metals from these matrices. The results for three metals were compared to those determined by graphite furnace atomic absorption spectroscopy. It was concluded that ICP-MS was an excellent instrumental approach for the determination of metals in these matrices.

  2. A comparison of the accumulation of phenanthrene by marine amphipods in water versus sediment

    SciTech Connect

    Fusi, T.; Weber, L.J.

    1995-12-31

    The objective of this research is to compare the accumulation of the polycyclic aromatic hydrocarbon phenanthrene by marine amphipods from sediment and interstitial water versus from a water only exposure system. The equilibrium partitioning theory assumes that the exposure and response of benthic invertebrates are the same when exposed to the same contaminant concentration in water and interstitial water. In this series of experiments, three infaunal marine amphipod species; Eohaustorius estuarius (non tube-forming, burrowing amphipod), Leptocheirus plumulosus (burrow-building amphipod) and Grandidierella japonica (tube-building amphipod), were exposed to {sup 14}C-phenanthrene under three experimental conditions: (1) sediment spiked at a concentration resulting in an interstitial water concentration of 2.5 {micro}g/l phenanthrene; (2) sediment spiked at a concentration resulting in interstitial water concentration of 2.5 {micro}g/l and the overlying water spiked at 2.5 {micro}g/l phenanthrene; (3) a water only exposure with the water at a concentration of 2.5 {micro}g/l phenanthrene, The exposures were conducted in a static renewal system with the overlying and exposure water being replaced every 8 hours. The bioaccumulation of phenanthrene was followed over 72 hours. In all three species of amphipods, the accumulation of phenanthrene was significantly greater in the water only exposure than in the two sediment exposures. At 72 hours, the amphipod body burdens of phenanthrene in the water only exposures were, depending on the species, 7 to 24 times that of the sediment only exposures. The results suggest that water only exposures may overestimate sediment or interstitial exposure to phenanthrene and other nonionic, lipophilic compounds.

  3. Reservoir sediments: a sink or source of chemicals at the surface water-groundwater interface.

    PubMed

    Ammar, Rawaa; Kazpard, Véronique; Wazne, Mahmoud; El Samrani, Antoine G; Amacha, Nabil; Saad, Zeinab; Chou, Lei

    2015-09-01

    This study delineates the physical, chemical, and biological effects resulting from anthropogenic and endogenic activities in a sensitive dammed reservoir situated in a semi-arid region. The reservoir is characterized by two major flow regimes: a wet fill hydrologic regime and a dry spill one. A seasonal sampling campaign was carried out over a period of 2 years (2011-2013) where water samples were collected across the water column and from piezometers just outside the perimeter of the reservoir. Similarly, sediments were collected from the corresponding areas beneath the water column. The water samples were analyzed for environmental isotopic ratios, elemental composition, and physical, biological and chemical parameters, whereas the sediment and algal samples were subjected to physical, mineralogical, spectroscopic, and microscopic analyses. This investigation indicated that the dam had resulted in the alteration of the biogeochemical cycle of nutrients as well as the degradation of the sediment and water quality. The hydrological and biogeochemical processes were found to induce vertical downward transport of chemicals towards the fine grained calcareous sediments during the fill mode, whereas the sediments acted as a source of a chemical flux upward through the water column and downward towards the groundwater during the spill mode. The geomorphological characteristics of the reservoir enhanced the strong hydrological connectivity between the surface water and the groundwater where the reservoir responded quickly to natural and anthropogenic changes in the upper watershed. The water and sediments in the sensitive spill mode were of poor quality and should receive more attention due to the potential hazard for the associated hydro-project and the sustainability of the agricultural soil in the long term. Thus, a safe water and sediment management plan should be implemented in order to improve the dam functionality and to safeguard the precious water resources

  4. Methane flux across the air-water interface - Air velocity effects

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Harriss, R. C.; Bartlett, K. B.

    1983-01-01

    Methane loss to the atmosphere from flooded wetlands is influenced by the degree of supersaturation and wind stress at the water surface. Measurements in freshwater ponds in the St. Marks Wildlife Refuge, Florida, demonstrated that for the combined variability of CH4 concentrations in surface water and air velocity over the water surface, CH4 flux varied from 0.01 to 1.22 g/sq m/day. The liquid exchange coefficient for a two-layer model of the gas-liquid interface was calculated as 1.7 cm/h for CH4 at air velocity of zero and as 1.1 + 1.2 v to the 1.96th power cm/h for air velocities from 1.4 to 3.5 m/s and water temperatures of 20 C.

  5. LIQUID AND GAS CHROMATOGRAPHIC ANALYSIS OF DIETHYL PHTHALATE IN WATER AND SEDIMENT

    EPA Science Inventory

    Diethyl phthalate was determined in water and sediment by high performance liquid chromatography (HPLC) and in water by gas-liquid chromatography with electron capture detection (GLC-ECD). Water samples were extracted with hexane, using a high-speed homogenizer-ultrasonic apparat...

  6. Rainfall-induced runoff from exposed streambed sediments: an important source of water pollution.

    PubMed

    Frey, S K; Gottschall, N; Wilkes, G; Grégoire, D S; Topp, E; Pintar, K D M; Sunohara, M; Marti, R; Lapen, D R

    2015-01-01

    When surface water levels decline, exposed streambed sediments can be mobilized and washed into the water course when subjected to erosive rainfall. In this study, rainfall simulations were conducted over exposed sediments along stream banks at four distinct locations in an agriculturally dominated river basin with the objective of quantifying the potential for contaminant loading from these often overlooked runoff source areas. At each location, simulations were performed at three different sites. Nitrogen, phosphorus, sediment, fecal indicator bacteria, pathogenic bacteria, and microbial source tracking (MST) markers were examined in both prerainfall sediments and rainfall-induced runoff water. Runoff generation and sediment mobilization occurred quickly (10-150 s) after rainfall initiation. Temporal trends in runoff concentrations were highly variable within and between locations. Total runoff event loads were considered large for many pollutants considered. For instance, the maximum observed total phosphorus runoff load was on the order of 1.5 kg ha. Results also demonstrate that runoff from exposed sediments can be a source of pathogenic bacteria. spp. and spp. were present in runoff from one and three locations, respectively. Ruminant MST markers were also present in runoff from two locations, one of which hosted pasturing cattle with stream access. Overall, this study demonstrated that rainfall-induced runoff from exposed streambed sediments can be an important source of surface water pollution. PMID:25602339

  7. 33 CFR 334.490 - Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for fighter and bombardment aircraft, U.S. Air... ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.490 Atlantic Ocean...

  8. 33 CFR 334.490 - Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for fighter and bombardment aircraft, U.S. Air... ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.490 Atlantic Ocean...

  9. 33 CFR 334.490 - Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for fighter and bombardment aircraft, U.S. Air... ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.490 Atlantic Ocean...

  10. Sediment-water distribution of contaminants of emerging concern in a mixed use watershed.

    PubMed

    Fairbairn, David J; Karpuzcu, M Ekrem; Arnold, William A; Barber, Brian L; Kaufenberg, Elizabeth F; Koskinen, William C; Novak, Paige J; Rice, Pamela J; Swackhamer, Deborah L

    2015-02-01

    This study evaluated the occurrence and distribution of 15 contaminants of emerging concern (CECs) in stream water and sediments in the Zumbro River watershed in Minnesota and compared these with sub-watershed land uses. Sixty pairs of sediment and water samples were collected across all seasons from four stream sites for over two years and analyzed for selected personal care products, pesticides, human and veterinary medications, and phytoestrogens. Spatial and temporal analyses indicate that pharmaceuticals and personal care products (urban/residential CECs) are significantly elevated in water and/or sediment at sites with greater population density (>100 people/km(2)) and percentage of developed land use (>8% of subwatershed area) than those with less population density and land area under development. Significant spatial variations of agricultural pesticides in water and sediment were detectable, even though all sites had a high percentage of agricultural land use. Seasonality in CEC concentration was observed in water but not in sediment, although sediment concentrations of three CECs did vary between years. Average measured non-equilibrium distribution coefficients exceeded equilibrium hydrophobic partitioning-based predictions for 5 of the 7 detected CECs by at least an order of magnitude. Agreement of measured and predicted distribution coefficients improved with increasing hydrophobicity and in-stream persistence. The more polar and degradable CECs showed greater variability in measured distributions across different sampling events. Our results confirm that CECs are present in urban and agricultural stream sediments, including those CECs that would typically be thought of as non-sorptive based on their log Kow values. These results and the observed patterns of sediment and water distributions augment existing information to improve prediction of CEC fate and transport, leading to more accurate assessments of exposure and risk to surface water ecosystems

  11. Effect of sediment settling on controlling golden mussel invasion in water transfer project

    NASA Astrophysics Data System (ADS)

    Xu, Mengzhen; Wang, Zhaoyin; Bogen, Jim; Pan, Baozhu

    2013-04-01

    Inter-basin water transfer projects have been widely used to solve uneven distribution of water resources and water shortage in China. Along with the transferring of water resources, golden mussel (Limnoperna fortunei), the filter-collector macro-invertebrate species originating from southern China has also been inadvertently transferred to new aquatic environment, resulting in quick and uncontrolled spread of the species. The golden mussels are invasive by nature and endowed with a strong byssus for attaching onto their habitat, allowing them to easily invade natural and artificial aquatic systems, which was resulted in high-density golden mussel attachment that causes serious bio-fouling. Invasion and bio-fouling by golden mussels in water transfer systems has drawn attention widely because it has resulted in high resistance to water flow, corrosion of pipe walls and even clogging of tunnels, as well as causing water pollution and ecological imbalance in the regions that receive water infested with golden mussels. Field investigation was conducted along the East River, which is the main drinking water resource for Cantong province and Hongkong, China, to study the natural habitats of golden mussels. Surveys of water transfer tunnels which carry water from the East River to several big cities in Cantong province were done to study golden mussel invasion and attachment in tunnels. It is found that in the natural habitat, golden mussels mainly attach to bedrock and bank stones and solid surfaces facing upstream, while no golden mussels are attached on the surfaces facing downstream and suffering sediment deposition. In the water transfer tunnels, golden mussel attachment densities of 40,000 individuals/m2 mainly occurred on the portion of tunnel walls which face downwards and thus avoid sedimentation. An experiment was designed to study the effect of sediment settling on golden mussel attachment. The results showed that settling of fine sediment particles affects

  12. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean.

    PubMed

    Gazeau, Frédéric; van Rijswijk, Pieter; Pozzato, Lara; Middelburg, Jack J

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study. PMID:24718610

  13. Impacts of Ocean Acidification on Sediment Processes in Shallow Waters of the Arctic Ocean

    PubMed Central

    Gazeau, Frédéric; van Rijswijk, Pieter; Pozzato, Lara; Middelburg, Jack J.

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study. PMID:24718610

  14. Sediment size distribution and composition in a reservoir affected by severe water level fluctuations.

    PubMed

    López, Pilar; López-Tarazón, José A; Casas-Ruiz, Joan P; Pompeo, Marcelo; Ordoñez, Jaime; Muñoz, Isabel

    2016-01-01

    The reservoir sediments are important sinks for organic carbon (OC), the OC burial being dependent on two opposite processes, deposition and mineralization. Hence factors such as severe water level fluctuations are expected to influence the rate of OC accumulation as they may affect both deposition and mineralization. The Barasona Reservoir has been historically threatened by siltation, whilst the use of water for irrigation involves a drastic decrease of the water level. In this context, we have studied the physical and chemical characteristics (grain size, major and minor elemental compositions, organic and inorganic carbon, and nitrogen) of the recent sediments of the Barasona Reservoir and the relationships among them in order to: a) elucidate the main processes governing OC accumulation, b) evaluate the rate of OC mineralization and c) approach the effect of drought on the sediment characteristics in this system. Our results indicated that Barasona sediments were dominated by fine silts (>60%) and clays (>20%), the mean particle size decreasing from tail to dam. Desiccation increased particle sorting and size distribution became bimodal, but no effect on average size was observed. Attending to the composition, Barasona sediments were very homogeneous with low concentrations of nitrogen (TN) and phosphorus (<1.2 g kg(-1) dw and <0.6 g kg(-1) dw, respectively) and high concentration of OC (≈36 g kg(-1) dw). TN was negatively related to dry weight. Sediment mixing due to drastic changes in water level may have favoured the observed homogeneity of Barasona sediments affecting carbon, major ions and grain size. The high amount of OC deposited in Barasona sediment suggested that the adsorption of OC onto fine particles was more important than in boreal lakes. The rate of oxygen consumption by wet sediment ranged from 2.26 to 3.15 mg O2 m(-2) day(-1), values close to those compiled for Mediterranean running waters. PMID:26105704

  15. Analytical Methods for Measuring Mercury in Water, Sediment and Biota

    SciTech Connect

    Lasorsa, Brenda K.; Gill, Gary A.; Horvat, Milena

    2012-06-07

    Mercury (Hg) exists in a large number of physical and chemical forms with a wide range of properties. Conversion between these different forms provides the basis for mercury's complex distribution pattern in local and global cycles and for its biological enrichment and effects. Since the 1960’s, the growing awareness of environmental mercury pollution has stimulated the development of more accurate, precise and efficient methods of determining mercury and its compounds in a wide variety of matrices. During recent years new analytical techniques have become available that have contributed significantly to the understanding of mercury chemistry in natural systems. In particular, these include ultra sensitive and specific analytical equipment and contamination-free methodologies. These improvements allow for the determination of total mercury as well as major species of mercury to be made in water, sediments and soils, and biota. Analytical methods are selected depending on the nature of the sample, the concentration levels of mercury, and what species or fraction is to be quantified. The terms “speciation” and “fractionation” in analytical chemistry were addressed by the International Union for Pure and Applied Chemistry (IUPAC) which published guidelines (Templeton et al., 2000) or recommendations for the definition of speciation analysis. "Speciation analysis is the analytical activity of identifying and/or measuring the quantities of one or more individual chemical species in a sample. The chemical species are specific forms of an element defined as to isotopic composition, electronic or oxidation state, and/or complex or molecular structure. The speciation of an element is the distribution of an element amongst defined chemical species in a system. In case that it is not possible to determine the concentration of the different individual chemical species that sum up the total concentration of an element in a given matrix, meaning it is impossible to

  16. Responses of wetland plants to effluents in water and sediment

    SciTech Connect

    Walsh, G.E.; Weber, D.E.; Nguyen, M.T.; Esry, L.K.

    1991-01-01

    Responses of two wetland vascular plants, Echinochloa crusgalli and Sesbania macrocarpa, exposed to effluents from a coke plant, a pulp mill, a wastewater treatment plant, and the herbicide, hexazinone, were measured in three types of tests: seed germination and early growth, seedling survival and growth in hydroponic culture, and seedling survival and growth in sand and synthetic sediments with clay, silt, and sand, 3, 5, 7.5, or 10% organic contents. There was no effect of effluents or herbicide on germination and survival was affected only by the herbicide. When compared to controls, growth rates were reduced significantly in all tests except for E. crusgalli exposed to effluent from a wastewater treatment plant. There, the effluent stimulated growth in sediments. Increasing concentrations of organic matter in sediments had little effect on toxicity of effluents, but did cause reduced effects of hexazinone.

  17. U-Th and 10Be constraints on sediment recycling in proglacial settings, Lago Buenos Aires, Patagonia

    NASA Astrophysics Data System (ADS)

    Cogez, Antoine; Herman, Frédéric; Pelt, Eric; Norton, Kevin; Darvill, Christopher; Christl, Marcus; Morvan, Gilles; Reuschlé, Thierry; Chabaux, François

    2016-04-01

    The sedimentary cycle includes the formation by erosion of rocks, transport and deposition. While erosion and deposition can be documented, the history of sediments between the time it is extracted from the rocks and ultimately deposited into basins remains a major challenge. However, the mechanism of transfer and alteration of the sediments during transport plays a key role in the evolution of basins, feedbacks between erosion and climate, and glacial-interglacial variability of sediment transport and weathering. This is particularly true in proglacial settings because large overdeepenings, in particular, are potential sediment traps for which the efficiency at evacuating those sediments is largely unknown. The Lago Buenos Aires moraines in Patagonia are particularly interesting because they are imbricated from the older in the outer part to the younger in the inner part of the system. We sampled fine grained sediments from these moraines and measured U-Th isotopes in the 4-50 μm silicate fraction. Deposition ages were refined using 10Be exposure ages. We show first that the comminution ages model can be improved by measuring also Th isotopes, from which weathering rates can be deduced. Moreover we show from our data that there is a time lag of 300 kyr on average between erosion and deposition in the moraine. This could be attributed to the long residence time of sediments in the lake overdeepening. This conclusion raises perspectives about the transport times and dynamic of the sediments during a whole sedimentary cycle, and the subsequent effect on weathering. This conclusion could also contradict some assumptions commonly made for our erosion rates/sediment fluxes reconstructions based on river sediments analysis, in recently deglaciated catchments.

  18. Behavior of Water Jet Accompanied with Air Suction

    NASA Astrophysics Data System (ADS)

    Kawakami, Hironobu; Ishido, Tsutomu; Ihara, Akio

    In order to atomize a liquid, the authors have investigated the behavior of air-water jets. In a series of experiments, we have discovered a strange phenomenon that the water jet accompanied with air suction from the free surface has made a periodic radial splash of water drop. The purpose of the present paper is to clear out the origin of this phenomenon and the behavior of water jet accompanied with air suction. The behavior of water jet has been photographed by a digital camera aided with a flashlight and high-speed video camera. Those experiments enable us to find the origin of a periodic radial splash due to a formation of single air bubble at the flow separation region inside the nozzle and due to explosive expansion of the bubble after injected in the free space. In order to analyze the radial splash of water, we have conducted the equation of spherical liquid membrane. The numerical results obtained have been compared with the experimental results and good agreement has been obtained in radial expansion velocity.

  19. Arsenic Redistribution Between Sediments and Water Near a Highly Contaminated Source

    SciTech Connect

    Keimowitz,A.; Zheng, Y.; Chillrud, S.; Mailloux, B.; Bok Jung, H.; Stute, M.; Simpson, H.

    2005-01-01

    Mechanisms controlling arsenic partitioning between sediment, groundwater, porewaters, and surface waters were investigated at the Vineland Chemical Company Superfund site in southern New Jersey. Extensive inorganic and organic arsenic contamination at this site (historical total arsenic >10 000 {micro}g L{sup -1} or >130 {micro}M in groundwater) has spread downstream to the Blackwater Branch, Maurice River, and Union Lake. Stream discharge was measured in the Blackwater Branch, and water samples and sediment cores were obtained from both the stream and the lake. Porewaters and sediments were analyzed for arsenic speciation as well as total arsenic, iron, manganese, and sulfur, and they indicate that geochemical processes controlling mobility of arsenic were different in these two locations. Arsenic partitioning in the Blackwater Branch was consistent with arsenic primarily being controlled by sulfur, whereas in Union Lake, the data were consistent with arsenic being controlled largely by iron. Stream discharge and arsenic concentrations indicate that despite large-scale groundwater extraction and treatment, >99% of arsenic transport away from the site results from continued discharge of high arsenic groundwater to the stream, rather than remobilization of arsenic in stream sediments. Changing redox conditions would be expected to change arsenic retention on sediments. In sulfur-controlled stream sediments, more oxic conditions could oxidize arsenic-bearing sulfide minerals, thereby releasing arsenic to porewaters and streamwaters; in iron-controlled lake sediments, more reducing conditions could release arsenic from sediments via reductive dissolution of arsenic-bearing iron oxides.

  20. Arsenic redistribution between sediments and water near a highly contaminated source.

    PubMed

    Keimowitz, Alison R; Zheng, Yan; Chillrud, Steven N; Mailloux, Brian; Jung, Hun Bok; Stute, Martin; Simpson, H James

    2005-11-15

    Mechanisms controlling arsenic partitioning between sediment, groundwater, porewaters, and surface waters were investigated at the Vineland Chemical Company Superfund site in southern New Jersey. Extensive inorganic and organic arsenic contamination at this site (historical total arsenic > 10 000 microg L(-1) or > 130 microM in groundwater) has spread downstream to the Blackwater Branch, Maurice River, and Union Lake. Stream discharge was measured in the Blackwater Branch, and water samples and sediment cores were obtained from both the stream and the lake. Porewaters and sediments were analyzed for arsenic speciation as well as total arsenic, iron, manganese, and sulfur, and they indicate that geochemical processes controlling mobility of arsenic were different in these two locations. Arsenic partitioning in the Blackwater Branch was consistent with arsenic primarily being controlled by sulfur, whereas in Union Lake, the data were consistent with arsenic being controlled largely by iron. Stream discharge and arsenic concentrations indicate that despite large-scale groundwater extraction and treatment, > 99% of arsenic transport away from the site results from continued discharge of high arsenic groundwater to the stream, rather than remobilization of arsenic in stream sediments. Changing redox conditions would be expected to change arsenic retention on sediments. In sulfur-controlled stream sediments, more oxic conditions could oxidize arsenic-bearing sulfide minerals, thereby releasing arsenic to porewaters and streamwaters; in iron-controlled lake sediments, more reducing conditions could release arsenic from sediments via reductive dissolution of arsenic-bearing iron oxides. PMID:16329197

  1. Survival of daphnia magna and hyalella azteca in cadmium-spiked water and sediment

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.; Krawczyk, D.F.

    1986-01-01

    Freshwater sediments and water were spiked with cadmium (Cd) in the laboratory, and toxicity tests were conducted with the cladoceran Daphnia magna and the amphipod Hyalella azteca to determine if Cd in the sediment would cause increased toxicity. The 48-h LC50 values for Daphnia in tests without sediment were 36, 33, 24, and 40 micrograms/L total Cd. Calculated free-ion (Cd/sup 2 +/)LC50 values for the same tests were 28, 25, 18 and 31 micrograms/L. LC50 values (48-h) determined for total Cd(uncentrifuged water sample) in the sediment-containing beakers were 252, 69, and 122 micrograms/L for Daphnia. LC50 values for dissolved Cd(centrifuged 10,000 rpm) in the sediment-containing beakers were 61, 27, and 100 micrograms/L for Daphnia. Higher total Cd LC50 values indicate that Cd adsorbed to soluble organic material was not biologically available. No significant mortality of Daphnia or Hyalella occurred in the flow-through tests in which sediment contained the same levels of Cd as in the static tests. Mortality was similar in beakers with and without Cd-spiked sediment, indicating that Cd in the sediment and adsorbed to organic materials was not available to cause increased mortality.

  2. Diffusive Release of Uranium from Contaminated Sediments into Capillary Fringe Pore Water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M.; Harsh, James B.

    2012-09-13

    We investigated the dynamics of U release between pore water fractions, during river stage changes from two contaminated capillary fringe sediments. Samples were from 7.0 m and 7.6 m below ground surface (bgs) in the Hanford 300 area. Sediments were packed into columns and saturated with Hanford groundwater for three to 84 days. After specified times, > 48 µm radius (calculated) sediment pores were drained, followed by draining pores to 15 µm radius. U release in the first two weeks was similar between sediments and pore sizes with a range of 4.4 to 5.6 µM U in the 14 day sample. The 7.0 m bgs sediment U declined in the larger pores to 0.22 µM at day 84, whereas the small pores released U to 6.7 µM at day 84. The 7.6 m bgs sediment released 1.4 µM on day 84, in the large pores, but continuously released U from the smaller pores (13.2 uM on day 84). The continuous release of U has resulted in a diffusion gradient from the smaller to larger pores. The observed differences in U pore-water concentrations between the two sediment samples were attributed to co-precipitation of U with carbonates. A mineral phase in the sediments was also identified as an U-carbonate species, similar to rutherfordine [UO2(CO3)].

  3. Element transformation rates and fluxes across the sediment-water interface of the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Lipka, Marko; Wegwerth, Antje; Dellwig, Olaf; Al-Raei, Abdul M.; Schoster, Frank; Böttcher, Michael E.

    2014-05-01

    Organic matter is mineralized in brackish-marine sediments by microbial activity using predominantly oxygen, sulfate, and metal oxides as electron acceptors. This leads to a reflux of carbon dioxide into the bottom waters. Under anoxic bottom water conditions, sulfate reduction dominates. Under specific conditions, shallow methane may be oxidized. Pore water profiles reflect biogeochemical processes, transformation rates and fluxes of dissolved species across the sediment-water interface. They are controlled by different factors like microbial activity, bottom water redox conditions, and availability of electron acceptors/donors. Microbial activity in the sediment leads to changes in redox conditions, formation of metabolites and may lead to the formation of authigenic minerals. As an example, organic matter mineralization and reduction of iron oxyhydroxides both may lead to the liberation of dissolved phosphate thereby leading to a reflux into the bottom waters. Hypoxic conditions will enhance this process. We present the results of a detailed biogeochemical investigation of interstitial waters from shallow sediments to study the biogeochemical processes in recent sediments and associated element fluxes at the sediment-water-interface in different areas of the Baltic Sea. Pore water and sediment samples were retrieved from short sediment cores that were collected with multicoring devices in key regions of the Baltic Sea. Pore waters were taken in sufficient depth resolution and analyzed for main and trace element concentrations (e.g., Mn, SO4, HS, PO4, DIC) to allow a modelling of steady-state transformation volumetric rates and element fluxes. A quantitative interpretation of vertical concentration profiles in the pore waters was performed using a diffusion-based modelling approach. Element fluxes across the sediment-water interface show for the Baltic Sea a dependence from bottom water redox conditions, sedimentology, organic contents, and formation conditions

  4. Contamination of estuarine water, biota, and sediment by halogenated organic compounds: A field study

    USGS Publications Warehouse

    Pereira, W.E.; Rostad, C.E.; Chiou, C.T.; Brinton, T.I.; Barber, L.B., II; Demcheck, D.K.; Demas, C.R.

    1988-01-01

    Studies conducted in the vicinity of an industrial outfall in the Calcasieu River estuary, Louisiana, have shown that water, bottom and suspended sediment, and four different species of biota are contaminated with halogenated organic compounds (HOC) including haloarenes. A "salting-out" effect in the estuary moderately enhanced the partitioning tendency of the contaminants into biota and sediments. Contaminant concentrations in water, suspended sediments, and biota were found to be far below the values predicted on the basis of the assumption of phase equilibria with respect to concentrations in bottom sediment. Relative concentration factors of HOC between biota (catfish) and bottom sediment increased with increasing octanol/estuarine water partition coefficients (Kow*), maximizing at log Kow* of about 5, although these ratios were considerably less than equilibrium values. In contrast, contaminant concentrations in water, biota, and suspended sediments were much closer to equilibrium values. Bioconcentration factors of HOC determined on the basis of lipid content for four different biotic species correlated reasonably well with equilibrium triolein/water partition coefficients (Ktw).

  5. Soil, Groundwater, Surface Water, and Sediments of Kennedy Space Center, Florida: Background Chemical and Physical Characteristics

    NASA Technical Reports Server (NTRS)

    Shmalzer, Paul A.; Hensley, Melissa A.; Mota, Mario; Hall, Carlton R.; Dunlevy, Colleen A.

    2000-01-01

    This study documented background chemical composition of soils, groundwater, surface; water, and sediments of Kennedy Space Center. Two hundred soil samples were collected, 20 each in 10 soil classes. Fifty-one groundwater wells were installed in 4 subaquifers of the Surficial Aquifer and sampled; there were 24 shallow, 16 intermediate, and 11 deep wells. Forty surface water and sediment samples were collected in major watershed basins. All samples were away from sites of known contamination. Samples were analyzed for organochlorine pesticides, aroclors, chlorinated herbicides, polycyclic aromatic hydrocarbons (PAH), total metals, and other parameters. All aroclors (6) were below detection in all media. Some organochlorine pesticides were detected at very low frequencies in soil, sediment, and surface water. Chlorinated herbicides were detected at very low frequencies in soil and sediments. PAH occurred in low frequencies in soiL, shallow groundwater, surface water, and sediments. Concentrations of some metals differed among soil classes, with subaquifers and depths, and among watershed basins for surface water but not sediments. Most of the variation in metal concentrations was natural, but agriculture had increased Cr, Cu, Mn, and Zn.

  6. A conceptual model for river water and sediment dispersal in the Santa Barbara Channel, California

    USGS Publications Warehouse

    Warrick, J.A.; Mertes, L.A.K.; Washburn, L.; Siegel, D.A.

    2004-01-01

    The ephemeral Santa Clara River delivers large amounts of freshwater and sediment to the eastern Santa Barbara Channel during brief, episodic discharge events. This discharge into the channel was characterized here with shipboard measurements during floods of 1997 and 1998. Within approximately 1-km of the river mouth, the river discharge quickly stratifies into a freshened, turbid surface plume and a bottom nephloid layer. Observations immediately off the Santa Clara River mouth on a peak day of river discharge revealed that sediment rapidly settled from the freshened surface waters, as suspended sediment in the freshened surface plume contained only ???6% of the sediment mass expected if the sediment mixed conservatively. On the two subsequent days the reduction of sediment mass in the surface plume continued at ???50% per day. These observations suggest that river sediment undergoes rapid initial settling within ???1-km of the river mouth, followed by somewhat slower rates of settling. Although we did not measure sedimentation or bottom boundary layer processes, our mass balance results suggest that almost all of the river sediment either escapes along or deposits upon the inner shelf seabed.

  7. Uptake of hydrophobic xenobiotics by fish in water laden with sediments from the Fraser River

    SciTech Connect

    Qiao, P.; Farrell, A.P.

    1996-09-01

    The authors examined the uptake of three hydrophobic chemicals, TCB (1,2,4-trichlorobenzene), PeCB (1,2,3,4,5-pentachlorobenzene), and HCBP (2,2{prime}, 4,4{prime},6,6{prime}-hexachlorobiphenyl), by unfed juvenile rainbow trout (Oncorhynchus mykiss) in test aquaria containing sediments from the Fraser River. The working hypothesis was that the low organic carbon content of the Fraser River sediments would increase the bioavailability of xenobiotics associated with these sediments. The test chemicals and sediments were introduced into aquaria 9 d before the fish were introduced.Measured concentrations of he chemicals in the bottom sediments, suspended sediments, and filtered (0.45 {micro}m) water suggested that the test system had reached a quasiequilibrium state by day 9. Subsequently, a 6-d exposure of fish in the test aquaria resulted in a significant accumulation of the test chemicals in the fish tissues and significant reductions in the chemical concentration of the bottom sediments, suspended sediments, and filtered water. Mass balance analysis suggests that the appearance of HCBP and PeCB in the fish after 6 d could not be accounted for solely by the amount of chemical dissolved in the water at the time when the fish were introduced. A large unaccounted-for fraction of TCB, possibly due to fish metabolism, precluded an accurate mass balance analysis for this chemical. Because chemical uptake in fish with the pharynx plugged (to eliminate the gut uptake route) was similar to that in control fish and because direct access to bottom sediments did not alter chemical uptake, the authors conclude that hydrophobic chemicals such as PeCB and HCBP associated with suspended sediments from the Fraser River can readily desorb and be taken up across the gill.

  8. Microscale Modelling of Water and Gas-Water Flows in Subsea Sand Sediment

    NASA Astrophysics Data System (ADS)

    Sato, T.; Sugita, T.; Hirabayashi, S.; Nagao, J.; Jin, Y.; Kiyono, F.

    2009-12-01

    Methane hydrate is a promising energy resource in the near future. Its production is a current hot topic and flow of methane gas with water in sediment sand layer is very important to predict the production rate. In this study, permeability of microscale sand layer was numerically simulated by a three-dimensional lattice Boltzmann method. Shapes of real sands were extracted by series expansion of spherical harmonics using CT-scan images of real subsea core samples. These extracted sands were located in a cubic lattice domain by a simulated annealing method to fit to given porosities. Pressure difference was imposed at the both end faces of the domain to flow water and methane gas. By this simulation, permeability of water phase and water-gas two-phase flow were analysed and compared well with existing models. This work was financially supported by Japan's Methane Hydrate R&D Program planned by Ministry of Economy, Trade and Industry (METI). 3D image of an extracted frame-sand grain Distribution of gas and water phases in computational domain for Sw=0.80

  9. Water Velocity and Bioturbation Alter Sediment Resuspension and Biogeochemistry in an Experimental Freshwater Mesocosm System

    NASA Astrophysics Data System (ADS)

    Spivak, A.; Vanni, M. J.

    2010-12-01

    Processes such as bioturbation and resuspension can affect organic matter decomposition by altering sediment redox conditions. Increased oxygen availability may, in turn, affect remineralization rates and larger scale processes such as benthic-pelagic coupling. However, relatively few studies have explicitly tested the simultaneous effects of bioturbation and water velocity on benthic biogeochemistry and sediment resuspension. Using a mesocosm system we conducted two experiments testing the effects of bioturbator identity on particulate and dissolved nutrient dynamics before and after a resuspension event (i.e. water velocity held constant at 0.12 m s-1 for 2 hr; Expt. 1) and rates of sediment resuspension with increasing water velocity (0.00 - 0.20 m s-1; Expt. 2). We manipulated bioturbator identity across four levels as sediments were undisturbed (control), manually punctured (2% of surface area), or disturbed by one of two fish species, either bluegill or catfish. For Expt. 1, the bioturbation treatments were applied for several days and measurements were made before and after the resuspension event. Initially, water column chlorophyll and total suspended sediment (TSS) concentrations were highest in the catfish treatments. Bioturbator identity did not affect the stoichiometry of TSS as strongly; C:N was unaffected by our treatments while N:P was lowest in the disturbed treatments. After the resuspension event, there was no difference in TSS concentrations or stoichiometric ratios across the bioturbation treatments. Dissolved nutrient flux rates were insensitive to the bioturbation treatments and were more strongly influenced by the resuspension event. For instance, sediment NO3- fluxes were negative (i.e. net flux into sediments) until after the resuspension event when they became positive. In Expt. 2, we gradually increased water velocity from 0.00 - 0.20 m s-1 and measured TSS concentrations only. TSS was initially highest in catfish treatments and lowest in

  10. Thermal regime of dune-covered sediments under gaining and losing water bodies

    NASA Astrophysics Data System (ADS)

    Cardenas, M. Bayani; Wilson, John L.

    2007-12-01

    We investigate the effects of current-bed form induced flow and heat transport through permeable-bottom sediments overlain by a marine or terrestrial water column that is gaining or losing deep groundwater. Heat transport is forced by the diel variation of temperature in the water column. The investigation utilizes sequentially coupled simulations of turbulent flow in the water column, and Darcy flow and heat transport in the sediments. The simulations address the question when, where, and by how much are diel water column temperature variations transmitted into sediments subjected to ambient-groundwater discharge? This is crucial information for detecting, observing, and predicting temperature-sensitive biogeochemical and ecological processes in the bottom sediments. When the groundwater gain or loss is small, it has no appreciable effect on temperatures in the sediments, which are controlled by heat conduction and current-bed form induced heat advection. As losing discharge increases, the temperature signal from the water column penetrates deeper into the sediments, with the largest temperature variations found under a downwelling zone along the stoss side of the bed form and damped temperature variations found near a narrow upwelling zone below the crest. Similar patterns are observed under gaining conditions, but with temperature variations penetrating to shallower depths; the interfacial exchange zone is diminished by upward movement of deep groundwater. Large gains or losses of deep groundwater prevent the formation of an interfacial exchange zone making heat transport almost vertically one-dimensional. The sensitivity of the sediment-thermal regime to hydrodynamic conditions increases with increasing water column current (Reynolds number) and with sediment permeability.

  11. Water Tank with Capillary Air/Liquid Separation

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Smith, Frederick; Edeen, Gregg; Almlie, Jay C.

    2010-01-01

    A bladderless water tank (see figure) has been developed that contains capillary devices that allow it to be filled and emptied, as needed, in microgravity. When filled with water, the tank shields human occupants of a spacecraft against cosmic radiation. A membrane that is permeable by air but is hydrophobic (neither wettable nor permeable by liquid water) covers one inside surface of the tank. Grooves between the surface and the membrane allow air to flow through vent holes in the surface as the tank is filled or drained. A margin of wettable surface surrounds the edges of the membrane, and all the other inside tank surfaces are also wettable. A fill/drain port is located in one corner of the tank and is covered with a hydrophilic membrane. As filling begins, water runs from the hydrophilic membrane into the corner fillets of the tank walls. Continued filling in the absence of gravity will result in a single contiguous air bubble that will be vented through the hydrophobic membrane. The bubble will be reduced in size until it becomes spherical and smaller than the tank thickness. Draining the tank reverses the process. Air is introduced through the hydrophobic membrane, and liquid continuity is maintained with the fill/drain port through the corner fillets. Even after the tank is emptied, as long as the suction pressure on the hydrophilic membrane does not exceed its bubble point, no air will be drawn into the liquid line.

  12. Presence of pyrethroid pesticides in water and sediments of Ebro River Delta

    NASA Astrophysics Data System (ADS)

    Feo, M. L.; Ginebreda, A.; Eljarrat, E.; Barceló, D.

    2010-11-01

    SummaryThe distribution of pyrethroid insecticides of the Ebro River Delta (NE Spain) was assessed by measuring concentrations in surface water and sediment samples. Pyrethroid extraction from water was carried out by ultrasound-assisted emulsification-extraction (UAEE), while the sediment was sonicated and cleaned up using Florisil cartridge. Method detection of limits (MLODs) for the 12 pyrethroids analyzed by gas chromatography-mass spectrometer in negative chemical ionization (GC-NCI-MS) ranged from 0.03 to 35.8 ng L -1 for water and 2.6 to 62.4 pg g -1 for sediment. Recoveries values were in the range of 47-105% for water and 51-105% for sediments, showing satisfactory robustness of the method for analyzing pyrethroids in water and sediment samples. Cypermethrin was detected in 22 water samples collected from Ebro River Delta, while deltamethrin was present only in three water samples at concentrations ranging from 0.73 ng L -1 to 57.2 ng L -1 and 2 ng L -1 to 58.8 ng L -1 for cypermethrin and deltamethrin, respectively. These concentration levels were higher than median lethal concentration (LC50) values found for deltamethrin and lower than LC50 values found for cypermethrin when short time toxic effects are considered. In sediment samples only cypermethrin was detected at concentration levels ranged from 8.27 ng g -1 to 71.9 ng g -1. These levels were higher than its LC50 values. Environmental dynamic behaviour and fate were also evaluated for cypermethrin measuring the sediment/water partition coefficient (ranging from 5.0 to 6.3) and kinetic data (half-life ranging between 13 and 50 days). Results were in good agreement to those reported in literature

  13. Sequestration of priority pollutant PAHs from sediment pore water employing semipermeable membrane devices.

    PubMed

    Williamson, Kelly S; Petty, Jimmie D; Huckins, James N; Lebo, Jon A; Kaiser, Edwin M

    2002-11-01

    Semipermeable membrane devices (SPMDs) were employed to sample sediment pore water in static exposure studies under controlled laboratory conditions using (control pond and formulated) sediments fortified with 15 priority pollutant polycyclic aromatic hydrocarbons (PPPAHs). The sediment fortification level of 750 ng/g was selected on the basis of what might be detected in a sediment sample from a contaminated area. The sampling interval consisted of 0, 4, 7, 14, and 28 days for each study. The analytical methodologies, as well as the extraction and sample cleanup procedures used in the isolation, characterization, and quantitation of 15 PPPAHs at different fortification levels in SPMDs, water, and sediment were reported previously (Williamson, M.S. Thesis, University of Missouri-Columbia, USA; Williamson et al., Chemosphere (This issue--PII: S0045-6535(02)00394-6)) and used for this project. Average (mean) extraction recoveries for each PPPAH congener in each matrix are reported and discussed. No procedural blank extracts (controls) were found to contain any PPPAH residues above the method quantitation limit, therefore, no matrix interferences were detected. The focus of this publication is to demonstrate the ability to sequester environmental contaminants, specifically PPPAHs, from sediment pore water using SPMDs and two different types of fortified sediment. PMID:12431008

  14. Measuring pyrethroids in sediment pore water using matrix-solid phase microextraction.

    PubMed

    Hunter, Wesley; Yang, Yu; Reichenberg, Fredrik; Mayer, Philipp; Gan, Jianying

    2009-01-01

    Pyrethroids are hydrophobic insecticides commonly used in both agricultural and urban environments. Their high toxicity to aquatic organisms, including benthic invertebrates, and detection in the sediment at many locations in California, U.S.A., have spawned interest in understanding their bioavailability in bed sediments. A recent study showed good correlation between uptake of 14C-permethrin in Chironomus tentans and solid-phase microextraction (SPME) fibers in sediments. The present study was directed at the development of an SPME technique applicable to trace levels of nonlabeled pyrethroids in sediment. Disposable polydimethylsiloxane fibers were used to detect freely dissolved pore-water concentrations of bifenthrin, fenpropathrin, cis-permethrin, trans-permethrin, cyfluthrin, cypermethrin, and esfenvalerate under agitated and static conditions. Partition equilibrium between fiber and sediment was reached in <5 d when the samples were agitated on a shaker at low speed, while much longer times (>23 d) were needed without agitation. Polydimethylsiloxane to water partition ratios (K(PDMS)) of the seven pyrethroids were measured separately and ranged from 2.83 x 10(5) to 1.89 x 10(6). When applied to field-contaminated sediments, agitated matrix-SPME was able to detect pore-water concentrations as low as 0.1 ng/L. The method developed in the present study may be coupled with bioassays to gain mechanistic understanding of factors affecting pyrethroid toxicities, and applied to field samples to better predict sediment toxicities from pyrethroid contamination. PMID:18712946

  15. Acclimation of Hydrilla verticillata to sediment anoxia in vegetation restoration in eutrophic waters.

    PubMed

    Wu, Juan; Dai, Yanran; Rui, Shengyang; Cui, Naxin; Zhong, Fei; Cheng, Shuiping

    2015-12-01

    Sediment anoxia generally results from intense organic enrichment and is a limiting factor in the restoration of vegetation in eutrophic waters. To investigate the effect of sediment anoxia on a typical pollution-tolerant submerged macrophyte species, Hydrilla verticillata, and acclimation mechanisms in the plant, a gradient of sediment anoxia was simulated with additions of sucrose to the sediment, which can stimulate increased concentrations of total nitrogen, NH4(+) and Fe in pore water. H. verticillata growth was significantly affected by highly anoxic conditions, as indicated by reduced total biomass in the 0.5 and 1% sucrose treatments. However, slight anoxia (0.1% sucrose addition) promoted growth, and the shoot biomass was 22.64% higher than in the control. In addition to morphologic alterations, H. verticillata showed physiological acclimations to anoxia, including increased anaerobic respiration and changes in carbon and nitrogen metabolism in roots. The soluble protein and soluble carbohydrate contents in roots of the 1% treatment were both significantly higher compared with those in the control. The increase in alcohol dehydrogenase activity and pyruvate content in the roots suggested that H. verticillata has a well-developed capacity for anaerobic fermentation. This study suggests that highly anoxic sediments inhibit the growth of H. verticillata and the species has a degree of tolerance to anoxic conditions. Further in situ investigations should be conducted on the interactions between sediment conditions and macrophytes to comprehensively evaluate the roles of sediment in the restoration of vegetation in eutrophic waters. PMID:26423394

  16. Sequestration of priority pollutant PAHs from sediment pore water employing semipermeable membrane devices

    USGS Publications Warehouse

    Williamson, K.S.; Petty, J.D.; Huckins, J.N.; Lebo, J.A.; Kaiser, E.M.

    2002-01-01

    Semipermeable membrane devices (SPMDs) were employed to sample sediment pore water in static exposure studies under controlled laboratory conditions using (control pond and formulated) sediments fortified with 15 priority pollutant polycyclic aromatic hydrocarbons (PPPAHs). The sediment fortification level of 750 ng/g was selected on the basis of what might be detected in a sediment sample from a contaminated area. The sampling interval consisted of 0, 4, 7, 14, and 28 days for each study. The analytical methodologies, as well as the extraction and sample cleanup procedures used in the isolation, characterization, and quantitation of 15 PPPAHs at different fortification levels in SPMDs, water, and sediment were reported previously (Williamson, M.S. Thesis, University of Missouri - Columbia, USA; Williamson et al., Chemosphere (This issue - PII: S0045-6535(02)00394-6)) and used for this project. Average (mean) extraction recoveries for each PPPAH congener in each matrix are reported and discussed. No procedural blank extracts (controls) were found to contain any PPPAH residues above the method quantitation limit, therefore, no matrix interferences were detected. The focus of this publication is to demonstrate the ability to sequester environmental contaminants, specifically PPPAHs, from sediment pore water using SPMDs and two different types of fortified sediment.

  17. A review of surface-water sediment fractions and their interactions with persistent manmade organic compounds

    USGS Publications Warehouse

    Witkowski, P.J.; Smith, J.A.; Fusillo, T.V.; Chiou, C.T.

    1987-01-01

    This paper reviews the suspended and surficial sediment fractions and their interactions with manmade organic compounds. The objective of this review is to isolate and describe those contaminant and sediment properties that contribute to the persistence of organic compounds in surface-water systems. Most persistent, nonionic organic contaminants, such as the chlorinated insecticides and polychlorinated biphenyls (PCBs), are characterized by low water solubilities and high octanol-water partition coefficients. Consequently, sorptive interactions are the primary transformation processes that control their environmental behavior. For nonionic organic compounds, sorption is primarily attributed to the partitioning of an organic contaminant between a water phase and an organic phase. Partitioning processes play a central role in the uptake and release of contaminants by sediment organic matter and in the bioconcentration of contaminants by aquatic organisms. Chemically isolated sediment fractions show that organic matter is the primary determinant of the sorptive capacity exhibited by sediment. Humic substances, as dissolved organic matter, contribute a number of functions to the processes cycling organic contaminants. They alter the rate of transformation of contaminants, enhance apparent water solubility, and increase the carrying capacity of the water column beyond the solubility limits of the contaminant. As a component of sediment particles, humic substances, through sorptive interactions, serve as vectors for the hydrodynamic transport of organic contaminants. The capabilities of the humic substances stem in part from their polyfunctional chemical composition and also from their ability to exist in solution as dissolved species, flocculated aggregates, surface coatings, and colloidal organomineral and organometal complexes. The transport properties of manmade organic compounds have been investigated by field studies and laboratory experiments that examine the

  18. Effects of sulfate-reducing bacteria on methylmercury at the sediment-water interface.

    PubMed

    Zeng, Lingxia; Luo, Guangjun; He, Tianrong; Guo, Yanna; Qian, Xiaoli

    2016-08-01

    Sediment cores (containing sediment and overlying water) from Baihua Reservoir (SW China) were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria (SRB) on mercury (Hg) methylation at sediment-water interfaces. Concentrations of dissolved methyl mercury (DMeHg) in the overlying water of the control cores with bioactivity maintained (BAC) and cores with only sulfate-reducing bacteria inhibited (SRBI) and bacteria fully inhibited (BACI) were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMeHg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations (r=-0.5311 and r=-0.4977 for BAC and SRBI, respectively). The water DMeHg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment-water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster (hgcAB), besides SRB, causing Hg methylation in the sediment-water system. PMID:27521953

  19. Screening of currently used pesticides in water, sediments and biota of the Guadalquivir River Basin (Spain).

    PubMed

    Masiá, Ana; Campo, Julián; Vázquez-Roig, Pablo; Blasco, Cristina; Picó, Yolanda

    2013-12-15

    The occurrence of 50 currently used pesticides and their transformation products in surface and waste waters, sediment and fish in the Guadalquivir River Basin was determined in 2010 and 2011. After selective sample extraction, pesticides were identified and quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The contamination profile in water and sediments is marked by the presence of organophosphorus and triazines. Transformation products were even at higher concentrations than parent pesticides. A wider range of pesticides was present in water than in sediments but none of them were detected in fish. The mean concentrations ranged from 0.2 to 13.0 ng/L in water and from 0.1 to 13.2 ng/g d.w. in sediment. The spatial distribution of most pesticides was consistent with the agricultural activities of the area or their urban applications. The waste water treatment plant effluents that impact the river are minor sources for few pesticides but for most of them run-off would be the most important contribution. The temporal distribution showed differences between both sampling campaigns related to the river flow. The low-flow produced a pesticide concentration effect, generating higher levels in water and accumulation in sediments. This forecasts a hazard in future scenarios if the current situation of the climate change and water scarcity evolves to more critical conditions highlighting the need of these monitoring studies. PMID:24140087

  20. A novel membrane device for the removal of water vapor and water droplets from air

    NASA Technical Reports Server (NTRS)

    Ray, Rod; Newbold, David D.; Mccray, Scott B.; Friesen, Dwayne T.; Kliss, Mark

    1992-01-01

    One of the key challenges facing NASA engineers is the development of systems for separating liquids and gases in microgravity environments. In this paper, a novel membrane-based phase separator is described. This device, known as a water recovery heat exchanger (WRHEX), overcomes the inherent deficiencies of current phase-separation technology. Specifically, the WRHEX cools and removes water vapor or water droplets from feed-air streams without the use of a vacuum or centrifugal force. As is shown in this paper, only a low-power air blower and a small stream of recirculated cool water is required for WRHEX operation. This paper presents the results of tests using this novel membrane device over a wide range of operating conditions. The data show that the WRHEX produces a dry air stream containing no entrained or liquid water - even when the feed air contains water droplets or mist. An analysis of the operation of the WRHEX is presented.

  1. Heavy Metals in Water and Sediment: A Case Study of Tembi River

    PubMed Central

    Shanbehzadeh, Saeed; Vahid Dastjerdi, Marzieh; Hassanzadeh, Akbar; Kiyanizadeh, Toba

    2014-01-01

    This study was carried out to examine heavy metals concentration in water and sediment of upstream and downstream of the entry of the sewage to the Tembi River, Iran. Samples were collected from upstream and downstream and were analyzed for Cd, Cr, Cu, Fe, Pb, Ni, and Zn by atomic absorption spectrophotometer. The results indicated that the average concentration of the metals in water and sediment on downstream was more than that of upstream. The comparison of the mean concentrations of heavy metals in water of the Tembi River with drinking water standards and those in the water used for agriculture suggests that the mean concentration of Cu and Zn lies within the standard range for drinking water and the mean concentration of Mn, Zn, and Pb lies within the standard range of agricultural water. The highest average concentration on downstream for Pb in water and for Mn in sediment was 1.95 and 820.5 ppm, respectively. Also, the lowest average concentration on upstream was identified for Cd in water and sediment 0.07 and 10 ppm, respectively. With regard to the results, it gets clear that using the water for recreational purposes, washing, and fishing is detrimental to human health and the environment. PMID:24616738

  2. Contaminants in surface water and sediments near the Tynagh silver mine site, County Galway, Ireland.

    PubMed

    O'Neill, A; Phillips, D H; Bowen, J; Sen Gupta, B

    2015-04-15

    A former silver mine in Tynagh, Co. Galway, Ireland is one of the most contaminated mine sites in Europe with maximum concentrations of Zn, As, Pb, Mn, Ni, Cu, and Cd far exceeding guideline values for water and sediment. The aims of this research were to 1) further assess the contamination, particularly metals, in surface water and sediment around the site, and 2) determine if the contamination has increased 10 years after the Environmental Protection Agency Ireland (EPAI) identified off-site contamination. Site pH is alkaline to neutral because CaCO3-rich sediment and rock material buffer the exposed acid generating sulphide-rich ore. When this study was compared to the previous EPAI study conducted 10 years earlier, it appeared that further weathering of exposed surface sediment had increased concentrations of As and other potentially toxic elements. Water samples from the tailings ponds and adjacent Barnacullia Stream had concentrations of Al, Cd, Mn, Zn and Pb above guideline values. Lead and Zn concentrations from the tailings pond sediment were 16 and 5 times higher, respectively, than concentrations reported 10 years earlier. Pb and Zn levels in most sediment samples exceeded the Expert Group (EGS) guidelines of 1000 and 5000 mg/kg, respectively. Arsenic concentrations were as high as 6238 mg/kg in the tailings ponds sediment, which is 62 and 862 times greater than the EGS and Canadian Soil Quality Guidelines (CSQG), respectively. Cadmium, Cu, Fe, Mn, Pb and Zn concentrations in water and sediment were above guideline values downstream of the site. Additionally, Fe, Mn and organic matter (OM) were strongly correlated and correlated to Zn, Pb, As, Cd, Cu and Ni in stream sediment. Therefore, the nearby Barnacullia Stream is also a significant pathway for contaminant transport to downstream areas. Further rehabilitation of the site may decrease the contamination around the area. PMID:25634731

  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. BENTHIC INVERTEBRATE BIOASSAYS WITH TOXIC SEDIMENT AND PORE WATER

    EPA Science Inventory

    The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods of making the sample dilutions required to generate dose-response relationships were compared. he assays studied were: (a) Microtox, a 15-min assay of Photobacterium...

  5. Organic matter diagenesis in shallow water carbonate sediments

    NASA Astrophysics Data System (ADS)

    Ingalls, Anitra E.; Aller, Robert C.; Lee, Cindy; Wakeham, Stuart G.

    2004-11-01

    Muddy carbonate deposits near the Dry Tortugas, Florida, are characterized by high organic carbon remineralization rates. However, approximately half of the total sedimentary organic matter potentially supporting remineralization is occluded in CaCO 3 minerals (intracrystalline). While a portion of nonintracrystalline organic matter appears to cycle rapidly, intracrystalline organic matter has an approximately constant concentration with depth, suggesting that as long as its protective mineral matrix is intact, it is not readily remineralized. Organic matter in excess of intracrystalline organic matter that is preserved may have a variety of mineral associations (e.g., intercrystalline, adsorbed or detrital). In surface sediment, aspartic acid contributed ˜22 mole % and ˜50 mole % to nonintracrystalline and intracrystalline pools, respectively. In deeper sediment (1.6-1.7m), the composition of hydrolyzable amino acids in both pools was similar (aspartic acid ˜40 mole %). Like amino acids, intracrystalline and nonintracrystalline fatty acids have different compositions in surface sediments, but are indistinguishable at depth. These data suggest that preserved organic matter in the nonintracrystalline pool is stabilized by its interactions with CaCO 3. Neutral lipids are present in very low abundances in the intracrystalline pool and are extensively degraded in both the intracrystalline and nonintracrystalline pools, suggesting that mineral interactions do not protect these compounds from degradation. The presence of chlorophyll- a, but absence of phytol, in the intracrystalline lipid pool demonstrates that chloropigments are present only in the nonintracrystalline pool. Sedimentary chloropigments decrease with depth at similar rates in Dry Tortugas sediments as found in alumino-silicate sediments from the Long Island Sound, suggesting that chloropigment degradation is largely unaffected by mineral interactions. Overall, however, inclusion and protection of

  6. Accumulation of Nitrogen in the Pore Water of Anoxic Lake Sediments

    NASA Astrophysics Data System (ADS)

    Iqbal, M. Z.; Fields, C. L.

    2005-05-01

    The impact of soil runoff nitrogen on the Silver Lake of Iowa was assessed in this study. Currently, the lake cannot support its designated uses as a recreational water body. Extensive algal blooms characterize the lake in late summer, lowering the dissolved oxygen content in water (< 2.0 mg/L). The goal of this study was to map the buildup of nitrogen in the pore water of lake sediments and come up with recommendations for restoration strategies. Sediment cores were taken from 20 sites along 5 transects in the lake. In the top 5 cm of the sediments, the pore water nitrogen ranges between 1.8 and 733.1 micro-gm of nitrate per gm of sediments. The average concentration is 94 micro-g/gm. Vertically, nitrate concentrations were measured at 90 micro-g/gm at 0-10 cm, 95 micro-g/gm at 10-20 cm, and 19 micro-g/gm at 20-30 cm. The sharp decline in nitrate below the 20 cm depth in the sediment is attributed to biochemical reduction of nitrate through denitrification in relatively older, much anoxic sediments. The above results indicate that sediments in Silver Lake are heavily contaminated with N trapped in the pore water. The primary sources of N are the surrounding croplands and an active hog lot on the southeastern lakeshore. The average rate of sedimentation in the lake has been 1 cm/year in the last 32 years. Upon sedimentation, the pore water N is slowly released to the lake water, thereby dramatically limiting the lake's capability to process incoming nutrients. The mass distribution of N in the lake was estimated as 3.66 x 103 kg (65%) in bottom sediments, 172 kg (3%) in suspended particulates, and 1.83 x 103 kg (32%) in the dissolved phase. Some of the recommendations made through this study include dredging the top 25 cm of lake sediments, applying buffer strips along the lake's northern and eastern shorelines, and reducing the application of N and P-based fertilizers.

  7. Economics of water injected air screw compressor systems

    NASA Astrophysics Data System (ADS)

    Venu Madhav, K.; Kovačević, A.

    2015-08-01

    There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such machines have proved to be insufficiently reliable and not cost effective. This paper describes an investigation carried out to determine the current limitations of water injected screw compressor systems and how these could be overcome in the 15-315 kW power range and delivery pressures of 6-10 bar. Modern rotor profiles and approach to sealing and cooling allow reasonably inexpensive air end design. The prototype of the water injected screw compressor air system was built and tested for performance and reliability. The water injected compressor system was compared with the oil injected and oil free compressor systems of the equivalent size including the economic analysis based on the lifecycle costs. Based on the obtained results, it was concluded that water injected screw compressor systems could be designed to deliver clean air free of oil contamination with a better user value proposition than the oil injected or oil free screw compressor systems over the considered range of operations.

  8. Grazing Land Management Strongly Controls Water Quality, Sediment and Channel Dynamics in Tallgrass Prairie Headwater Networks

    NASA Astrophysics Data System (ADS)

    Grudzinski, B. G.; Daniels, M. D.

    2013-12-01

    In the prairie remnants of North America, watershed sediment regimes are heavily influenced by livestock grazing practices. Despite dramatic declines in stream water quality and ecosystem function concomitant with increasing gazing pressures, there have been no studies to quantitatively assess the relationship between various grazing treatments and sediment production in natural grassland ecosystems. In this study, we evaluate suspended sediment transport and channel morphology in the Flint Hills physiographic province using a paired whole-watershed approach, including 2 replicates of high density cattle grazing, 2 replicates of low density cattle grazing, 3 replicates of bison grazing and 3 replicates of no grazing. As expected, results demonstrate that cattle grazing operations increase e-coli, sediment concentrations and increase channel width. However, no significant differences in e-coli, suspended sediment dynamics or channel geomorphology were found between bison grazed and ungrazed watersheds.

  9. Water, Air, Earth and Cosmic Radiation

    NASA Astrophysics Data System (ADS)

    Bassez, Marie-Paule

    2015-06-01

    In the context of the origin of life, rocks are considered mainly for catalysis and adsorption-desorption processes. Here it is shown how some rocks evolve in energy and might induce synthesis of molecules of biological interest. Radioactive rocks are a source of thermal energy and water radiolysis producing molecular hydrogen, H2. Mafic and ultramafic rocks evolve in water and dissolved carbon dioxide releasing thermal energy and H2. Peridotites and basalts contain ferromagnesian minerals which transform through exothermic reactions with the generation of heat. These reactions might be triggered by any heating process such as radioactive decay, hydrothermal and subduction zones or post-shock of meteorite impacts. H2 might then be generated from endothermic hydrolyses of the ferromagnesian minerals olivine and pyroxene. In both cases of mafic and radioactive rocks, production of CO might occur through high temperature hydrogenation of CO2. CO, instead of CO2, was proven to be necessary in experiments synthesizing biological-type macromolecules with a gaseous mixture of CO, N2 and H2O. In the geological context, N2 is present in the environment, and the activation source might arise from cosmic radiation and/or radionuclides. Ferromagnesian and radioactive rocks might consequently be a starting point of an hydrothermal chemical evolution towards the abiotic formation of biological molecules. The two usually separate worlds of rocks and life are shown to be connected through molecular and thermodynamic chemical evolution. This concept has been proposed earlier by the author (Bassez J Phys: Condens Matter 15:L353-L361, 2003, 2008a, 2008b; Bassez Orig Life Evol Biosph 39(3-4):223-225, 2009; Bassez et al. 2011; Bassez et al. Orig Life Evol Biosph 42(4):307-316, 2012, Bassez 2013) without thermodynamic details. This concept leads to signatures of prebiotic chemistry such as radionuclides and also iron and magnesium carbonates associated with serpentine and/or talc, which

  10. Water, air, Earth and cosmic radiation.

    PubMed

    Bassez, Marie-Paule

    2015-06-01

    In the context of the origin of life, rocks are considered mainly for catalysis and adsorption-desorption processes. Here it is shown how some rocks evolve in energy and might induce synthesis of molecules of biological interest. Radioactive rocks are a source of thermal energy and water radiolysis producing molecular hydrogen, H2. Mafic and ultramafic rocks evolve in water and dissolved carbon dioxide releasing thermal energy and H2. Peridotites and basalts contain ferromagnesian minerals which transform through exothermic reactions with the generation of heat. These reactions might be triggered by any heating process such as radioactive decay, hydrothermal and subduction zones or post-shock of meteorite impacts. H2 might then be generated from endothermic hydrolyses of the ferromagnesian minerals olivine and pyroxene. In both cases of mafic and radioactive rocks, production of CO might occur through high temperature hydrogenation of CO2. CO, instead of CO2, was proven to be necessary in experiments synthesizing biological-type macromolecules with a gaseous mixture of CO, N2 and H2O. In the geological context, N2 is present in the environment, and the activation source might arise from cosmic radiation and/or radionuclides. Ferromagnesian and radioactive rocks might consequently be a starting point of an hydrothermal chemical evolution towards the abiotic formation of biological molecules. The two usually separate worlds of rocks and life are shown to be connected through molecular and thermodynamic chemical evolution. This concept has been proposed earlier by the author (Bassez J Phys: Condens Matter 15:L353-L361, 2003, 2008a, 2008b; Bassez Orig Life Evol Biosph 39(3-4):223-225, 2009; Bassez et al. 2011; Bassez et al. Orig Life Evol Biosph 42(4):307-316, 2012, Bassez 2013) without thermodynamic details. This concept leads to signatures of prebiotic chemistry such as radionuclides and also iron and magnesium carbonates associated with serpentine and/or talc

  11. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms

    NASA Astrophysics Data System (ADS)

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-05-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4–12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system.

  12. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms.

    PubMed

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-01-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4-12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system. PMID:27225540

  13. Environmental Fate of Chiral Herbicide Fenoxaprop-ethyl in Water-Sediment Microcosms

    PubMed Central

    Jing, Xu; Yao, Guojun; Liu, Donghui; Liu, Mingke; Wang, Peng; Zhou, Zhiqiang

    2016-01-01

    The environmental fate of the herbicide fenoxaprop-ethyl (FE) in water, sediment and water-sediment microcosm was studied and degradation products fenoxaprop (FA), ethyl-2-(4-hydroxyphenoxy)propanoate (EHPP), 2-(4-hydroxyphenoxy)propanoic acid (HPPA) and 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) were monitored. FE, FA, EHPP and HPPA were chiral and the environmental behavior was investigated on an enantiomeric level. In water, sediment and water-sediment microcosms, fenoxaprop-ethyl degraded very fast with half-lives less than 1 day and it was found the herbicidally inactive S-enantiomer degraded faster. Fenoxaprop was the main primary degradation product which was quickly formed and the further degradation was relatively slow with half-lives of 6.4–12.4 days, and the S-enantiomer degraded faster too. EHPP, HPPA and CDHB could be found and S-EHPP and S-HPPA were degraded preferentially. The effects of microorganism and water content were investigated and it was found that the enantioselectivity was attributed to microorganisms. In sediment, the main degradation pathway of fenoxaprop-ethyl was hydrolysis and the degradation rate of fenoxaprop-ethyl increased with water content. The degradation products and enantioselectivity should be considered for the impact of fenoxaprop-ethyl on the aquatic system. PMID:27225540

  14. Field Evaluation Of Arsenic Transport Across The Ground Water/Surface Water Interface: Speciation In Sediment Material

    EPA Science Inventory

    The solubility and mobility of arsenic in ground water are influenced by a variety of processes in the northeastern US subjective to geogenic and anthropogenic sources. This presentation will discuss the speciation of arsenic in sediment profiles resulting from ground water disc...

  15. Sedimentation patterns on a cold-water coral mound off Mauritania

    NASA Astrophysics Data System (ADS)

    Eisele, Markus; Frank, Norbert; Wienberg, Claudia; Titschack, Jürgen; Mienis, Furu; Beuck, Lydia; Tisnerat-Laborde, Nadine; Hebbeln, Dierk

    2014-01-01

    An unconformity-bound glacial sequence (135 cm thick) of a coral-bearing sediment core collected from the flank of a cold-water coral mound in the Banda Mound Province off Mauritania was analysed. In order to study the relation between coral framework growth and its filling by hemipelagic sediments, U-series dates obtained from the cold-water coral species Lophelia pertusa were compared to 14C dates of planktonic foraminifera of the surrounding matrix sediments. The coral ages, ranging from 45.1 to 32.3 ka BP, exhibit no clear depositional trend, while on the other hand the 14C dates of the matrix sediment provide ages within a much narrower time window of <3000 yrs (34.6-31.8 cal ka BP), corresponding to the latest phase of the coral growth period. In addition, high-resolution computer tomography data revealed a subdivision of the investigated sediment package into three distinct parts, defined by the portion and fragmentation of corals and associated macrofauna as well as in the density of the matrix sediments. Grain size spectra obtained on the matrix sediments show a homogeneous pattern throughout the core sediment package, with minor variations. These features are interpreted as indicators of redeposition. Based on the observed structures and the dating results, the sediments were interpreted as deposits of a mass wasting event, namely a debris flow. During this event, the sediment unit must have been entirely mixed; resulting in averaging of the foraminifera ages from the whole unit and giving randomly distributed coral ages. In this context, for the first time mass wasting is proposed to be a substantial process of mound progradation by exporting material from the mound top to the flanks. Hence, it may not only be an erosional feature but also widening the base of the mound, thus allowing further vertical mound growth.

  16. Analysis of pesticides in surface water and sediment from Yolo Bypass, California, 2004-2005

    USGS Publications Warehouse

    Smalling, Kelly L.; Orlando, James L.; Kuivila, Kathryn M.

    2005-01-01

    Inputs to the Yolo Bypass are potential sources of pesticides that could impact critical life stages of native fish. To assess the direct inputs during inundation, pesticide concentrations were analyzed in water, in suspended and bed-sediment samples collected from six source watersheds to the Yolo Bypass, and from three sites within the Bypass in 2004 and 2005. Water samples were collected in February 2004 from the six input sites to the Bypass during the first flood event of the year representing pesticide inputs during high-flow events. Samples were also collected along a transect across the Bypass in early March 2004 and from three sites within the Bypass in the spring of 2004 under low-flow conditions. Low-flow data were used to understand potential pesticide contamination and its effects on native fish if water from these areas were used to flood the Bypass in dry years. To assess loads of pesticides to the Bypass associated with suspended sediments, large-volume water samples were collected during high flows in 2004 and 2005 from three sites, whereas bed sediments were collected from six sites in the fall of 2004 during the dry season. Thirteen current-use pesticides were detected in surface water samples collected during the study. The highest pesticide concentrations detected at the input sites to the Bypass corresponded to the first high-flow event of the year. The highest pesticide concentrations at the two sites sampled within the Bypass during the early spring were detected in mid-April following a major flood event as the water began to subside. The pesticides detected and their concentrations in the surface waters varied by site; however, hexazinone and simazine were detected at all sites and at some of the highest concentrations. Thirteen current-use pesticides and three organochlorine insecticides were detected in bed and suspended sediments collected in 2004 and 2005. The pesticides detected and their concentrations varied by site and sediment

  17. Use of the mercury record in Red Tarn sediments to reveal air pollution history and the implications of catchment erosion.

    PubMed

    Yang, Handong; Smyntek, Peter

    2014-11-01

    Red Tarn is a cirque lake with a small ratio of terrestrial area to lake area, surrounded by glacial edges with little soil in the catchment. A sediment core taken from the deepest area of the lake was (210)Pb dated and validated by (137)Cs and (241)Am stratigraphic records. The core was analysed for mercury (Hg) and other elements. The results show Hg pollution before the mid-19th century, and thereafter, a rapid increase in Hg pollution into modern time, followed by a decline in pollution since 1968-1970. This agrees well with the decline in UK Hg emissions since the Clear Air Act of 1968. The results suggest that the core has recorded Hg air pollution history, and it can be used to benchmark Hg changes in the sediments from other lakes in the region up to the late 1980s. However, increased (210)Pb fluxes after the late 1980s indicate enhanced catchment erosion, which has brought more legacy Hg in the catchment into the lake. As a consequence, since 2000, the Hg in the sediment record no longer reflects the atmospheric Hg deposition. The core shows how dominant Hg sources for the lake changed from atmospheric deposition to the catchment inputs, and demonstrates that contaminated catchment inputs have not only increased Hg fluxes to the lake sediments but have also increased Hg concentrations in the sediments. PMID:25224269

  18. Eutrophication in the northern Adriatic Sea: Pore water and sediment studies

    SciTech Connect

    Hammond, D.E.; Berelson, W.M. ); Giordani, P.; Langone, L.; Frignani, M.; Ravaioli, M. )

    1990-01-09

    The northern Adriatic Sea has been plagued by problems of eutrophication. This area is relatively shallow (maximum depth = 60m), becoming stratified during the summer months which inhibits oxygen transport to bottom waters. Anthropogenic nutrient loading in rivers entering the northern Adriatic (Po River being the largest) has increased nutrient input to this system and stimulated algal growth. Cores were collected for studies of pore water and solid phase chemistry at 6 stations in this region. [sup 210]Pb was used to constrain sediment accumulation rates and a range of 0-0.5 cm/yr was determined at different stations. Excess [sup 234]Th was only found in the upper 1-2 cm, suggesting that bioturbation is largely restricted to shallow depths. Pore water profiles show evidence of irrigation, and mean diffusive fluxes for oxygen, silica phosphate and ammonia are generally 20-90% of the fluxes obtained from benthic chamber measurements. This is consistent with previous work in this area in which studies of radon fluxes indicated that irrigation plays an important role in sediment-water exchange. Pore water profiles in the northern portion of the study area (near the Po River Delta) were markedly different than profiles in the south; sediments in the north are substantially more acidic and have high concentrations of dissolved iron and phosphate. From the alkalinity vs. TCO[sub 2] relationship in sediment pore waters it appears that differences in reactions involving the reduction of iron oxides and the exchange of magnesium for iron in clays are responsible for this regional difference in pore water properties. Sediments close to the Po apparently undergo more iron-magnesium exchange, while more distal sediments are limited in their ability to do so. Other pore water observations are limited in their ability to do so. Other pore water observations and trends regarding the shape of the silica profiles (which show shallow maxima) will be discussed.

  19. Exchange of nutrients across the sediment-water interface in intertidal ria systems (SW Europe)

    NASA Astrophysics Data System (ADS)

    Ospina-Alvarez, N.; Caetano, M.; Vale, C.; Santos-Echeandía, J.; Bernárdez, P.; Prego, R.

    2014-01-01

    Concentrations of nitrate, nitrite, ammonium, phosphate and silicate were determined in river water, tidal water that floods the intertidal sediment (flooding water) and pore water of those sediments in the Northern Galician Rias of Ortigueira and Viveiro (NW Iberian Peninsula). The field surveys were done in the productive seasons of spring and summer 2008. Short-sediment cores and tidal flooding water were sampled at the intertidal area during the first 20 min that the tide inundates the sampling site. Nutrient fluxes of rivers (Lourido and Landro) flowing into the rias were in the order of H4SiO4 > NO3- > NH4+ > HPO42 Nutrients input from those rivers were low relative to the nutrient discharge of the entire coastal area. Striking changes of nutrient concentrations in flooding and pore waters of intertidal sediments were observed in the short periods of tidal inundation. Nutrient fluxes driven by molecular diffusion and tide-induced transport across the sediment-water interface were quantified and compared to the nutrient river contribution. Diffusive fluxes ranged from 9.3 to 13.7 nmol·cm- 2·d- 1 for nitrate and nitrite, - 1.32 to 30.1 nmol·cm- 2·d- 1 for ammonium, - 0.01 to 0.49 nmol·cm- 2·d- 1 for phosphate, and - 13.2 to 0.2 nmol·cm- 2·d- 1 for silicate. Tide-induced transport always exceeded diffusive fluxes, with differences reaching up to four orders of magnitude for silicate. The overall results of this study emphasize the relevance of tidal water movement in promoting the sediment-water exchange of nutrients in intertidal sub-ecosystems.

  20. Sources of Atmospheric Pollutants Impacting Air and Water Quality in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Gertler, A. W.; Cahill, T. A.; Gillies, J.; Kuhns, H.

    2008-12-01

    Starting in the second half of the 20th century, decline in Lake Tahoe's water clarity and degradation in the basin's air quality have become major concerns due to its unique scenic features. Gaseous and particulate nitrogen (N) and particulate phosphorus (P) loading via direct atmospheric deposition and sediment transport to the lake have also been implicated as responsible for its eutrophication and decline in water clarity. Estimates suggest that atmospheric N deposition contributes 55% of the total N loading to the lake, while atmospheric P deposition contributes 15% of the total P loading. In order to improve both air quality and, as a consequence, water quality, it is necessary to develop an understanding of the sources of the atmospheric pollutants. Once this is accomplished, it is possible to implement cost-effective strategies to reduce this impact. This paper summarizes the findings of a series of studies performed to determine the levels and sources of ambient air pollutants in the basin. Projects have included the development of a Tahoe-specific emissions inventory, long-term measurements of road dust resuspension, modeling to determine the fraction of pollutants coming from in-basin vs. out-of-basin sources, particulate source apportionment, and estimates of nitric acid deposition. These studies found that the pollutants most closely connected to the decline in water quality come largely from within basin sources, as opposed to those coming from the Central Valley and upwind urban areas of California. These results indicate regulators need to control pollutant emissions within the Tahoe basin in order to reduce the impact of atmospheric pollutants on both air and water quality.

  1. Normalized rare earth elements in water, sediments, and wine: identifying sources and environmental redox conditions

    USGS Publications Warehouse

    Piper, David Z.; Bau, Michael

    2013-01-01

    The concentrations of the rare earth elements (REE) in surface waters and sediments, when normalized on an element-by-element basis to one of several rock standards and plotted versus atomic number, yield curves that reveal their partitioning between different sediment fractions and the sources of those fractions, for example, between terrestrial-derived lithogenous debris and seawater-derived biogenous detritus and hydrogenous metal oxides. The REE of ancient sediments support their partitioning into these same fractions and further contribute to the identification of the redox geochemistry of the sea water in which the sediments accumulated. The normalized curves of the REE that have been examined in several South American wine varietals can be interpreted to reflect the lithology of the bedrock on which the vines may have been grown, suggesting limited fractionation during soil development.

  2. Spatial and temporal analysis of land cover change, sedimentation and water quality in the Lake Issaqueena watershed, South Carolina

    NASA Astrophysics Data System (ADS)

    Pilgrim, Cassie Mechele

    .1% cultivated). From 2005 to 2009, there was an increase of 21.5% in residential/ other development. Sampling depth ranged from 0.1 meters to 0.3 meters. Water temperature fluctuated corresponding to changing air temperatures, and dissolved oxygen content fluctuated as a factor of water temperature. Inorganic nitrogen content was higher from December to April possibly due to application of fertilizers prior to the growing season. Fecal coliform levels stayed relatively the same, there was however, a slight decrease overall, likely due to the decrease in pasture/ grassland. Turbidity remained relatively the same from 1962 to 2005, but a slight decrease in pH can be observed at both stations. Sedimentation analysis has shown that overall the lake surface area has decreased by 11.333 hectares and lake volume has decreased by 320,800 m3, while catchment area increased by 6.99 hectares. Average annual precipitation rates were shown to have no direct correlation with these bathymetric measurements, and it is hypothesized that changes in land cover, slope and extreme precipitation events are largely responsible for sedimentation in Lake Issaqueena.

  3. Enzyme activities in the water column and in shallow permeable sediments from the northeastern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Arnosti, C.; Ziervogel, K.; Ocampo, L.; Ghobrial, S.

    2009-09-01

    The activities of extracellular enzymes that initiate the microbial remineralization of high molecular weight organic matter were investigated in the water column and sandy surface sediments at two sites in the northeastern Gulf of Mexico. Six fluorescently labeled polysaccharides were hydrolyzed rapidly in the water column as well as in permeable sediments. This result contrasts with previous studies carried out in environments dominated by fine-grained muds, in which the spectrum of enzymes active in the water column is quite limited compared to that of the underlying sediments. Extracts of Spirulina, Isochrysis, and Thalassiosira were also used to measure hydrolysis rates in water from one of the sites. Rates of hydrolysis of the three plankton extracts were comparable to those of the purified polysaccharides. The broad spectrum and rapid rates of hydrolysis observed in the water column at both sites in the northeastern Gulf of Mexico may be due to the permeable nature of the sediments. Fluid flux through the sediments is sufficiently high that the entire 1.5 m deep water column could filter though the sediments on timescales of a few days to two weeks. Movement of water through sediments may also transport dissolved enzymes from the sediment into the water column, enhancing the spectrum as well as the rate of water column enzymatic activities. Such interaction between the sediments and water column would permit water column microbial communities to access high molecular weight substrates that might otherwise remain unavailable as substrates.

  4. Laboratory measurements of physical, chemical, and optical characteristics of Lake Chicot sediment waters

    NASA Technical Reports Server (NTRS)

    Witte, W. G.; Whitlock, C. H.; Usry, J. W.; Morris, W. D.; Gurganus, E. A.

    1981-01-01

    Reflectance, chromaticity, diffuse attenuation, beam attenuation, and several other physical and chemical properties were measured for various water mixtures of lake bottom sediment. Mixture concentrations range from 5 ppm to 700 ppm by weight of total suspended solids in filtered deionized tap water. Upwelled reflectance is a nonlinear function of remote sensing wave lengths. Near-infrared wavelengths are useful for monitoring highly turbid waters with sediment concentrations above 100 ppm. It is found that both visible and near infrared wavelengths, beam attenuation correlates well with total suspended solids ranging over two orders of magnitude.

  5. Air pollution history elucidated from anthropogenic spherules and their magnetic signatures in marine sediments offshore of Southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Horng, Chorng-Shern; Huh, Chih-An; Chen, Kuo-Hang; Huang, Pin-Ru; Hsiung, Kan-Hsi; Lin, Hui-Ling

    2009-03-01

    Kaohsiung City and its neighborhood in the southwestern coastal plain of Taiwan have suffered serious air pollution since the region became the largest center for heavy-industry on the island. In order to unravel the air pollution history of the region, four 210Pb- and 137Cs-dated sediment box cores recovered in 2006 from offshore of this area were chosen for magnetic and petrographic analyses. The data were used to distinguish changes in concentration, composition and grain size of magnetic particles in the sediments due to inputs of anthropogenic magnetic spherules. Sedimentation rates have been reasonably constant for the last one hundred years, except at the core tops which were affected by a turbidite layer induced by a typhoon in 2005. Down-core profiles of mass-specific magnetic susceptibility ( χ) and saturation isothermal remanent magnetization (SIRM) are similar among the cores, and reflect similar trends to magnetic spherule counts. This reveals that χ and SIRM of modern marine sediments can be used as air pollution indicators for nearby industrialized upwind areas. The studied record indicates that industrialization of the area was gradual during 1950-1980 and boomed afterward, resulting in a high production of airborne magnetic spherules, which is consistent with evidence for poor air quality at that time. Optical and scanning electron microscopic (SEM) surveys of magnetic extracts indicate that the magnetic spherules have grain sizes ranging from a few micrometers up to 50 μm and consist mainly of iron oxides with variable Si, Al, and Ca contents. X-ray diffraction analysis on magnetic extracts from different depths in the cores further indicates that magnetite and pyrrhotite, which are derived from terrigenous detritus, form the magnetic constituents of the sediments before the area was industrialized. In contrast, during the industrial boom, anthropogenic magnetite and hematite spherules became the dominant magnetic particles in the sediments

  6. Total Hg and methyl Hg distribution in sediments of selected Louisiana water bodies.

    PubMed

    Delaune, Ronald D; Gambrell, Robert P; Devai, Istvan; Jugsujinda, Aroon; Kongchum, Manoch

    2009-05-01

    Sediment samples (543) collected from selected Louisiana streams and lakes were analyzed for total Hg and methyl Hg content. The average total Hg content among 543 samples was 92.3 +/- 95.1 microg kg(-1). The average methyl Hg content in the samples was 0.68 +/- 0.80 microg kg(-1). Methyl Hg accounted for an average of 0.73% of the total Hg in sediment. Linear regression analysis of total Hg versus methyl Hg content of the sediment showed methyl Hg content was significantly correlated to total Hg content of sediment (P > 0.01, n = 537) and sediment organic matter content. (P > 0.01, n = 536) Methyl Hg was also positively correlated to clay (P > 0.01, n = 537) and inversely correlated to sand content of sediment (P > 0.01, n = 537). Total Hg and methyl Hg content in these sediments was within the normal range reported elsewhere indicating no significant industrial or municipal Hg contamination. A comparison of selected water bodies with fishing advisories showed no relationship to total Hg and methyl Hg in sediment. PMID:19337918

  7. Concentration of arsenic in water, sediments and fish species from naturally contaminated rivers.

    PubMed

    Rosso, Juan José; Schenone, Nahuel F; Pérez Carrera, Alejo; Fernández Cirelli, Alicia

    2013-04-01

    Arsenic (As) may occur in surface freshwater ecosystems as a consequence of both natural contamination and anthropogenic activities. In this paper, As concentrations in muscle samples of 10 fish species, sediments and surface water from three naturally contaminated rivers in a central region of Argentina are reported. The study area is one of the largest regions in the world with high As concentrations in groundwater. However, information of As in freshwater ecosystems and associated biota is scarce. An extensive spatial variability of As concentrations in water and sediments of sampled ecosystems was observed. Geochemical indices indicated that sediments ranged from mostly unpolluted to strongly polluted. The concentration of As in sediments averaged 6.58 μg/g ranging from 0.23 to 59.53 μg/g. Arsenic in sediments barely followed (r = 0.361; p = 0.118) the level of contamination of water. All rivers showed high concentrations of As in surface waters, ranging from 55 to 195 μg/L. The average concentration of As in fish was 1.76 μg/g. The level of contamination with As differed significantly between species. Moreover, the level of bioaccumulation of As in fish species related to the concentration of As in water and sediments also differed between species. Whilst some fish species seemed to be able to regulate the uptake of this metalloid, the concentration of As in the large catfish Rhamdia quelen mostly followed the concentration of As in abiotic compartments. The erratic pattern of As concentrations in fish and sediments regardless of the invariable high levels in surface waters suggests the existence of complex biogeochemical processes behind the distribution patterns of As in these naturally contaminated ecosystems. PMID:23179469

  8. A new device for collection of interstitial water from wetland sediments

    USGS Publications Warehouse

    Euliss, N.H., Jr.; Barnes, R.K.

    1992-01-01

    A sampler for collection of interstitial water from wetland sediments is described. It differs from other sampling devices because it does not have to be filled with solution to facilitate diffusion, it does not have to be removed from the wetland to collect samples, and it can be used to draw repeated samples over time from identical locations. The device facilitates 'in situ' measurement of a wide range of abiotic parameters such as electrical conductivity, redox potential, and pH in wetland sediments. The device has application in ecological investigations of sediment-borne wildlife diseases, studies of benthic invertebrates, measurement of nutrient exchange, and other aspects of wetland ecology.

  9. Diagenesis of carbonate sediments: interaction of magnesium in sea water with mineral grains.

    PubMed

    Berner, R A

    1966-07-01

    Samples of natural fine-grained carbonate sediment from Florida Bay, Florida, undergo mole-for-mole cation exchange with aqueous solutions of MgCl(2) and CaCl(2) in the laboratory. The exchange reaction, which involves the surface of the grains of sediment, can be essentially described by a simple mass action-law equation. Enrichment of Mg++ beyond the amounts found within particle interiors should take place on the surface of CaCo(3) sediments immersed in sea water; it may be on both exchangeable and unexchangeable sites. PMID:17831506

  10. 33 CFR 334.490 - Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean off Georgia Coast; air-to-air and air-to-water gunnery and bombing ranges for fighter and bombardment aircraft, U.S. Air Force. 334.490 Section 334.490 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE...

  11. Propagation of density disturbances in air-water flow

    NASA Technical Reports Server (NTRS)

    Nassos, G. P.

    1969-01-01

    Study investigated the behavior of density waves propagating vertically in an atmospheric pressure air-water system using a technique based on the correlation between density change and electric resistivity. This information is of interest to industries working with heat transfer systems and fluid power and control systems.

  12. Earth, Air, Fire and Water in Our Elements

    ERIC Educational Resources Information Center

    Lievesley, Tara

    2007-01-01

    The idea that everything is made of the four "elements", earth, air, fire and water, goes back to the ancient Greeks. In this article, the author talks about the origins of ideas about the elements. The author provides an account that attempts to summarise thousands of years of theoretical development of the elements in a thousand words or so.

  13. MONITORING CYCLICAL AIR-WATER ELEMENTAL MERCURY EXCHANGE

    EPA Science Inventory

    Previous experimental work has demonstrated that elemental mercury evasion from natural water displays a diel cycle; evasion rates during the day can be two to three times evasion rates observed at night. A study with polychlorinated biphenyls (PCBS) found that diurnal PCB air/wa...

  14. VOLATILIZATION RATES FROM WATER TO INDOOR AIR PHASE II

    EPA Science Inventory

    Contaminated water can lead to volatilization of chemicals to residential indoor air. Previous research has focused on only one source (shower stalls) and has been limited to chemicals in which gas-phase resistance to mass transfer is of marginal significance. As a result, attemp...

  15. External exposure to radionuclides in air, water, and soil

    SciTech Connect

    Eckerman, K.F.; Ryman, J.C.

    1996-05-01

    Federal Guidance Report No. 12 tabulates dose coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, water, and soil. The dose coefficients are intended for use by Federal Agencies in calculating the dose equivalent to organs and tissues of the body.

  16. Water and Air Measures That Make 'PureSense'

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Each day, we read about mounting global concerns regarding the ability to sustain supplies of clean water and to reduce air contamination. With water and air serving as life s most vital elements, it is important to know when these environmental necessities may be contaminated, in order to eliminate exposure immediately. The ability to respond requires an understanding of the conditions impacting safety and quality, from source to tap for water, and from outdoor to indoor environments for air. Unfortunately, the "time-to-know" is not immediate with many current technologies, which is a major problem, given the greater likelihood of risky situations in today s world. Accelerating alert and response times requires new tools, methods, and technologies. New solutions are needed to engage in more rapid detection, analysis, and response. This is the focus of a company called PureSense Environmental, Inc., which evolved out of a unique relationship with NASA. The need for real-time management and operations over the quality of water and air, and the urgency to provide new solutions, were reinforced by the events of September 11, 2001. This, and subsequent events, exposed many of the vulnerabilities facing the multiple agencies tasked with working in tandem to protect communities from harmful disaster. Much has been done since September 11 to accelerate responses to environmental contamination. Partnerships were forged across the public and private sectors to explore, test, and use new tools. Methods and technologies were adopted to move more astutely from proof-of-concept to working solutions.

  17. Developing Water Quality Critera for Suspended and Bedded Sediments-Illustrative Example Application.

    EPA Science Inventory

    The U. S. EPA's Framework for Developing Suspended and Bedded Sediments (SABS) Water Quality Criteria (SABS Framework) provides a consistent process, technical methods, and supporting materials to enable resource managers to develop ambient water quality criteria for one of the m...

  18. Land conversion to bioenergy production: water budget and sediment output in a semiarid grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass based bioenergy production has been considered a feasible alternative of land use for the mixed-grass prairie and marginal croplands in the High Plains. However, little is known of the effect of this land use change on the water cycle and associated sediment output in this water controll...

  19. DEVELOPMENT AND DEMONSTRATION OF A BIDIRECTIONAL ADVECTIVE FLUX METER FOR SEDIMENT-WATER INTERFACE

    EPA Science Inventory

    A bidirectional advective flux meter for measuring water transport across the sediment-water interface has been successfully developed and field tested. The flow sensor employs a heat-pulse technique combined with a flow collection funnel for the flow measurement. Because the dir...

  20. COSOLVENT EFFECTS ON PHENANTHRENE SORPTION-DESORPTION ON A FRESH-WATER SEDIMENT

    EPA Science Inventory

    This study evaluated the effects of the water-miscible cosolvent methanol on the sorption-desorption of phenanthrene by the natural organic matter (NOM) of a fresh-water sediment. A biphasic pattern was observed in the relationship between the log of the carbon-normalized sorpti...

  1. The symbiotic relationship of sediment and biofilm dynamics at the sediment water interface of oil sands industrial tailings ponds.

    PubMed

    Reid, T; VanMensel, D; Droppo, I G; Weisener, C G

    2016-09-01

    Within the oil sands industry, tailings ponds are used as a means of retaining tailings until a reclamation technology such as end pit lakes (EPLs) can be developed and optimized to remediate such tailings with a water cap (although dry-land strategies for tailing reclamation are also being developed). EPLs have proven successful for other mining ventures (e.g. metal rock mines) in eventually mitigating contaminant loads to receiving waters once biochemical remediation has taken place (although the duration for this to occur may be decades). While the biological interactions at the sediment water interface of tailings ponds or EPLs have been shown to control biogeochemical processes (i.e. chemical fluxes and redox profiles), these have often been limited to static microcosm conditions. Results from such experiments may not tell the whole story given that the sediment water interface often represents a dynamic environment where erosion and deposition may be occurring in association with microbial growth and decay. Mobilization of sediments and associated contaminants may therefore have a profound effect on remediation rates and, as such, may decrease the effectiveness of EPLs as viable reclamation strategies for mining industries. Using a novel core erosion system (U-GEMS), this paper examines how the microbial community can influence sediment water interface stability and how the biofilm community may change with tailings age and after disturbance (biofilm reestablishment). Shear strength, eroded mass measurements, density gradients, high-resolution microscopy, and microbial community analyses were made on 2 different aged tailings (fresh and ∼38 years) under biotic and abiotic conditions. The same experiments were repeated as duplicates with both sets of experiments having consolidation/biostabilization periods of 21 days. Results suggest that the stability of the tailings varies between types and conditions with the fresh biotic tailings experiencing up to 75

  2. Water harvesting and sediment trapping in exclosures - A gully diversion experiment in the Tigray Highlands, Ethiopia

    NASA Astrophysics Data System (ADS)

    Descheemaeker, K.; Nyssen, J.; Poesen, J.; Raes, D.; Terryn, L.; Haile, M.; Muys, B.; Deckers, J.

    2009-04-01

    Due to rapid vegetation restoration, exclosures (i.e. areas protected from grazing) are an effective and efficient measure for soil and water conservation. As a result, exclosures have become a widespread measure to combat the severe soil erosion and to rehabilitate the degraded land in the Tigray highlands of northern Ethiopia. Given the high infiltration rates and sediment trapping capacity of exclosures, this study investigates to what extent these characteristics can be optimized through the diversion of runoff water from an eroding gully into a well-restored exclosure. A representative exclosure of 20 years old was selected for the gully diversion experiment. The exclosure was located on a steep limestone escarpment and was cut by a strongly eroding gully. The runoff from the gully was diverted into the exclosure by three diversion structures and canals, which led the runoff about 50 - 100 m into the exclosure and allowed it to infiltrate gradually. At the bottom of the exclosure, a cut-off drain served to evacuate the excess water back into the gully. The aim of the experimental set-up was (1) to supply additional water to the restoring vegetation in the exclosure so as to increase biomass production, (2) to decrease sediment and runoff output from the catchment, (3) to decrease gully erosion rates. The experiment was evaluated using a sediment budget and a water balance. The sediment budget of the gully diversion system was drawn up based on records of the sediment load in the runoff water of the gully and measurements of the volumes of sediment deposited in the exclosure. The water balance of the exclosure system was developed based on measurements of the additional runoff input at the three inlet canals and of the outflow of excess runoff water in the cut-off drain. Runoff discharge measurements were made using v-notches in the canals. Weekly soil water content measurements allowed for calibration and validation of the BUDGET soil water balance model. This

  3. Water yield and sediment export in small, partially glaciated Alpine watersheds in a warming climate

    NASA Astrophysics Data System (ADS)

    Micheletti, Natan; Lane, Stuart N.

    2016-06-01

    Climate change is expected to modify the hydrological and geomorphological dynamics of mountain watersheds significantly, so impacting on downstream water yield and sediment supply. However, such watersheds are often poorly instrumented, making it difficult to link recent and rapid climate change to landscape response. Here we combine unique records of river flow and sediment export, with historical archival imagery to test the hypothesis that climate warming has substantially increased both water yield and sediment export from small Alpine watersheds (<3 km2) characterized by small (<0.5 km2 surface) glaciers. To examine ice and landform response to climate change, we apply archival digital photogrammetry to historical aerial imagery available from 1967 to present. We use the resulting data on ice loss, in combination with reliable records of stream flow from hydroelectric power intakes and climate data to approximate a water budget and to determine the evolution of different contributions to river flow. We use the stream flow records to estimate volumetric sediment transport capacity and compare this with the volumes of sand and gravel exported from the watersheds, quantified from records of intake flushing. The data show clearly that climate forcing since the early 1980s has been accompanied by a net increase in both water yield and sediment transport capacity, and we attribute these as signals of reduced snow accumulation and glacier recession. However, sediment export has not responded in the same way and we attribute this to limits on sediment delivery to streams because of poor rockwall-hillslope-channel connectivity. However, we do find that extreme climate conditions can be seen in sediment export data suggesting that these, rather than mean climate warming, may dominate watershed response.

  4. [Structure-functional studies of the White sea water and bottom sediments].

    PubMed

    Korneeva, G A; Stepanova, E A

    2001-01-01

    Statistical analysis of dynamic indices of biopolymers enzymatic destruction in unstratified and stratified. White Sea water has revealed specific properties of protease and amylase activities. We analyzed the component composition and hydrolytic enzymatic activities in the surface layer of the bottom sediments (0-2 cm). The relationship between protease and amylase enzymatic activities in the surface sediments with different content of pelite fraction is discussed. PMID:11236571

  5. Magnetic field-enhanced sedimentation of nanopowder magnetite in water flow.

    PubMed

    Bakhteeva, Iu; Medvedeva, I; Byzov, I; Zhakov, S; Yermakov, A; Uimin, M; Shchegoleva, N

    2015-01-01

    Sedimentation dynamics of magnetite (γ-Fe3O4) nanopowder (10-20 nm) in water in a gradient magnetic field Bmax=0.3 T, (dB/dz)max=0.13 T/cm was studied for different water flow speeds and starting particle concentrations (0.1 and 1.0 g/l). The aggregates formation in water was monitored under the same conditions. In cyclical water flow, the velocity of particle sedimentation increases significantly in comparison to its rate in still water, which corresponds to the intensified aggregate formation. However, at a water flow speed more than 0.1 cm/s sedimentation velocity slows down, which might be connected to aggregate destruction in a faster water flow. Correlation between sedimentation time and the nanoparticle concentration in water does not follow the trend expected for spherical superparamagnetic particles. In our case sedimentation time is shorter for c=0.1 g/l in comparison with that for c=1 g/l. We submit that such a feature is caused by particle self-organization in water into complex structures of fractal type. This effect is unexplained in the framework of existing theoretical models of colloids systems, so far. Provisional recommendations are suggested for the design of a magnetic separator on the permanent magnets base. The main device parameters are magnetic field intensity B≥0.1 T, magnetic field gradient (dB/dz)max≈(0.1-0.2) T/cm, and water flow speed V<0.15 cm/s. For particle concentration c=1 g/l, purification of water from magnetite down to ecological and hygienic standards is reached in 80 min, for c=0.1 g/l the time is reduced down to 50 min. PMID:25650300

  6. An algorithm for the retrieval of suspended sediment in coastal waters of China from AVHRR data

    NASA Astrophysics Data System (ADS)

    Li, Yan; Huang, Wei; Fang, Ming

    1998-04-01

    An algorithm using an analytical model based on the difference of the NOAA/AVHRR (Advanced Very High Resolution Radiometer) Channel 1 (580-680 nm) and Channel 2 (720-1100 nm) reflectance data is developed for the retrieval of suspended sediment in coastal and shelf waters. The model assumes that the suspended sediment concentration, S, is a function of the difference of the water leaving reflectance of Channels 1 and 2, Rd. The formula is governed by the optical parameters of water and suspended sediment, including volume scattering and absorption coefficients of the two channels. The analytical model yielded a best fit curve when the water leaving reflectance of the two channels were plotted against each other for Case 2 water, where the suspended sediment concentration ranged from 5 to over 100 g m -3. A standard curve of S against Rd was obtained. Using Tassan (1994)'s recommendations for the contribution of water and suspended sediment to the in-water absorption and backscattering coefficients in his three-component color model, the suspended sediment concentration corresponding to the maximum point of Rd was about 60 g m -3, and was independent of the atmospheric optical properties. Thus, this process provides a convenient tool to remove the atmospheric fluctuations of atmospheric transmittance by reconciling the maximum point of the image with the standard curve. The algorithm was tested using data from seven transects in the China Sea, and the retrieved results for the Zhujiang (Pearl River) Estuary were compared with the sea-truth data with good agreement. This suggests that the algorithm can be used as a seasonal regional model for water masses along the China coast.

  7. A comparison of solids collected in sediment traps and automated water samplers

    USGS Publications Warehouse

    Bartsch, L.A.; Rada, R.G.; Sullivan, J.F.

    1996-01-01

    Sediment traps are being used in some pollution monitoring programs in the USA to sample suspended solids for contaminant analyses. This monitoring approach assumes that the characteristics of solids obtained in sediment traps are the same as those collected in whole-water sampling devices. We tested this assumption in the upper Mississippi River, based on the inorganic particle-size distribution (determined with a laser particle- analyzer) and volatile matter content of solids (a surrogate for organic matter). Cylindrical sediment traps (aspect ratio 3) were attached to a rigid mooring device and deployed in a flowing side channel in Navigation Pool 7 of the upper Mississippi River. On each side of the mooring device, a trap was situated adjacent to a port of an autosampler that collected raw water samples hourly to form 2-d composite samples. Paired samples (one trap and one raw water, composite sample) were removed from each end of the mooring device at 2-d intervals during the 30-d study period and compared. The relative particle collection efficiency of paired samplers did not vary temporally. Particle-size distributions of inorganic solids from sediment traps and water samples were not significantly different. The volatile matter content of solids was lesser in sediment traps (mean, 9.5%) than in corresponding water samples (mean, 22.7%). This bias may have been partly due to under-collection of phytoplankton (mainly cyanobacteria), which were abundant in the water column during the study. The positioning of water samplers and sediment traps in the mooring device did not influence the particle-size distribution or total solids of samples. We observed a small difference in the amount of organic matter collected by water samplers situated at opposite ends of the mooring device.

  8. Effect of cations on the solubilization/deposition of triclosan in sediment-water-rhamnolipid system.

    PubMed

    Chen, Yuanbo; Hu, Yongyou; Guo, Qian; Yan, Jia; Wu, Wenjin

    2016-09-01

    Cations had great influence on the self-assembly of rhamnolipid, which in turn affected the fate of triclosan. The migration of triclosan from sediment to water benefited its biodegradation but it could be transformed into more toxic compounds. To regulate the fate of triclosan and reduce environmental risks extremely, the effect of four common cations in surface water (Na(+)/K(+)/Ca(2+)/Mg(2+)) on the solubilization/deposition of triclosan in sediment-water-rhamnolipid system was investigated. The interaction among cations, triclosan and rhamnolipid was explored based on self-assembly of rhamnolipid and water solubility of triclosan in rhamnolipid solutions. Results showed that cations had little influence on the fate of triclosan in the absence of rhamnolipid. Cations, especially Ca(2+)/Mg(2+), reduced the critical micelle concentration, micellar size and zeta potential of rhamnolipid solutions. The changes in self-assembly of rhamnolipid with different cations led to the difference of residual rhamnolipid concentration in water, which was nearly invariant with 0.01 M Na(+)/K(+) while decreased significantly with 0.01 M Ca(2+)/Mg(2+). Consequently, water solubility of triclosan in rhamnolipid solutions increased with the addition of Na(+)/K(+) whereas decreased with Ca(2+)/Mg(2+). In sediment-water- rhamnolipid system, triclosan was slightly solubilized from sediment to water with Na(+)/K(+) while deposited in sediment with Ca(2+)/Mg(2+). These findings provided an alternative application of rhamnolipid for the remediation of triclosan-polluted sediment. PMID:27341150

  9. Spatial Variability of Metals in Surface Water and Sediment in the Langat River and Geochemical Factors That Influence Their Water-Sediment Interactions

    PubMed Central

    Lim, Wan Ying; Aris, Ahmad Zaharin; Zakaria, Mohamad Pauzi

    2012-01-01

    This paper determines the controlling factors that influence the metals' behavior water-sediment interaction facies and distribution of elemental content (75As, 111Cd, 59Co, 52Cr, 60Ni, and 208Pb) in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals' concentration varied among stations. Metal concentrations of water ranged between 0.08–24.71 μg/L for As, <0.01–0.53 μg/L for Cd, 0.06–6.22 μg/L for Co, 0.32–4.67 μg/L for Cr, 0.80–24.72 μg/L for Ni, and <0.005–6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47–30.04 mg/kg for As, 0.02–0.18 mg/kg for Cd, 0.87–4.66 mg/kg for Co, 4.31–29.04 mg/kg for Cr, 2.33–8.25 mg/kg for Ni and 5.57–55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb) were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans. PMID:22919346

  10. Occurrence of macrophyte monocultures in drainage ditches relates to phosphorus in both sediment and water.

    PubMed

    van Zuidam, Jeroen P; Peeters, Edwin Thm

    2013-01-01

    Monocultures of functional equivalent species often negatively affect nutrient cycling and overall biodiversity of aquatic ecosystems. The importance of water and sediment nutrients for the occurrence of monocultures was analysed using field data from drainage ditches. Ranges of nutrients were identified that best explained the occurrence of monocultures of Elodea nuttallii (Planch.) St. John (Waterweed type), monocultures of duckweed (Duckweed type) and the occurrence of a diverse submerged vegetation (Mixed type). Results indicated these three vegetation types occurred at distinctive ranges of phosphorus in water and sediment. Sediment phosphorus distinguished monocultures from the Mixed type, with the two monocultures occurring at two to four times higher concentrations. The Waterweed type occurred at higher sediment phosphorus levels than the mixed type, showed a higher degree of dominance and lower number of red list species. Phosphorus concentrations in water were four to six times higher in the Duckweed type compared to the Waterweed and Mixed type. The three vegetation types had comparable total biomass which was unexpected. This comparability was likely caused by duckweed only growing at the water surface at the highest nutrient levels and the limited space in drainage ditches for increased submerged biomass development at high nutrient availability. Possible measures to limit the occurrence of monocultures, and thereby increasing the ecological quality, are discussed with focus on lowering phosphorus concentrations in both water and sediment and on removal of plant species that develop into monocultures. PMID:24255858

  11. Determination of organochlorine pesticide residue in sediment and water from the Densu river basin, Ghana.

    PubMed

    Kuranchie-Mensah, Harriet; Atiemo, Sampson Manukure; Palm, Linda Maud Naa-Dedei; Blankson-Arthur, Sarah; Tutu, Anita Osei; Fosu, Paul

    2012-01-01

    The distribution of organochlorine pesticides in the aquatic ecosystem from the Densu river revealed varying levels of concentration in water and the sediment samples. Three locations were sampled along the river to evaluate the levels of organochlorine pesticide residue in the river. Sediment and surface water samples were extracted by soxhlet and liquid-liquid extraction respectively and analyzed using Gas Chromatograph coupled with electron capture detector. The detectable organochlorine pesticides were gamma-hexachlorocyclohexane (HCH), delta-hexachlorocyclohexane, heptachlor, aldrin and dieldrin. The other pesticides that were investigated are gamma-chlordane, alpha endosulfan, endosulfan sulfate, p,p'-DDT and its metabolite p,p'-DDE, methoxychlor, endrin and its metabolite endrin aldehyde and endrin ketone. The order of increasing frequency of detection of samples was higher in sediment than water. In sediment, the mean concentration ranged from 0.030 μg kg(-1) dry weight (endrin) to 10.98 μg kg(-1) dry weight (aldrin). The highest detected concentration of organochlorine in water was endosulfan sulfate with mean concentration of 0.185 μg L(-1). Analysis of variance indicated significant differences for most organochlorine pesticide residue in the sediment sampled from the various locations. Some of the levels of organochlorine pesticides detected in water were relatively high compared to guideline values set by World Health Organization and Australia and thus could be harmful if the trend is not checked. PMID:22123529

  12. Enhanced phosphorus flux from overlying water to sediment in a bioelectrochemical system.

    PubMed

    Yang, Qinzheng; Zhao, Huazhang; Zhao, Nannan; Ni, Jinren; Gu, Xuejing

    2016-09-01

    This report proposed a novel technique for the regulation of phosphorus flux based on a bioelectrochemical system. In the simulated water system, a simple in situ sediment microbial fuel cell (SMFC) was constructed. SMFC voltage was increased with time until it was 0.23V. The redox potential of the sediment was increased from -220mV to -178mV during the process. Phosphorus concentration in the water system was decreased from 0.1mg/L to 0.01mg/L, compared with 0.09mg/L in the control. The installation of a SMFC produced an external current and internal circuit, which promoted the transfer of phosphate in overlying water to the sediment, enhanced the microbial oxidation of Fe(2+), and increased the formation of stable phosphorus in sediment. In conclusion, phosphorus flux from the overlying water to sediment was enhanced by SMFC, which has the potential to be used for eutrophication control of water bodies. PMID:27240233

  13. Microbial Response to Experimentally Controlled Redox Transitions at the Sediment Water Interface.

    PubMed

    Frindte, Katharina; Allgaier, Martin; Grossart, Hans-Peter; Eckert, Werner

    2015-01-01

    The sediment-water interface of freshwater lakes is characterized by sharp chemical gradients, shaped by the interplay between physical, chemical and microbial processes. As dissolved oxygen is depleted in the uppermost sediment, the availability of alternative electron acceptors, e.g. nitrate and sulfate, becomes the limiting factor. We performed a time series experiment in a mesocosm to simulate the transition from aerobic to anaerobic conditions at the sediment-water interface. Our goal was to identify changes in the microbial activity due to redox transitions induced by successive depletion of available electron acceptors. Monitoring critical hydrochemical parameters in the overlying water in conjunction with a new sampling strategy for sediment bacteria enabled us to correlate redox changes in the water to shifts in the active microbial community and the expression of functional genes representing specific redox-dependent microbial processes. Our results show that during several transitions from oxic-heterotrophic condition to sulfate-reducing condition, nitrate-availability and the on-set of sulfate reduction strongly affected the corresponding functional gene expression. There was evidence of anaerobic methane oxidation with NOx. DGGE analysis revealed redox-related changes in microbial activity and expression of functional genes involved in sulfate and nitrite reduction, whereas methanogenesis and methanotrophy showed only minor changes during redox transitions. The combination of high-frequency chemical measurements and molecular methods provide new insights into the temporal dynamics of the interplay between microbial activity and specific redox transitions at the sediment-water interface. PMID:26599000

  14. Toxicity assessment of wastewaters, river waters, and sediments in Austria using cost-effective microbiotests.

    PubMed

    Latif, Muna; Licek, Elisabeth

    2004-08-01

    The toxicity and chemical quality of surface water and sediment in the River Traun in Austria were studied because of recurrent fish mortality in some alpine rivers over the last few years. The analyses were carried out on samples collected during winter and summer upstream and downstream of two municipal wastewater treatment plants (WWTPs) and on effluents taken at the points of discharge of these two plants. Toxicity tests were performed on 20 samples of surface water, effluent, and sediment pore water. The test battery was composed of microbiotests with protozoans (Protoxkit F), microalgae (Algaltoxkit F), crustaceans (Daphtoxkit F magna and Thamnotoxkit F), and a higher plant (seed germination and root elongation assay on cress). Direct contact tests were performed on whole sediment with crustaceans (Ostracodtoxkit F). The physical-chemical characteristics of the surface water, effluent, and sediment pore water samples analyzed were conductivity, total hardness, pH, O(2), BOD(5), TOC, DOC, AOX, NH(4), NH(3), NO(2), PO(4)--P, Cd, Pb, Cu, and Zn. The toxicity data were expressed as percentage mortality or percentage inhibition, depending on the effect criterion of the respective assay. None of the water samples collected upstream and downstream of the WWTPs showed any significant (short-term) toxicity in either winter or in summer, but the effluents of the first municipal wastewater treatment plant were toxic to some of the test biota. All the sediment pore water samples induced serious inhibition of root growth of cress, and several pore waters were toxic to other test biota as well, particularly at the outlets of the WWTPs. The toxic character of some sediments was confirmed by direct contact tests with the ostracod crustacean. The chemical analyses did not reveal particularly high concentrations of any chemical that is very toxic. As a result no direct causal relationship could be established between the detected toxic effects and the chemical composition of

  15. Summary of suspended-sediment concentration data, San Francisco Bay, California, water year 2009

    USGS Publications Warehouse

    Buchanan, Paul A.; Morgan, Tara L.

    2012-01-01

    Suspended-sediment concentration data were collected by the U.S. Geological Survey in San Francisco Bay during water year 2009 (October 1, 2008–September 30, 2009). Optical sensors and water samples were used to monitor suspended-sediment concentration at two sites in Suisun Bay, one site in San Pablo Bay, two sites in Central San Francisco Bay, and one site in South San Francisco Bay. Sensors were positioned at two depths at most sites to help define the vertical variability of suspended sediments. Water samples were collected periodically and analyzed for concentrations of suspended sediment. The results of the analyses were used to calibrate the output of the optical sensors so that a record of suspended-sediment concentrations could be derived. This report presents the data-collection methods used and summarizes, in graphs, the suspended-sediment concentration data collected from October 2008 through September 2009. Calibration curves and plots of the processed data for each sensor also are presented.

  16. Summary of suspended-sediment concentration data, San Francisco Bay, California, water year 2010

    USGS Publications Warehouse

    Buchanan, Paul A.; Morgan, Tara L.

    2014-01-01

    Suspended-sediment concentration data were collected by the U.S. Geological Survey in San Francisco Bay during water year 2010 (October 1, 2009–September 30, 2010). Turbidity sensors and water samples were used to monitor suspended-sediment concentration at two sites in Suisun Bay, one site in San Pablo Bay, three sites in Central San Francisco Bay, and one site in South San Francisco Bay. Sensors were positioned at two depths at most sites to help define the vertical variability of suspended sediments. Water samples were collected periodically and analyzed for concentrations of suspended sediment. The results of the analyses were used to calibrate the output of the turbidity sensors so that a record of suspended-sediment concentrations could be computed. This report presents the data-collection methods used and summarizes, in graphs, the suspended-sediment concentration data collected from October 2009 through September 2010. Calibration curves and plots of the processed data for each sensor also are presented.

  17. Summary of Suspended-Sediment Concentration Data, San Francisco Bay, California, Water Year 2006

    USGS Publications Warehouse

    Buchanan, Paul A.; Lionberger, Megan A.

    2009-01-01

    Suspended-sediment concentration data were collected by the U.S. Geological Survey in San Francisco Bay during water-year 2006 (October 1, 2005-September 30, 2006). Optical sensors and water samples were used to monitor suspended-sediment concentration at two sites in Suisun Bay, one site in San Pablo Bay, two sites in Central San Francisco Bay, and one site in South San Francisco Bay. Sensors were positioned at two depths at most sites to help define the vertical variability of suspended sediments. Water samples were collected periodically and analyzed for concentrations of suspended sediment. The results of the analyses were used to calibrate the output of the optical sensors so that a record of suspended-sediment concentrations could be derived. This report presents the data-collection methods used and summarizes, in graphs, the suspended-sediment concentration data collected from October 2005 through September 2006. Calibration curves and plots of the processed data for each sensor also are presented.

  18. Development of Layered Sediment Structure and its Effects on Pore Water Transport and Hyporheic Exchange

    SciTech Connect

    Packman, Aaron I.; Marion, Andrea; Zaramella, Mattia; Chen, Cheng; Gaillard, Jean-François; Keane, Denis T.

    2008-04-15

    Hyporheic exchange is known to provide an important control on nutrient and contaminant fluxes across the stream-subsurface interface. Similar processes also mediate interfacial transport in other permeable sediments. Recent research has focused on understanding the mechanics of these exchange processes and improving estimation of exchange rates in natural systems. While the structure of sediment beds obviously influences pore water flow rates and patterns, little is known about the interplay of typical sedimentary structures, hyporheic exchange, and other transport processes in fluvial/alluvial sediments. Here we discuss several processes that contribute to local-scale sediment heterogeneity and present results that illustrate the interaction of overlying flow conditions, the development of sediment structure, pore water transport, and stream-subsurface exchange. Layered structures are shown to develop at several scales within sediment beds. Surface sampling is used to analyze the development of an armor layer in a sand-and-gravel bed, while innovative synchrotron-based X-ray microtomography is used to observe patterns of grain sorting within sand bedforms. We show that layered bed structures involving coarsening of the bed surface increase interfacial solute flux but produce an effective anisotropy that favors horizontal pore water transport while limiting vertical penetration.

  19. Quantification of sediment-water interactions in a polluted tropical river through biogeochemical modeling

    NASA Astrophysics Data System (ADS)

    Trinh, Anh Duc; Meysman, Filip; Rochelle-Newall, Emma; Bonnet, Marie Paule

    2012-09-01

    Diagenetic modeling presents an interesting and robust way to understand sediment-water column processes. Here we present the application of such a model to the Day River in Northern Vietnam, a system that is subject to high levels of domestic wastewater inputs from the Hanoi metropolitan area. Experimental data from three areas of different water and sediment quality, combined with some additional data from the river, are used to set up and calibrate a diagenetic model. The model was used to determine the role of the sediments as a sink for carbon and nutrients and shows that in the dry season, 27% of nitrogen, 25% of carbon, and 38% of phosphorus inputs into the river system are stored in sediments. The corresponding numbers during the rainy season are 15%, 10%, and 20%, respectively. The diagenetic model was then used to test the impact of an improvement in the treatment of Hanoi's municipal wastewater. We show that improved wastewater treatment could reduce by about 17.5% the load of organic matter to the sediment. These results are the first to highlight the importance of sediments as a potential removal mechanism of organic matter and nutrients from the water column in this type of highly impacted tropical urban river, further demonstrating that rivers need to be considered as reaction sites and not just as inert conduits.

  20. An Integrated Assessment of Sediment Remediation in a Midwestern U.S. Stream Using Sediment Chemistry, Water Quality, Bioassessment and Fish Biomarkers

    EPA Science Inventory

    A comprehensive biological, sediment and water quality study of the lower Little Scioto River near Marion, Ohio, USA was undertaken in July 2007 to evaluate the effectiveness of removal of creosote-contaminated sediment. The study area covered 7.5 river miles (RMs) of the river, ...

  1. Comparative studies on extraction of sediment interstitial waters: Discussion and comment on the current state of interstitial water studies

    USGS Publications Warehouse

    Manheim, F. T.

    1974-01-01

    The implication by Murthy and Ferrell (1972)that interstitial water studies are in a confused state is criticized on the basis that the authors have not drawn on a considerable body of data, especially Soviet studies since the 1950's, and results of the Deep Sea Drilling Project. Pressure filtration systems for extracting interstitial waters are currently the methods of choice for marine studies and have achieved substantial reliability and reproducibility. Although gaps and problems remain, many aspects of interstitial composition of marine sediments have been clarified; these include the substantial constancy of composition of interstitial waters in deep sea pelagic deposits, depletion of interstitial cations owing to authigenic mineral formation in more rapidly accumulated (especially terrigenous) sediments, and special phenomena in sediments overlying salt deposits. ?? 1974.

  2. Factors controlling the silicon isotope distribution in waters and surface sediments of the Peruvian coastal upwelling

    NASA Astrophysics Data System (ADS)

    Ehlert, Claudia; Grasse, Patricia; Mollier-Vogel, Elfi; Böschen, Tebke; Franz, Jasmin; de Souza, Gregory F.; Reynolds, Ben C.; Stramma, Lothar; Frank, Martin

    2012-12-01

    We present the first systematic study of the silicon isotope composition in the water column (δ30Si) and in diatoms (δ30Sidiatom) from the underlying surface sediments in a coastal upwelling region. The surface waters upwelling on the shelf off Peru are mainly fed by southward flowing subsurface waters along the coast, which show a mean δ30Si of +1.5‰. The concentration of dissolved silicic acid (Si(OH)4) increases towards the south in these waters and with increasing water depth, suggesting lateral mixing with water masses from the south and intense remineralisation of particulate biogenic silica (bSiO2) in the water column and in the surface sediments. Surface waters in the realm of the most intense upwelling between 5°S and 15°S have only marginally elevated δ30Si values (δ30Si = +1.7‰) with respect to the source Si isotope composition, whereas further north and south, where upwelling is less pronounced, surface waters are more strongly fractionated (δ30Si up to +2.8‰) due to the stronger utilisation of the smaller amounts of available Si(OH)4. The degree of Si(OH)4 utilisation in the surface waters along the shelf estimated from the Si(OH)4 concentration data ranges from 51% to 93%. The δ30Sidiatom values of hand-picked diatoms in the underlying surface sediments vary from +0.6‰ to +2.0‰, which is within the range of the expected fractionation between surface waters and diatoms. The fractionation signal in the surface waters produced during formation of the diatoms is reflected by the δ30Sidiatom values in the underlying sediments, with the lowest δ30Sidiatom values in the main upwelling region. The silicon isotope compositions of bSiO2 (δ30Si) from the same surface sediment samples are generally much lower than the δ30Sidiatom signatures indicating a significant contamination of the bSiO2 with biogenic siliceous material other than diatoms, such as sponge spicules. This shift towards lighter δ30Si values by up to -1.3‰ compared to

  3. Water and sediment dynamics in a small Mediterranean cultivated catchment under cracking soils

    NASA Astrophysics Data System (ADS)

    Inoubli, Nesrine; Raclot, Damien; Moussa, Roger; Habaieb, Hamadi; Le Bissonnais, Yves

    2016-04-01

    Shrink-swell soils, such as those in a Mediterranean climate regime, can cause changes in terms of hydrological and erosive responses due to the changing soil water storage conditions. Only a limited number of long-term studies have focused on the impacts on both hydrological and erosive responses and their interactions in an agricultural environment. In this context, this study aims to document the dynamics of cracks, runoff and soil erosion within a small Mediterranean cultivated catchment and to quantify the influence of crack processes on the water and sediment supplied to a reservoir located at the catchment outlet. Detailed monitoring of the presence of topsoil cracks was conducted within the Kamech catchment (ORE OMERE, Tunisia), and runoff and suspended sediment loads were continuously measured over a long period of time (2005-2012) at the outlets of a field (1.32 ha) and a catchment (263 ha). Analysis of the data showed that topsoil cracks were open approximately half of the year and that the rainfall regime and water table level conditions locally control the seasonal cracking dynamics. Topsoil cracks appeared to seriously affect the generation of runoff and sediment concentrations and, consequently, sediment yields, with similar dynamics observed at the field and catchment outlets. A similar time lag in the seasonality between water and sediment delivery was observed at these two scales: although the runoff rates were globally low during the presence of topsoil cracks, most sediment transport occurred during this period associated with very high sediment concentrations. This study underlines the importance of a good prediction of runoff during the presence of cracks for reservoir siltation considerations. In this context, the prediction of cracking effects on runoff and soil erosion is a key factor for the development of effective soil and water management strategies and downstream reservoir preservation.

  4. Air and water quality monitor assessment of life support subsystems

    NASA Technical Reports Server (NTRS)

    Whitley, Ken; Carrasquillo, Robyn L.; Holder, D.; Humphries, R.

    1988-01-01

    Preprotype air revitalization and water reclamation subsystems (Mole Sieve, Sabatier, Static Feed Electrolyzer, Trace Contaminant Control, and Thermoelectric Integrated Membrane Evaporative Subsystem) were operated and tested independently and in an integrated arrangement. During each test, water and/or gas samples were taken from each subsystem so that overall subsystem performance could be determined. The overall test design and objectives for both subsystem and integrated subsystem tests were limited, and no effort was made to meet water or gas specifications. The results of chemical analyses for each of the participating subsystems are presented along with other selected samples which were analyzed for physical properties and microbiologicals.

  5. Speciation and fate of trace metals in estuarine sediments under reduced and oxidized conditions, Seaplane Lagoon, Alameda Naval Air Station (USA)

    PubMed Central

    Carroll, Susan; O'Day, Peggy A; Esser, Brad; Randall, Simon

    2002-01-01

    We have identified important chemical reactions that control the fate of metal-contaminated estuarine sediments if they are left undisturbed (in situ) or if they are dredged. We combined information on the molecular bonding of metals in solids from X-ray absorption spectroscopy (XAS) with thermodynamic and kinetic driving forces obtained from dissolved metal concentrations to deduce the dominant reactions under reduced and oxidized conditions. We evaluated the in situ geochemistry of metals (cadmium, chromium, iron, lead, manganese and zinc) as a function of sediment depth (to 100 cm) from a 60 year record of contamination at the Alameda Naval Air Station, California. Results from XAS and thermodynamic modeling of porewaters show that cadmium and most of the zinc form stable sulfide phases, and that lead and chromium are associated with stable carbonate, phosphate, phyllosilicate, or oxide minerals. Therefore, there is minimal risk associated with the release of these trace metals from the deeper sediments contaminated prior to the Clean Water Act (1975) as long as reducing conditions are maintained. Increased concentrations of dissolved metals with depth were indicative of the formation of metal HS- complexes. The sediments also contain zinc, chromium, and manganese associated with detrital iron-rich phyllosilicates and/or oxides. These phases are recalcitrant at near-neutral pH and do not undergo reductive dissolution within the 60 year depositional history of sediments at this site. The fate of these metals during dredging was evaluated by comparing in situ geochemistry with that of sediments oxidized by seawater in laboratory experiments. Cadmium and zinc pose the greatest hazard from dredging because their sulfides were highly reactive in seawater. However, their dissolved concentrations under oxic conditions were limited eventually by sorption to or co-precipitation with an iron (oxy)hydroxide. About 50% of the reacted CdS and 80% of the reacted ZnS were

  6. Monitoring of nutrients, pesticides, and metals in waters, sediments, and fish of a wetland.

    PubMed

    Salvadó, V; Quintana, X D; Hidalgo, M

    2006-10-01

    Wetland areas are of extraordinary importance for the conservation of wildlife. The Aiguamolls de l'Empordà Natural Park, located in Girona (northeast Spain), is one of the few areas in Europe acting as a way station for migratory birds. The natural park is made up of a brackish water reserve and a fresh water reserve. Agriculture and tourism, which are concentrated especially around coastal population centers, are the main activities in this area and result in the release into the environment of nutrients, pesticides, and heavy metals. This article aims to investigate the presence of nutrients, selected pesticides (organochlorine compounds, permethrin and triazines) and metals (Cr, Cu, Cd, Ni and Pb) in water, sediments, and fish samples. In the case of water, seasonal variations in levels of contamination were also monitored. Comparison was made of the fresh and brackish water reserves and concentration factors for metals and pesticides in sediment were determined. We conclude that the most significant sources of contamination in the natural park are from the entry of pesticides and nutrients into surface waters and sediments as a result of the intensive farming activity of the surrounding areas. The pesticides with the greatest presence were found to be lindane, heptachlor epoxide, permethrin, and atrazine. Among the metals analyzed, Cu and Cr presented the highest concentrations in surface waters and sediments. PMID:16763761

  7. The marine geochemistry of actinium-227: Evidence for its migration through sediment pore water

    SciTech Connect

    Nozaki, Yoshiyuki; Yamada, Masatoshi ); Nikaido, Hirofumi )

    1990-10-01

    {sup 227}Ac with a half life of 21.8 years has a potential utility as a tracer of deep water circulation and mixing studies on time scales less than 100 years. Here the authors present the first measurement of {sup 227}Ac profile in the pore water of Northwest Pacific deep-sea sediment and in the {approximately}10,000 m long water column of Izu-Ogasawara Trench. The results clearly show that {sup 227}Ac is supplied from the sediment to the overlying water through migration in the pore water. The model calculation indicates that the molecular diffusion alone through sediment porewater can support only a half of the standing crop of excess {sup 227}Ac in the water column and the enhanced supply of {sup 227}Ac by particle mixing is necessary to account for the remainder. Thus, bioturbation in the deep sea plays an important role in controlling the flux of some short-lived radionuclides such as {sup 227}Ac and {sup 228}Ra across the sediment-water interface.

  8. 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.

  9. Diffusive release of uranium from contaminated sediments into capillary fringe pore water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M.; Harsh, James B.

    2012-10-01

    Despite remediation efforts at the former nuclear weapons facility at the Hanford site (Washington State), leaching of uranium (U) from contaminated sediments to the ground water persists at the Hanford 300 Area. Flooding of contaminated capillary fringe sediments due to seasonal changes in the Columbia River stage has been identified as a reason of continued U supply to ground water. We investigated the release of U from Hanford capillary fringe sediments to pore water. Contaminated Hanford sediments were packed into reservoirs of centrifugal filter devices and saturated with Columbia River water for 3 to 84 days at varying solution-to-solid ratios (1:3, 1:1, 5:1, 10:1, 25:1 mL:g). After specified times, samples were centrifuged to a gravimetric water content of 0.11 ± 0.06 g g-1. Within the first three days, there was an initial rapid release of 6-9% of total U from the sediments into the pore water, independent of the solution-to-solid ratio. After 14 days of reaction, however, the experiments with the narrowest solution-to-solid ratios (1:3 and 1:1 mL:g) showed a decline in dissolved U concentrations. The removal of U from the solution phase was accompanied by removal of Ca and HCO3-. Geochemist workbench simulations, conducted using measured solution concentrations from experiments, indicated that calcite could precipitate in the 1:3 solution-to-solid ratio experiment. After the rapid initial release in the first three days for the 5:1, 10:1, and 25:1 solution-to-solid ratio experiments, there was sustained release of U into the pore water. Up to 22% of total U was released on day 84 for the 25:1 solution-to-solid ratio reaction. This sustained release of U from the sediments had diffusion-limited kinetics.

  10. Suspended sediment concentration mapping based on the MODIS satellite imagery in the East China inland, estuarine, and coastal waters

    NASA Astrophysics Data System (ADS)

    Yang, Xianping; Sokoletsky, Leonid; Wei, Xiaodao; Shen, Fang

    2016-04-01

    The purpose of this research is to improve the retrieval accuracy for the suspended sediment concentration (SSC) from in situ and satellite remote sensing measurements in turbid East China estuarine and coastal waters. For this aim, three important tasks are formulated and solved: 1) an estimation of remote-sensing reflectance spectra R rs(λ) after atmospheric correction; 2) an estimation of R rs(λ) from the radiometric signals above the air-water surface; and 3) an estimation of SSC from R rs(λ). Six different models for radiometric R rs(λ) determination and 28 models for SSC versus R rs(λ) are analyzed based on the field observations made in the Changjiang River estuary and its adjacent coastal area. The SSC images based on the above-mentioned analysis are generated for the area.

  11. Simultaneous Investigation of Sediment Transport and Water Quality Parameters Using An In Situ Measurement Device

    NASA Astrophysics Data System (ADS)

    Prochnow, J. V.

    Though quality of surface waters has improved remarkably over the last twenty years, the contaminant load of soft cohesive sediments remained comparatively unimproved. That is why the new European water framework directive addresses contaminant loaded sediments and postulates criteria for assessing sediment quality. Surveys into contaminated sediment behaviour have revealed adsorption/desorption characteristics of individual toxins. Biomonitoring of pollutant pressure on specific benthic organ- isms on the other hand can be useful to elucidate potential dangers to aquatic ecosys- tems. However, it is yet unknown how a given contaminant loaded sediment will re- spond to different hypercritical flow conditions in terms of release rates and partition- ing of xenobiotica. On this account a small in situ measuring device (EROSIMESS) was constructed, that features simultaneous determination of suspended sediment con- centration (optical turbidity meter), dissolved oxygen levels, pH and temperature (membrane probes) under predefined hydraulic conditions. Samples of the suspen- sion can be withdrawn for subsequent chemical analysis. Bottom shear stresses up to 5N/m2 can be generated by means of a propeller that resides in cylindrical perspex tube (erosion chamber) two centimeters above the sediment bed. Baffles on the in- ner wall of the cylinder prevent a solid body rotation of the suspension by creating additional turbulence and a second propeller straight beneath the concentration me- ter inhibits the development of a concentration gradient within the chamber. A small CCD-camera is used to control positioning of the device. It can be used in water- depths up to 5m. The control unit consists of a trigger box and an ordinary laptop computer running LabView. EROSIMESS has been successfully used in various stud- ies on contaminant release, eutrophication, and SOD (sediment oxygen demand) in rivers (Spree: Germany; Maun: UK), reservoirs (Heimbach, Haus Ley: Germany), and

  12. [Study on polarization spectral feature of suspended sediment in the water body].

    PubMed

    Zhu, Jin; Wang, Xian-Hua; Pan, Bang-Long

    2012-07-01

    Remote sensing of lake water based on water-leaving radiance is to retrieve the concentrations of suspended sediment, phytoplankton and yellow substance which have great impacts on spectrum to assess the water quality. Howerver, because of the complexity of the lake water compositons and the interference between the different components, it is of great difficulty to get accurate results with the reflectance spectrum method developed recently. In the present paper, the authors firstly discussed the reflectance and polarization spectral feature of suspended sediment water body, found out the relations of the reflectance and the degree of polarization of water-leaving radiance and the concentration of suspended sediment at the sensitive bands. The authors also compared the effectiveness of the retrieval approaches based on reflectance and polarization in laboratory water body and Chaohu water body respectively. The results show that in the lake water body where the constituents are very complex, the polarization information has greater capacity of anti-jamming, therefore it will have great potential applictions in lake water quality remote sensing. PMID:23016352

  13. Water volume and sediment accumulation in Lake Linganore, Frederick County, Maryland, 2009

    USGS Publications Warehouse

    Sekellick, Andrew J.; Banks, S.L.

    2010-01-01

    To assist in understanding sediment and phosphorus loadings and the management of water resources, a bathymetric survey was conducted at Lake Linganore in Frederick County, Maryland in June 2009 by the U.S. Geological Survey, in cooperation with the City of Frederick and Frederick County, Maryland. Position data and water-depth data were collected using a survey grade echo sounder and a differentially corrected global positioning system. Data were compiled and edited using geographic information system software. A three-dimensional triangulated irregular network model of the lake bottom was created to calculate the volume of stored water in the reservoir. Large-scale topographic maps of the valley prior to inundation in 1972 were provided by the City of Frederick and digitized. The two surfaces were compared and a sediment volume was calculated. Cartographic representations of both water depth and sediment accumulation were produced along with an area/capacity table. An accuracy assessment was completed on the resulting bathymetric model. Vertical accuracy at the 95-percent confidence level for the collected data, the bathymetric surface model, and the bathymetric contour map was calculated to be 0.95 feet, 1.53 feet, and 3.63 feet, respectively. The water storage volume of Lake Linganore was calculated to be 1,860 acre-feet at full pool elevation. Water volume in the reservoir has decreased by 350 acre-feet (about 16 percent) in the 37 years since the dam was constructed. The total calculated volume of sediment deposited in the lake since 1972 is 313 acre-feet. This represents an average rate of sediment accumulation of 8.5 acre-feet per year since Linganore Creek was impounded. A sectional analysis of sediment distribution indicates that the most upstream third of Lake Linganore contains the largest volume of sediment whereas the section closest to the dam contains the largest amount of water. In comparison to other Maryland Piedmont reservoirs, Lake Linganore

  14. Laboratory upwelled radiance and reflectance spectra of Kerr reservoir sediment waters

    NASA Technical Reports Server (NTRS)

    Witte, W. G.; Whitlock, C. H.; Morris, W. D.; Gurganus, E. A.

    1982-01-01

    Reflectance, chromaticity, and several other physical and chemical properties were measured for various water mixtures of bottom sediments taken from two sites at Kerr Reservoir, Virginia. Mixture concentrations ranged from 5 to 1000 ppm by weight of total suspended solids (TSS) in filtered deionized tap water. The two sets of radiance and reflectance spectra obtained were similar in shape and magnitude for comparable values of TSS. Upwelled reflectance was observed to be a nonlinear function of TSS with the degree of curvature a function of wavelength. Sediment from the downstream site contained a greater amount of particulate organic carbon than from the upstream site. No strong conclusions can be made regarding the effects of this difference on the radiance and reflectance spectra. Near-infrared wavelengths appear useful for measuring highly turbid water with concentrations up to 1000 ppm or more. Chromaticity characteristics do not appear useful for monitoring sediment loads above 150 ppm.

  15. Hg bioaccumulation in a contaminated flowing water system-sediment, macroinvertebrates, and fish interactions

    NASA Astrophysics Data System (ADS)

    Pizarro-Barraza, C.; Gustin, M. S.; Peacock, M.

    2010-12-01

    The Truckee River (TR) of Nevada/California USA has been and is impacted physically and chemically by human actions. Previous work has shown a significant difference in mercury (Hg) concentrations of fish and water collected above and below the confluence of Steamboat Creek (SBC) with the river. Steamboat Creek is contaminated with Hg due to legacy milling of gold and silver ore at Washoe Lake. We investigated the potential for Hg concentrations in water, sediments and macroinvertebrates to be latent indicators of potential sources of methylmercury (MeHg) for fish species. Sites below SBC showed significantly higher Hg concentrations in water, sediments, macroinvertebrates, and fish. Not only were MeHg concentrations in sediments associated with specific environmental conditions, but sediments from the shore versus the active channel appeared to be an important source of MeHg to waters during periods of high flow. Data showed that areas with high Hg concentrations in sediments were also locations of elevated Hg concentrations in some species of macroinvertebrates. Bioaccumulation was observed not only as a function of tropic stature for fish in the reach impacted by SBC, but also for macroinvertebrates with predator species having higher concentrations than collectors and omnivorous.

  16. Release of elements to natural water from sediments of Lake Roosevelt, Washington, USA

    USGS Publications Warehouse

    Paulson, Anthony J.; Cox, Stephen E.

    2007-01-01

    Reservoir sediments from Lake Roosevelt (WA, USA) that were contaminated with smelter waste discharged into the Columbia River (BC, Canada) were examined using three measures of elemental release reflecting varying degrees of physical mixing and time scales. Aqueous concentrations of Cd, Cu, Pb, and Zn in the interstitial water of reservoir sediments, in the gently stirred overlying waters of incubated sediment cores, and in supernatants of aggressively tumbled slurries of reservoir sediments generally were higher than the concentrations from a reference site. When compared to chronic water-quality criteria, all three measures of release suggest that slag-contaminated sediments near the U.S.-Canadian border are potentially toxic as a result of Cu release and Pb release in two of the three measures. All three measures of Cd release suggest potential toxicity for one site farther down the reservoir, probably contaminated as a result of transport and adsorption of Cd from smelter liquid waste. Releases of Zn and As did not appear to be potentially toxic. Carbonate geochemistry indirectly affects the potential toxicity by increasing water hardness.

  17. Microbial diversity in shallow-water hydrothermal sediments of Kueishan Island, Taiwan as revealed by pyrosequencing.

    PubMed

    Wang, Li; Cheung, Man Kit; Kwan, Hoi Shan; Hwang, Jiang-Shiou; Wong, Chong Kim

    2015-11-01

    Kueishan Island is a young volcanic island in the southernmost edge of the Okinawa Trough in the northeastern part of Taiwan. A cluster of hydrothermal vents is located off the southeastern tip of the Island at water depths between 10 and 80 m. This paper presents the results of the first study on the microbial communities in bottom sediments collected from the shallow-water hydrothermal vents of Kueishan Island. Small-subunit ribosomal RNA gene-based high-throughput 454 pyrosequencing was used to characterize the assemblages of bacteria, archaea, and small eukaryotes in sediment samples collected at various distances from the hydrothermal vents. Sediment from the vent area contained the highest diversity of archaea and the lowest diversity of bacteria and small eukaryotes. Epsilonproteobacteria were the most abundant group in the vent sediment, but their abundance decreased with increasing distance from the vent area. Most Epsilonproteobacteria belonged to the mesophilic chemolithoautotrophic genera Sulfurovum and Sulfurimonas. Recent reports on these two genera have come from deep-sea hydrothermal vents. Conversely, the relative contribution of Gammaproteobacteria to the bacterial community increased with increasing distance from the vent area. Our study revealed the contrasting effects of venting on the benthic bacterial and archaeal communities, and showed that the sediments of the shallow-waters hydrothermal vents were dominated by chemoautotrophic bacteria. The present work broadens our knowledge on microbial diversity in shallow-water hydrothermal vent habitats. PMID:26132902

  18. Assessment of metal toxicity in sediment pore water from Lake Macquarie, Australia.

    PubMed

    Doyle, C J; Pablo, F; Lim, R P; Hyne, R V

    2003-04-01

    Recent investigations into the level of heavy metal enrichment in the sediments of Lake Macquarie have indicated that significant contamination has occurred over the past 100 years, with elevated levels of lead, zinc, cadmium, copper, and selenium being observed in most parts of the lake. Pore water extracted from sediments showing the greatest contamination by these metals exhibited toxicity to the larval development of the sea urchin Heliocidaris tuberculata. However, an analysis of pore water metal concentrations revealed that the concentrations of these metals were too low to cause toxicity. Rather, pore water toxicity was highly correlated with manganese for the majority of sites sampled; subsequent spiking experiments confirmed manganese as a cause of toxicity. Current levels of manganese in the sediments of Lake Macquarie have arisen from natural sources and are not the result of anthropogenic activities. These results reiterate the importance of identifying the causes of toxicity in assessments of sediment contamination, particularly when testing sediment pore waters using sensitive early life stages. PMID:12712294

  19. Analysis of heavy metals concentration in water and sediment in the Hara biosphere reserve, southern Iran.

    PubMed

    Nowrouzi, Mohsen; Mansouri, Borhan; Nabizadeh, Sahar; Pourkhabbaz, Alireza

    2014-02-01

    This study determined the concentration of heavy metals (Al, Cr, Cu, and Zn) in water and sediments at nine sites in the Hara biosphere reserve of southern Iran during the summer and winter 2010. Determination of Al, Cr, Cu, and Zn in water was carried out by graphite furnace atomic absorption spectrometer (Shimadzu, AA 610s) and in sediment by flame atomic absorption spectrometer (Perkin Elmer, AA3030). Results showed that the heavy metal concentrations in the water samples decreased in the sequence of Zn > Al > Cu > Cr, while in sediment samples were Cr > Zn > Cu > Al. Data analysis indicated that with the exception of Al, there was a Pearson's correlation coefficient between pH and Cu, Zn, and Cr at α = 0.01, 0.05, and 0.001 in sediment (in winter), respectively. There were also significant differences between heavy metals of Cr, Cu, and Zn during the two seasons (p < 0.001) in the water and sediment. PMID:22740619

  20. Diffusive release of uranium from contaminated sediments into capillary fringe pore water

    SciTech Connect

    Rod, Kenton A.; Wellman, Dawn M.; Flury, Markus; Pierce, Eric M; Harsh, James B.

    2012-01-01

    Despite remediation efforts at the former nuclear weapons facility, leaching of uranium (U) from contaminated sediments to the ground water persists at the Hanford site 300 Area. Flooding of contaminated capillary fringe sediments due to seasonal changes in the Columbia River stage has been identified as a source for U supply to ground water. We investigated U release from Hanford capillary fringe sediments by packing sediments into reservoirs of centrifugal filter devices and saturated with Columbia River water for 3 to 84 days at varying solution-to-solid ratios. After specified times, samples were centrifuged. Within the first three days, there was an initial rapid release of 6-9% of total U, independent of the solution-to-solid ratio. After 14 days of reaction, however, the experiments with the narrowest solution-to-solid ratios showed a decline in dissolved U concentrations. The removal of U from the solution phase was accompanied by removal of Ca and HCO3-. Geochemical modeling indicated that calcite could precipitate in the narrowest solution-to-solid ratio experiment. After the rapid initial release in the first three days for the wide solution-to-solid ratio experiments, there was sustained release of U into the pore water. This sustained release of U from the sediments had diffusion-limited kinetics.

  1. Identification of Water-Quality Trends Using Sediment Cores from Dillon Reservoir, Summit County, Colorado

    USGS Publications Warehouse

    Greve, Adrienne I.; Spahr, Norman E.; Van Metre, Peter C.; Wilson, Jennifer T.

    2001-01-01

    Since the construction of Dillon Reservoir, in Summit County, Colorado, in 1963, its drainage area has been the site of rapid urban development and the continued influence of historical mining. In an effort to assess changes in water quality within the drainage area, sediment cores were collected from Dillon Reservoir in 1997. The sediment cores were analyzed for pesticides, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and trace elements. Pesticides, PCBs, and PAHs were used to determine the effects of urban development, and trace elements were used to identify mining contributions. Water-quality and streambed-sediment samples, collected at the mouth of three streams that drain into Dillon Reservoir, were analyzed for trace elements. Of the 14 pesticides and 3 PCBs for which the sediment samples were analyzed, only 2 pesticides were detected. Low amounts of dichloro-diphenyldichloroethylene (DDE) and dichloro-diphenyldichloroethane (DDD), metabolites of dichlorodiphenyltrichloroethane (DDT), were found at core depths of 5 centimeters and below 15 centimeters in a core collected near the dam. The longest core, which was collected near the dam, spanned the entire sedimentation history of the reservoir. Concentrations of total combustion PAH and the ratio of fluoranthene to pyrene in the core sample decreased with core depth and increased over time. This relation is likely due to growth in residential and tourist populations in the region. Comparisons between core samples gathered in each arm of the reservoir showed the highest PAH concentrations were found in the Tenmile Creek arm, the only arm that has an urban area on its shores, the town of Frisco. All PAH concentrations, except the pyrene concentration in one segment in the core near the dam and acenaphthylene concentrations in the tops of three cores taken in the reservoir arms, were below Canadian interim freshwater sediment-quality guidelines. Concentrations of arsenic, cadmium

  2. Total and Methyl Mercury Distribution in Water, Sediment, and Fish tissue in New England Streams

    NASA Astrophysics Data System (ADS)

    Chalmers, A. T.; Krabbenhoft, D. P.

    2001-05-01

    Conditions that are conducive to the methylation of mercury are of particular concern because methyl mercury (MeHg) is the most toxic mercury species and is rapidly bioaccumulated and biomagnified in wildlife and man. The New England Coastal Basins study unit, as part of the U.S. Geological Survey's National Water Quality Assessment program, has evaluated relations between concentrations of total mercury (HgT) and MeHg in stream water and bed sediment, and HgT in fish tissue at sites with a variety of watershed characteristics. Fifty-five stream sites from Rhode Island to Maine were sampled for water and bed sediment during 1998 - 2000. A subset of 27 sites was sampled for fish tissue. Sediment, water, and fish tissue samples were collected during summer low flow conditions within a week of each other to show patterns of MeHg accumulation and partitioning relative to site and watershed conditions. Concentrations of HgT in water and bed sediment ranged from 1 to 13 nanograms per liter (ng/L) and from 7 to 3,100 nanograms per gram (ng/g) dry weight, respectively. Concentrations of MeHg in water and sediment ranged from 0.04 to 1.8 ng/L and from 1 to 38 ng/g dry weight, respectively, and were positively correlated with concentrations of organic carbon. Methylation efficiency, as estimated by MeHg/HgT, ranged from 0.003 to 0.282 for sediment and water samples, with a median value of 0.071. Methylation efficiency was highest at sampling sites with low urbanization and high organic carbon concentrations. HgT concentrations in fish tissue (mixed sunfish species) ranged from 42 to 349 ng/g wet weight and were positively correlated with concentrations of MeHg in water and bed sediment. A positive relation was not observed between HgT concentrations in fish tissue and HgT concentrations in water and bed sediment. These preliminary results indicate a high potential for mercury bioaccumulation in aquatic organisms in New England streams.

  3. Sediment transport and evaluation of sediment surrogate ratings in the Kootenai River near Bonners Ferry, Idaho, Water Years 2011–14

    USGS Publications Warehouse

    Wood, Molly S.; Fosness, Ryan L.; Etheridge, Alexandra B.

    2015-01-01

    Acoustic surrogate ratings were developed between backscatter data collected using acoustic Doppler velocity meters (ADVMs) and results of suspended-sediment samples. Ratings were successfully fit to various sediment size classes (total, fines, and sands) using ADVMs of different frequencies (1.5 and 3 megahertz). Surrogate ratings also were developed using variations of streamflow and seasonal explanatory variables. The streamflow surrogate ratings produced average annual sediment load estimates that were 8–32 percent higher, depending on site and sediment type, than estimates produced using the acoustic surrogate ratings. The streamflow surrogate ratings tended to overestimate suspended-sediment concentrations and loads during periods of elevated releases from Libby Dam as well as on the falling limb of the streamflow hydrograph. Estimates from the acoustic surrogate ratings more closely matched suspended-sediment sample results than did estimates from the streamflow surrogate ratings during these periods as well as for rating validation samples collected in water year 2014. Acoustic surrogate technologies are an effective means to obtain continuous, accurate estimates of suspended-sediment concentrations and loads for general monitoring and sediment-transport modeling. In the Kootenai River, continued operation of the acoustic surrogate sites and use of the acoustic surrogate ratings to calculate continuous suspended-sediment concentrations and loads will allow for tracking changes in sediment transport over time.

  4. Connecting Water Quality With Air Quality Through Microbial Aerosols

    NASA Astrophysics Data System (ADS)

    Dueker, M. Elias

    Aerosol production from surface waters results in the transfer of aquatic materials (including nutrients and bacteria) to air. These materials can then be transported by onshore winds to land, representing a biogeochemical connection between aquatic and terrestrial systems not normally considered. In urban waterfront environments, this transfer could result in emissions of pathogenic bacteria from contaminated waters. Despite the potential importance of this link, sources, near-shore deposition, identity and viability of microbial aerosols are largely uncharacterized. This dissertation focuses on the environmental and biological mechanisms that define this water-air connection, as a means to build our understanding of the biogeochemical, biogeographical, and public health implications of the transfer of surface water materials to the near-shore environment in both urban and non-urban environments. The effects of tidal height, wind speed and fog on coastal aerosols and microbial content were first quantified on a non-urban coast of Maine, USA. Culture-based, culture-independent, and molecular methods were used to simultaneously sample microbial aerosols while monitoring meteorological parameters. Aerosols at this site displayed clear marine influence and high concentrations of ecologically-relevant nutrients. Coarse aerosol concentrations significantly increased with tidal height, onshore wind speed, and fog presence. Tidal height and fog presence did not significantly influence total microbial aerosol concentrations, but did have a significant effect on culturable microbial aerosol fallout. Molecular analyses of the microbes settling out of near-shore aerosols provided further evidence of local ocean to terrestrial transport of microbes. Aerosol and surface ocean bacterial communities shared species and in general were dominated by organisms previously sampled in marine environments. Fog presence strengthened the microbial connection between water and land through

  5. Impact of Reservoir Sediment Scour on Water Quality in a Downstream Estuary.

    PubMed

    Cerco, Carl F; Noel, Mark R

    2016-05-01

    The Conowingo Reservoir is situated at the lower terminus of the Susquehanna ---River watershed, immediately above Chesapeake Bay. Since construction, the reservoir has been filling with sediment to the point where storage capacity is nearly exhausted. The potential for release of accumulated sediments, organic matter, and nutrients, especially through the action of storm scour, causes concern for water quality in Chesapeake Bay. We used hydrodynamic and eutrophication models to examine the effects of watershed loads and scour loads on bay water quality under total maximum daily load conditions. Results indicate that increased suspended solids loads are not a threat to bay water quality. For most conditions, solids scoured from the reservoir settle out before the season during which light attenuation is critical. The organic matter and nutrients associated with the solids are, however, detrimental. This material settles to the estuary bottom and is mineralized in bed sediments. Carbon diagenesis spurs oxygen consumption in bottom sediments and in the water column via release of chemical oxygen demand. The nutrients are recycled to the water column and stimulate algal production. As a result of a scour event, bottom-water dissolved oxygen declines up to 0.2 g m, although the decline is 0.1 g m or less when averaged over the summer season. Surface chlorophyll increases 0.1 to 0.3 mg m during the summer growing season. PMID:27136156

  6. Studies on monitoring the heavy metal contents in water, sediment and snail species in Latipada reservoir.

    PubMed

    Waykar, Bhalchandra; Petare, Ram

    2016-07-01

    The concentrations of zinc, copper, cadmium and lead in surface water, sediments and two native snail species, Bellamya bengalensis and Melanoides tuberculata from Latipada reservoir were determined. The concentrations of cadmium and lead in surface water were higher than the WHO recommended limits for drinking water standards; where as those of zinc and copper were within the permissible limits. The concentrations of zinc, copper, cadmium and lead were higher in sediments than in water. The observed bioaccumulated level of zinc, copper, cadmium and lead in Bellamya bengalensis were Zn- 197.22, Cu- 172.14, Cd- 11.59 and Pb- 112.57 μg g(-1), while in Melanoides tuberculata were Zn- 136.59, Cu- 132.04, Cd- 13.25 and Pb- 27.69 μg g(-1). The metal concentrations in both species of snails were higher than those of the water and sediment. Bioaccumulated metal concentrations, Bio-Water Accumulation Factor (BWAF) and Bio-Sediment Accumulation Factor (BSAF) values indicated that Bellamya bengalensis had high potential for zinc, copper and lead bioaccumulation than Melanoides tuberculata, while Melanoides tuberculata had high potential for cadmium than Bellamya bengalensis. Therefore, Bellamya bengalensis is proposed as sentinel organism for monitoring zinc, copper and lead, while Melanoides tuberculata for monitoring cadmium in freshwater. PMID:27498505

  7. Metal speciation and attenuation in stream waters and sediments contaminated by landfill leachate

    NASA Astrophysics Data System (ADS)

    Ettler, Vojtěch; Matura, Marek; Mihaljevič, Martin; Bezdička, Petr

    2006-02-01

    The degree of metal contamination (Zn, Pb, Cu, Ni, Cd) has been investigated in the vicinity of an old unmonitored municipal landfill in Prague, Czech Republic, where the leachate is directly drained into a surface stream. The water chemistry was coupled with investigation of the stream sediment ( aqua regia extract, sequential extraction, voltammetry of microparticles) and newly formed products (SEM/EDS, XRD). The MINTEQA2 speciation-solubility calculation showed that the metals (Zn, Pb, Cu, Ni) are mainly present as carbonate complexes in leachate-polluted surface waters. These waters were oversaturated with respect to Fe(III) oxyhydroxides, calcite (CaCO3) and other carbonate phases. Three metal attenuation mechanisms were identified in leachate-polluted surface waters: (i) spontaneous precipitation of metal-bearing calcite exhibiting significant concentrations of trace elements (Fe, Mn, Mg, Sr, Ba, Pb, Zn, Ni); (ii) binding to Fe(III) oxyhydroxides (mainly goethite, FeOOH) (Pb, Zn, Cu, Ni); and (iii) preferential bonding to sediment organic matter (Cu). These processes act as the key scavenging mechanisms and significantly decrease the metal concentrations in leachate-polluted water within 200 m from the direct leachate outflow into the stream. Under the near-neutral conditions governing the sediment/water interface in the landfill environment, metals are strongly bound in the stream sediment and remain relatively immobile.

  8. Reactivity of recently deposited organic matter: Degradation of lipid compounds near the sediment-water interface

    NASA Astrophysics Data System (ADS)

    Canuel, Elizabeth A.; Martens, Christopher S.

    1996-05-01

    The usefulness of biomarker compounds buried in marine sediments depends upon a quantita tive understanding of the effects of early diagenesis on their distribution. To address this, a new experimental approach was utilized to determine rates of degradation in a coastal sediment. Rates of degradation for solvent-extractable lipid components were quantified in four sediment horizons composed of newly accumulated organic matter (31-144 days since deposition). Sediment accumulation rate data derived from changes in the inventory of Be-7 ( t 1/2 = 53.3 days) were combined with concentration data for lipid biomarker compounds, enabling us to evaluate the reactivity of organic matter in the upper 8 cm of the rapidly accumulating sediments of Cape Lookout Bight, North Carolina, USA (CLB). Net rates of loss and rate constants were calculated for individual compounds belonging to three classes of lipids: fatty acids, sterols, and n-alkanes. Individual components showed a range in reactivity, in some cases (fatty acids), attributable to differences in their biological sources. Rates and rate constants were consistently highest in the surficial sediments (0-2.5 cm), indicating that the reactivity of a given molecule(s) decreases over time, and beginning soon after deposition. Comparison with apparent rate constants ( k') calculated over longer timescales (one and ten years) shows that steady-state diagenetic models underestimate rates of degradation at or near the sediment-water interface by an order of magnitude.

  9. Estuary Turbulence and Air-Water Carbon Dioxide Exchange

    NASA Astrophysics Data System (ADS)

    Orton, Philip Mark

    The mixing of constituents between estuarine bottom and surface waters or between estuarine surface waters and the atmosphere are two topics of growing interest, in part due to the potentially important role of estuaries in global carbon budgets. These two types of mixing are typically driven by turbulence, and a research project was developed to improve the scientific understanding of atmospheric and tidal controls on estuary turbulence and airwater exchange processes. Highlights of method development and field research on the Hudson River estuary include several deployments of bottom mounted current profilers to quantify the turbulent kinetic energy (TKE) budget, and construction and deployment of an instrumented catamaran that makes autonomous measurements of air-water CO2 exchange (FCO2), water TKE dissipation at 50 cm depth (epsilon50), and other physical properties just above and below the air-water interface. On the Hudson, wind correlates strongly with epsilon50, but surface water speed and airwater heat flux also have moderate correlations with epsilon50. In partially mixed estuaries such as the Hudson, as well as salt wedge estuaries, baroclinic pressure forcing typically causes spring ebb tides to have much stronger upper water column shear than flood tides. The Hudson data are used to show that this shear leads to local shear instability and stronger near-surface turbulence on spring ebbs. Also, buoyancy budget terms are compared to demonstrate how water-to-air heat fluxes can influence stratification and indirectly influence epsilon50. Looking more closely at the role of wind forcing, it is demonstrated that inland propagation of the sea breeze on warm sunny days leads to arrival in phase with peak solar forcing at seaward stations, but several hours later at up-estuary stations. Passage of the sea breeze front raises the air-water CO2 flux by 1-2 orders of magnitude, and drives epsilon50 comparable to spring tide levels in the upper meter of the water

  10. Study of photocatalytic degradation of tributyltin, dibutylin and monobutyltin in water and marine sediments.

    PubMed

    Brosillon, Stephan; Bancon-Montigny, Chrystelle; Mendret, Julie

    2014-08-01

    This study reports on the first assessment of the treatment of sediments contaminated by organotin compounds using heterogeneous photocatalysis. Photocatalysis of organotins in water was carried out under realistic concentration conditions (μgL(-1)). Degradation compounds were analyzed by GC-ICP-MS; a quasi-complete degradation of tributyltin (TBT) in water (99.8%) was achieved after 30min of photocatalytic treatment. The degradation by photolysis was about (10%) in the same conditions. For the first time decontamination of highly polluted marine sediments (certified reference material and harbor sediments) by photocatalysis proves that the use of UV and the production of hydroxyl radicals are an efficient way to treat organotins adsorbed onto marine sediment despite the complexity of the matrix. In sediment, TBT degradation yield ranged from 32% to 37% after only 2h of irradiation (TiO2-UV) and the by-products: dibutyltin (DBT) and monobutyltin (MBT) were degraded very rapidly in comparison with TBT. It was shown that during photocatalysis of organotins in sediments, the hydroxyl radical attack and photolysis are the two ways for the degradation of adsorbed TBT. PMID:24613444

  11. Biphilic Surfaces for Enhanced Water Collection from Humid Air

    NASA Astrophysics Data System (ADS)

    Benkoski, Jason; Gerasopoulos, Konstantinos; Luedeman, William

    Surface wettability plays an important role in water recovery, distillation, dehumidification, and heat transfer. The efficiency of each process depends on the rate of droplet nucleation, droplet growth, and mass transfer. Unfortunately, hydrophilic surfaces are good at nucleation but poor at shedding. Hydrophobic surfaces are the reverse. Many plants and animals overcome this tradeoff through biphilic surfaces with patterned wettability. For example, the Stenocara beetle uses hydrophilic patches on a superhydrophobic background to collect fog from air. Cribellate spiders similarly collect fog on their webs through periodic spindle-knot structures. In this study, we investigate the effects of wettability patterns on the rate of water collection from humid air. The steady state rate of water collection per unit area is measured as a function of undercooling, angle of inclination, water contact angle, hydrophilic patch size, patch spacing, area fraction, and patch height relative to the hydrophobic background. We then model each pattern by comparing the potential and kinetic energy of a droplet as it rolls downwards at a fixed angle. The results indicate that the design rules for collecting fog differ from those for condensation from humid air. The authors gratefully acknowledge the Office of Naval Research for financial support through Grant Number N00014-15-1-2107.

  12. Impact of water column acidification on protozoan bacterivory at the lake sediment-water interface.

    PubMed

    Tremaine, S C; Mills, A L

    1991-03-01

    Although the impact of acidification on planktonic grazer food webs has been extensively studied, little is known about microbial food webs either in the water column or in the sediments. Protozoon-bacterium interactions were investigated in a chronically acidified (acid mine drainage) portion of a lake in Virginia. We determined the distribution, abundance, apparent specific grazing rate, and growth rate of protozoa over a pH range of 3.6 to 6.5. Protozoan abundance was lower at the most acidified site, while abundance, in general, was high compared with other systems. Specific grazing rates were uncorrelated with pH and ranged between 0.02 and 0.23 h, values similar to those in unacidified systems. The protozoan community from an acidified station was not better adapted (P = 0.95) to low-pH conditions than a community from an unacidified site (multivariate analysis of variance on growth rates for each community incubated at pHs 4, 5, and 6). Both communities had significantly lower (P < 0.05) growth rates at pHs 4 and 5 than at pH 6. Reduced protozoan growth rates coupled with high grazing rates and relatively higher bacterial yields (ratio of bacterial-protozoan standing stock) at low pH indicate reduced net protozoan growth efficiency and a metabolic cost of acidification to the protozoan community. However, the presence of an abundant, neutrophilic protozoan community and high bacterial grazing rates indicates that acidification of Lake Anna has not inhibited the bacterium-protozoon link of the sediment microbial food web. PMID:16348443

  13. Impact of water column acidification on protozoan bacterivory at the lake sediment-water interface

    SciTech Connect

    Tremaine, S.C.; Mills, A.L. )

    1991-03-01

    Although the impact of acidification on planktonic grazer food webs has been extensively studied, little is known about microbial food webs either in the water column or in the sediments. Protozoan-bacterium interactions were investigated in a chronically acidified (acid mine drainage) portion of a lake in Virginia. The authors determined the distribution, abundance, apparent specific grazing rate, and growth rate of protozoa over a pH range of 3.6 to 6.5. Protozoan abundance was lower at the most acidified site, while abundance, in general, was high compared with other systems. Specific grazing rates were uncorrelated with pH and ranged between 0.02 and 0.23 h{sup {minus}1}, values similar to those in unacidified systems. The protozoan community from an acidified station was not better adapted to low-pH conditions than a community from an unacidified site (multivariate analysis of variance on growth rates for each community incubated at pHs 4, 5, and 6). Both communities had significantly lower growth rates at pHs 4 and 5 than at pH 6. Reduced protozoan growth rates coupled with high grazing rates and relatively higher bacterial yields (ratio of bacterial-protozoan standing stock) at low pH indicate reduced net protozoan growth efficiency and a metabolic cost of acidification to the protozoan community. However, the presence of an abundant, neutrophilic protozoan community and high bacterial grazing rates indicates that acidification of Lake Anna has not inhibited the bacterium-protozoan link of the sediment microbial food web.

  14. Parameterisation for National Scale Modelling of Macronutrient Emissions to Water and Air

    NASA Astrophysics Data System (ADS)

    Trodahl, M.; Jackson, B. M.

    2013-12-01

    Globally, increases in emissions to atmosphere and water associated with the biogeochemical cycling of carbon, nitrogen and phosphorous are concerning. While the sources of these emissions are varied, agricultural and other primary production land uses have been identified as both major contributors to some emissions, and potential sinks. Specifically targeted solutions are being sought to reduce emissions and increase storage in these areas. LUCI (the Land Utilisation and Capability Indicator) is a GIS framework developed to consider the impacts of land use on various ecosystem services in a holistic and spatially explicit manner. It is designed to work at a variety of scales, from sub-field to catchment, using readily available national data that can be supplemented with local knowledge. Current tools available with the framework include flood mitigation, habitat connectivity, erosion and sediment delivery, agricultural productivity, carbon sequestration, and water quality. At present LUCI models emissions of N and P to water using an export coefficient approach linked to land use, land management and soils, and models emissions to air of carbon dioxide only; methane and nitrous oxide are not currently considered. This study aims to refine the representation in LUCI of N and P emissions to water and develop preliminary approaches for representing methane and nitrous oxide emissions to air. The ultimate aim is the provision of a set of model representations and associated parameters that can better represent emissions to air and water and suggest spatially explicit solutions that will not undermine, and may benefit, enterprise and/or community economic assets. The physical processes associated with emissions are being investigated and categorised based on land management, soil and climate regimes for two case study countries - Wales and New Zealand. Preliminary parameters, associated modelled results and potential future refinements are presented and discussed.

  15. HPLC-PFD determination of priority pollutant PAHs in water, sediment, and semipermeable membrane devices

    USGS Publications Warehouse

    Williamson, K.S.; Petty, J.D.; Huckins, J.N.; Lebo, J.A.; Kaiser, E.M.

    2002-01-01

    High performance liquid chromatography coupled with programmable fluorescence detection was employed for the determination of 15 priority pollutant polycyclic aromatic hydrocarbons (PPPAHs) in water, sediment, and semipermeable membrane devices (SPMDs). Chromatographic separation using this analytical method facilitates selectivity, sensitivity (ppt levels), and can serve as a non-destructive technique for subsequent analysis by other chromatographic and spectroscopic techniques. Extraction and sample cleanup procedures were also developed for water, sediment, and SPMDs using various chromatographic and wet chemical methods. The focus of this publication is to examine the enrichment techniques and the analytical methodologies used in the isolation, characterization, and quantitation of 15 PPPAHs in different sample matrices.

  16. Water and sediment transport modeling of a large temporary river basin in Greece.

    PubMed

    Gamvroudis, C; Nikolaidis, N P; Tzoraki, O; Papadoulakis, V; Karalemas, N

    2015-03-01

    The objective of this research was to study the spatial distribution of runoff and sediment transport in a large Mediterranean watershed (Evrotas River Basin) consisting of temporary flow tributaries and high mountain areas and springs by focusing on the collection and use of a variety of data to constrain the model parameters and characterize hydrologic and geophysical processes at various scales. Both monthly and daily discharge data (2004-2011) and monthly sediment concentration data (2010-2011) from an extended monitoring network of 8 sites were used to calibrate and validate the Soil and Water Assessment Tool (SWAT) model. In addition flow desiccation maps showing wet and dry aquatic states obtained during a dry year were used to calibrate the simulation of low flows. Annual measurements of sediment accumulation in two reaches were used to further calibrate the sediment simulation. Model simulation of hydrology and sediment transport was in good agreement with field observations as indicated by a variety of statistical measures used to evaluate the goodness of fit. A water balance was constructed using a 12 year long (2000-2011) simulation. The average precipitation of the basin for this period was estimated to be 903 mm yr(-1). The actual evapotranspiration was 46.9% (424 mm yr(-1)), and the total water yield was 13.4% (121 mm yr(-1)). The remaining 33.4% (302 mm yr(-1)) was the amount of water that was lost through the deep groundwater of Taygetos and Parnonas Mountains to areas outside the watershed and for drinking water demands (6.3%). The results suggest that the catchment has on average significant water surplus to cover drinking water and irrigation demands. However, the situation is different during the dry years, where the majority of the reaches (85% of the river network are perennial and temporary) completely dry up as a result of the limited rainfall and the substantial water abstraction for irrigation purposes. There is a large variability in the

  17. Managing dredged sediment placement in open-water disposal sites, Upper Chesapeake Bay

    USGS Publications Warehouse

    Panageotou, W.

    2002-01-01

    The maintenance dredging of fine-grained sediment which accumulated in shipping channels in the Upper Chesapeake was discussed. The capacity of open-water sites was maximized in an environmentally acceptable manner to provide adequate time for the development of beneficial use or confined placement sites. The additional water column turbidity generated by dragging operations and bottom sediment movement during placement raised environmental concerns which weighted against the need to maximize capacity. The inter-agency team overseeing site management provided a mechanism to implement operational changes which maximized site capacity and insured operational use through the projected life span of the site.

  18. 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

  19. Modeling water and sediment contamination of Lake Pontchartrain following pump-out of Hurricane Katrina floodwater.

    PubMed

    Dortch, Mark S; Zakikhani, Mansour; Kim, Sung-Chan; Steevens, Jeffery A

    2008-05-01

    Levee failure and overtopping as a result of Hurricane Katrina caused major flooding of New Orleans, Louisiana. Floodwaters, which were contaminated with heavy metals, organic chemicals, and fecal coliform bacteria (FCB), were pumped into neighboring Lake Pontchartrain during dewatering. The impact of levee failure on water and benthic sediment concentrations in the lake was investigated by applying a numerical water quality model coupled to a three-dimensional, numerical hydrodynamic model. The model was used to compute water and benthic sediment concentrations throughout the lake for lead, arsenic, benzo(a)pyrene (BaP), and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), and water concentrations for FCB. Computed concentrations resulting from actual pumped discharges with levee failure and overtopping were compared to computed concentrations resulting from pumped discharges without levee failure or overtopping, and concentrations from both sets of conditions were compared to ecological water and sediment quality screening guideline values. The model indicated that incremental increases above pre-Katrina benthic sediment concentrations are about a factor of 10 greater with dewatering of the floodwaters than with dewatering of storm water without flooding. However, these increases for the metals are small relative to pre-Katrina concentrations. The results showed that the ecological screening-level sediment quality guideline values were exceeded for BaP and DDE in areas near the south shoreline of the lake as a result of floodwater pump-out, whereas, this was not the case for storm water removal without flooding. The model showed that lake water column concentrations should be about the same during both dewatering conditions regardless of whether there is flooding or not. PMID:17399885

  20. Sediment and water discharge rates of Turkish Black Sea rivers before and after hydropower dam construction

    SciTech Connect

    Hay, B.J. )

    1994-06-01

    Presently, the water discharge rate to the Black Sea by Turkish rivers is approximately 41 km[sup 3]/yr. The sediment discharge rate of Turkish rivers to the Black Sea is 28 x 10[sup 6] t/yr. Before construction of the hydroelectric dams, the sediment discharge rate was approximately 70 x 10[sup 6] t/yr. The sharp reduction in sediment load is largely a result of the dams near the mouths of the Yesil Irmak and Kizil Irmak rivers. Before the construction of dams, Turkish rivers contributed approximately one third of the total amount of sediment received by the Black Sea from all surrounding rivers. The life-span of the major reservoirs varies from approximately only one century (Yesil Irmak river reservoirs) to several thousand years (Sakarya river reservoirs). Life-span for the large Altinkaya Dam reservoir is estimated with approximately 500 yr.

  1. Muddy Water and American Agriculture: How to Best Control Sedimentation From Agricultural Land?

    NASA Astrophysics Data System (ADS)

    Lovejoy, Stephen B.; Lee, John Gary; Beasley, David B.

    1985-08-01

    The role of agricultural sediment in water quality is well documented. While numerous policies have been advocated and initiated, it still appears to be a significant problem. The present analysis concentrates on the outcome of several policy alternatives in terms of sediment delivery and project costs. These results are obtained by combining social science investigation of probable farmer behavior under a variety of scenarios with a hydrologic simulation model which predicts the sediment delivery with different land uses. This integration of social science behavioral research with the hydrologic response simulation model provides a framework to assess the environmental effectiveness of alternative policies aimed at reducing sedimentation. While the results presented here are preliminary, this approach seems to offer great promise as a tool for federal, state and local conservation agencies in their efforts to efficiently and effectively use their limited resources to reduce soil loss.

  2. Aquatic Sediments.

    ERIC Educational Resources Information Center

    Sanville, W. D.; And Others

    1978-01-01

    Presents a literature review of aquatic sediments and its effect upon water quality, covering publications of 1976-77. This review includes: (1) sediment water interchange; (2) chemical and physical characterization; and (3) heavy water in sediments. A list of 129 references is also presented. (HM)

  3. Proton Transfers at the Air-Water Interface

    NASA Astrophysics Data System (ADS)

    Mishra, Himanshu

    Proton transfer reactions at the interface of water with hydrophobic media, such as air or lipids, are ubiquitous on our planet. These reactions orchestrate a host of vital phenomena in the environment including, for example, acidification of clouds, enzymatic catalysis, chemistries of aerosol and atmospheric gases, and bioenergetic transduction. Despite their importance, however, quantitative details underlying these interactions have remained unclear. Deeper insight into these interfacial reactions is also required in addressing challenges in green chemistry, improved water quality, self-assembly of materials, the next generation of micro-nanofluidics, adhesives, coatings, catalysts, and electrodes. This thesis describes experimental and theoretical investigation of proton transfer reactions at the air-water interface as a function of hydration gradients, electrochemical potential, and electrostatics. Since emerging insights hold at the lipid-water interface as well, this work is also expected to aid understanding of complex biological phenomena associated with proton migration across membranes. Based on our current understanding, it is known that the physicochemical properties of the gas-phase water are drastically different from those of bulk water. For example, the gas-phase hydronium ion, H3O +(g), can protonate most (non-alkane) organic species, whereas H 3O+(aq) can neutralize only relatively strong bases. Thus, to be able to understand and engineer water-hydrophobe interfaces, it is imperative to investigate this fluctuating region of molecular thickness wherein the 'function' of chemical species transitions from one phase to another via steep gradients in hydration, dielectric constant, and density. Aqueous interfaces are difficult to approach by current experimental techniques because designing experiments to specifically sample interfacial layers (< 1 nm thick) is an arduous task. While recent advances in surface-specific spectroscopies have provided

  4. Nutrient exchange across the sediment-water interface in the Potomac River estuary

    USGS Publications Warehouse

    Callender, E.; Hammond, Douglas E.

    1982-01-01

    The flux of ammonia, phosphate, silica and radon-222 from Potomac tidal river and estuary sediments is controlled by processes occurring at the sediment-water interface and within surficial sediment. Calculated diffusive fluxes range between 0??6 and 6??5 mmol m-2 day-1 for ammonia, 0??020 and 0??30 mmol m-2 day-1 for phosphate, and 1??3 and 3??8 mmol m-2 day-1 for silica. Measured in situ fluxes range between 1 and 21 mmol m-2 day-1 for ammonia, 0??1 and 2??0 mmol m-2 day-1 for phosphate, and 2 and 19 mmol m-2 day-1 for silica. The ratio of in situ fluxes to diffusive fluxes (flux enhancement) varied between 1??6 and 5??2 in the tidal river, between 2??0 and 20 in the transition zone, and from 1??3 to 5??1 in the lower estuary. The large flux enhancements from transition zone sediments are attributed to macrofaunal irrigation. Nutrient flux enhancements are correlated with radon flux enhancements, suggesting that fluxes may originate from a common region and that nutrients are regenerated within the upper 10-20 cm of the sediment column. The low fluxes of phosphate from tidal viver sediments reflect the control benthic sediment exerts on phosphorus through sorption by sedimentary iron oxyhydroxides. In the tidal river, benthic fluxes of ammonia and phosphate equal one-half and one-third of the nutrient input of the Blue Plains sewage treatment plant. In the tidal Potomac River, benthic sediment regeneration supplies a significant fraction of the nutrients utilized by primary producers in the water column during the summer months. ?? 1982.

  5. Nutrient exchange across the sediment-water interface in the Potomac River estuary

    NASA Astrophysics Data System (ADS)

    Callender, Edward; Hammond, Douglas E.

    1982-10-01

    The flux of ammonia, phosphate, silica and radon-222 from Potomac tidal river and estuary sediments is controlled by processes occurring at the sediment-water interface and within surficial sediment. Calculated diffusive fluxes range between 0·6 and 6·5 mmol m -2 day -1 for ammonia, 0·020 and 0·30 mmol m -2 day -1 for phosphate, and 1·3 and 3·8 mmol m -2 day -1 for silica. Measured in situ fluxes range between 1 and 21 mmol m -2 day -1 for ammonia, 0·1 and 2·0 mmol m -2 day -1 for phosphate, and 2 and 19 mmol m -2 day -1 for silica. The ratio of in situ fluxes to diffusive fluxes (flux enhancement) varied between 1·6 and 5·2 in the tidal river, between 2·0 and 20 in the transition zone, and from 1·3 to 5·1 in the lower estuary. The large flux enhancements from transition zone sediments are attributed to macrofaunal irrigation. Nutrient flux enhancements are correlated with radon flux enhancements, suggesting that fluxes may originate from a common region and that nutrients are regenerated within the upper 10-20 cm of the sediment column. The low fluxes of phosphate from tidal viver sediments reflect the control benthic sediment exerts on phosphorus through sorption by sedimentary iron oxyhydroxides. In the tidal river, benthic fluxes of ammonia and phosphate equal one-half and one-third of the nutrient input of the Blue Plains sewage treatment plant. In the tidal Potomac River, benthic sediment regeneration supplies a significant fraction of the nutrients utilized by primary producers in the water column during the summer months.

  6. Environmental effects of hydrothermal alteration and historical mining on water and sediment quality in Central Colorado

    USGS Publications Warehouse

    Church, S.E.; Fey, D. L.; Klein, T.L.; Schmidt, T.S.; Wanty, R.B.; deWitt, E.H.; Rockwell, B.W.; San, Juan C.A.

    2009-01-01

    The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km2 area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical base- and precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment quality are restricted to catchments in which historical mining has occurred. Water, streambed sediment, and aquatic insects were collected from (1) catchments underlain by single lithogeochemical units, some of which were hydrothermally altered, that had not been prospected or mined; (2) catchments that contained evidence of prospecting, most of which contain hydrothermally altered rock, but no historical mining; and (3) catchments, all of which contain hydrothermally altered rock, where historical but now inactive mines occur. Geochemical data determined from catchments that did not contain hydrothermal alteration or historical mines met water quality criteria and sediment quality guidelines. Base-metal concentrations from these types of catchments showed small geochemical variations that reflect host lithology. Hydrothermal alteration and mineralization typically are associated with igneous rocks that have intruded older bedrock in a catchment. This alteration was regionally mapped and characterized primarily through the analysis of remote sensing data acquired by the ASTER satellite sensor. Base-metal concentrations among unaltered rock types showed small geochemical variations that reflect host lithology. Base-metal concentrations were elevated in sediment from catchments underlain by hydrothermally altered rock. Classification of catchments on the basis of mineral deposit types proved to be an efficient and accurate method for discriminating catchments that have degraded water and sediment quality. Only about 4.5 percent of the study area has been affected by historical mining

  7. Impacts of sewage of a pulp and paper industry on the sediments of Vigozero water basin

    NASA Astrophysics Data System (ADS)

    Natalia, Belkina

    2010-05-01

    The studies of sediments of Vigozero reservoir with 1969 for 2009 are presented. Vigozero water basin belongs to pool of the White Sea. It's watershed area is 16 800 km2, water surface area is 1140 km2, volume of lake - 6,46 km3, average depth - 6,2 m, the maximum depth - 23 m, the water residence time -1,14 years. Northern part of Vigozero reservoir tests influence of sewage of Segeja pulp and paper mill, operating since 1938. Zones of pollution of a bottom are allocated: 1- solid waste; 2 - active silt, lignin, cellulose; 3 - transformed suspended solids. Distribution and stratification of deposits, their physical and chemical parameters is investigated. It is shown, that change of a chemical compound of sediments is connected with volume and qualitative of sewage. The tendency to the extension of polluted zones and to spreading of organic pollution all the bottom is considered. Maximum settling velocity was fixed in 1980 -1985. Accumulation of the organic compounds in sediments at that time resulted in the development of high internal loading. Change of an ecological situation in Vigozero water basin, connected with falling volumes of manufacture last 20 years, has affected sediment genesis processes, therefore the concentrations of organic substances and biogenic elements have decreased in a superficial layer of sediments, concentration of iron has increased. Now, transformation of the organic substances, which have been saved up earlier, demands significant amounts of oxygen. Variability of pH and Eh of sediments indicates unstable oxidation-reduction conditions. Ore formations on a redox-barrier interfere with transport of substances from deposits in water. The work was supported in part by Russian Foundation for Basic Research (grant № 08-05-98811).

  8. Preservation of forcing signals in shallow water carbonate sediments

    NASA Astrophysics Data System (ADS)

    Hill, Jon; Wood, Rachel; Curtis, Andrew; Tetzlaff, Daniel M.

    2012-11-01

    No consensus has been reached on whether the metre-scale cycles that commonly occur in peritidal carbonates are predominately a product of external relative sea-level variations (allocycles) or an intrinsic property of carbonate production generated via the interaction of non-linear processes (autocycles). For any forcing signal such as eustatic sea-level change, to be detectable in stratigraphy its effects must be preserved. Here, a deterministic, three-dimensional geological process model is used to explore how such cycles are preserved in the geological record in the presence of autocyclic processes. Each simulation produced cycle thickness distributions that are statistically indistinguishable from a theoretical Poisson process, regardless of whether auto- or allo-cycles dominated. Spectral analysis of depositional time series constructed from idealised geological sections showed that all detectable signals occurred within the Milankovitch forcing frequency bands, even when no Milankovitch forcing was present. Thus, it is deduced that from any geological section alone, external forcing signals are detectable but are not distinguishable from autocyclically produced signals. Interestingly, there is no correlation between the percentage of sediment preserved and the accuracy with which signals are detectable in the preserved sediment: in some model realisations, even with preservation as low as 40%, the correct forcing signal can be detected accurately while, conversely, sections with preservation as high as 90% can have poor signal preservation. The reverse can also be true in other models. It is therefore concluded that distinguishing allocyclic and autocyclic forcing in shallow marine or peritidal carbonate successions is likely to be extremely difficult except in cases of extraordinary sedimentary preservation and dating accuracy.

  9. Ra isotopes as a tracer of sediment-water column exchange in the North Sea

    NASA Astrophysics Data System (ADS)

    Burt, William; Thomas, Helmuth; Pätsch, Johannnes; Omar, Abdirahman; Schrum, Corinna; Daewel, Ute

    2014-05-01

    Quantifying the benthic flux of short-lived radium isotopes (224Ra and 223Ra) provides information regarding the extent, and the dominant processes governing sediment-water column exchange in the North Sea. For this purpose we employed three independent measurement techniques including sediment incubation chambers, water column inventories, and a surface mass-balance. Incubation results from 11 stations indicate significant spatial variability in Radium efflux throughout the North Sea, as well as a strong dependence on the stirring rate of the overlying water column. Both inventory and mass-balance methods yield consistently higher benthic fluxes for the Southern North Sea than incubation-based estimates due to the inability of the laboratory incubations to recreate the in-situ mixing conditions present in the well-mixed Southern North Sea. Furthermore, fluxes in the Southern North Sea are higher than those previously reported in other regions, likely due to high rates of sediment irrigation induced by strong tidal and wind mixing near the interface of permeable sandy sediments. The seasonality of distributions and the magnitudes of both benthic and coastal Ra fluxes are further examined by applying Ra as a passive tracer in the 3-dimensional hydrodynamics of the ECOSMO model. Finally, flux estimates combined with direct measurements of porewater Ra activities yield volume fluxes [L m-2 d-1], which when further applied to porewater concentrations of carbon or nutrient species, can provide important information regarding the role of sediments in North Sea biogeochemistry.

  10. Widespread potential for microbial MTBE degradation in surface-water sediments

    USGS Publications Warehouse

    Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H.

    2001-01-01

    Microorganisms indigenous to stream and lake bed sediments, collected from 11 sites throughout the United States, demonstrated significant mineralization of the fuel oxygenate, methyl-tert-butyl ether (MTBE). Mineralization of [U-14C]MTBE to 14CO2 ranged from 15 to 66% over 50 days and did not differ significantly between sediments collected from MTBE contaminated sites and from sites with no history of MTBE exposure. This result suggests that even the microbial communities indigenous to newly contaminated surface water systems will exhibit some innate ability to attenuate MTBE under aerobic conditions. The magnitude of MTBE mineralization was related to the sediment grain size distribution. A pronounced, inverse correlation (p < 0.001; r2 = 0.73) was observed between the final recovery of 14CO2 and the percentage content of silt and clay sized grains (grain diameter < 0.125 mm). The results of this study indicate that the microorganisms that inhabit the bed sediments of streams and lakes can degrade MTBE efficiently and that this capability is widespread in the environment. Thus aerobic bed sediment microbial processes may provide a significant environmental sink for MTBE in surface water systems throughout the United States and may contribute to the reported transience of MTBE in some surface waters.

  11. Distribution of metals in water and bed sediment in a mineral-rich watershed, Montana, USA

    USGS Publications Warehouse

    Nagorski, S.A.; Moore, J.N.; Smith, D.B.

    2002-01-01

    We sampled the Blackfoot River (Montana) and its major tributaries from the headwaters of the basin to near its confluence with the Clark Fork River over the course of 5 days in August 1998. We measured streamflow, collected fine-grained (<63 ??m) streambed sediment, and sampled the dissolved (operationally defined as <0.2 ??m) phase of the surface water using clean techniques. Water and sediment collected from near the historic Heddleston mining district contained the highest concentrations of most trace elements in the basin. Many solute trace metals were at their highest several kilometers downstream from the mining district, where the river flows through an unremediated marsh system that has collected mine wastes in the past. Downstream of the headwaters area, water and bed sediment metal concentrations declined sharply. Comparison of sediment samples with those collected by other workers in August 1989 and August 1995 do not show evidence of basin-scale long term changes, despite the onset of remediation efforts in 1993. The area of the proposed McDonald gold deposit near the confluence of the Landers Fork with the Blackfoot River was not contributing anomalous concentrations of naturally-occurring dissolved and bed-sediment metals into the basin. ?? IMWA Springer-Verlag 2002.

  12. Control factors and scale analysis of annual river water, sediments and carbon transport in China

    NASA Astrophysics Data System (ADS)

    Song, Chunlin; Wang, Genxu; Sun, Xiangyang; Chang, Ruiying; Mao, Tianxu

    2016-05-01

    Under the context of dramatic human disturbances on river system, the processes that control the transport of water, sediment, and carbon from river basins to coastal seas are not completely understood. Here we performed a quantitative synthesis for 121 sites across China to find control factors of annual river exports (Rc: runoff coefficient; TSSC: total suspended sediment concentration; TSSL: total suspended sediment loads; TOCL: total organic carbon loads) at different spatial scales. The results indicated that human activities such as dam construction and vegetation restoration might have a greater influence than climate on the transport of river sediment and carbon, although climate was a major driver of Rc. Multiple spatial scale analyses indicated that Rc increased from the small to medium scale by 20% and then decreased at the sizable scale by 20%. TSSC decreased from the small to sizeable scale but increase from the sizeable to large scales; however, TSSL significantly decreased from small (768 g·m‑2·a‑1) to medium spatial scale basins (258 g·m‑2·a‑1), and TOCL decreased from the medium to large scale. Our results will improve the understanding of water, sediment and carbon transport processes and contribute better water and land resources management strategies from different spatial scales.

  13. Control factors and scale analysis of annual river water, sediments and carbon transport in China.

    PubMed

    Song, Chunlin; Wang, Genxu; Sun, Xiangyang; Chang, Ruiying; Mao, Tianxu

    2016-01-01

    Under the context of dramatic human disturbances on river system, the processes that control the transport of water, sediment, and carbon from river basins to coastal seas are not completely understood. Here we performed a quantitative synthesis for 121 sites across China to find control factors of annual river exports (Rc: runoff coefficient; TSSC: total suspended sediment concentration; TSSL: total suspended sediment loads; TOCL: total organic carbon loads) at different spatial scales. The results indicated that human activities such as dam construction and vegetation restoration might have a greater influence than climate on the transport of river sediment and carbon, although climate was a major driver of Rc. Multiple spatial scale analyses indicated that Rc increased from the small to medium scale by 20% and then decreased at the sizable scale by 20%. TSSC decreased from the small to sizeable scale but increase from the sizeable to large scales; however, TSSL significantly decreased from small (768 g·m(-2)·a(-1)) to medium spatial scale basins (258 g·m(-2)·a(-1)), and TOCL decreased from the medium to large scale. Our results will improve the understanding of water, sediment and carbon transport processes and contribute better water and land resources management strategies from different spatial scales. PMID:27166177

  14. Control factors and scale analysis of annual river water, sediments and carbon transport in China

    PubMed Central

    Song, Chunlin; Wang, Genxu; Sun, Xiangyang; Chang, Ruiying; Mao, Tianxu

    2016-01-01

    Under the context of dramatic human disturbances on river system, the processes that control the transport of water, sediment, and carbon from river basins to coastal seas are not completely understood. Here we performed a quantitative synthesis for 121 sites across China to find control factors of annual river exports (Rc: runoff coefficient; TSSC: total suspended sediment concentration; TSSL: total suspended sediment loads; TOCL: total organic carbon loads) at different spatial scales. The results indicated that human activities such as dam construction and vegetation restoration might have a greater influence than climate on the transport of river sediment and carbon, although climate was a major driver of Rc. Multiple spatial scale analyses indicated that Rc increased from the small to medium scale by 20% and then decreased at the sizable scale by 20%. TSSC decreased from the small to sizeable scale but increase from the sizeable to large scales; however, TSSL significantly decreased from small (768 g·m−2·a−1) to medium spatial scale basins (258 g·m−2·a−1), and TOCL decreased from the medium to large scale. Our results will improve the understanding of water, sediment and carbon transport processes and contribute better water and land resources management strategies from different spatial scales. PMID:27166177

  15. Zinc, copper, cadmium, and lead concentrations in water, sediment, and Anadara senilis in a tropical estuary.

    PubMed

    Bakary, Inza; Yao, Koffi Marcellin; Etchian, Olivier Assoi; Soro, Metongo Bernard; Trokourey, Albert; Bokra, Yobou

    2015-12-01

    Spatial and seasonal contaminations of zinc, copper, cadmium, and lead were assessed simultaneously in water, sediment, and in the bivalve Arca senilis from the Milliardaires Bay (Cote d'Ivoire) between February and October 2008. The metal load in sediments doubled from the dry season to the rainy season. On the contrary, metal concentrations in waters decreased significantly from the dry season to the rainy season. Zn and Pb concentrations in A. senilis showed similar seasonal variation with sediments. On the other hand, A. senilis regulated Cu concentrations by eliminating about twelve times the concentration accumulated during the dry season. Apparent Zn, Cu, Cd, and Pb concentration gradients were observed, but no significant differences between stations for sediment, water, and A. senilis. Concentrations in sediment increased from stations close to Abidjan Harbor towards farther stations, while concentrations in A. senilis showed a reverse gradient. The distribution gradient of A. senilis indicates pollution from local sources, but a transplant experiment is needed to better understand the observed spatial trend. Zn and Cu concentrations may pose little risk to human health and the environment, but they are the highest on the regional scale. On the contrary, Cd and Pb concentrations in A. senilis exceeded the maximum allowable limits set by the European Commission. Complementary studies including chemical speciation should be considered to provide a more accurate assessment of the risk of heavy metals to the environment. PMID:26581608

  16. Partitioning of Total Dissolved Salts, Boron and Selenium in Pariette Wetland Water, Sediments and Benthic Organisms

    NASA Astrophysics Data System (ADS)

    Jacobson, A. R.; Jones, C. P.; Vasudeva, P.; Powelson, D.; Grossl, P.

    2014-12-01

    The Pariette Wetlands located in the Uinta Basin, UT, were developed by the BLM in part to mitigate salinity associated with irrigation drainage and runoff from flowing to the Green River, a tributary of the Colorado River. The wetlands are fed by runoff from upstream agricultural irrigation, and natural subsurface and overland flow through the Uintah formation, which is seleniferous, and saline. Concentrations of Total Dissolved Salts (TDS), boron (B) and selenium (Se) in the wetlands exceed the total maximum daily loads developed to meet the US EPA's water quality planning and management regulations (40CFR 130). This is of concern because the wetlands are home to populations of migratory birds, waterfowl, raptors, and numerous small mammals. A mass balance of the Se concentrations of water flowing into and out of the wetlands indicates that 80% of the Se is stored or lost within the system. Additional data suggest that the majority of the Se is associated with the sediments. Little information is available regarding the TDS and B. Therefore we will determine the whether B and other salts are accumulating in the wetland systems, and if so where. We sampled water, sediment, benthic organisms, and wetland plants, in 4 of the 23 ponds from the flood control inlet to water flowing out to the Green River. Sediments were collected at 3 depths (0-2 cm, 2-7 cm, and 7+ cm) at 3-4 locations within each pond including the inlet, outlet and at least one site near a major wetland plant community. Benthic organisms were sampled from the 0-2 cm and 2-7 cm sediment layers. Sediment and organism samples were digested with HNO3 and HClO4 prior to analysis of total Se by HGAAS. Hot water extractable B and DPTA extractable B were analyzed by ICP-AES. TDS was estimated from EC in the sediment and organisms extracts and direct analysis in the water. Preliminary results found that Se in the sediments decreases with depth. Se concentrations in the benthic organisms is approximately 4

  17. Pesticide pollution of soil, water and air in Delhi area, India.

    PubMed

    Pillai, M K

    1986-11-01

    In India organochlorine insecticides such as DDT and HCH constitute more than 70% of the pesticides used at present. Its continued use has given interest to monitor for the last few years the extent of organochlorine insecticide residues in soil, water, air and rain water in Delhi area. Out of the 50 samples each of soil and earthworms collected from different parts 48 samples showed that soil and earthworms contained 0-2.61 and 0-37.74 mg Kg-1 of total DDT residues respectively. The area near the vicinity of the DDT factory showed high levels of DDT residues. A two-year survey of the Yamuna river in Delhi showed that water contained an average of 0.24 ug L-1 and the bottom sediment had 0.24 mg Kg-1 of total DDT residues. The fishes collected from the Yamuna river showed very high bioaccumulation of DDT residues. The air and rainwater samples monitored from 3 different areas for two years indicated that DDT was more near the DDT factory area while HCH was more near a commercial complex. These results indicate that the overall organochlorine-residue levels in Delhi is not alarming. It probably indicates that DDT and HCH are more rapidly dissipated and degraded in a tropical country like India. PMID:3810135

  18. Modeling of membrane processes for air revitalization and water recovery

    NASA Technical Reports Server (NTRS)

    Lange, Kevin E.; Foerg, Sandra L.; Dall-Bauman, Liese A.

    1992-01-01

    Gas-separation and reverse-osmosis membrane models are being developed in conjunction with membrane testing at NASA JSC. The completed gas-separation membrane model extracts effective component permeabilities from multicomponent test data, and predicts the effects of flow configuration, operating conditions, and membrane dimensions on module performance. Variable feed- and permeate-side pressures are considered. The model has been applied to test data for hollow-fiber membrane modules with simulated cabin-air feeds. Results are presented for a membrane designed for air drying applications. Extracted permeabilities are used to predict the effect of operating conditions on water enrichment in the permeate. A first-order reverse-osmosis model has been applied to test data for spiral wound membrane modules with a simulated hygiene water feed. The model estimates an effective local component rejection coefficient under pseudosteady-state conditions. Results are used to define requirements for a detailed reverse-osmosis model.

  19. Modelling of Air Bubble Rising in Water and Polymeric Solution

    NASA Astrophysics Data System (ADS)

    Hassan, N. M. S.; Khan, M. M. K.; Rasul, M. G.; Subaschandar, N.

    2010-06-01

    This study investigates a Computational Fluid Dynamics (CFD) model for a single air bubble rising in water and xanthan gum solution. The bubble rise characteristics through the stagnant water and 0.05% xanthan gum solution in a vertical cylindrical column is modelled using the CFD code Fluent. Single air bubble rise dispersed into the continuous liquid phase has been considered and modelled for two different bubble sizes. Bubble velocity and vorticity magnitudes were captured through a surface-tracking technique i.e. Volume of Fluid (VOF) method by solving a single set of momentum equations and tracking the volume fraction of each fluid throughout the domain. The simulated results of the bubble flow contours at two different heights of the cylindrical column were validated by the experimental results and literature data. The model developed is capable of predicting the entire flow characteristics of different sizes of bubble inside the liquid column.

  20. Spatial and temporal trends in surface water and sediment contamination in the Laurentian Great Lakes.

    PubMed

    Marvin, Chris; Painter, Scott; Williams, Donald; Richardson, Violeta; Rossmann, Ronald; Van Hoof, Patricia

    2004-05-01

    Data from recent sediment and surface water surveys have been collated and mapped to illustrate the spatial distribution of contaminants across the entire Great Lakes basin. Information from historical surveys, together with data from surface water monitoring programs in three major connecting channels, has also been collated in order to evaluate temporal trends. In general, Lakes Superior and Michigan exhibited the lowest levels of sediment contamination while Lake Ontario had the highest. Contaminants such as gamma-HCH (lindane) and dieldrin were ubiquitous in surface waters across the entire basin, which was indicative of atmospheric sources. The distribution of other compounds including hexachlorobenzene, octachlorostyrene and mirex indicated the presence of local sources within the watersheds of the connecting channels. Surficial sediment contamination was found to have decreased markedly since the late 1960s and 1970s. Similarly, surface water contamination decreased over the period 1986-1997 with concentrations of dieldrin, hexachlorobenzene, octachlorostyrene and mirex reduced by over 50%. However, the spatial distributions of both sediment and surface water contamination indicate that further effort is warranted in reducing local sources of contaminants, particularly in Lake Ontario. PMID:14749077

  1. Electrochemical peroxidation of PCBs and VOCs in superfund site water and sediments

    SciTech Connect

    Scrudato, R.J.; Chiarenzelli, J.R.

    1996-12-31

    An electrochemical peroxidation (ECP) process has been developed and used to degrade polychlorinated biphenyls (PCB) and volatile organic compounds (VOC)-contaminated water, sludge, and sediments at a New York State Federal and State Superfund Site. The process involves passing an oscillating low-amperage (<10 amps) current through steel electrodes immersed in an acidified water or sediment slurry into which hydrogen peroxide (<1,000 ppm) is added. The generated free radicals attack organic compounds, including organo-metallic complexes and refractory compounds including PCBs. PCB degradation ranged from about 30% to 80% in experiments involving Federal Superfund Site sediments; total PCBs were reduced by {approximately}97% to 68%, respectively, in water and slurry collected from a State Superfund subsurface storage tank. VOC bench-scale experiments involved chloroethane, 1,1-dichloroethane, dichloromethane, 1,1,1-trichloroethane, and acetone and after a 3-min ECP treatment, degradation ranged from >94% to about 99.9%. Results indicate the ECP is a viable process to degrade organic contaminants in water and sediment suspensions. Because the treated water suspensions are acidified, select trace metal sorbed to the particulates is solubilized and therefore can be segregated from the particulates, offering a process that simultaneously degrades organic contaminants and separates trace metals. 19 refs., 1 fig., 4 tabs.

  2. Physicochemical and Analytical Data for Tributary Water, Lake Water, and Lake Sediment, Lake Arrowhead, Clay and Archer Counties, Texas, 2006

    USGS Publications Warehouse

    Wilson, Jennifer T.; Musgrove, MaryLynn; Haynie, Monti M.; Van Metre, Peter C.

    2008-01-01

    Lake Arrowhead is a reservoir about 24 kilometers southeast of Wichita Falls, Texas, that provides drinking water for the city of Wichita Falls and surrounding areas. The U.S. Geological Survey, in cooperation with the City of Wichita Falls, did a study in 2006 to assess conditions contributing to elevated arsenic concentrations in Lake Arrowhead. This report describes the sampling and analytical methods, quality assurance, and physicochemical and analytical data. Physiochemical properties were measured in and water samples were collected from five tributaries to Lake Arrowhead (Little Wichita River, West Little Post Oak Creek, East Little Post Oak Creek, Deer Creek, and an unnamed tributary) immediately after storms. Lake water measuring and sampling were done approximately monthly from January through September 2006 at three deep-water sites and seasonally, in January and August 2006, at three shallow-water sites. Cores of lake bottom sediment were collected from five sites on August 30, 2006. Arsenic concentrations in tributary water samples ranged from 1.5 to 6.3 and 0.5 to 4.8 micrograms per liter for unfiltered and filtered samples, respectively. The highest arsenic concentrations were in samples collected from the West Little Post Oak Creek sampling site. Physicochemical properties in lake water varied with depth and season. Dissolved arsenite plus arsenate concentrations in lake water samples generally were between 3 and 5 micrograms per liter. Arsenite concentrations typically were below the laboratory reporting level of 0.6 microgram per liter. There were no detections of monomethylarsonate or dimethylarsinate. The concentration of arsenic in lake sediment samples ranged from 4.4 to 11.2 milligrams per kilogram, with a median of 6.4 milligrams per kilogram. The median arsenic concentration of the five top-interval sediment samples was 8.8 milligrams per kilogram, which generally is higher than the concentrations estimated to be on suspended sediment in

  3. Simulation Studies to Explore Biodegradation in Water-Sediment Systems: From OECD 308 to OECD 309.

    PubMed

    Shrestha, Prasit; Junker, Thomas; Fenner, Kathrin; Hahn, Stefan; Honti, Mark; Bakkour, Rani; Diaz, Cecilia; Hennecke, Dieter

    2016-07-01

    Studies according to OECD 308 and OECD 309 are performed to simulate the biodegradation of chemicals in water-sediment systems in support of persistence assessment and exposure modeling. However, several shortcomings of OECD 308 have been identified that hamper data evaluation and interpretation, and its relation to OECD 309 is still unclear. The present study systematically compares OECD 308 and OECD 309 and two variants thereof to derive recommendations on how to experimentally address any shortcomings and improve data for persistence and risk assessment. To this end, four (14)C-labeled compounds with different biodegradation and sorption behavior were tested across standard OECD 308 and 309 test systems and two modified versions thereof. The well-degradable compounds showed slow equilibration and the least mineralization in OECD 308, whereas the modified systems provided the highest degree of mineralization. Different lines of evidence suggest that this was due to increased oxygenation of the sediment in the modified systems. Particularly for rapidly degrading compounds, non-extractable residue formation was in line with degradation and did not follow the sediment-water ratio. For the two more slowly degrading compounds, sorption in OECD 309 (standard and modified) increased with time beyond levels proposed by equilibrium partitioning, which could be attributed to the grinding of the sediment through the stirring of the sediment suspension. Overall, the large differences in degradation observed across the four test systems suggest that refined specifications in test guidelines are required to reduce variability in test outcomes. At the same time, the amount of sediment and its degree of oxygenation emerged as drivers across all test systems. This suggests that a unified description of the systems was possible and would pave the way toward a more consistent consideration of degradation in the water-sediment systems across different exposure situations and

  4. Heavy metal concentrations in water, suspended matter, and sediment from Gökova Bay, Turkey.

    PubMed

    Balkis, Nuray; Aksu, Abdullah; Okuş, Erdoğan; Apak, Reşat

    2010-08-01

    The contents of heavy metals (Fe, Mn, Pb, Cu, Cd, and Hg) dissolved in water and suspended solids of Gökova Bay--partly and fully sampled in 2005 and 2006, respectively--are quite higher than the average values encountered in uncontaminated sea water. The high concentrations are associated with terrestrial inputs from the mining zones and anthropogenic (domestic+industrial) sources. Moreover, the distribution of Fe and Cu is affected by primary production because these elements function as nutrients in biological activities. The Cr, Ni, and Fe concentrations of surface sediments are above the shale average. The Cr and Ni contents of surface sediments representative of river mouths strongly correlate with total phosphorus contents. In a sulfide-poor environment, Pb and Cu were concentrated at a higher ratio in surface sediments than Cd, probably due to higher stabilities of their surface complexes with amorphous iron oxides and clay minerals existing as major components in the sediments. The exceptional enrichment of Zn may be attributed to double oxide formation with amorphous iron oxides in sediments. The high metal values are most probably caused by terrestrial inputs from anthropogenic sources and the mining zones at the southeast part of the bay. The Al, Mn, Pb, Cu, Zn, and Hg contents are below the shale average. The low values have possibly originated from the coarse-grained sandy sediments having a low affinity for metals. There are no distinct differences in the metal distributions in water and suspended matter between the years 2005 and 2006 in the bay, probably due to low sedimentation rates. PMID:19565345

  5. Heat and dissolved oxygen exchanges between the sediment and water column in a shallow salty lagoon

    NASA Astrophysics Data System (ADS)

    Fuente, Alberto

    2014-04-01

    Dissolved oxygen (DO) and heat exchanges across the water-sediment interface (WSI) of a shallow lagoon are controlled by processes occurring on both sides of the WSI, particularly volumetric source and sink on the sediment side and turbulent transport on the waterside. This article presents and analyzes measurements of DO (Js) and heat (Hg) fluxes across the WSI in the extremely shallow lagoon of Salar del Huasco (20.274°S, 68.883°W, 3800 m above sea level), where volumetric source of DO and heat exists in the sediment layer, related to benthic primary production and absorption of solar radiation, respectively. Microprofiles of temperature and DO were measured, and they were used for measuring Js and Hg, and volumetric source/sink terms in the sediments. This information was used to propose and validate the simple theoretical framework to predict both the magnitude and direction of Js and Hg. On the one hand, Js can be predicted with a simple algebraic expression, where the diffusional mass transfer coefficient defines the magnitude of Js while the direction is controlled by the balance between DO production and consumption in the sediments. On the other hand, solar radiation is absorbed in the upper sediments, and this heat diffuses toward the water column and the sediments. The heat flux toward the water column also induces unstable convection that promotes vertical transport across the WSI. The theoretical framework proposed here will help to understand DO and heat budgets of shallow aquatic systems in which solar radiation reaches the WSI.

  6. Hyporheic Temperature Dynamics: Predicting Hyporheic Temperatures Based on Travel Time Assuming Instantaneous Water-Sediment Conduction

    NASA Astrophysics Data System (ADS)

    Kraseski, K. A.

    2015-12-01

    Recently developed conceptual frameworks and new observations have improved our understanding of hyporheic temperature dynamics and their effects on channel temperatures. However, hyporheic temperature models that are both simple and useful remain elusive. As water moves through hyporheic pathways, it exchanges heat with hyporheic sediment through conduction, and this process dampens the diurnal temperature wave of the water entering from the channel. This study examined the mechanisms underlying this behavior, and utilized those findings to create two simple models that predict temperatures of water reentering the channel after traveling through hyporheic pathways for different lengths of time. First, we developed a laboratory experiment to represent this process and determine conduction rates for various sediment size classes (sand, fine gravel, coarse gravel, and a proportional mix of the three) by observing the time series of temperature changes between sediment and water of different initial temperatures. Results indicated that conductions rates were near-instantaneous, with heat transfer being completed on the scale of seconds to a few minutes of the initial interaction. Heat conduction rates between the sediment and water were therefore much faster than hyporheic flux rates, rendering reasonable an assumption of instantaneous conduction. Then, we developed two simple models to predict time series of hyporheic water based on the initial diurnal temperature wave and hyporheic travel distance. The first model estimates a damping coefficient based on the total water-sediment heat exchange through each diurnal cycle. The second model solves the heat transfer equation assuming instantaneous conduction using a simple finite difference algorithm. Both models demonstrated nearly complete damping of the sine wave over the distance traveled in four days. If hyporheic exchange is substantial and travel times are long, then hyporheic damping may have large effects on

  7. Use of Surfactants to Decrease Air-Water Interfacial Tension During Sparging (OKC, OK)

    EPA Science Inventory

    Air sparging is a remediation procedure of injecting air into polluted ground water. The primary intention of air sparging is to promote biodegradation of volatile organic compounds (VOCs) in the groundwater passing through the treatment sector. Sparging treatment efficiency dep...

  8. Use of Surfactants to Decrease Air-Water Interfacial Tension During Sparging

    EPA Science Inventory

    Air sparging is a remediation procedure of injecting air into polluted ground water. The primary intention of air sparging is to promote biodegradation of volatile organic compounds (VOCs) in the groundwater passing through the treatment sector. Sparging treatment efficiency dep...

  9. Patterns in bacterial and archaeal community structure and diversity in western Beaufort Sea sediments and waters

    NASA Astrophysics Data System (ADS)

    Hamdan, L. J.; Sikaroodi, M.; Coffin, R. B.; Gillevet, P. M.

    2010-12-01

    A culture-independent phylogenetic study of microbial communities in water samples and sediment cores recovered from the Beaufort Sea slope east of Point Barrow, Alaska was conducted. The goal of the work was to describe community composition in sediment and water samples and determine the influence of local environmental conditions on microbial populations. Archaeal and bacterial community composition was studied using length heterogeneity-polymerase chain reaction (LH-PCR) and multitag pyrosequencing (MTPS). Sediment samples were obtained from three piston cores on the slope (~1000m depth) arrayed along an east-west transect and one core from a depth of approximately 2000m. Discrete water samples were obtained using a CTD-rosette from three locations adjacent to piston core sites. Water sample were selected at three discrete depths within a vertically stratified (density) water column. The microbial community in near surface waters was distinct from the community observed in deeper stratified layers of the water column. Multidimensional scaling analysis (MDS) revealed that water samples from mid and deep stratified layers bore high similarity to communities in cores collected in close proximity. Overall, the highest diversity (bacteria and archaea) was observed in a core which had elevated methane concentration relative to other locations. Geochemical (e.g., bulk organic and inorganic carbon pools, nutrients, metabolites) and physical data (e.g. depth, water content) were used to reveal the abiotic factors structuring microbial communities. The analysis indicates that sediment water content (porosity) and inorganic carbon concentration are the most significant structuring elements on Beaufort shelf sedimentary microbial communities.

  10. Air-water analogy and the study of hydraulic models

    NASA Technical Reports Server (NTRS)

    Supino, Giulio

    1953-01-01

    The author first sets forth some observations about the theory of models. Then he established certain general criteria for the construction of dynamically similar models in water and in air, through reference to the perfect fluid equations and to the ones pertaining to viscous flow. It is, in addition, pointed out that there are more cases in which the analogy is possible than is commonly supposed.

  11. Air and water pollution control: a benefit-cost assessment

    SciTech Connect

    Freeman, A.M. III

    1982-01-01

    Freeman attempts to assess the net benefits associated with environmental programs dealing with air and water quality. He concludes that stationary controls have been justified, but that mobile sources and water controls, as presently designed and implemented, have had costs greater than benefits to society. The reviewer notes that the book is more than just a compendium of mechanistic, technical detail; there is rather, far more general information on how economists view environmental problems than suggested by the title. An example is the discussions of the various approaches to valuing environmental benefits.

  12. Bacterial Swimming at Air/Water and Oil/Water Interfaces

    NASA Astrophysics Data System (ADS)

    Morse, Michael; Huang, Athena; Li, Guanglai; Tang, Jay

    2012-02-01

    The microbes inhabiting the planet over billions of years have adapted to diverse physical environments of water, soil, and interfaces between water and either solid or air. Following recent studies on bacterial swimming and accumulation near solid surfaces, we turn our attention to the behavior of Caulobacter crescentus, a singly flagellated bacterium, at water/air and water/oil interfaces. The latter is motivated by relevance to microbial degradation of crude oil in light of the recent oil spill in the Gulf of Mexico. Our ongoing study suggests that Caulobacter swarmer cells tend to get physically trapped at both water/air and water/oil interfaces, accumulating at the surface to a greater degree than boundary confinement properties like that of solid surfaces would predict. At the water/air interface, swimmers move in tight circles at half the speed of swimmers in the bulk fluid. At the water/oil interface, swimming circles are even tighter with further reduced swimming speed. We report experimental data and present preliminary analysis of the findings based on low Reynolds number hydrodynamics, the known surface tension, and surface viscosity at the interface. The analysis will help determine properties of the bacterium such as their surface charge and hydrophobicity.

  13. Tangential stress beneath wind-driven air water interfaces

    NASA Astrophysics Data System (ADS)

    Banner, Michael L.; Peirson, William L.

    1998-06-01

    The detailed structure of the aqueous surface sublayer flow immediately adjacent to the wind-driven air water interface is investigated in a laboratory wind-wave flume using particle image velocimetry (PIV) techniques. The goal is to investigate quantitatively the character of the flow in this crucial, very thin region which is often disrupted by microscale breaking events. In this study, we also examine critically the conclusions of Okuda, Kawai & Toba (1977), who argued that for very short, strongly forced wind-wave conditions, shear stress is the dominant mechanism for transmitting the atmospheric wind stress into the water motion waves and surface drift currents. In strong contrast, other authors have more recently observed very substantial normal stress contributions on the air side. The availability of PIV and associated image technology now permits a timely re-examination of the results of Okuda et al., which have been influential in shaping present perceptions of the physics of this dynamically important region. The PIV technique used in the present study overcomes many of the inherent shortcomings of the hydrogen bubble measurements, and allows reliable determination of the fluid velocity and shear within 200 [mu]m of the instantaneous wind-driven air water interface.

  14. Coaxial injector spray characterization using water/air as simulants

    NASA Technical Reports Server (NTRS)

    Zaller, Michelle M.; Klem, Mark D.

    1991-01-01

    Quantitative information about the atomization of injector sprays is required to improve the accuracy of computational models that predict the performance and stability of liquid propellant rocket engines. An experimental program is being conducted at NASA-Lewis to measure the drop size and velocity distributions in shear coaxial injector sprays. A phase/Doppler interferometer is used to obtain drop size data in water air shear coaxial injector sprays. Droplet sizes and axial component of droplet velocities are measured at different radii for various combinations of water flow rate, air flow rate, injector liquid jet diameter, injector annular gap, and liquid post recess. Sauter mean diameters measured in the spray center 51 mm downstream of the liquid post tip range from 28 to 68 microns, and mean axial drop velocities at the same location range from 37 to 120 m/s. The shear coaxial injector sprays show a high degree of symmetry; the mean drop size and velocity profiles vary with liquid flow rate, post recess, and distance from the injector face. The drop size data can be used to estimate liquid oxygen/hydrogen spray drop sizes by correcting property differences between water-air and liquid oxygen/hydrogen.

  15. New research on bioregenerative air/water purification systems

    NASA Technical Reports Server (NTRS)

    Johnson, Anne H.; Ellender, R. D.; Watkins, Paul J.

    1991-01-01

    For the past several years, air and water purification systems have been developed and used. This technology is based on the combined activities of plants and microorganisms as they function in a natural environment. More recently, researchers have begun to address the problems associated with indoor air pollution. Various common houseplants are currently being evaluated for their abilities to reduce concentrations of volatile organic compounds (VOCS) such as formaldehyde and benzene. With development of the Space Exploration Initiative, missions will increase in duration, and problems with resupply necessitates implementation of regenerative technology. Aspects of bioregenerative technology have been included in a habitat known as the BioHome. The ultimate goal is to use this technology in conjunction with physicochemical systems for air and water purification within closed systems. This study continued the risk assessment of bioregenerative technology with emphasis on biological hazards. In an effort to evaluate the risk for human infection, analyses were directed at enumeration of fecal streptococci and enteric viruses with the BioHome waste water treatment system.

  16. Sudden Clearing of Estuarine Waters upon Crossing the Threshold from Transport to Supply Regulation of Sediment Transport as an Erodible Sediment Pool is Depleted: San Francisco Bay, 1999

    USGS Publications Warehouse

    Schoellhamer, D.H.

    2011-01-01

    The quantity of suspended sediment in an estuary is regulated either by transport, where energy or time needed to suspend sediment is limiting, or by supply, where the quantity of erodible sediment is limiting. This paper presents a hypothesis that suspended-sediment concentration (SSC) in estuaries can suddenly decrease when the threshold from transport to supply regulation is crossed as an erodible sediment pool is depleted. This study was motivated by a statistically significant 36% step decrease in SSC in San Francisco Bay from water years 1991-1998 to 1999-2007. A quantitative conceptual model of an estuary with an erodible sediment pool and transport or supply regulation of sediment transport is developed. Model results confirm that, if the regulation threshold was crossed in 1999, SSC would decrease rapidly after water year 1999 as observed. Estuaries with a similar history of a depositional sediment pulse followed by erosion may experience sudden clearing. ?? 2011 Coastal and Estuarine Research Federation (outside the USA).

  17. Water selenium speciation and sediment fractionation in a California flow-through wetland system

    USGS Publications Warehouse

    Gao, S.; Tanii, K.K.; Peters, D.W.; Herbel, M.J.

    2000-01-01

    A flow-through wetland system was established in the Tulare Lake Drainage District (TLDD) in California to determine if selenium (Se) from saline irrigation drainage can be removed prior to impoundment in evaporation basins to reduce potential toxicity to waterbirds. The objective of this research was to evaluate Se speciation, accumulation, and fractionation in the waters and sediments of the newly developed wetland system. The inlet water was dominated by selenate [Se(VI), 92%], with smaller percentages of selenite [Se(IV), 5%] and organic Se [org-Se(-II), 3%]. For the outflow water, the average percentage of Se(VI) was 72% in November 1997 and 59% in February 1999. This change may be due to an increase in either residence time and/or accumulation of organic detrital matter, which may enhance Se(VI) reduction processes. Selenium accumulation, transformation, and incorporation with the solid phase were all intensified in the surface sediment (<20 cm). The highest total Se concentrations in the sediments were found in the top 5 cm and concentrations dramatically decreased with depth. Elemental Se [Se(0)], as extracted by Na2SO3, was the largest fraction (average of 46%) of the total sediment Se, followed by organic matter-associated Se (OM-Se) extracted by NaOH (average of 34%). Soluble, adsorbed, and carbonate-associated Se, as extracted by KCl, K2HPO4 (pH 8.0), and NaOAc (pH 5.0), were about 3, 10, and 3% of the total sediment Se, respectively. After establishing the wetland for 2 yr, significant Se removal from the flowing water was observed. The major sink mechanisms in the sediment are reduction to Se(0) and immobilization into the organic phase.A flow-through wetland system was established in the Tulare Lake Drainage District (TLDD) in California to determine if selenium (Se) from saline irrigation drainage can be removed prior to impoundment in evaporation basins to reduce potential toxicity to waterbirds. The objective of this research was to evaluate Se

  18. Energy and air emission effects of water supply.

    PubMed

    Stokes, Jennifer R; Horvath, Arpad

    2009-04-15

    Life-cycle air emission effects of supplying water are explored using a hybrid life-cycle assessment For the typically sized U.S. utility analyzed, recycled water is preferable to desalination and comparable to importation. Seawater desalination has an energy and air emission footprint that is 1.5-2.4 times larger than that of imported water. However, some desalination modes fare better; brackish groundwater is 53-66% as environmentally intensive as seawater desalination. The annual water needs (326 m3) of a typical Californian that is met with imported water requires 5.8 GJ of energy and creates 360 kg of CO2 equivalent emissions. With seawater desalination, energy use would increase to 14 GJ and 800 kg of CO2 equivalent emissions. Meeting the water demand of California with desalination would consume 52% of the state's electricity. Supply options were reassessed using alternative electricity mixes, including the average mix of the United States and several renewable sources. Desalination using solar thermal energy has lower greenhouse gas emissions than that of imported and recycled water (using California's electricity mix), but using the U.S. mix increases the environmental footprint by 1.5 times. A comparison with a more energy-intensive international scenario shows that CO2 equivalent emissions for desalination in Dubai are 1.6 times larger than in California. The methods, decision support tool (WEST), and results of this study should persuade decision makers to make informed water policy choices by including energy consumption and material use effects in the decision-making process. PMID:19475934

  19. Extending the analytical window for water-soluble organic matter in sediments by aqueous Soxhlet extraction

    NASA Astrophysics Data System (ADS)

    Schmidt, Frauke; Koch, Boris P.; Witt, Matthias; Hinrichs, Kai-Uwe

    2014-09-01

    Dissolved organic matter (DOM) in marine sediments is a complex mixture of thousands of individual constituents that participate in biogeochemical reactions and serve as substrates for benthic microbes. Knowledge of the molecular composition of DOM is a prerequisite for a comprehensive understanding of the biogeochemical processes in sediments. In this study, interstitial water DOM was extracted with Rhizon samplers from a sediment core from the Black Sea and compared to the corresponding water-extractable organic matter fraction (<0.4 μm) obtained by Soxhlet extraction, which mobilizes labile particulate organic matter and DOM. After solid phase extraction (SPE) of DOM, samples were analyzed for the molecular composition by Fourier Transform Ion-Cyclotron Resonance Mass Spectrometry (FT-ICR MS) with electrospray ionization in negative ion mode. The average SPE extraction yield of the dissolved organic carbon (DOC) in interstitial water was 63%, whereas less than 30% of the DOC in Soxhlet-extracted organic matter was recovered. Nevertheless, Soxhlet extraction yielded up to 4.35% of the total sedimentary organic carbon, which is more than 30-times the organic carbon content of the interstitial water. While interstitial water DOM consisted primarily of carbon-, hydrogen- and oxygen-bearing compounds, Soxhlet extracts yielded more complex FT-ICR mass spectra with more peaks and higher abundances of nitrogen- and sulfur-bearing compounds. The molecular composition of both sample types was affected by the geochemical conditions in the sediment; elevated concentrations of HS- promoted the early diagenetic sulfurization of organic matter. The Soxhlet extracts from shallow sediment contained specific three- and four-nitrogen-bearing molecular formulas that were also detected in bacterial cell extracts and presumably represent proteinaceous molecules. These compounds decreased with increasing sediment depth while one- and two-nitrogen-bearing molecules increased

  20. AirSWOT: An Airborne Platform for Surface Water Monitoring

    NASA Astrophysics Data System (ADS)

    Rodriguez, E.; Moller, D.; Smith, L. C.; Pavelsky, T. M.; Alsdorf, D. E.

    2010-12-01

    The SWOT mission, expected to launch in 2020, will provide global measurements of surface water extent and elevation from which storage change and discharge can be derived. SWOT-like measurements are not routinely used by the hydrology community, and their optimal use and associated errors are areas of active research. The purpose of AirSWOT, a system that has been proposed to NASA’s Instrument Incubator Program, is to provide SWOT-like measurements to the hydrology and ocean community to be used to advance the understanding and use of SWOT data in the pre-launch phase. In the post-launch phase, AirSWOT will be used as the SWOT calibration/validation platform. The AirSWOT payload will consist of Kaspar, a multi-beam Ka-band radar interferometer able to produce elevations over a 5 km swath with centimetric precision. The absolute elevation accuracy of the AirSWOT system will be achieved with a combination of high precision Inertial Motion Units (IMUs), ground calibration points, and advanced calibration techniques utilizing a priori knowledge. It is expected that the accuracy of AirSWOT will exceed or match SWOT’s accuracy requirements. In addition to elevation measurements, the AirSWOT payload will include a near-infrared camera able to provide coincident high-resolution optical imagery of the water bodies imaged by the radar. In its initial hydrology deployments, AirSWOT will investigate four field sites: the Ohio-Mississippi confluence, the lower Atchafalaya River on the Mississippi River Delta, the Yukon River basin near Fairbanks, and the Sacramento River, California. The Ohio-Mississippi confluence is targeted for its large discharge, modest slope, and control structures that modulate Ohio but not Mississippi River slopes and elevations. The lower Atchafalaya River includes low slopes, wetlands with differing vegetation types, and some open lakes. Vegetation includes Cyprus forests, floating macrophytes, and grass marshes, all of which impact radar returns

  1. Pleistocene meteoric pore water in dated marine sediment cores off Callao, Peru

    NASA Astrophysics Data System (ADS)

    Kriete, Cornelia; Suckow, Axel; Harazim, Bodo

    2004-03-01

    During cruise SO 147 of the German research vessel SONNE, a large decrease in salinity with depth was found in the pore water at a site about 10 sea miles off Callao, Lima, Peru. The origin of this freshening was investigated in a multidisciplinary approach using geochemical, geochronological and isotope hydrological methods. The methodology applied is a possible strategy to deal with anomalous pore water freshenings and if necessary to put them into the general framework of submarine groundwater discharge. Concentrations of the major and conservative elements (e.g., Na, K, Cl, B, Br) decrease at the same ratios. Deuterium ( δD) and oxygen-18 ( δ18O) data reveal the meteoric origin of the fresh water end member, indicating a mixture of 30% seawater and 70% fresh water at a depth in sediment of about 10 m. 210Pb and 137Cs sedimentation rates determined by gamma spectrometry range between 2 and 4.5 mm/y for the last century whereas values derived from AMS 14C for the last millennia give mean rates smaller than 1 mm/y. This indicates strongly varying sedimentation conditions. Nevertheless, from the geochronological data it can be concluded that the origin of the fresh water end member is situated in sediments of Pleistocene age. Literature data of the isotope signature of modern water in the nearby Lima aquifer are clearly different from the calculated values for the fresh water end member in the pore waters. On the basis of the isotopic altitude effect described in the literature, the isotopic signature of the fresh pore water end member can be explained as rain water directly infiltrated into the Lima aquifer. In contrast, this infiltration is negligible there under present-day arid climatic conditions. Theoretical considerations on pore water advective and diffusive transport give further indications that the fresh pore water end member is entrapped paleowater of Pleistocene origin. The observed pore water freshening and the geochemical and geochronological data

  2. Sediment and water toxicity evaluations for the Clinch River ecological risk assessment

    SciTech Connect

    Gonzalez, A.M.; Phipps, T.L.; Kszos, L.A.

    1995-12-31

    The sediment and surface water at three sites in the Clinch River and six sites in Poplar Creek were evaluated by means of toxicity tests with aquatic organisms. The results of these tests were used as one of the lines of evidence in an assessment of ecological risk due to contaminants, transported from the Oak Ridge Reservation, to the off-site sediment and water environment. Results from a suite of six whole sediment, elutriate and pore water toxicity tests were summarized in terms of survival (Hyalella azteca, Daphnia magna, Anodonta imbecillis, Ceriodaphnia dubia), fecundity (Daphnia magna) or light output reduction (Microtox{reg_sign}). Results from the water toxicity tests were summarized in terms of reduction in survival or fecundity of C. dubia, and survival or growth of Pimephales promelas. Toxicity test results (covering a period of about 1 6 months) showed little difference between reference site media and media from sites of concern. They also showed no strong spatial or temporal response pattern. These results are further supported by the presence of indigenous Chironomus and Hexagenia spp. in the sediment samples. Toxicity results will be discussed with respect to three issues. Two criteria were used to define significant differences between reference sites and sites of concern: a difference of 20%, and statistical significance at a = 0.05. Secondly, the relevance of comparing mean responses to control vs. reference site will be discussed. Lastly, toxicity results are consistent with site characterization information which suggest that contaminants of concern in sediment are buried under clean sediment, effectively isolating the material from potential human or ecological exposure.

  3. Sediment microbial communities in Great Boiling Spring are controlled by temperature and distinct from water communities

    PubMed Central

    Cole, Jessica K; Peacock, Joseph P; Dodsworth, Jeremy A; Williams, Amanda J; Thompson, Daniel B; Dong, Hailiang; Wu, Geng; Hedlund, Brian P

    2013-01-01

    Great Boiling Spring is a large, circumneutral, geothermal spring in the US Great Basin. Twelve samples were collected from water and four different sediment sites on four different dates. Microbial community composition and diversity were assessed by PCR amplification of a portion of the small subunit rRNA gene using a universal primer set followed by pyrosequencing of the V8 region. Analysis of 164 178 quality-filtered pyrotags clearly distinguished sediment and water microbial communities. Water communities were extremely uneven and dominated by the bacterium Thermocrinis. Sediment microbial communities grouped according to temperature and sampling location, with a strong, negative, linear relationship between temperature and richness at all taxonomic levels. Two sediment locations, Site A (87–80 °C) and Site B (79 °C), were predominantly composed of single phylotypes of the bacterial lineage GAL35 (p̂=36.1%), Aeropyrum (p̂=16.6%), the archaeal lineage pSL4 (p̂=15.9%), the archaeal lineage NAG1 (p̂=10.6%) and Thermocrinis (p̂=7.6%). The ammonia-oxidizing archaeon ‘Candidatus Nitrosocaldus' was relatively abundant in all sediment samples <82 °C (p̂=9.51%), delineating the upper temperature limit for chemolithotrophic ammonia oxidation in this spring. This study underscores the distinctness of water and sediment communities in GBS and the importance of temperature in driving microbial diversity, composition and, ultimately, the functioning of biogeochemical cycles. PMID:23235293

  4. Sediment dynamic at the water-sediment interface of the Thau Lagoon (S. France) from seasonal to century time scales using radiogenic and comosgenic nuclides

    NASA Astrophysics Data System (ADS)

    Jouanneau, J.-M.; Schmidt, S.; Weber, O.; Lecroart, P.; Radakovitch, O.; Gilbert, F.; Jezequel, D.

    2003-04-01

    Among the factors disturbing the sedimentary record the most important are massive sediment displacement, erosion, bioturbation, and human activities. As a part of the PNEC supported Microbent programme, we investigated sedimentation processes to determine sediment deposit/erosion cycle at the water-sediment interface in relation with these potential perturbations. The investigated area is the Thau Lagoon, located in the south of France and strongly influenced by human activities (Sete industrial harbour, oyster farming). Two main sites were investigated: C4 in the middle of the lagoon in order to have a reference site, C5 nearby oyster farming. Sediment cores, up to 50cm in length, were collected in Dec. 2001, April, July and August 2002. Interface sediments have been studied using classical sedimentological parameters (radiography, grain size distribution) and analysis of the radionuclides Th-234, Be-7, Pb-210 and Cs-137 (gamma and alpha spectrometry). On a century time scale, 210Pb and 137Cs profiles indicate well defined sedimentation rates at both sites (around 0.2 0.3 cm per year). Nevertheless at the central site, C4, cores seem to register episodic changes in mean granulometry, presenting recurrently peaks. The upper 10 cm of Pb-210 profiles at site C5 exhibit a mixed layer associated with coarser sediments: these could be in relation with biological or dredging activity. On a seasonal time scale, Th-234 and Be-7 both show seasonal variations in activities and in penetration within the sediment. As these radionuclides are mainly carried by the fine particles, such variations must reflected associated variations of silt content of surface sediments. Fine sediment accumulation is a balance between deposition (settling, bioaccumulation) and erosion. Summer period seems to correspond to the most favourable season for deposition for the Thau lagoon. This study clearly illustrates the interest of radionuclides of different input and half-life to describe in

  5. Metals in sediments: bioavailability and toxicity in a tropical reservoir used for public water supply.

    PubMed

    Cardoso-Silva, Sheila; Da Silva, Daniel Clemente Vieira Rego; Lage, Fernanda; de Paiva, Teresa Cristina Brazil; Moschini-Carlos, Viviane; Rosa, André Henrique; Pompêo, Marcelo

    2016-05-01

    Sediments may be a repository of contaminants in freshwater ecosystems. One way to assess the quality of this compartment, in terms of potentially bioavailable metals, is by the analysis of acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM). In order to investigate the bioavailability, toxicity, and compartmentalization of different metals (Cd, Cr, Cu, Ni, Pb, Zn), sampling of surface sediments was performed at nine stations along the Paiva Castro reservoir (São Paulo, Brazil). The metals were analyzed using atomic absorption spectroscopy. Sediment organic matter (OM), organic carbon (OC), and grain size were also measured. The parameters pH, EH, temperature, and dissolved oxygen were determined at the sediment-water interface. Chronic and acute toxicological tests were performed with sediments from the area where water was extracted for the public water supply. Low levels of OM, associated with loss of stratification in the water column, explained the relatively low AVS values. The molar ratio ∑[SEM]-[AVS]/fOC was less than 130 mmol/kg(-1) for all the sampling stations, indicating that the metals were not bioavailable. With the exception of Cd, metal levels were in accordance with background concentrations and the threshold effect level (TEL) established by the Canadian Council of Ministers of the Environment. The ecotoxicological tests confirmed the absence of toxic effects to biota. Application of principal component analysis indicated the presence of four compartments along the reservoir: (1) a riverine zone, potentially threatened by contamination with Cd; (2) an intermediate zone; (3) a limnic area; and (4) the area where water was taken for the public water supply. PMID:27117444

  6. Distribution of heavy metals in water, particulate matter and sediments of Gediz River (Eastern Aegean).

    PubMed

    Kucuksezgin, F; Uluturhan, E; Batki, H

    2008-06-01

    The present paper is the first document of heavy metal levels in surficial sediment, water and particulate matter of the Gediz River collected from five different sites in August, October 1998, February, June 1999. The present work attempts to establish the status of distribution and environmental implications of metals in the sediment, water and particulate matter and their possible sources of derivation. The concentrations of mercury ranged 0.037-0.81, 120-430; lead 0.59-1.5, 190-8,100; copper 0.24-1.6, 30-180; zinc 0.19-2.9, 10-80; manganese 30-170, 20-490; nickel 0.39-9.0, 100-510; iron 1.3-687, 100-6,200 microg/l in water and particulate matter, respectively. The maximum values in water were generally obtained in summer periods due to industrial and agricultural activities at Muradiye. The particulate metal concentrations also generally showed increased levels from the upper Gediz to the mouth of the river. Calculation of metal partition coefficients shows that the relative importance of the particulate and the water phases varies in response to water hydrochemistry and suspended solid content, but that most elements achieve a conditional equilibrium in the Gediz River. The metals ranged between Hg: 0.25-0.49, Cr: 59-814, Pb: 38-198, Cu: 15-148, Zn: 34-196, Mn: 235-1,371, Ni: 35-175, and Fe: 10,629-72,387 mg/kg in sediment. The significant increase of metals found in Muradiye suggested a pollution effect, related to anthropogenic wastes. Also, relatively high concentrations of Ni and Mn occurred in sampling site upstream, due to geochemical composition of the sediments. Maximum values of contamination factor for metals were noticed for sediment of Muradiye. The sampling stations have very high degree of contamination indicating serious anthropogenic pollution. PMID:17846908

  7. Chronic toxicity of tire and road wear particles to water- and sediment-dwelling organisms.

    PubMed

    Panko, Julie M; Kreider, Marisa L; McAtee, Britt L; Marwood, Christopher

    2013-01-01

    Tire and road wear particles (TRWP) consist of a complex mixture of rubber, and pavement released from tires during use on road surfaces. Subsequent transport of the TRWP into freshwater sediments has raised some concern about the potential adverse effects on aquatic organisms. Previous studies have shown some potential for toxicity for tread particles, however, toxicity studies of TRWP collected from a road simulator system revealed no acute toxicity to green algae, daphnids, or fathead minnows at concentrations up to 10,000 mg/kg under conditions representative of receiving water bodies. In this study, the chronic toxicity of TRWP was evaluated in four aquatic species. Test animals were exposed to whole sediment spiked with TRWP at concentrations up to 10,000 mg/kg sediment or elutriates from spiked sediment. Exposure to TRWP spiked sediment caused mild growth inhibition in Chironomus dilutus but had no adverse effect on growth or reproduction in Hyalella azteca. Exposure to TRWP elutriates resulted in slightly diminished survival in larval Pimephales promelas but had no adverse effect on growth or reproduction in Ceriodaphnia dubia. No other endpoints in these species were affected. These results, together with previous studies demonstrating no acute toxicity of TRWP, indicate that under typical exposure conditions TRWP in sediments pose a low risk of toxicity to aquatic organisms. PMID:23001428

  8. Aluminum forms in stream sediment: Relation to bedrock geology and water chemistry

    SciTech Connect

    Turner, R.R.; Bogle, M.A.; Zeiler, M.A.; Mulholland, P.J.; Elwood, J.W.; Cook, R.B.

    1987-01-01

    Longitudinal gradients in sediment and water chemistry were characterized in a high elevation stream in the southern Appalachian Mountains, USA, to elucidate the geochemical behavior of aluminum across gradients in pH (4.5 to 6.5) and elevation (1120 to 1895 m). Observed gradients are driven in part by the presence of pyritic bedrock, which occurs at higher elevations and yields acidity when exposed to oxidation by landslide activity. Exchangeable Al in sediment (estimated using potassium chloride) varied in response to monomeric Al in streamwater and thus decreased downstream. Organic Al in sediment (estimated using sodium pyrophosphate) did not vary in proportion to the organic carbon content of sediment. Amorphous Al in sediment (estimated as the difference between oxalate- and pyrophosphate-extractable Al) and Al extractable with acidified streamwater (pH 4.5) was lowest at the more acidic sites. These results suggest that increases in soluble Al in downstream reaches during episodic pH depressions could be due in part to the release of adsorbed and/or precipitated Al in sediment.

  9. Statistical modelling of variability in sediment-water nutrient and oxygen fluxes

    NASA Astrophysics Data System (ADS)

    Serpetti, Natalia; Witte, Ursula; Heath, Michael

    2016-06-01

    Organic detritus entering, or produced, in the marine environment is re-mineralised to inorganic nutrient in the seafloor sediments. The flux of dissolved inorganic nutrient between the sediment and overlying water column is a key process in the marine ecosystem, which binds the biogeochemical sub-system to the living food web. These fluxes are potentially affected by a wide range of physical and biological factors and disentangling these is a significant challenge. Here we develop a set of General Additive Models (GAM) of nitrate, nitrite, ammonia, phosphate, silicate and oxygen fluxes, based on a year-long campaign of field measurements off the north-east coast of Scotland. We show that sediment grain size, turbidity due to sediment re-suspension, temperature, and biogenic matter content were the key factors affecting oxygen consumption, ammonia and silicate fluxes. However, phosphate fluxes were only related to suspended sediment concentrations, whilst nitrate fluxes showed no clear relationship to any of the expected drivers of change, probably due to the effects of denitrification. Our analyses show that the stoichiometry of nutrient regeneration in the ecosystem is not necessarily constant and may be affected by combinations of processes. We anticipate that our statistical modelling results will form the basis for testing the functionality of process-based mathematical models of whole-sediment biogeochemistry.

  10. Comprehensive sediment toxicity assessment of Hessian surface waters using Lumbriculus variegatus and Chironomus riparius.

    PubMed

    Galluba, Simone; Oetken, Matthias; Oehlmann, Jörg

    2012-01-01

    The objective of this study was a sediment assessment of predominantly small rivers in the German federal state of Hesse. For this purpose, sediment samples were taken at 50 study sites with different contamination levels. The benthic invertebrates Chironomus riparius (Diptera) and Lumbriculus variegatus (Oligochaeta) were used as test species and exposed to whole sediments in chronic laboratory experiments. The bioassays were carried out on the basis of OECD guidelines 218 and 225 for the testing of chemicals. For about 50 % of the study sites chemical analytical data for pollutants from environmentally important substance classes like metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organotin compounds were available. These data were used to analyze correlations between effects in the bioassays and measured chemical contaminations at sampling sites. For 22 % of the sediments ecologically relevant adverse effects were observed. In the majority of these cases effects occurred in only one of the biotests, and only one sediment sample exerted a negative effect on both test organisms. There was no significant correlation between biological responses and chemical data considering substance classes. However, there was a weak positive correlation between arsenic concentration and both worm number and worm biomass as well as a weak positive correlation between single PAHs and worm biomass. In some sediment tests elevated ammonia concentrations occurred in the overlying water so that an influence of these partially toxic concentrations on the test results cannot be ruled out. PMID:22375534

  11. Geotechnical properties of dredged marine sediments treated at high water/cement ratio

    NASA Astrophysics Data System (ADS)

    Rekik, Boubaker; Boutouil, Mohamed

    2009-06-01

    Cement and lime are widely employed in soil and sediment treatment for an improvement of geotechnical properties, such as an increase in mechanical strength which enables beneficial use in various geotechnical applications. In this study, fine organic-rich dredged harbour sediments of 120% relative water content were treated with dry cement at contents varying between 2% and 10% of bulk sediment wet weight. Tests based on assessments of one-dimensional compression and Atterberg limits were performed on untreated and cement-treated sediments for various curing periods, as well as grain-size, SEM and X-ray diffraction analyses. The results confirm that increasing the cement content improves the geotechnical properties of these harbour sediments. Already in the early phase of curing (first 3 days of curing), particle size increases while sediment plasticity decreases. Changes in the compressibility behaviour include an increase in apparent preconsolidation pressure, in the compression index C c and in the primary consolidation coefficient C v, and a decrease in the secondary compression index C_α . This means that the new materials are characterized by a behaviour intermediate between that of fine and that of coarser soils.

  12. A guide to the proper selection and use of federally approved sediment and water-quality samplers

    USGS Publications Warehouse

    Davis, Broderick E.; Federal Interagency Sedimentation Project

    2005-01-01

    As interest in the health of rivers and streams increases3, and new water-quality regulations4 are promulgated, interest in sediment and water-quality sampling equipment and technologies has increased. While much information on the subject exists, a comprehensive summary document of sediment sampling equipment and technology is lacking. This report seeks to provide such a summary.

  13. Phytoremediation Of Mercury And Methylmercury Contaminated Sediments By Water Hyacinth (Eichhornia crassipes)

    EPA Science Inventory

    Phytoremediation has potential to be implemented at mercury (Hg) and methylmercury (MeHg) contaminated sites. Water hyacinths (Eichhornia crassipes) were investigated for their ability to assimilate Hg and MeHg into plant biomass, in both aquatic and sediment-associated f...

  14. Bench-Scale Investigation Of Mercury Phytoremediation By Water Hyacinths (Eichhornia crassipes) In Heavily Contaminated Sediments

    EPA Science Inventory

    Phytoremediation has the potential to be implemented at mercury (Hg) and methylmercury (MeHg) contaminated sites. Water hyacinths (Eichhornia crassipes) were investigated for their ability to assimilate Hg and MeHg into plant biomass, in both aquatic and sediment-associat...

  15. Phytoremediation of Mercury- and Methyl Mercury-Contaminated Sediments by Water Hyacinth (Eichhornia crassipes)

    EPA Science Inventory

    Phytoremediation has the potential for implementation at Hg- (Hg) and methylHg (MeHg)-contaminated sites. Water hyacinths (Eichhornia crassipes) were investigated for their ability to assimilate Hg and MeHg into plant biomass, in both aquatic and sediment-associated forms...

  16. CALCULATION OF SOIL-WATER AND BENTHIC SEDIMENT PARTITION COEFFICIENTS FOR MERCURY

    EPA Science Inventory

    To accurately model mercury transport to water bodies, an assessment of this pollutant's behavior in the watershed is critical. Partition coefficients, defined as an estimate of the ratio of the pollutant concentration sorbed onto soil/sediment particles to the pollutant concentr...

  17. Selenium in water, sediment, plants, invertebrates, and fish in the Blackfoot River drainage

    USGS Publications Warehouse

    Hamilton, S.J.; Buhl, K.J.

    2004-01-01

    Nine stream sites in the Blackfoot River watershed in southeastern Idaho were sampled in September 2000 for water, surficial sediment, aquatic plants, aquatic invertebrates, and fish. Selenium was measured in these aquatic ecosystem components, and a hazard assessment was performed on the data. Water quality characteristics such as pH, hardness, and specific conductance were relatively uniform among the nine sites examined. Selenium was elevated in water, sediment, aquatic plants, aquatic invertebrates, and fish from several sites suggesting deposition in sediments and food web cycling through plants and invertebrates. Selenium was elevated to concentrations of concern in water at eight sites (>5 ??g/L), sediment at three sites (>2 ??g/g), aquatic plants at four sites (>4 ??g/g), aquatic invertebrates at five sites (>3 ??g/g), and fish at seven sites (>4 ??g/g in whole body). The hazard assessment of selenium in the aquatic environment suggested low hazard at Sheep Creek, moderate hazard at Trail Creek, upper Slug Creek, lower Slug Creek, and lower Blackfoot River, and high hazard at Angus Creek, upper East Mill Creek, lower East Mill Creek, and Dry Valley Creek. The results of this study are consistent with results of a previous investigation and indicate that selenium concentrations from the phosphate mining area of southeastern Idaho were sufficiently elevated in several ecosystem components to cause adverse effects to aquatic resources in the Blackfoot River watershed. ?? 2004 Kluwer Academic Publishers.

  18. Including Sediment-Associated Bacteria Resuspension and Settling in SWAT Predictions of Microbial Water Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Streambed sediments have been shown to serve as environmental reservoirs for bacteria, including pathogenic strains. The Soil and Water Assessment Tool (SWAT) has been augmented with bacteria subroutine in 2005. Bacteria die-off is the only in-stream process considered in the current SWAT. The purpo...

  19. MULTISPECTRAL TECHNIQUES FOR REMOTE MONITORING OF SEDIMENT IN WATER: A FEASIBILITY INVESTIGATION

    EPA Science Inventory

    A data acquisition and analysis program has been undertaken to demonstrate the feasibility of remote multispectral techniques for monitoring suspended sediment concentrations in natural water bodies. Two hundred surface albedo measurements (400 to 1,000 nanometers) were made at L...

  20. ASSESSING WATER QUALITY CHANGES IN THE LAKES OF THE NORTHEASTERN UNITED STATES USING SEDIMENT DIATOMS

    EPA Science Inventory

    Diatom assemblages were selected as indicators of lake condition and to assess historical lake water quality changes in 257 lakes in the northeastern United States. The "top" (surface sediments, present-day) and "bottom" (generally from >30 cm deep, representing historical condit...

  1. Sediment Quality in Near Coastal Waters of the Gulf of Mexico: Influence of Hurricane Katrina

    EPA Science Inventory

    The results from this study represent a synoptic analysis of sediment quality in coastal waters of Lake Pontchartrain and Mississippi Sound two months after the landfall of Hurricane Katrina. Post-hurricane conditions were compared to pre-hurricane (2000-2004) conditions, for se...

  2. Heavy metals in water, sediments and submerged macrophytes in ponds around the Dianchi Lake, China.

    PubMed

    Wang, Zhixiu; Yao, Lu; Liu, Guihua; Liu, Wenzhi

    2014-09-01

    Through retaining runoff and pollutants such as heavy metals from surrounding landscapes, ponds around a lake play an important role in mitigating the impacts of human activities on lake ecosystems. In order to determine the potential for heavy metal accumulation of submerged macrophytes, we investigated the concentrations of 10 heavy metals (i.e., As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in water, sediments, and submerged macrophytes collected from 37 ponds around the Dianchi Lake in China. Our results showed that both water and sediments of these ponds were polluted by Pb. Water and sediments heavy metal concentrations in ponds received urban and agricultural runoff were not significantly higher than those in ponds received forest runoff. This result indicates that a large portion of heavy metals in these ponds may originate from atmospheric deposition and weathering of background soils. Positive relationships were found among heavy metal concentrations in submerged macrophytes, probably due to the coaccumulation of heavy metals. For most heavy metals, no significant relationships were found between submerged macrophytes and their water and sediment environments. The maximum concentrations of Cr, Fe and Ni in Ceratophyllum demersum were 4242, 16,429 and 2662mgkg(-1), respectively. The result suggests that C. demersum is a good candidate species for removing heavy metals from polluted aquatic environments. PMID:25011115

  3. 30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Water, sediment, or slurry impoundments and impounding structures; inspection requirements; correction of hazards; program requirements. 77.216-3 Section 77.216-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY...

  4. Biodegradation screening of chemicals in an artificial matrix simulating the water-sediment interface.

    PubMed

    Baginska, Ewelina; Haiss, Annette; Kümmerer, Klaus

    2015-01-01

    Biodegradation is the most important attenuation process for most of organic chemicals in the environment. This process decides whether the organic substance itself or its degradation products rests in the environment and should be considered for a further risk assessment. This work presents the development of a water sediment screening test, based on OECD guideline 308, with a high significance to environmental conditions and with a good reproducibility and consistency of results. The increased reproducibility was achieved by creating an artificial and standardized medium, based on the existing OECD guidelines OECD 302C, 301D and 218. Each test consisted of five different series: blank, quality control, test, toxicity control and abiotic control. Biodegradation was assessed by measurement of pressure difference in closed vessels using the OxiTop(®) system. Aniline, diethylene glycol and sodium acetate were used to optimize and validate test conditions. Additionally, two pharmaceuticals: Acetaminophen and ciprofloxacin (CIP) were tested as an example of possible test application. Acetaminophen was mainly removed from the system by biodegradation whereas CIP was removed from water phase by sorption onto sediment. Water sediment test proved to be a promising tool for the biodegradation investigation of chemicals in the water-sediment interface. PMID:25460767

  5. Relationship between water chemistry and sediment mineralogy in the Cerro Prieto geothermal field: a preliminary report

    SciTech Connect

    Valette-Silver, J.N.; Thompson, J.M.; Ball, J.W.

    1981-01-01

    The chemical compositions of waters collected from the Cerro Prieto geothermal production wells and hydrothermal emanations are different. Compared to the Cerro Prieto well waters, the surficial waters generally contain significantly less potassium, slightly less calcium and chloride, and significantly more magnesium and sulfate. In comparison to the unaltered sediments, the changes in the mineralogy of the altered sediments appear to be controlled by the type of emanation (well, spring, mud pot, geyser, fumarole, or cold pool). However, an increase in quartz and potassium feldspar percentages seems to be characteristic of the majority of the sediments in contact with geothermal fluids. Preliminary attempts to model the chemical processes occurring in the Cerro Prieto geothermal field using chemical equilibrium calculations are reported. For this purpose the chemical compositions of thermal waters (well and surficial emanation) were used as input data to make calculations with SOLMNEQ and WATEQ2 computer programs. Then the theoretical mineral composition of altered sediments was predicted and compared to the mineralogy actually observed in the solid samples.

  6. KINETIC STUDIES OF THE REDUCTION OF AROMATIC AZO COMPOUNDS IN ANAEROBIC SEDIMENT/WATER SYSTEMS

    EPA Science Inventory

    The reductive transformation of azobenzene and selected derivatives was investigated in anaerobic sediment/water systems. The azo compounds exhibited pseudo-first-order disappearance kinetics through at least three half-lives. The reduction kinetics of these compounds was studied...

  7. WATER EROSION PREDICTION PROJECT (WEPP) TECHNOLOGY FOR ASSESSMENT OF RUNOFF, SOIL LOSS AND SEDIMENT YIELD POTENTIAL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Water Erosion Prediction Project (WEPP) model is a process-based, distributed parameter, continuous simulation computer program for estimation of runoff, soil loss and sediment yield from fields and small watersheds. In addition to having large databases for application to a multitude of U.S. s...

  8. Field Validation of Molybdenum Accumulation in Sediments as an Indication of Hypoxic Water Conditions

    EPA Science Inventory

    Accumulation of authigenic molybdenum (Mo) in marine sediments has often been used as qualitative indicator of periods of hypoxic bottom water, but rarely, if ever, used quantitatively. Laboratory experiments have shown that the accumulation rate of Mo may serve as a quantitative...

  9. Molybdenum Accumulation in Marine Sediments as an Indicator of Hypoxic Water Conditions (NACAETAC)

    EPA Science Inventory

    Direct monitoring of hypoxic water column conditions over large spatial and temporal extents is difficult due to the substantial logistical and financial investment required. Recent studies have indicated that concentrations of molybdenum (Mo) in marine sediments may serve as a u...

  10. Evaluation Of Selected Sorption Materials For Capping Mercury-Contaminated Fresh Water Sediments

    EPA Science Inventory

    Fate and transport of mercury (Hg) and methylmercury (MeHg) within the aquatic environment involves many complex and interconnected pathways. MeHg is formed mainly at the sediment-water interface, just below which there is a transition from oxic to anoxic conditions. The format...

  11. WATER LEVEL DRAWDOWN TRIGGERS SYSTEM-WIDE BUBBLE RELEASE FROM RESERVOIR SEDIMENTS

    EPA Science Inventory

    Reservoirs are an important anthropogenic source of methane and ebullition is a key pathway by which methane stored in reservoir sediments can be released to the atmosphere. Changes in hydrostatic pressure during periods of falling water levels can trigger bubbling events, sugge...

  12. Centrifugal sedimentation immunoassays for multiplexed detection of enteric bacteria in ground water.

    PubMed

    Litvinov, Julia; Moen, Scott T; Koh, Chung-Yan; Singh, Anup K

    2016-01-01

    Waterborne pathogens pose significant threat to the global population and early detection plays an important role both in making drinking water safe, as well as in diagnostics and treatment of water-borne diseases. We present an innovative centrifugal sedimentation immunoassay platform for detection of bacterial pathogens in water. Our approach is based on binding of pathogens to antibody-functionalized capture particles followed by sedimentation of the particles through a density-media in a microfluidic disk. Beads at the distal end of the disk are imaged to quantify the fluorescence and determine the bacterial concentration. Our platform is fast (20 min), can detect as few as ∼10 bacteria with minimal sample preparation, and can detect multiple pathogens simultaneously. The platform was used to detect a panel of enteric bacteria (Escherichia coli, Salmonella typhimurium, Shigella, Listeria, and Campylobacter) spiked in tap and ground water samples. PMID:26858815

  13. Parameterization of biogeochemical sediment-water fluxes using in-situ measurements and a steady-state diagenetic model

    EPA Science Inventory

    Diagenetic processes are important drivers of water column biogeochemistry in coastal areas. For example, sediment oxygen consumption can be a significant contributor to oxygen depletion in hypoxic systems, and sediment–water nutrient fluxes support primary productivity in ...

  14. Solving the problem at the source: Controlling Mn release at the sediment-water interface via hypolimnetic oxygenation.

    PubMed

    Bryant, Lee D; Hsu-Kim, Heileen; Gantzer, Paul A; Little, John C

    2011-12-01

    One of the primary goals of hypolimnetic oxygenation systems (HOx) from a drinking water perspective is to suppress sediment-water fluxes of reduced chemical species (e.g., manganese and iron) by replenishing dissolved oxygen (O(2)) in the hypolimnion. Manganese (Mn) in particular is becoming a serious problem for water treatment on a global scale. While it has been established that HOx can increase sediment O(2) uptake rates and subsequently enhance the sediment oxic zone via elevated near-sediment O(2) and mixing, the influence of HOx on sediment-water fluxes of chemical species with more complicated redox kinetics like Mn has not been comprehensively evaluated. This study was based on Mn and O(2) data collected primarily in-situ to characterize both the sediment and water column in a drinking-water-supply reservoir equipped with an HOx. While diffusive Mn flux out of the sediment was enhanced by HOx operation due to an increased concentration driving force across the sediment-water interface, oxygenation maintained elevated near-sediment and porewater O(2) levels that facilitated biogeochemical cycling and subsequent retention of released Mn within the benthic region. Results show that soluble Mn levels in the lower hypolimnion increased substantially when the HOx was turned off for as little as ∼48 h and the upper sediment became anoxic. Turning off the HOx for longer periods (i.e., several weeks) significantly impaired water quality due to sediment Mn release. Continual oxygenation maintained an oxic benthic region sufficient to prevent Mn release to the overlying source water. PMID:22000717

  15. Methane in water columns and sediments of the north western Sea of Japan

    NASA Astrophysics Data System (ADS)

    Vereshchagina, Olga F.; Korovitskaya, Elena V.; Mishukova, Galina I.

    2013-02-01

    This paper presents the results of methane measurements in water and sediments, first performed along the north western continental slope and abyssal plain of the Sea of Japan. Methane concentrations in the study area were very low. However, some features of its distribution are revealed. The highest dissolved methane concentrations (10-14 nmol kg-1) are characteristic of the pycnocline layer at a depth of 30-50 m in the northern shallow stations. With increasing depth, the methane is reduced to minimum values (0.5-1.0 nmol kg-1). The greatest variability in methane concentrations was observed in the layers at 0-500 m, which can be explained by the hydrodynamic conditions of the environment on the slope. Methane plumes (1.7 and 1.3 nmol kg-1) on the northern section were recorded at the depth of 1250 and 1495 m, respectively. Plumes (1.2 nmol kg-1) are also observed on near bottom layers at the deepest (more than 3000 m) stations. CH4 concentration in bottom sediments is also low (from 1 nmol kg-1 at 7 cm level to 752 nmol kg-1 at the 53 cm level of the core sediment in the northern part). Reduced sediments in the southern part of the study region have maximal methane concentration for sediment (2549 nmol kg-1) at the horizon 44 cm bsf (below sea floor) with a smell of H2S. These results assume a close relation of CH4 with sediment properties. A few stations with maximum methane (86-101 nmol kg-1) in the surface sediment layer are at the foot of a steep slope. Herewith, the highest abundance of some pericarid species was observed at the points with the highest values of methane concentrations in the surface sediment layer. Weak methane seepage can cause anoxic marine waters. Methane emission from water to the atmosphere is low because its concentration is close to equilibrium in surface water. An improved formula for calculating the methane flux of water into the atmosphere, taking into account high wind speeds, is presented in the paper.

  16. Coupling between pore water fluxes, structural heterogeneity, and biogeochemical processes controls contaminant mobility, bioavailability, and toxicity in sediments

    NASA Astrophysics Data System (ADS)

    Xie, M.; Fetters, K.; Jarrett, B.; Yuen, J.; Cadoux, C.; EI-Natour, M.; Packman, A. I.; Gaillard, J.; Burton, G.

    2012-12-01

    Sediments can serve as both sinks and sources of contaminants in aquatic systems. Contaminants are typically not sequestered permanently in sediments, and instead release slowly to the water column, posing an ongoing threat to aquatic ecosystems and human health. Many processes, including hydrodynamic transport, sediment diagenesis, and bioturbation regulate the behavior and effects of contaminants in sediments. While many of these processes have been studied individually, it is extremely important to understand how they interact to control the form, flux and toxicity of metals in sediments. We used well-defined experimental mesocosms to investigate the effects of hydrodynamic and biological processes on the redistribution of metals between sediments, pore water and overlying water, associated changes in metals speciation, and resulting bioavailability and toxicity to benthic organisms. Metals speciation was evaluated in deposited and resuspended particles using x-ray absorption spectroscopy. We also used time-lapse photography and oxygen optode imaging to evaluate how bioturbation and bioirrigation control sediment structure, sediment mixing process, and oxygen delivery to sediments. In the extremely fine sediments used here, local contaminant fluxes are mainly dominated by diffusion, but episodic bioturbation and resuspension cause extreme variability in contaminant flux and increases oxidation of reduced sediments. Metals contamination substantially reduced bioturbation by indwelling organisms. Sediment resuspension decreased survival and increased tissue burden of epi-benthic organisms. Bioturbation mixed sediments as deep as several centimeters, while associated bioirrigation through worm burrows delivered oxygen over an order of magnitude deeper than local diffusion. These results show that it is important to understand how local transport processes, sediment chemistry, and biological activity interact to control rates and patterns of metals speciation and

  17. An expression for the water sediment moving layer in unsteady flows

    NASA Astrophysics Data System (ADS)

    Berta, A. M.; Bianco, G.

    2009-04-01

    During floods the effects of sediment transport in river beds cannot be neglected, either by a morphological or an hydrodynamical point of view. Sediment transport is here studied through the "moving layer", i.e. the water-sediment layer which moves in the lower part of a flow. Moving layer variations along rivers lead to depositions and erosions and are typically unsteady, but are often tackled with expressions developed for steady (equilibrium) conditions, as a consequence of the still limited knowledge of the sediment transport in strong time-dependent conditions and of the scarcity of experimental measures. In this paper we develop an expression for the moving layer in unsteady condition, and calibrate it with experimental data. During laboratory tests, we have in fact reproduced a rapidly changing unsteady flow by the erosion of a steep slope, built with non-cohesive granular sediments. Along the slopes, for fixed discharges, moving layer depths have shown to increase from upstream to downstream, showing a clear tendency toward equilibrium conditions. Knowing the equilibrium achievement has anyway presented many difficulties, being influenced by choice of the equilibrium expression and moreover by the estimation of the parameters involved (for example friction angle..). Even though water-sediment flows ranged from hyper-concentrated to ordinary bed load transport, we have experimentally quantified and used for the calibration only data (sediment concentrations, bed and free surface slopes, moving layer depths, etc...) relevant to hyper-concentrated mono-dimensional flows, occurred for slope gradients in the range 3% - 20%. Consequently, our model can be applied both on open channels and on embankments/dams providing that the flows can be modelled as mono-dimensional, and that slopes and applied shear stress levels fall within the considered ranges.

  18. Effects of 1,2,4-trichlorobenzene on estuarine macrobenthic communities exposed via water and sediment

    SciTech Connect

    Tagatz, M.E.; Plaia, G.R.; Deans, C.H.

    1985-12-01

    Macrobenthic animal communities that colonized sand-filled aquaria were exposed to 1,2,4-trichlorobenzene (TCB), a recent replacement for polycholorinated biphenyls in the electrical industry. In one test, communities established by planktonic larvae entrained in continuously supplied unfiltered seawater for 50 days were exposed to waterborne TCB for 6 days; in the second test, the toxicant was added to the sediment before 8 weeks of colonization. Concentrations that affected community structure were usually two orders of magnitude lower for waterborne TCB than for sediment-bound TCB, but the same types of organisms were affected by each route of exposure. The lowest TCB concentrations (measured) that affected average numbers of individuals exposed via the water were 0.04 mg/liter for mollusks, 0.4 mg/liter for arthropods, and 4 mg/liter for annelids. Average number of species was significantly lower than the control at 4 mg/liter. For TCB exposures via the sediment, the lowest concentrations (nominal) that affected average numbers of individuals were 100 micrograms/g for mollusks and echinoderms, and 1000 micrograms/g for arthropods and annelids. Average number of species in experimental aquaria was significantly lower than the control at greater than or equal to 100 micrograms/g. TCB persisted in sediments, but some leached into water throughout the 8-week exposure via sediment.

  19. [Sediment heavy metals quality criteria for fresh waters based on biological effect database approach].

    PubMed

    Zhang, Ting; Zhong, Wen-Jue; Zeng, Yi; Zhu, Ling-Yan

    2012-09-01

    Heavy metals are the important pollutants in sediments, which can cause serious damage to benthonic organisms and aquatic ecology, while biological effect database approach (BEDA) is a widely used method for assessing sediment quality in developed countries or regions. This paper introduced the concrete steps of this approach, and built the sediment quality criteria of five heavy metals (Cu, Zn, Cd, Pb, and Ni) for fresh waters. The comparability, reliability, and predictability of the criteria were also tested. It was shown that the threshold effect level (TEL) of the Cd, Ni, Pb, Zn, and Cu was 3.0, 31.4, 47.3, 74.9, and 45.5 mg x kg(-1) dry mass, and the probable effect level (PEL) of the Cd, Ni, Pb, Zn, and Cu was 19, 76.9, 204.1, 403.6, and 181.1 mg x kg(-1) dry mass basis, respectively. Except for Zn, the TEL and PEL for the Cu, Cd, Pb, and Ni were consistent with the definitional biological effect of the heavy metals, being accor-dance with the demands of sediment quality criteria for protecting benthic organisms and having high reliability, and thus, could be used as the proposed sediment quality criteria for fresh waters in China. PMID:23286020

  20. Toxicity of sediments and interstitial waters form the Southern California Bight

    SciTech Connect

    Bay, S.; Greenstein, D.; Brown, J.; Jirik, A.

    1995-12-31

    The toxicity of 72 sediment samples collected during the EMAP Southern California Bight Pilot Project (SCBPP) was measured. Sediments from the mainland shelf between Point Conception and the Mexican border were collected from various depths and tested for toxicity using two methods. The toxicity of bulk sediment was measured using a 10-day amphipod (Ampelisca abdita) survival test. Interstitial water was also extracted from the samples and tested for toxicity using a 72-hour sea urchin (Strongylocentrotus purpuratus) embryo development test. Amphipod survival was high (> 80%) at all stations tested, although several sites near large sewage outfalls had statistically significant reductions in survival. No interference related to grain size variation was observed with the amphipod test. Most of the interstitial water samples produced abnormal sea urchin embryo development. Effects were not related to the presumed level of sediment contamination, but rather to ammonia concentration in virtually all cases. The impacts of sample handling procedures and ammonia on sediment toxicity data interpretation will be discussed.

  1. Distribution of total mercury and methyl mercury in water, sediment, and fish from South Florida estuaries

    USGS Publications Warehouse

    Kannan, K.; Smith, R.G., Jr.; Lee, R.F.; Windom, H.L.; Heitmuller, P.T.; Macauley, J.M.; Summers, J.K.

    1998-01-01

    Concentrations of total mercury and methyl mercury were determined in sediment and fish collected from estuarine waters of Florida to understand their distribution and partitioning. Total mercury concentrations in sediments ranged from 1 to 219 ng/g dry wt. Methyl mercury accounted for, on average, 0.77% of total mercury in sediment. Methyl mercury concentrations were not correlated with total mercury or organic carbon content in sediments. The concentrations of total mercury in fish muscle were between 0.03 and 2.22 (mean: 0.31) ??g/g, wet wt, with methyl mercury contributing 83% of total mercury. Methyl mercury concentrations in fish muscle were directly proportional to total mercury concentrations. The relationship of total and methyl mercury concentrations in fish to those of sediments from corresponding locations was fish-species dependent, in addition to several abiotic factors. Among fish species analyzed, hardhead catfish, gafftopsail catfish, and sand seatrout contained the highest concentrations of mercury. Filtered water samples from canals and creeks that discharge into the Florida Bay showed mercury concentrations of 3-7.4 ng/L, with methyl mercury accounting for <0.03-52% of the total mercury. Consumption of fish containing 0.31 ??g mercury/g wet wt, the mean concentration found in this study, at rates greater than 70 g/day, was estimated to be hazardous to human health.

  2. Linear alkylbenzene sulfonate tolerance in bacteria isolated from sediment of tropical water bodies polluted with detergents.

    PubMed

    Eniola, Kehinde I T; Olayemi, Albert B

    2008-12-01

    The discharge of untreated detergent-bearing waste introduces linear alklcylbenzene sulfonates (LAS) to the aquatic environment. The surfactant persists in some streams and rivers in Nigeria, some is adsorbed to suspended materials and end in the sediment of the receiving water bodies. In this study, bacteria isolated from sediments of some tropical detergent-effluent-polluted streams were tested for tolerance to LAS using the media dilution technique. LAS-tolerance was indicated by growth of the bacteria in the presence of the surfactant. The pH, concentrations of surfactant, population of heterotrophic bacteria and population of LAS-tolerant bacteria in the sediments were determined. A direct relationship (r = 0.9124) was found between the alkaline conditions (pH= 8.2-12.0) and high surfactant concentrations (45-132 mg/g) in the sediment. The sediments harboured a high population and a wide variety of bacteria; the populations of viable heterotrophic bacteria (VHB: 2.9 x 10(5) to 1.2 x 10(7) cfu/g) and LAS tolerant bacteria (LTB: 1.5 x 10(4) to 1.2 x 10(6) cfu/g) had a direct relationship (r = 0.9500). An inverse relationship resulted between each of them and the concentration of surfactant in the sediment, r(VHB/LAS) = -0.9303 and r(LTB/LAS) = -0.9143, respect