Surface fractal dimension, water adsorption efficiency, and cloud nucleation activity of insoluble aerosol.

PubMed

Laaksonen, Ari; Malila, Jussi; Nenes, Athanasios; Hung, Hui-Ming; Chen, Jen-Ping

2016-05-03

Surface porosity affects the ability of a substance to adsorb gases. The surface fractal dimension D is a measure that indicates the amount that a surface fills a space, and can thereby be used to characterize the surface porosity. Here we propose a new method for determining D, based on measuring both the water vapour adsorption isotherm of a given substance, and its ability to act as a cloud condensation nucleus when introduced to humidified air in aerosol form. We show that our method agrees well with previous methods based on measurement of nitrogen adsorption. Besides proving the usefulness of the new method for general surface characterization of materials, our results show that the surface fractal dimension is an important determinant in cloud drop formation on water insoluble particles. We suggest that a closure can be obtained between experimental critical supersaturation for cloud drop activation and that calculated based on water adsorption data, if the latter is corrected using the surface fractal dimension of the insoluble cloud nucleus.

Surface fractal dimension, water adsorption efficiency, and cloud nucleation activity of insoluble aerosol

NASA Astrophysics Data System (ADS)

Laaksonen, Ari; Malila, Jussi; Nenes, Athanasios; Hung, Hui-Ming; Chen, Jen-Ping

2016-05-01

Surface porosity affects the ability of a substance to adsorb gases. The surface fractal dimension D is a measure that indicates the amount that a surface fills a space, and can thereby be used to characterize the surface porosity. Here we propose a new method for determining D, based on measuring both the water vapour adsorption isotherm of a given substance, and its ability to act as a cloud condensation nucleus when introduced to humidified air in aerosol form. We show that our method agrees well with previous methods based on measurement of nitrogen adsorption. Besides proving the usefulness of the new method for general surface characterization of materials, our results show that the surface fractal dimension is an important determinant in cloud drop formation on water insoluble particles. We suggest that a closure can be obtained between experimental critical supersaturation for cloud drop activation and that calculated based on water adsorption data, if the latter is corrected using the surface fractal dimension of the insoluble cloud nucleus.

Residue determination and levels of glyphosate in surface waters, sediments and soils associated with oil palm plantation in Tasik Chini, Pahang, Malaysia

NASA Astrophysics Data System (ADS)

Mardiana-Jansar, K.; Ismail, B. S.

2014-09-01

Levels of glyphosate and its main metabolite were determined in surface water, soil and sediment samples from an oil palm plantation area located at Tasik Chini, Pahang, Malaysia. The optimization analytical method has been developed for the determination of glyphosate herbicide and its metabolite amino-methyl-phosphonic acid (AMPA) in surface waters to a level of 0.1μg/L, while in sediments and soils to a level of 0.5μg/g with a good linearity in the calibration range of 1-100μg/L. The procedure involves a pre-columnderivatization step with 9-fluorenyl-methyl-chloroformate (FMOC-Cl) yielding highly fluorescent derivatives of the analytes which can be determined by HPLC with fluorescence detection. In the field, levels of glyphosate in surface waters ranges from not detected to 1.0mg/L, while in soils and sediments were from not detected to 6.0mg/kg. For AMPA, the residues in surface waters were between not detected to 2.0mg/L, while in soil and sediment samples were from not detected to 5mg/kg. This variation of glyphosate and AMPA levels depended directly on time of pesticide application and the season.

Models of Fate and Transport of Pollutants in Surface Waters

ERIC Educational Resources Information Center

Okome, Gloria Eloho

2013-01-01

There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

Summary of surface-water hydrologic data for the Houston metropolitan area, Texas, water years 1964-89

USGS Publications Warehouse

Liscum, Fred; Brown, D.W.; Kasmarek, M.C.

1997-01-01

The study area, a metropolitan area in southeast Texas about 45 miles north of the Gulf of Mexico, has been undergoing extensive urban development since the 1950s. The Houston Urban Runoff Program was begun by the U.S. Geological Survey in water year 1964 to define the magnitude and frequency of flood peaks, to determine the impact of continuing urban development on surface-water hydrologic responses, and to determine variations in stream water quality for different flow conditions, seasons, and urban development. An extensive data base has been developed.During water years 1964-89, the Houston Urban Runoff Program collected information from a total of 54 U.S. Geological Survey streamflow-gaging stations, 30 U.S. Geological Survey water-quality sampling sites, and 102 rain gages (operated by the U.S. Geological Survey, the National Weather Service, and local agencies). In addition, basin characteristics were developed to aid in understanding the effects of urban development on surface-water hydrologic responses.Surface-water hydrologic data on diskettes describe the 54 U.S. Geological Survey streamflow-gaging stations, list annual peaks (and where available, peaks above an arbitrary base) for 50 streamflow sites, tabulate 1,125 storm hydrographs from 43 sites, and document 102 waterquality parameters determined from 3,242 available samples.

A solid phase extraction-ion chromatography with conductivity detection procedure for determining cationic surfactants in surface water samples.

PubMed

Olkowska, Ewa; Polkowska, Żaneta; Namieśnik, Jacek

2013-11-15

A new analytical procedure for the simultaneous determination of individual cationic surfactants (alkyl benzyl dimethyl ammonium chlorides) in surface water samples has been developed. We describe this methodology for the first time: it involves the application of solid phase extraction (SPE-for sample preparation) coupled with ion chromatography-conductivity detection (IC-CD-for the final determination). Mean recoveries of analytes between 79% and 93%, and overall method quantification limits in the range from 0.0018 to 0.038 μg/mL for surface water and CRM samples were achieved. The methodology was applied to the determination of individual alkyl benzyl quaternary ammonium compounds in environmental samples (reservoir water) and enables their presence in such types of waters to be confirmed. In addition, it is a simpler, less time-consuming, labour-intensive, avoiding use of toxic chloroform and significantly less expensive methodology than previously described approaches (liquid-liquid extraction coupled with liquid chromatography-mass spectrometry). Copyright © 2013 Elsevier B.V. All rights reserved.

Interaction between ground water and surface water in Taylor Slough and vicinity, Everglades National Park, South Florida; study methods and appendixes

USGS Publications Warehouse

Harvey, Judson W.; Jackson, J.M.; Mooney, R.H.; Choi, Jungyill

2000-01-01

The data presented in this report are products of an investigation that quantified interactions between ground water and surface water in Taylor Slough in Everglades National Park. Determining the extent of hydrologic interactions between wetland surface water and ground water in Taylor Slough is important because the balance of freshwater flow in the lower part of the Slough is uncertain. Although freshwater flows through Taylor Slough are quite small in comparison to Shark Slough (the larger of the two major sloughs in Everglades National Park), flows through Taylor Slough are especially important to the ecology of estuarine mangrove embayments of northeastern Florida Bay. Also, wetland and ground- water interactions must be quantified if their role in affecting water quality is to be determined. In order to define basic hydrologic characteristics of the wetland, depth of wetland peat was mapped, and hydraulic conductivity and vertical hydraulic gradients in peat were determined. During specific time periods representing both wet and dry conditions in the area, the distribution of major ions, nutrients, and water stable isotopes throughout the slough were determined. The purpose of chemical measurements was to identify an environmental tracer could be used to quantify ground-water discharge.

Network global navigation satellite system surveys to harmonize American and Canadian datum for the Lake Champlain Basin

USGS Publications Warehouse

Flynn, Robert H.; Rydlund, Jr., Paul H.; Martin, Daniel J.

2016-03-08

Lake-gage water-surface elevations determined during the 3 days of surveys were converted to water-surface elevations referenced to the North American Vertical Datum of 1988 by using calculated offsets and historical water-surface elevations. In this report, an “offset” refers to the adjustment that needs to be applied to published data from a particular gage to produce elevation data referenced to the North American Vertical Datum of 1988. Offsets presented in this report can be used in the evaluation of water-surface elevations in a common datum for Lake Champlain and the Richelieu River. In addition, the water-level data referenced to the common datum (as determined from the offsets) may be used to calibrate flow models and support future modeling studies developed for Lake Champlain and the Richelieu River.

The influence of lithology on surface water sources

EPA Science Inventory

Understanding the temporal and spatial variability of surface water sources within a basin is vital to our ability to manage the impacts of climate variability and land cover change. Water stable isotopes can be used as a tool to determine geographic and seasonal sources of water...

Input and fate of anthropogenic estrogens and gadolinium in surface water and sewage plants in the hydrological basin of Prague (Czech Republic).

PubMed

Morteani, Giulio; Möller, Peter; Fuganti, Andrea; Paces, Tomas

2006-06-01

The concentration of the estrogens 17beta-estradiol, estriol, estrone, 17alpha-ethinylestradiol, mestranol and norethisterone and of the anthropogenic gadolinium (Gd(ant)) has been determined in the creeks and rivers, sewage treatment plants and water works of the city of Prague. The rapid degradation of estrogens in surface water allows the estrogen concentration gradient to be used as a very precise and sensitive guideline by which to pin-point sewage leaks into surface run-off water. The rather conservative behavior of Gd(ant) in surface and ground water documents in the present case the presence of sewage water in the surface water cycle.

Microwave remote sensing of soil water content

NASA Technical Reports Server (NTRS)

Cihlar, J.; Ulaby, F. T.

1975-01-01

Microwave remote sensing of soils to determine water content was considered. A layered water balance model was developed for determining soil water content in the upper zone (top 30 cm), while soil moisture at greater depths and near the surface during the diurnal cycle was studied using experimental measurements. Soil temperature was investigated by means of a simulation model. Based on both models, moisture and temperature profiles of a hypothetical soil were generated and used to compute microwave soil parameters for a clear summer day. The results suggest that, (1) soil moisture in the upper zone can be predicted on a daily basis for 1 cm depth increments, (2) soil temperature presents no problem if surface temperature can be measured with infrared radiometers, and (3) the microwave response of a bare soil is determined primarily by the moisture at and near the surface. An algorithm is proposed for monitoring large areas which combines the water balance and microwave methods.

Hydrology of Bishop Creek, California: An Isotopic Analysis

Treesearch

Michael L. Space; John W. Hess; Stanley D. Smith

1989-01-01

Five power generation plants along an eleven kilometer stretch divert Bishop Creek water for hydro-electric power. Stream diversion may be adversely affecting the riparian vegetation. Stable isotopic analysis is employed to determine surface water/ground-water interactions along the creek. surface water originates primarily from three headwater lakes. Discharge into...

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...

Real-time direct measurement of liquid (water) evaporation by simple disturbance inhibited interfometry technique

NASA Astrophysics Data System (ADS)

Kim, Yong Gi

2017-11-01

A real-time in-situ interferometry method was proposed to measure water (liquid) evaporation directly over the liquid surface inside the reservoir. The direct evaporation measurement relied on the counting the number of sinusoidal fringes. As the water inside reservoir evaporated, the depth of the water decreases a little thus the optical path length changes. Evaporation signals have been determined as a function of the focusing beam position of the signal beam over the liquid surface. In interferometry technique, the most limiting factors are surface disturbances and vibrations over the liquid surface. This limiting factor was simply inhibited by placing a long cylindrical aluminum tube around the signal beam of the interferometer over the liquid surface. A small diameter cylindrical Al tube diminished vibrations and wind induced surface ripples more effectively than that of the larger one. Water evaporation was successfully measured in real-time with a warm water and cold water even under windy condition with an electric fan. The experimental results demonstrated that the interferometry technique allows determining of liquid evaporation in real-time. Interferometric technique opens up a new possibility of methodology for liquid evaporation measurement even in several environmental disturbances, such as, vibration, surface disturbance, temperature change and windy environments.

Use of experimentally determined Henry's Law and salting-out constants for ethanol in seawater for determination of the saturation state of ethanol in coastal waters.

PubMed

Willey, Joan D; Powell, Jacqueline P; Avery, G Brooks; Kieber, Robert J; Mead, Ralph N

2017-09-01

The Henry's law constant for ethanol in seawater was experimentally determined to be 221 ± 4 M/atm at 22 °C compared with 247 ± 6 M/atm in pure water. The salting out coefficient for ethanol was 0.13 M -1 . In seawater ln(K H ) = -(12.8 ± 0.7) + (5310 ± 197)/T where K H is in M atm -1 and temperature is in K. This plus the salting out coefficient allow calculation of K H for any estuarine or sea water between 1 and 35 °C. High concentrations of dissolved organic carbon do not affect K H values in fresh or seawater. Nearshore surface waters were usually undersaturated with respect to gas phase ethanol except when air concentrations decreased, whereas surface seawater 40 km from shore was supersaturated. The percent saturation in surface waters is driven primarily by changes in air concentrations because these change quickly (hours) and more extensively than surface water. This study allows calculation of ethanol saturation states from air and surface water concentrations which is a necessary step to define the role of surface oceans in the global biogeochemical cycling of ethanol both now and in the future as use of ethanol biofuel continues to grow. Copyright © 2017 Elsevier Ltd. All rights reserved.

A novel orthogonal transmission-virtual grating method and its applications in measuring micro 3-D shape of deformed liquid surface

NASA Astrophysics Data System (ADS)

Liu, Zhanwei; Huang, Xianfu; Xie, Huimin

2013-02-01

Deformed liquid surface directly involves the surface tension, which can always be used to account for the kinematics of aquatic insects in gas-liquid interface and the light metal floating on the water surface. In this paper a novel method based upon deformed transmission-virtual grating is proposed for determination of deformed liquid surface. By addressing an orthogonal grating (1-5 line/mm) under the transparent water groove and then capturing images from upset of the deformed water surface, a displacement vector of full-field which directly associates the 3-D deformed liquid surface then can be evaluated by processing the recorded deformed fringe pattern in the two directions (x- and y-direction). Theories and equations for the method are thoroughly delivered. Validation test to measure the deformed water surface caused by a Chinese 1-cent coin has been conducted to demonstrate the ability of the developed method. The obtained results show that the method is robust in determination of micro 3-D surface of deformed liquid with a submicron scale resolution and with a wide range application scope.

The physics of water droplets on surfaces: exploring the effects of roughness and surface chemistry

NASA Astrophysics Data System (ADS)

Eid, K. F.; Panth, M.; Sommers, A. D.

2018-03-01

This paper explores the fluid property commonly called surface tension, its effect on droplet shape and contact angle, and the major influences of contact angle behaviour (i.e. surface roughness and surface chemistry). Images of water droplets placed on treated copper surfaces are used to measure the contact angles between the droplets and the surface. The surface wettability is manipulated either by growing a self-assembled monolayer on the surface to make it hydrophobic or by changing the surface roughness. The main activities in this experiment, then, are (1) preparing and studying surfaces with different surface wettability and roughness; (2) determining the shape and contact angles of water droplets on these surfaces; and (3) demonstrating the spontaneous motion of water droplets using surface tension gradients.

Interfacial Effects on the Band Edges of Functionalized Si Surfaces in Liquid Water

DOE PAGES

Pham, Tuan Anh; Lee, Donghwa; Schwegler, Eric; ...

2014-11-17

By combining ab initio molecular dynamics simulations and many-body perturbation theory calculations of electronic energy levels, we determined the band edge positions of functionalized Si(111) surfaces in the presence of liquid water, with respect to vacuum and to water redox potentials. We considered surface terminations commonly used for Si photoelectrodes in water splitting experiments. We found that, when exposed to water, the semiconductor band edges were shifted by approximately 0.5 eV in the case of hydrophobic surfaces, irrespective of the termination. The effect of the liquid on band edge positions of hydrophilic surfaces was much more significant and determined bymore » a complex combination of structural and electronic effects. These include structural rearrangements of the semiconductor surfaces in the presence of water, changes in the orientation of interfacial water molecules with respect to the bulk liquid, and charge transfer at the interfaces, between the solid and the liquid. Our results showed that the use of many-body perturbation theory is key to obtain results in agreement with experiments; they also showed that the use of simple computational schemes that neglect the detailed microscopic structure of the solid–liquid interface may lead to substantial errors in predicting the alignment between the solid band edges and water redox potentials.« less

Determination of total arsenic and arsenic species in drinking water, surface water, wastewater, and snow from Wielkopolska, Kujawy-Pomerania, and Lower Silesia provinces, Poland.

PubMed

Komorowicz, Izabela; Barałkiewicz, Danuta

2016-09-01

Arsenic is a ubiquitous element which may be found in surface water, groundwater, and drinking water. In higher concentrations, this element is considered genotoxic and carcinogenic; thus, its level must be strictly controlled. We investigated the concentration of total arsenic and arsenic species: As(III), As(V), MMA, DMA, and AsB in drinking water, surface water, wastewater, and snow collected from the provinces of Wielkopolska, Kujawy-Pomerania, and Lower Silesia (Poland). The total arsenic was analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and arsenic species were analyzed with use of high-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Obtained results revealed that maximum total arsenic concentration determined in drinking water samples was equal to 1.01 μg L(-1). The highest concentration of total arsenic in surface water, equal to 3778 μg L(-1) was determined in Trująca Stream situated in the area affected by geogenic arsenic contamination. Total arsenic concentration in wastewater samples was comparable to those determined in drinking water samples. However, significantly higher arsenic concentration, equal to 83.1 ± 5.9 μg L(-1), was found in a snow sample collected in Legnica. As(V) was present in all of the investigated samples, and in most of them, it was the sole species observed. However, in snow sample collected in Legnica, more than 97 % of the determined concentration, amounting to 81 ± 11 μg L(-1), was in the form of As(III), the most toxic arsenic species.

Assessment of volatile organic compounds in surface water at West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 1999

USGS Publications Warehouse

Olsen, Lisa D.; Spencer, Tracey A.

2000-01-01

The U.S. Geological Survey (USGS) collected 13 surface-water samples and 3 replicates from 5 sites in the West Branch Canal Creek area at Aberdeen Proving Ground from February through August 1999, as a part of an investigation of ground-water contamination and natural attenuation processes. The samples were analyzed for volatile organic compounds, including trichloroethylene, 1,1,2,2-tetrachloroethane, carbon tetrachloride, and chloroform, which are the four major contaminants that were detected in ground water in the Canal Creek area in earlier USGS studies. Field blanks were collected during the sampling period to assess sample bias. Field replicates were used to assess sample variability, which was expressed as relative percent difference. The mean variability of the surface-water replicate analyses was larger (35.4 percent) than the mean variability of ground-water replicate analyses (14.6 percent) determined for West Branch Canal Creek from 1995 through 1996. The higher variability in surface-water analyses is probably due to heterogeneities in the composition of the surface water rather than differences in sampling or analytical procedures. The most frequently detected volatile organic compound was 1,1,2,2- tetrachloroethane, which was detected in every sample and in two of the replicates. The surface-water contamination is likely the result of cross-media transfer of contaminants from the ground water and sediments along the West Branch Canal Creek. The full extent of surface-water contamination in West Branch Canal Creek and the locations of probable contaminant sources cannot be determined from this limited set of data. Tidal mixing, creek flow patterns, and potential effects of a drought that occurred during the sampling period also complicate the evaluation of surface-water contamination.

Thermophoretically driven water droplets on graphene and boron nitride surfaces

NASA Astrophysics Data System (ADS)

Rajegowda, Rakesh; Kannam, Sridhar Kumar; Hartkamp, Remco; Sathian, Sarith P.

2018-05-01

We investigate thermally driven water droplet transport on graphene and hexagonal boron nitride (h-BN) surfaces using molecular dynamics simulations. The two surfaces considered here have different wettabilities with a significant difference in the mode of droplet transport. The water droplet travels along a straighter path on the h-BN sheet than on graphene. The h-BN surface produced a higher driving force on the droplet than the graphene surface. The water droplet is found to move faster on h-BN surface compared to graphene surface. The instantaneous contact angle was monitored as a measure of droplet deformation during thermal transport. The characteristics of the droplet motion on both surfaces is determined through the moment scaling spectrum. The water droplet on h-BN surface showed the attributes of the super-diffusive process, whereas it was sub-diffusive on the graphene surface.

Determining the mean hydraulic gradient of ground water affected by tidal fluctuations

USGS Publications Warehouse

Serfes, Michael E.

1991-01-01

Tidal fluctuations in surface-water bodies produce progressive pressure waves in adjacent aquifers. As these pressure waves propagate inland, ground-water levels and hydraulic gradients continuously fluctuate, creating a situation where a single set of water-level measurements cannot be used to accurately characterize ground-water flow. For example, a time series of water levels measured in a confined aquifer in Atlantic City, New Jersey, showed that the hydraulic gradient ranged from .01 to .001 with a 22-degree change in direction during a tidal day of approximately 25 hours. At any point where ground water tidally fluctuates, the magnitude and direction of the hydraulic gradient fluctuates about the mean or regional hydraulic gradient. The net effect of these fluctuations on ground-water flow can be determined using the mean hydraulic gradient, which can be calculated by comparing mean ground- and surface-water elevations. Filtering methods traditionally used to determine daily mean sea level can be similarly applied to ground water to determine mean levels. Method (1) uses 71 consecutive hourly water-level observations to accurately determine the mean level. Method (2) approximates the mean level using only 25 consecutive hourly observations; however, there is a small error associated with this method.

Estimation of real-time N load in surface water using dynamic data driven application system

Treesearch

Y. Ouyang; S.M. Luo; L.H. Cui; Q. Wang; J.E. Zhang

2011-01-01

Agricultural, industrial, and urban activities are the major sources for eutrophication of surface water ecosystems. Currently, determination of nutrients in surface water is primarily accomplished by manually collecting samples for laboratory analysis, which requires at least 24 h. In other words, little to no effort has been devoted to monitoring real-time variations...

Kinetic model of water vapour adsorption by gluten-free starch

NASA Astrophysics Data System (ADS)

Ocieczek, Aneta; Kostek, Robert; Ruszkowska, Millena

2015-01-01

This study evaluated the kinetics of water vapour adsorption on the surface of starch molecules derived from wheat. The aim of the study was to determine an equation that would allow estimation of water content in tested material in any timepoint of the adsorption process aimed at settling a balance with the environment. An adsorption isotherm of water vapour on starch granules was drawn. The parameters of the Guggenheim, Anderson, and De Boer equation were determined by characterizing the tested product and adsorption process. The equation of kinetics of water vapour adsorption on the surface of starch was determined based on the Guggenheim, Anderson, and De Boer model describing the state of equilibrium and on the model of a first-order linear inert element describing the changes in water content over time.

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 ...

Effect of Surface-mantle Water Exchange Parameterizations on Exoplanet Ocean Depths

NASA Astrophysics Data System (ADS)

Komacek, Thaddeus D.; Abbot, Dorian S.

2016-11-01

Terrestrial exoplanets in the canonical habitable zone may have a variety of initial water fractions due to random volatile delivery by planetesimals. If the total planetary water complement is high, the entire surface may be covered in water, forming a “waterworld.” On a planet with active tectonics, competing mechanisms act to regulate the abundance of water on the surface by determining the partitioning of water between interior and surface. Here we explore how the incorporation of different mechanisms for the degassing and regassing of water changes the volatile evolution of a planet. For all of the models considered, volatile cycling reaches an approximate steady state after ∼ 2 {Gyr}. Using these steady states, we find that if volatile cycling is either solely dependent on temperature or seafloor pressure, exoplanets require a high abundance (≳ 0.3 % of total mass) of water to have fully inundated surfaces. However, if degassing is more dependent on seafloor pressure and regassing mainly dependent on mantle temperature, the degassing rate is relatively large at late times and a steady state between degassing and regassing is reached with a substantial surface water fraction. If this hybrid model is physical, super-Earths with a total water fraction similar to that of the Earth can become waterworlds. As a result, further understanding of the processes that drive volatile cycling on terrestrial planets is needed to determine the water fraction at which they are likely to become waterworlds.

Experimental und numerical investigations on cooling efficiency of Air-Mist nozzles on steel during continuous casting

NASA Astrophysics Data System (ADS)

Arth, G.; Taferner, M.; Bernhard, C.; Michelic, S.

2016-07-01

Cooling strategies in continuous casting of steel can vary from rapid cooling to slow cooling, mainly controlled by adjusting the amount of water sprayed onto the surface of the product. Inadequate adjustment however can lead to local surface undercooling or reheating, leading to surface and inner defects. This paper focuses on cooling efficiency of Air-Mist nozzles on casted steel and the experimental and numerical prediction of surface temperature distributions over the product width. The first part explains the determination of heat transfer coefficients (HTC) on laboratory scale, using a so called nozzle measuring stand (NMS). Based on measured water distributions and determined HTC's for air-mist nozzles using the NMS, surface temperatures are calculated by a transient 2D-model on a simple steel plate, explained in the second part of this paper. Simulations are carried out varying water impact density and spray water distribution, consequently influencing the local HTC distribution over the plate width. Furthermore, these results will be interpreted with regard to their consequence for surface and internal quality of the cast product. The results reveal the difficulty of correct adjustment of the amount of sprayed water, concurrent influencing water distribution and thus changing HTC distribution and surface temperature.

Characterization of the surface properties of wheat spikelet components

USDA-ARS?s Scientific Manuscript database

The physicochemical surface properties of wheat spikelet components were determined. The water and water:acetone (1:1, v/v) contact angle for the glumes and lemmas of two wheat cultivars were measured. The results demonstrate that the surface chemistry and ultrastructure of glume and lemma tissues...

Interaction between ground water and surface water in the northern Everglades and relation to water budget and mercury cycling; study methods and appendixes

USGS Publications Warehouse

Harvey, Judson W.; Krupa, S.L.; Gefvert, C.J.; Choi, Jungyill; Mooney, R.H.; Giddings, J.B.

2000-01-01

The data presented in this report are products of an investigation that quantified interactions between ground water and surface water at several study sites in the northern Everglades. Goals included identifying the major geologic controls and human alterations that affect interactions between ground water and surface water, and determining how those interactions affect mercury contamination. The primary study area was the 3,815-acre Everglades Nutrient Removal (ENR), a wetland constructed in the early 1990s as a prototype Stormwater Treatment Area (STA), to determine the effectiveness in removing excess nutrients from agricultural drainage. In order to ensure that results from ENR are broadly informative, work was also conducted in Water Conservation Area-2A (WCA-2A), a 105,000-acre basin surrounded by levees. In the past 50 years, WCA-2A has experienced extensive re- engineering of water flow, alterations in the pattern of water-level fluctuations and timing of fire frequency, as well as substantial ecological changes. The most visible ecological alteration is the change in dominance over the past 30 years from a sawgrass wetland to cattail wetland in the northeastern part of WCA-2A. The drastic change in vegetation in WCA-2A resulted at least in part from inputs of excess phosphorus from agricultural drainage. Substantial data collection programs were already in progress in both ENR and WCA- 2A when the present work began. The South Florida Water Management District (SFWMD) constructed the ENR project in 1994 to determine the effectiveness of constructed wetlands for water treatment. Measurements of surface water flow and water quality were made frequently in ENR between 1994 and 1998. Fewer ground water data were collected at ENR, and almost all of it was collected from shallow wells emplaced on perimeter levees. In contrast to the short-term nature of data collection in ENR, hydrologic and chemical data were collected over a much longer period in WCA-2A (since at least the mid- 1970s), but the number of sites and data- collection frequency is much less. Very little prior ground water data were available in WCA-2A. Given the availability of prior information, the present study emphasized the collection of ground water field data, particularly in the interior wetland areas of ENR and WCA- 2A. New wells were emplaced to permit the geologic, hydraulic, and chemical sampling that was needed to characterize interactions between surface water and ground water. In particular, lithology and hydraulic properties of the Surficial aquifer were determined, ground water flow paths and velocities were delineated, hydrologic fluxes between surface water and ground water were measured, and water budgets and surface- subsurface fluxes of mercury were determined. The purpose of this report is to compile under one cover all of the data collected in this investigation. In addition, the report contains a detailed description of the study methods and information about study sites, borehole drilling, well construction, seepage meter installation, and hydraulic and geochemical chemical sampling. Data interpretations are the subject of a companion report.

Constraining Water Vapor Abundance on Mars using a Coupled Heat-Water Transport Model and Seasonal Frost Observations

NASA Astrophysics Data System (ADS)

Bapst, J.; Byrne, S.

2016-12-01

The stability of water ice on Mars' surface is determined by its temperature and the density of water vapor at the bottom of the atmosphere. Multiple orbiting instruments have been used to study column-integrated water abundance in the martian atmosphere, resolving the global annual water cycle. However, poor knowledge of the vertical distribution of water makes constraining its abundance near the surface difficult. One must assume a mixing regime to produce surface vapor density estimates. More indirectly, one can use the appearance and disappearance of seasonal water frost, along with ice stability models, to estimate this value. Here, we use derived temperature and surface reflectance data from MGS TES to constrain a 1-D thermal diffusion model, which is coupled to an atmospheric water transport model. TES temperatures are used to constrain thermal properties of our modeled subsurface, while changes in TES albedo can be used to determine the timing of water frost. We tune the density of water vapor in the atmospheric model to match the observed seasonal water frost timing in the northern hemisphere, poleward of 45°N. Thus, we produce a new estimate for the water abundance in the lower atmosphere of Mars and how it varies seasonally and geographically. The timing of water frost can be ambiguous in TES data, especially at lower latitudes where the albedo contrast between frosted and unfrosted surfaces is lower (presumably due to lesser areal coverage of water frost). The uncertainty in frost timing with our approach is <20° LS ( 40 sols), and will be used to define upper and lower bounds in our estimate of vapor density. The implications of our derived vapor densities on the stability of surface and subsurface water ice will be discussed.

Thermophoretically driven water droplets on graphene and boron nitride surfaces.

PubMed

Rajegowda, Rakesh; Kannam, Sridhar Kumar; Hartkamp, Remco; Sathian, Sarith P

2018-05-25

We investigate thermally driven water droplet transport on graphene and hexagonal boron nitride (h-BN) surfaces using molecular dynamics simulations. The two surfaces considered here have different wettabilities with a significant difference in the mode of droplet transport. The water droplet travels along a straighter path on the h-BN sheet than on graphene. The h-BN surface produced a higher driving force on the droplet than the graphene surface. The water droplet is found to move faster on h-BN surface compared to graphene surface. The instantaneous contact angle was monitored as a measure of droplet deformation during thermal transport. The characteristics of the droplet motion on both surfaces is determined through the moment scaling spectrum. The water droplet on h-BN surface showed the attributes of the super-diffusive process, whereas it was sub-diffusive on the graphene surface.

Determining the Most Efficient and Cost-Effective Pumping Schemes for Treating Contaminated Aquifers

DTIC Science & Technology

1993-08-01

of both surface water and groundwater, while some base-operated water-supply systems receive water from off-site municipal sources. To the extent...well field for municipal water supply, or a surface-water supply reservoir that is recharged by groundwater flow. As with plume stabilization, flow...waters is not addressed. In addition, the public rarely condones this method if the contaminated well supplies municipal or private drinking water. Natural

The occurrence and distribution of a group of organic micropollutants in Mexico City's water sources.

PubMed

Félix-Cañedo, Thania E; Durán-Álvarez, Juan C; Jiménez-Cisneros, Blanca

2013-06-01

The occurrence and distribution of a group of 17 organic micropollutants in surface and groundwater sources from Mexico City was determined. Water samples were taken from 7 wells, 4 dams and 15 tanks where surface and groundwater are mixed and stored before distribution. Results evidenced the occurrence of seven of the target compounds in groundwater: salicylic acid, diclofenac, di-2-ethylhexylphthalate (DEHP), butylbenzylphthalate (BBP), triclosan, bisphenol A (BPA) and 4-nonylphenol (4-NP). In surface water, 11 target pollutants were detected: same found in groundwater as well as naproxen, ibuprofen, ketoprofen and gemfibrozil. In groundwater, concentration ranges of salicylic acid, 4-NP and DEHP, the most frequently found compounds, were 1-464, 1-47 and 19-232 ng/L, respectively; while in surface water, these ranges were 29-309, 89-655 and 75-2,282 ng/L, respectively. Eleven target compounds were detected in mixed water. Concentrations in mixed water were higher than those determined in groundwater but lower than the detected in surface water. Different to that found in ground and surface water, the pesticide 2,4-D was found in mixed water, indicating that some pollutants can reach areas where they are not originally present in the local water sources. Concentration of the organic micropollutants found in this study showed similar to lower to those reported in water sources from developed countries. This study provides information that enriches the state of the art on the occurrence of organic micropollutants in water sources worldwide, notably in megacities of developing countries. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of submicrogram-per-liter concentrations of caffeine in surface water and groundwater samples by solid-phase extraction and liquid chromatography

USGS Publications Warehouse

Burkhardt, M.R.; Soliven, P.P.; Werner, S.L.; Vaught, D.G.

1999-01-01

A method for determining submicrogram-per-liter concentrations of caffeine in surface water and groundwater samples has been developed. Caffeine is extracted from a 1 L water sample with a 0.5 g graphitized carbon-based solid-phase cartridge, eluted with methylene chloride-methanol (80 + 20, v/v), and analyzed by liquid chromatography with photodiode-array detection. The single-operator method detection limit for organic-free water samples was 0.02 ??g/L. Mean recoveries and relative standard deviations were 93 ?? 13% for organicfree water samples fortified at 0.04 ??g/L and 84 ?? 4% for laboratory reagent spikes fortified at 0.5 ??g/L. Environmental concentrations of caffeine ranged from 0.003 to 1.44 ??g/L in surface water samples and from 0.01 to 0.08 ??g/L in groundwater samples.

Estimation of subsurface thermal structure using sea surface height and sea surface temperature

NASA Technical Reports Server (NTRS)

Kang, Yong Q. (Inventor); Jo, Young-Heon (Inventor); Yan, Xiao-Hai (Inventor)

2012-01-01

A method of determining a subsurface temperature in a body of water is disclosed. The method includes obtaining surface temperature anomaly data and surface height anomaly data of the body of water for a region of interest, and also obtaining subsurface temperature anomaly data for the region of interest at a plurality of depths. The method further includes regressing the obtained surface temperature anomaly data and surface height anomaly data for the region of interest with the obtained subsurface temperature anomaly data for the plurality of depths to generate regression coefficients, estimating a subsurface temperature at one or more other depths for the region of interest based on the generated regression coefficients and outputting the estimated subsurface temperature at the one or more other depths. Using the estimated subsurface temperature, signal propagation times and trajectories of marine life in the body of water are determined.

[ASSESSMENT OF POTENTIAL RISK FOR CONTAMINATION OF SURFACE WATER RESERVOIRS BY PATHOGENS OF HUMAN PARASITIC DISEASES].

PubMed

Khromenkova, E P; Dimidova, L L; Dumbadze, O S; Aidinov, G T; Shendo, G L; Agirov, A Kh; Batchaev, Kh Kh

2015-01-01

Sanitary and parasitological studies of the waste effluents and surface reservoir waters were conducted in the south of Russia. The efficiency of purification of waste effluents from the pathogens of parasitic diseases was investigated in the region's sewage-purification facilities. The water of the surface water reservoirs was found to contain helminthic eggs and larvae and intestinal protozoan cysts because of the poor purification and disinfection of service fecal sewage waters. The poor purification and disinvasion of waste effluents in the region determine the potential risk of contamination of the surface water reservoirs and infection of the population with the pathogens of human parasitic diseases.

High Pressure Cosmochemistry of Major Planetary Interiors: Laboratory Studies of the Water-rich Region of the System Ammonia-water

NASA Technical Reports Server (NTRS)

Nicol, M.; Johnson, M.; Koumvakalis, A. S.

1985-01-01

The behavior of gas-ice mixtures in major planets at very high pressures was studied. Some relevant pressure-temperature-composition (P-T-X) regions of the hydrogen (H2)-helium (He)-water (H2O-ammonia (NH3)-methane (CH4) phase diagram were determined. The studies, and theoretical model, of the relevant phases, are needed to interpret the compositions of ice-gas systems at conditions of planetary interest. The compositions and structures of a multiphase, multicomponent system at very high pressures care characterized, and the goal is to characterize this system over a wide range of low and high temperatures. The NH3-H2O compositions that are relevant to planetary problems yet are easy to prepare were applied. The P-T surface of water was examined and the corresponding surface for NH3 was determined. The T-X diagram of ammonia-water at atmospheric pressure was studied and two water-rich phases were found, NH3-2H2O (ammonia dihydrate), which melts incongruently, and NH3.H2O (ammonia monohydrate), which is nonstoichiometric and melts at a higher temperature than the dihydrate. It is suggested that a P-T surface at approximately the monohydrate composition and the P-X surface at room temperature is determined.

Questa baseline and pre-mining ground-water quality investigation. 5. Well installation, water-level data, and surface- and ground-water geochemistry in the Straight Creek drainage basin, Red River Valley, New Mexico, 2001-03

USGS Publications Warehouse

Naus, Cheryl A.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Donohoe, Lisa C.; Hunt, Andrew G.; Paillet, Frederick L.; Morin, Roger H.; Verplanck, Philip L.

2005-01-01

The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, northern New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site, proximal analog. The Straight Creek drainage basin, chosen for this purpose, consists of the same quartz-sericite-pyrite altered andesitic and rhyolitic volcanic rock of Tertiary age as the mine site. The weathered and rugged volcanic bedrock surface is overlain by heterogeneous debris-flow deposits that interfinger with alluvial deposits near the confluence of Straight Creek and the Red River. Pyritized rock in the upper part of the drainage basin is the source of acid rock drainage (pH 2.8-3.3) that infiltrates debris-flow deposits containing acidic ground water (pH 3.0-4.0) and bedrock containing water of circumneutral pH values (5.6-7.7). Eleven observation wells were installed in the Straight Creek drainage basin. The wells were completed in debris-flow deposits, bedrock, and interfingering debris-flow and Red River alluvial deposits. Chemical analyses of ground water from these wells, combined with chemical analyses of surface water, water-level data, and lithologic and geophysical logs, provided information used to develop an understanding of the processes contributing to the chemistry of ground water in the Straight Creek drainage basin. Surface- and ground-water samples were routinely collected for determination of total major cations and selected trace metals; dissolved major cations, selected trace metals, and rare-earth elements; anions and alkalinity; and dissolved-iron species. Rare-earth elements were determined on selected samples only. Samples were collected for determination of dissolved organic carbon, mercury, sulfur isotopic composition (34S and 18O of sulfate), and water isotopic composition (2H and 18O) during selected samplings. One set of ground-water samples was collected for helium-3/tritium and chlorofluorocarbon (CFC) age dating. Several lines of evidence indicate that surface water is the primary input to the Straight Creek ground-water system. Straight Creek streamflow and water levels in wells closest to the apex of the Straight Creek debris fan and closest to Straight Creek itself appear to respond to the same seasonal inputs. Oxygen and hydrogen isotopic compositions in Straight Creek surface water and ground water are similar, and concentrations of most dissolved constituents in most Straight Creek surface-water and shallow (debris-flow and alluvial) aquifer ground-water samples correlate strongly with sulfate (concentrations decrease linearly with sulfate in a downgradient direction). After infiltration of surface water, dilution along the flow path is the dominant mechanism controlling ground-water chemistry. However, concentrations of some constituents can be higher in ground water than can be accounted for by concentrations in Straight Creek surface water, and additional sources of these constituents must therefore be inferred. Constituents for which concentrations in ground water can be high relative to surface water include calcium, magnesium, strontium, silica, sodium, and potassium in ground water from debris-flow and alluvial aquifers and manganese, calcium, magnesium, strontium, sodium, and potassium in ground water from the bedrock aquifer. All ground water is a calcium sulfate type, often at or near gypsum saturation because of abundant gypsum in the aquifer material developed from co-existing calcite and pyrite mineralization. Calcite dissolution, the major buffering mechanism for bedrock aquifer ground water, also contributes to relatively higher calcium concentrations in some ground water. The main source of the second most abundant cation, magnesium, is probably dissolution of magnesium-rich carbonates or silicates. Strontium may also be

Development of a Model to Correct Multi-View Angle above Water Measurements for the Analysis of the Bidirectional Reflectance of Coral and Other Reef Substrates

NASA Astrophysics Data System (ADS)

Miller, I.; Forster, B. C.; Laffan, S. W.

2012-07-01

Spectral reflectance characteristics of substrates in a coral reef environment are often measured in the field by viewing a substrate at nadir. However, viewing a substrate from multiple angles would likely result in different spectral characteristics for most coral reef substrates and provide valuable information on structural properties. To understand the relationship between the morphology of a substrate and its spectral response it is necessary to correct the observed above-water radiance for the effects of atmosphere and water attenuation, at a number of view and azimuth angles. In this way the actual surface reflectance can be determined. This research examines the air-water surface interaction for two hypothetical atmospheric conditions (clear Rayleigh scattering and totally cloudcovered) and the global irradiance reaching the benthic surface. It accounts for both water scattering and absorption, with simplifications for shallow water conditions, as well as the additive effect of background reflectance being reflected at the water-air surface at angles greater than the critical refraction angle (~48°). A model was developed to correct measured above-water radiance along the refracted view angle for its decrease due to path attenuation and the "n squared law of radiance" and the additive surface reflectance. This allows bidirectional benthic surface reflectance and nadir-normalised reflectance to be determined. These theoretical models were adapted to incorporate above-water measures relative to a standard, diffuse, white reference panel. The derived spectral signatures of a number of coral and non-coral benthic surfaces compared well with other published results, and the signatures and nadir normalised reflectance of the corals and other benthic surface classes indicate good class separation.

A novel theoretical probe of the SrTiO3 surface under water-splitting conditions

NASA Astrophysics Data System (ADS)

Letchworth-Weaver, Kendra; Gunceler, Deniz; Arias, Tomás; Plaza, Manuel; Huang, Xin; Brock, Joel; Rodriguez-López, Joaquin; Abruña, Hector

2014-03-01

Understanding the reaction mechanisms required to generate hydrogen fuel by photoelectrolysis of water is essential to energy conversion research. These reaction pathways are strongly influenced by the geometry and electronic structure of the electrode surface under water-splitting conditions. Electrochemical microscopy has demonstrated that biasing a SrTiO3 (001) surface can lead to an increase in water-splitting activity. In operando X-ray reflectivity measurements at the Cornell High Energy Synchrotron Source (CHESS) correlate this increase in activity to a significant reorganization in the surface structure but are unable to determine the exact nature of this change. Joint Density-Functional Theory (JDFT), a rigorous yet computationally efficient alternative to molecular dynamics, provides a quantum-mechanical description of an electrode surface in contact with an aqueous environment, and a microscopically detailed description of the interfacial liquid structure. Our JDFT calculations determine the structure of the activated SrTiO3 surface and explore why it is correlated with higher activity for water splitting. With no empirical parameters whatsoever, we predict the X-ray crystal truncation rods for SrTiO3, finding excellent agreement with experiment. Funded by the Energy Materials Center at Cornell (EMC2).

Effects of land disposal of municipal sewage sludge on fate of nitrates in soil, streambed sediment, and water quality

USGS Publications Warehouse

Tindall, James A.; Lull, Kenneth J.; Gaggiani, Neville G.

1994-01-01

This study was undertaken to determine the effects of sewage-sludge disposal at the Lowry sewage-sludge-disposal area, near Denver, Colorado, on ground- and surface-water quality, to determine the fate of nitrates from sludge leachate, and to determine the source areas of leachate and the potential for additional leaching from the disposal area.Sewage-sludge disposal began in 1969. Two methods were used to apply the sludge: burial and plowing. Also, the sludge was applied both in liquid and cake forms. Data in this report represent the chemical composition of soil and streambed sediment from seven soil- and four streambed-sampling sites in 1986, chemical and bacterial composition of ground water from 28 wells from 1981 to 1987, and surface-water runoff from seven water-sampling sites from 1984 to 1987. Ground water samples were obtained from alluvial and bedrock aquifers. Samples of soil, streambed sediment, ground water and surface water were obtained for onsite measurement and chemical analysis. Measurements included determination of nitrogen compounds and major cations and anions, fecal-coliform and -streptococcus bacteria, specific conductance, and pH.Thirteen wells in the alluvial aquifer in Region 3 of the study area contain water that was probably affected by sewage-sludge leachate. The plots of concentration of nitrate with time show seasonal trends and trends caused by precipitation. In addition to yearly fluctuation, there were noticeable increases in ground-water concentrations of nitrate that coincided with increased precipitation. After 3 years of annual ground-water-quality monitoring and 4 years of a quarterly sampling program, it has been determined that leachate from the sewage-sludge-disposal area caused increased nitrite plus nitrate (as nitrogen) concentration in the alluvial ground water at the site. Soil analyses from the disposal area indicate that organic nitrogen was the dominant form of nitrogen in the soil.As a result of investigations at the research site, it has been determined that a potentially large source of contamination exists in the soils of the study area owing to increased concentrations of nitrogen, sodium, calcium, magnesium, sulfate, bicarbonate, and chloride because of sewage disposal. Continued monitoring of surface and ground water for nitrogen and the other ions previously mentioned is required to assess long-term effects of municipal sludge disposal on water quality.

Effects of land disposal of municipal sewage sludge on fate of nitrates in soil, streambed sediment, and water quality

NASA Astrophysics Data System (ADS)

Tindall, James A.; Lull, Kenneth J.; Gaggiani, Neville G.

1994-12-01

This study was undertaken to determine the effects of sewage-sludge disposal at the Lowry sewage-sludge-disposal area, near Denver, Colorado, on ground- and surface-water quality, to determine the fate of nitrates from sludge leachate, and to determine the source areas of leachate and the potential for additional leaching from the disposal area. Sewage-sludge disposal began in 1969. Two methods were used to apply the sludge: burial and plowing. Also, the sludge was applied both in liquid and cake forms. Data in this report represent the chemical composition of soil and streambed sediment from seven soil- and four streambed-sampling sites in 1986, chemical and bacterial composition of ground water from 28 wells from 1981 to 1987, and surface-water runoff from seven water-sampling sites from 1984 to 1987. Ground water samples were obtained from alluvial and bedrock aquifers. Samples of soil, streambed sediment, ground water and surface water were obtained for onsite measurement and chemical analysis. Measurements included determination of nitrogen compounds and major cations and anions, fecal-coliform and -streptococcus bacteria, specific conductance, and pH. Thirteen wells in the alluvial aquifer in Region 3 of the study area contain water that was probably affected by sewage-sludge leachate. The plots of concentration of nitrate with time show seasonal trends and trends caused by precipitation. In addition to yearly fluctuation, there were noticeable increases in ground-water concentrations of nitrate that coincided with increased precipitation. After 3 years of annual ground-water-quality monitoring and 4 years of a quarterly sampling program, it has been determined that leachate from the sewage-sludge-disposal area caused increased nitrite plus nitrate (as nitrogen) concentration in the alluvial ground water at the site. Soil analyses from the disposal area indicate that organic nitrogen was the dominant form of nitrogen in the soil. As a result of investigations at the research site, it has been determined that a potentially large source of contamination exists in the soils of the study area owing to increased concentrations of nitrogen, sodium, calcium, magnesium, sulfate, bicarbonate, and chloride because of sewage disposal. Continued monitoring of surface and ground water for nitrogen and the other ions previously mentioned is required to assess long-term effects of municipal sludge disposal on water quality.

Determination of the Wave Parameters from the Statistical Characteristics of the Image of a Linear Test Object

NASA Astrophysics Data System (ADS)

Weber, V. L.

2018-03-01

We statistically analyze the images of the objects of the "light-line" and "half-plane" types which are observed through a randomly irregular air-water interface. The expressions for the correlation function of fluctuations of the image of an object given in the form of a luminous half-plane are found. The possibility of determining the spatial and temporal correlation functions of the slopes of a rough water surface from these relationships is shown. The problem of the probability of intersection of a small arbitrarily oriented line segment by the contour image of a luminous straight line is solved. Using the results of solving this problem, we show the possibility of determining the values of the curvature variances of a rough water surface. A practical method for obtaining an image of a rectilinear luminous object in the light rays reflected from the rough surface is proposed. It is theoretically shown that such an object can be synthesized by temporal accumulation of the image of a point source of light rapidly moving in the horizontal plane with respect to the water surface.

Imaging spectrometer measurement of water vapor in the 400 to 2500 nm spectral region

NASA Technical Reports Server (NTRS)

Green, Robert O.; Roberts, Dar A.; Conel, James E.; Dozier, Jeff

1995-01-01

The Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) measures the total upwelling spectral radiance from 400 to 2500 nm sampled at 10 nm intervals. The instrument acquires spectral data at an altitude of 20 km above sea level, as images of 11 by up to 100 km at 17x17 meter spatial sampling. We have developed a nonlinear spectral fitting algorithm coupled with a radiative transfer code to derive the total path water vapor from the spectrum, measured for each spatial element in an AVIRIS image. The algorithm compensates for variation in the surface spectral reflectance and atmospheric aerosols. It uses water vapor absorption bands centered at 940 nm, 1040 nm, and 1380 nm. We analyze data sets with water vapor abundances ranging from 1 to 40 perceptible millimeters. In one data set, the total path water vapor varies from 7 to 21 mm over a distance of less than 10 km. We have analyzed a time series of five images acquired at 12 minute intervals; these show spatially heterogeneous changes of advocated water vapor of 25 percent over 1 hour. The algorithm determines water vapor for images with a range of ground covers, including bare rock and soil, sparse to dense vegetation, snow and ice, open water, and clouds. The precision of the water vapor determination approaches one percent. However, the precision is sensitive to the absolute abundance and the absorption strength of the atmospheric water vapor band analyzed. We have evaluated the accuracy of the algorithm by comparing several surface-based determinations of water vapor at the time of the AVIRIS data acquisition. The agreement between the AVIRIS measured water vapor and the in situ surface radiometer and surface interferometer measured water vapor is 5 to 10 percent.

Investigation of surface water behavior during glaze ice accretion

NASA Technical Reports Server (NTRS)

Hansman, R. John, Jr.; Turnock, Stephen R.

1990-01-01

A series of experimental investigations that focused on isolating the primary factors that control the behavior of unfrozen surface water during glaze ice accretion were conducted. Detailed microvideo observations were made of glaze ice accretions on 2.54 cm diam cylinders in a closed-loop refrigerated wind tunnel. Distinct zones of surface water behavior were observed; a smooth wet zone in the stagnation region with a uniform water film, a rough zone where surface tension effects caused coalescence of surface water into stationary beads, and a zone where surface water ran back as rivulets. The location of the transition from the smooth to the rough zone was found to migrate towards the stagnation point with time. Comparative tests were conducted to study the effect of the substrate thermal and roughness properties on ice accretion. The importance of surface water behavior was evaluated by the addition of a surface tension reducing agent to the icing tunnel water supply, which significantly altered the accreted glaze ice shape. Measurements were made to determine the contact angle behavior of water droplets on ice. A simple multizone modification to current glaze ice accretion models was proposed to include the observed surface roughness behavior.

Figure 12(a) Effects of Inclining Water. Figure 12(b) Sand. NASA document NASA-TN-D-56 An investigation to determine conditions under which downwash from VTOL aircraft will start surface erosion from various types of terrain

NASA Image and Video Library

1959-05-04

Figure 12(a) Effects of Inclining Water. Figure 12(b) Sand. NASA-TN-D-56 An investigation to determine conditions under which downwash from VTOL aircraft will start surface erosion from various types of terrain.

Groundwater-surface water interactions and their effects on ecosystem metabolism in a coastal wetland: example from the Florida Everglades

NASA Astrophysics Data System (ADS)

Price, R. M.; Zapata, X.; Koch, G. R.

2013-05-01

Groundwater typically has higher concentrations of salts and nutrients as compared to surface waters in coastal wetlands affected by saltwater intrusion. Discharge of the nutrient-laden brackish groundwater is expected to influence ecosystem function in the overlying surface water. In the coastal Everglades, elevated concentrations of phosphorus have been observed in the underlying groundwater due to water-rock interactions occurring as seawater intrudes into the coastal carbonate aquifer. The objective of this research was to determine the timing and amount of brackish groundwater discharge to the coastal wetlands of the Everglades and to evaluate the effects of the groundwater discharge on the surface water chemistry and ecosystem metabolism. The timing of groundwater discharge was determined by four techniques including a water balance, hydraulic gradient, temperature, and geochemical tracers. Groundwater discharge rates were quantified from well data using Darcy's Law. Ecosystem metabolism was estimated as daily rates of gross primary production (GPP), ecosystem respiration (R) and net ecosystem production (NEP) from free-water, diel changes in dissolved oxygen. Over 2 years, all four groundwater discharge techniques converged as to the timing of groundwater discharge which was greatest between May and July. Surface water chemistry was fresh from September through February, but became brackish to hypersaline between March and July, concurrent with the times of highest brackish groundwater discharge. Phosphorus concentrations as well as GPP and R were observed to spike in the surface water during the times of greatest groundwater discharge. The results of this research support the conclusions that brackish groundwater discharge effects surface water chemistry and ecosystem function in the coastal Everglades.

Surface and ground water quality in a restored urban stream affected by road salts

EPA Science Inventory

In 2001 research began in Minebank Run, MD to examine the impact of restoration on water quality. Our research area was to determine if road salts in the surface and ground waters are detrimental to the stream channel restoration. The upstream reach (UP), above the Baltimore I-...

A deformable surface model for real-time water drop animation.

PubMed

Zhang, Yizhong; Wang, Huamin; Wang, Shuai; Tong, Yiying; Zhou, Kun

2012-08-01

A water drop behaves differently from a large water body because of its strong viscosity and surface tension under the small scale. Surface tension causes the motion of a water drop to be largely determined by its boundary surface. Meanwhile, viscosity makes the interior of a water drop less relevant to its motion, as the smooth velocity field can be well approximated by an interpolation of the velocity on the boundary. Consequently, we propose a fast deformable surface model to realistically animate water drops and their flowing behaviors on solid surfaces. Our system efficiently simulates water drop motions in a Lagrangian fashion, by reducing 3D fluid dynamics over the whole liquid volume to a deformable surface model. In each time step, the model uses an implicit mean curvature flow operator to produce surface tension effects, a contact angle operator to change droplet shapes on solid surfaces, and a set of mesh connectivity updates to handle topological changes and improve mesh quality over time. Our numerical experiments demonstrate a variety of physically plausible water drop phenomena at a real-time rate, including capillary waves when water drops collide, pinch-off of water jets, and droplets flowing over solid materials. The whole system performs orders-of-magnitude faster than existing simulation approaches that generate comparable water drop effects.

Role of gravity in the formation of bacterial colonies with a hydrophobic surface layer

NASA Astrophysics Data System (ADS)

Puzyr, A. P.; Tirranen, L. K.; Krylova, T. Y.; Borodina, E. V.

A simple technique for determining hydrophobic-hydrophilic properties of bacterial colonies surface, which involves putting a drop of liquid with known properties (e.g. water, oil) on their surface, has been described. This technique allows quick estimate of wettability of bacterial colony surface, i.e. its hydrophobic-hydrophilic properties. The behaviour of water drops on colonies of bacteria Bacillus five strains (of different types) has been studied. It was revealed that 1) orientation in the Earth gravity field during bacterial growth can define the form of colonies with hydrophobic surface; 2) the form and size of the colony are dependent on the extention ability, most probably, of the hydrophobic layer; 3) the Earth gravity field (gravity) serves as a 'pump' providing and keeping water within the colony. We suppose that at growing colonies on agar media the inflow of water-soluble nutrient materials takes place both due to diffusion processes and directed water current produced by the gravity. The revealed effect probably should be taken into consideration while constructing the models of colonies growing on dense nutrient media. The easily determined hydrophobic properties of colonies surface can become a systematic feature after collecting more extensive data on the surface hydrophobic-hydrophilic properties of microorganism colonies of other types and species.

Signal Processing for Determining Water Height in Steam Pipes with Dynamic Surface Conditions

NASA Technical Reports Server (NTRS)

Lih, Shyh-Shiuh; Lee, Hyeong Jae; Bar-Cohen, Yoseph

2015-01-01

An enhanced signal processing method based on the filtered Hilbert envelope of the auto-correlation function of the wave signal has been developed to monitor the height of condensed water through the steel wall of steam pipes with dynamic surface conditions. The developed signal processing algorithm can also be used to estimate the thickness of the pipe to determine the cut-off frequency for the low pass filter frequency of the Hilbert Envelope. Testing and analysis results by using the developed technique for dynamic surface conditions are presented. A multiple array of transducers setup and methodology are proposed for both the pulse-echo and pitch-catch signals to monitor the fluctuation of the water height due to disturbance, water flow, and other anomaly conditions.

The Research of Correlation of Water Surface Spectral and Sediment Parameters

NASA Astrophysics Data System (ADS)

Li, J.; Gong, G.; Fang, W.; Sun, W.

2018-04-01

In the method of survey underwater topography using remote sensing, and the water surface spectral reflectance R, which remote sensing inversion results were closely related to affects by the water and underwater sediment and other aspects, especially in shallow nearshore coastal waters, different sediment types significantly affected the reflectance changes. Therefore, it was of great significance of improving retrieval accuracy to explore the relation of sediment and water surface spectral reflectance. In this study, in order to explore relationship, we used intertidal sediment sand samples in Sheyang estuary, and in the laboratory measured and calculated the chroma indicators, and the water surface spectral reflectance. We found that water surface spectral reflectance had a high correlation with the chroma indicators; research result stated that the color of the sediment had an very important impact on the water surface spectral, especially in Red-Green chroma a*. Also, the research determined the sensitive spectrum bands of the Red-Green chroma a*, which were 636-617 nm, 716-747 nm and 770-792 nm.

Characteristics of hierarchical micro/nano surface structure formation generated by picosecond laser processing in water and air

NASA Astrophysics Data System (ADS)

Rajab, Fatema H.; Whitehead, David; Liu, Zhu; Li, Lin

2017-12-01

Laser surface texturing or micro/nano surface structuring in the air has been extensively studied. However, until now, there are very few studies on the characteristics of laser-textured surfaces in water, and there was no reported work on picosecond laser surface micro/nano-structuring in water. In this work, the surface properties of picosecond laser surface texturing in water and air were analysed and compared. 316L stainless steel substrates were textured using a picosecond laser. The surface morphology and the chemical composition were characterised using Philips XL30 FEG-SEM, EDX and confocal laser microscopy. The wettability of the textured surfaces was determined using a contact angle analyser FTA 188. Results showed that a variety of hierarchical micro/nano surface patterns could be controlled by a suitable adjustment of laser parameters. Not only surface morphology but also remarkable differences in wettability, optical reflectivity and surface oxygen content were observed for different types of surface textures produced by laser surface texture in water and air. The possible mechanisms of the changes in the behaviour of laser-textured surfaces are discussed.

Structure and stability of pyrophyllite edge surfaces: Effect of temperature and water chemical potential

NASA Astrophysics Data System (ADS)

Kwon, Kideok D.; Newton, Aric G.

2016-10-01

The surfaces of clay minerals, which are abundant in atmospheric mineral dust, serve as an important medium to catalyze ice nucleation. The lateral edge surface of 2:1 clay minerals is postulated to be a potential site for ice nucleation. However, experimental investigations of the edge surface structure itself have been limited compared to the basal planes of clay minerals. Density functional theory (DFT) computational studies have provided insights into the pyrophyllite edge surface. Pyrophyllite is an ideal surrogate mineral for the edge surfaces of 2:1 clay minerals as it possesses no or little structural charge. Of the two most-common hydrated edge surfaces, the AC edge, (1 1 0) surface in the monoclinic polytype notation, is predicted to be more stable than the B edge, (0 1 0) surface. These stabilities, however, were determined based on the total energies calculated at 0 K and did not consider environmental effects such as temperature and humidity. In this study, atomistic thermodynamics based on periodic DFT electronic calculations was applied to examine the effects of environmental variables on the structure and thermodynamic stability of the common edge surfaces in equilibrium with bulk pyrophyllite and water vapor. We demonstrate that the temperature-dependent vibrational energy of sorbed water molecules at the edge surface is a significant component of the surface free energy and cannot be neglected when determining the surface stability of pyrophyllite. The surface free energies were calculated as a function of temperature from 240 to 600 K and water chemical potential corresponding to conditions from ultrahigh vacuum to the saturation vapor pressure of water. We show that at lower water chemical potentials (dry conditions), the AC and B edge surfaces possessed similar stabilities; at higher chemical potentials (humid conditions) the AC edge surface was more stable than the B edge surface. At high temperatures, both surfaces showed similar stabilities regardless of the water chemical potential. The equilibrium morphology of pyrophyllite crystals is also expected to be dependent on these two environmental variables. Surface defects may impact the surface reactivity. We discuss the thermodynamic stability of a possible Si cation vacancy defect which provides additional hydroxyl group on the surface.

SPRINGFIELD SURFACE WATER ACTION MONITORING PARTNERSHIP(SSWAMP)

EPA Science Inventory

The objectives of this project are as follows: 1) To determine the baseline chemical and biological characteristics of the water bodies and to determine the baseline levels of nutrients, metals and organic contaminants in the sediments. To determine the current level of mercur...

Determination of cloud liquid water content using the SSM/I

NASA Technical Reports Server (NTRS)

Alishouse, John C.; Snider, Jack B.; Westwater, Ed R.; Swift, Calvin T.; Ruf, Christopher S.

1990-01-01

As part of a calibration/validation effort for the special sensor microwave/imager (SSM/I), coincident observations of SSM/I brightness temperatures and surface-based observations of cloud liquid water were obtained. These observations were used to validate initial algorithms and to derive an improved algorithm. The initial algorithms were divided into latitudinal-, seasonal-, and surface-type zones. It was found that these initial algorithms, which were of the D-matrix type, did not yield sufficiently accurate results. The surface-based measurements of channels were investigated; however, the 85V channel was excluded because of excessive noise. It was found that there is no significant correlation between the SSM/I brightness temperatures and the surface-based cloud liquid water determination when the background surface is land or snow. A high correlation was found between brightness temperatures and ground-based measurements over the ocean.

The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces

PubMed Central

Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

2016-01-01

The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions–dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing. PMID:27063149

Chemical effect on ozone deposition over seawater

EPA Science Inventory

Surface layer resistance plays an important role in determining ozone deposition velocity over seawater. Recent studies suggest that surface layer resistance over sea-water is influenced by wind-speed and chemical interaction at the air-water interface. Here, we investigate the e...

Assessment of the Unintentional Reuse of Municipal Wastewater

NASA Astrophysics Data System (ADS)

Okasaki, S.; Fono, L.; Sedlak, D. L.; Dracup, J. A.

2002-12-01

Many surface waters that receive wastewater effluent also serve as source waters for drinking water treatment plants. Recent research has shown that a number of previously undiscovered wastewater-derived contaminants are present in these surface waters, including pharmaceuticals and human hormones, several of which are suspected carcinogens or endocrine disrupters and are, as of yet, unregulated through drinking water standards. This research has been designed to determine the extent of contamination of specific wastewater-derived contaminants in surface water bodies that both receive wastewater effluent and serve as a source of drinking water to a sizeable population. We are testing the hypothesis that surface water supplies during low flow are potentially of worse quality than carefully monitored reclaimed water. The first phase of our research involves: (1) the selection of sites for study; (2) a hydrologic analysis of the selected sites to determine average flow of the source water during median- and low-flow conditions; and (3) the development and testing of chemical analyses, including both conservative and reactive tracers that have been studied in microcosms and wetlands for attenuation rates. The second phase involves the development and use of the hydrologic model QUAL2E to simulate each of the selected watersheds in order to estimate potential stream water quality impairments at the drinking water intake at each site. The results of the model are verified with field sampling at designated locations at each site. We expect to identify several critical river basins where surface water at the drinking water intake contains sufficient wastewater-derived contaminants to warrant concern. If wastewater-derived contaminants are detected, we will estimate the average annual exposure of consumers of this water. We will compare these expected and actual concentrations with typical constituent concentrations found in wastewater that has undergone advanced treatment for reclamation. We may demonstrate that the surface water supplies during low flow are actually of worse quality than carefully monitored reclaimed water.

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

NASA Astrophysics Data System (ADS)

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-10-01

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

METHOD 530 DETERMINATION OF SELECT SEMIVOLATILE ORGANIC CHEMICALS IN DRINKING WATER BY SOLID PHASE EXTRACTION AND GAS CHROMATOGRAPHY/ MASS SPECTROMETRY (GC/MS)

EPA Science Inventory

1.1. This is a gas chromatography/mass spectrometry (GC/MS) method for the determination of selected semivolatile organic compounds in drinking waters. Accuracy and precision data have been generated in reagent water, and in finished ground and surface waters for the compounds li...

Characterization of the adsorption of water vapor and chlorine on microcrystalline silica

NASA Technical Reports Server (NTRS)

Skiles, J. A.; Wightman, J. P.

1979-01-01

The characterization of water adsorption on silica is necessary to an understanding of how hydrogen chloride interacts with silica. The adsorption as a function of outgas temperatures of silica and as a function of the isotherm temperature was studied. Characterization of the silica structure by infrared analysis, X-ray diffraction and differential scanning calorimetry, surface area determinations, characterization of the sample surface by electron spectroscopy for chemical analysis (ESCA), and determinations of the heat of immersion in water of silica were investigated. The silica with a scanning electron microscope was examined.

Status and trends of dissolved oxygen in Corpus Christi Bay, Texas, U.S.A.

PubMed

Applebaum, Sally; Montagna, Paul A; Ritter, Christine

2005-08-01

The purpose of this study was to determine status and long-term trends of dissolved oxygen concentrations (DO) in Corpus Christi Bay, Texas, U.S.A. A 20-year record of randomized stations was used to determine the trend of surface water DO, salinity, and temperature over space and time. A 13-year record of two fixed stations was used to determine the temporal nutrient trends. A 10-year record of fixed stations in the southeastern region of Corpus Christi Bay was used to determine the status of disturbance caused by low DO in bottom waters. From 1982 to 2002, there was a significant decrease in surface water DO at a rate of 0.06 mg L(-1) yr(-1) and a significant increase in surface water temperature at a rate of 0.07 degrees C yr(-1). The southeastern region of Corpus Christi Bay had the lowest average DO, and during July and August, DO are steadily declining at a rate of 0.09 mg L(-1) yr(-1). It is not likely that eutrophication is causing hypoxia, because freshwater inflow rates have significantly decreased since 1941 and nutrient levels have not changed from 1987 to 2000. Even though long-term trends indicate that average surface DO is decreasing, disturbance by hypoxia appears to be stable, but this may be due to just eight years of data. In fact, if the current trend continues, surface water DO will not meet exceptional aquatic life standards (< or = 5 mg L(-1)) in 2032.

Adsorption of Egg-PC to an Air/Water and Triolein/Water Bubble Interface: Use of the 2-Dimensional Phase Rule to Estimate the Surface Composition of a Phospholipid/Triolein/Water Surface as a Function of Surface Pressure

PubMed Central

Mitsche, Matthew A.; Wang, Libo; Small, Donald M.

2010-01-01

Phospholipid monolayers play a critical role in the structure and stabilization of biological interfaces including all membranes, the alveoli of the lung, fat droplets in adipose tissue, and lipoproteins. The behavior of phospholipids in bilayers and at an air-water interface is well understood. However, the study of phospholipids at oil-water interfaces is limited due to technical challenges. In this study, egg-phosphatidylcholine (EPC) was deposited from small unilamellar vesicles onto a bubble of either air or triolein (TO) formed in a low salt buffer. The surface tension (γ) was measured using a drop tensiometer. We observed that EPC binds irreversibly to both interfaces and at equilibrium exerts ~12 and 15 mN/m of pressure (Π) at an air and TO interface, respectively. After EPC was bound to the interface, the unbound EPC was washed out of the cuvette and the surface was compressed to study the Π/area relationship. To determine the surface concentration (Γ), which cannot be measured directly, compression isotherms from a Langmuir trough and drop tensiometer were compared. The air-water interfaces had identical characteristics using both techniques, thus Γ on the bubble can be determined by overlaying the two isotherms. TO and EPC are both surface active so in a mixed TO/EPC monolayer both molecules will be exposed to water. Since TO is less surface active than EPC, as Π increases the TO is progressively ejected. To understand the Π/area isotherm of EPC on a TO bubble, a variety of TO-EPC mixtures were spread at the air-water interface. The isotherms show an abrupt break in the curve caused by the ejection of TO from the monolayer into a new bulk phase. By overlaying the compression isotherm above the ejection point with a TO bubble compression isotherm, Γ can be estimated. This allows determination of Γ of EPC on a TO bubble as a function of Π. PMID:20151713

Adsorption of egg phosphatidylcholine to an air/water and triolein/water bubble interface: use of the 2-dimensional phase rule to estimate the surface composition of a phospholipid/triolein/water surface as a function of surface pressure.

PubMed

Mitsche, Matthew A; Wang, Libo; Small, Donald M

2010-03-11

Phospholipid monolayers play a critical role in the structure and stabilization of biological interfaces, including all membranes, the alveoli of the lungs, fat droplets in adipose tissue, and lipoproteins. The behavior of phospholipids in bilayers and at an air-water interface is well understood. However, the study of phospholipids at oil-water interfaces is limited due to technical challenges. In this study, egg phosphatidylcholine (EPC) was deposited from small unilamellar vesicles onto a bubble of either air or triolein (TO) formed in a low-salt buffer. The surface tension (gamma) was measured using a drop tensiometer. We observed that EPC binds irreversibly to both interfaces and at equilibrium exerts approximately 12 and 15 mN/m of pressure (Pi) at an air and TO interface, respectively. After EPC was bound to the interface, the unbound EPC was washed out of the cuvette, and the surface was compressed to study the Pi/area relationship. To determine the surface concentration (Gamma), which cannot be measured directly, compression isotherms from a Langmuir trough and drop tensiometer were compared. The air-water interfaces had identical characteristics using both techniques; thus, Gamma on the bubble can be determined by overlaying the two isotherms. Both TO and EPC are surface-active, so in a mixed TO/EPC monolayer, both molecules will be exposed to water. Since TO is less surface-active than EPC, as Pi increases, the TO is progressively ejected. To understand the Pi/area isotherm of EPC on a TO bubble, a variety of TO-EPC mixtures were spread at the air-water interface. The isotherms show an abrupt break in the curve caused by the ejection of TO from the monolayer into a new bulk phase. By overlaying the compression isotherm above the ejection point with a TO bubble compression isotherm, Gamma can be estimated. This allows determination of Gamma of EPC on a TO bubble as a function of Pi.

Using satellite-based estimates of evapotranspiration and groundwater changes to determine anthropogenic water fluxes in land surface models

USDA-ARS?s Scientific Manuscript database

Irrigation is a widely used water management practice that is often poorly parameterized in land surface and climate models. Previous studies have addressed this issue via use of irrigation area, applied water inventory data, or soil moisture content. These approaches have a variety of drawbacks i...

RAPID MEASUREMENT OF BACTERIAL FECAL INDICATORS IN SURFACE WATERS BY QUANTITATIVE POLYMERASE CHAIN REACTION (QPCR) ANALYSIS

EPA Science Inventory

Current methods for determining fecal contamination of recreational waters rely on the culture of bacterial indicators and require at least 24 hours to determine whether the water is unsafe for use. By the time monitoring results are available, exposures have already occurred. N...

Protein immobilization on epoxy-activated thin polymer films: effect of surface wettability and enzyme loading.

PubMed

Chen, Bo; Pernodet, Nadine; Rafailovich, Miriam H; Bakhtina, Asya; Gross, Richard A

2008-12-02

A series of epoxy-activated polymer films composed of poly(glycidyl methacrylate/butyl methacrylate/hydroxyethyl methacrylate) were prepared. Variation in comonomer composition allowed exploration of relationships between surface wettability and Candida antartica lipase B (CALB) binding to surfaces. By changing solvents and polymer concentrations, suitable conditions were developed for preparation by spin-coating of uniform thin films. Film roughness determined by AFM after incubation in PBS buffer for 2 days was less than 1 nm. The occurrence of single CALB molecules and CALB aggregates at surfaces was determined by AFM imaging and measurements of volume. Absolute numbers of protein monomers and multimers at surfaces were used to determine values of CALB specific activity. Increased film wettability, as the water contact angle of films increased from 420 to 550, resulted in a decreased total number of immobilized CALB molecules. With further increases in the water contact angle of films from 55 degrees to 63 degrees, there was an increased tendency of CALB molecules to form aggregates on surfaces. On all flat surfaces, two height populations, differing by more than 30%, were observed from height distribution curves. They are attributed to changes in protein conformation and/or orientation caused by protein-surface and protein-protein interactions. The fraction of molecules in these populations changed as a function of film water contact angle. The enzyme activity of immobilized films was determined by measuring CALB-catalyzed hydrolysis of p-nitrophenyl butyrate. Total enzyme specific activity decreased by decreasing film hydrophobicity.

A "First Principles" Potential Energy Surface for Liquid Water from VRT Spectroscopy of Water Clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldman, N; Leforestier, C; Saykally, R J

We present results of gas phase cluster and liquid water simulations from the recently determined VRT(ASP-W)III water dimer potential energy surface. VRT(ASP-W)III is shown to not only be a model of high ''spectroscopic'' accuracy for the water dimer, but also makes accurate predictions of vibrational ground-state properties for clusters up through the hexamer. Results of ambient liquid water simulations from VRT(ASP-W)III are compared to those from ab initio Molecular Dynamics, other potentials of ''spectroscopic'' accuracy, and to experiment. The results herein represent the first time that a ''spectroscopic'' potential surface is able to correctly model condensed phase properties of water.

Determination of phenol compounds in surface water matrices by bar adsorptive microextraction-high performance liquid chromatography-diode array detection.

PubMed

Neng, Nuno R; Nogueira, José M F

2014-07-03

Bar adsorptive microextraction combined with liquid desorption followed by high performance liquid chromatography with diode array detection (BAµE-LD/HPLC-DAD) is proposed for the determination of trace levels of five phenol compounds (3-nitrophenol, 4-nitrophenol, bisphenol-A, 4-n-octylphenol and 4-n-nonylphenol) in surface water matrices. By using a polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phase, high selectivity and efficiency is achieved even against polydimethylsiloxane through stir bar sorptive extraction. Assays performed by BAµE(PS-DVB)-LD/HPLC-DAD on 25 mL water samples spiked at the 10.0 µg/L levels yielded recoveries over 88.0%±5.7% for all five analytes, under optimized experimental conditions. The analytical performance showed good precision (RSD<15%), detection limits of 0.25 µg/L and linear dynamic ranges (1.0-25.0 μg/L) with determination coefficient higher than 0.9904. By using the standard addition method, the application of the present method to surface water matrices allowed very good performances at the trace level. The proposed methodology proved to be a suitable alternative to monitor phenol compounds in surface water matrices, showing to be easy to implement, reliable, sensitive and requiring a low sample volume.

Application of Geographic Information System Methods to Identify Areas Yielding Water that will be Replaced by Water from the Colorado River in the Vidal and Chemehuevi Areas, California, and the Mohave Mesa Area, Arizona

USGS Publications Warehouse

Spangler, Lawrence E.; Angeroth, Cory E.; Walton, Sarah J.

2008-01-01

Relations between the elevation of the static water level in wells and the elevation of the accounting surface within the Colorado River aquifer in the vicinity of Vidal, California, the Chemehuevi Indian Reservation, California, and on Mohave Mesa, Arizona, were used to determine which wells outside the flood plain of the Colorado River are presumed to yield water that will be replaced by water from the Colorado River. Wells that have a static water-level elevation equal to or below the elevation of the accounting surface are presumed to yield water that will be replaced by water from the Colorado River. Geographic Information System (GIS) interpolation tools were used to produce maps of areas where water levels are above, below, and near (within ? 0.84 foot) the accounting surface. Calculated water-level elevations and interpolated accounting-surface elevations were determined for 33 wells in the vicinity of Vidal, 16 wells in the Chemehuevi area, and 35 wells on Mohave Mesa. Water-level measurements generally were taken in the last 10 years with steel and electrical tapes accurate to within hundredths of a foot. A Differential Global Positioning System (DGPS) was used to determine land-surface elevations to within an operational accuracy of ? 0.43 foot, resulting in calculated water-level elevations having a 95-percent confidence interval of ? 0.84 foot. In the Vidal area, differences in elevation between the accounting surface and measured water levels range from -2.7 feet below to as much as 17.6 feet above the accounting surface. Relative differences between the elevation of the water level and the elevation of the accounting surface decrease from west to east and from north to south. In the Chemehuevi area, differences in elevation range from -3.7 feet below to as much as 8.7 feet above the accounting surface, which is established at 449.6 feet in the vicinity of Lake Havasu. In all of the Mohave Mesa area, the water-level elevation is near or below the elevation of the accounting surface. Differences in elevation between water levels and the accounting surface range from -0.2 to -11.3 feet, with most values exceeding -7.0 feet. In general, the ArcGIS Triangulated Irregular Network (TIN) Contour and Natural Neighbor tools reasonably represent areas where the elevation of water levels in wells is above, below, and near (within ? 0.84 foot) the elevation of the accounting surface in the Vidal and Chemehuevi study areas and accurately delineate areas around outlying wells and where anomalies exist. The TIN Contour tool provides a strict linear interpolation while the Natural Neighbor tool provides a smoothed interpolation. Using the default options in ArcGIS, the Inverse Distance Weighted (IDW) and Spline tools also reasonably represent areas above, below, and near the accounting surface in the Vidal and Chemehuevi areas. However, spatial extent of and boundaries between areas above, below, and near the accounting surface vary among the GIS methods, which results largely from the fundamentally different mathematical approaches used by these tools. The limited number and spatial distribution of wells in comparison to the size of the areas, and the locations and relative differences in elevation between water levels and the accounting surface of wells with anomalous water levels also influence the contouring by each of these methods. Qualitatively, the Natural Neighbor tool appears to provide the best representation of the difference between water-level and accounting-surface elevations in the study areas, on the basis of available well data.

UHF RiverSonde observations of water surface velocity at Threemile Slough, California

USGS Publications Warehouse

Teague, C.C.; Barrick, D.E.; Lilleboe, P.M.; Cheng, R.T.; Ruhl, C.A.

2005-01-01

A UHF RiverSonde system, operating near 350 MHz, has been in operation at Threemile Slough in central California, USA since September 2004. The water in the slough is dominated by tidal effects, with flow reversals four times a day and a peak velocity of about 0.8 m/s in each direction. Water level and water velocity are continually measured by the U. S. Geological Survey at the experiment site. The velocity is measured every 15 minutes by an ultrasonic velocity meter (UVM) which determines the water velocity from two-way acoustic propagation time-difference measurements made across the channel. The RiverSonde also measures surface velocity every 15 minutes using radar resonant backscatter techniques. Velocity and water level data are retrieved through a radio data link and a wideband internet connection. Over a period of several months, the radar-derived mean surface velocity has been very highly correlated with the UVM index velocity several meters below the surface, with a coefficient of determination R2 of 0.976 and an RMS difference of less than 10 cm/s. The wind has a small but measurable effect on the velocities measured by both instruments. In addition to the mean surface velocity across the channel, the RiverSonde system provides an estimate of the cross-channel variation of the surface velocity. ?? 2005 IEEE.

Quantitatively identifying the roles of interfacial water and solid surface in governing peptide adsorption.

PubMed

Xu, Zhijun; Yang, Xiao; Wei, Qichao; Zhao, Weilong; Cui, Beiliang; Yang, Xiaoning; Sahai, Nita

2018-06-11

Understanding the molecular mechanism of protein adsorption on solids is critical to their applications in materials synthesis and tissue engineering. Though the water phase at the surface/water interface has been recognized as three types: free water in the bulk region, intermediate water phase and surface-bound water layers adjacent to the surface, the roles of the water and surface in determining the protein adsorption are not clearly identified, particularly at the quantitative level. Herein, we provide a methodology involving the combination of microsecond strengthen sampling simulation and force integration to quantitatively characterize the water-induced contribution and the peptide-surface interactions into the adsorption free energy. Using hydroxyapatite and graphene surfaces as examples, we demonstrate how the distinct interfacial features dominate the delicate force balance between these two thermodynamics parameters, leading to surface preference/resistance to peptide adsorption. Specifically, the water layer provides sustained repelling force against peptide adsorption, as indicated by a monotonic increase in the water-induced free energy profile, whereas the contribution to the free energy from the surface effect is thermodynamically favorable, thus acting as the dominant driving force for peptide adsorptions. More importantly, the revealed adsorption mechanism is critically dictated by the distribution of water phase at the solid/water interface, which plays a crucial role in establishing the force balance between the interactions of the peptide with the water layer and the surface. For the HAP surface, the charged peptide exhibits strong binding affinity to the surface, which is ascribed to the controlling contribution of peptide-surface interaction in the intermediate water phase and the surface-bound water layers are observed as the origin of bioresistance of solid surfaces towards the adsorption of charge-neutral peptides. The preferred peptide adsorption on the graphene, however, is dominated by the surface-induced component at the water layers adjacent to the surface. Our results further elucidate that the intermediate water phase significantly shortens the effective range of the surface dispersion force to guide the diffusion of the peptide to the interface, in sharp contrast to the observation in interfacial systems involving the strong water-surface interaction.

Estimation of sea surface temperature from remote sensing in the 11-13 micron window region

NASA Technical Reports Server (NTRS)

Prabhakara, C.; Dalu, G.; Kunde, V. G.

1974-01-01

The Nimbus 3 and 4 IRIS spectral data in the 11-13 micron water vapor window region are analyzed to determine the sea surface temperature (SST). The high spectral resolution data of IRIS are averaged over approximately 1 micron wide intervals to simulate channels of a radiometer to measure the SST. Three channels are utilized to measure SST over cloud-free oceans. However, two of these channels are sufficient in routine SST determination. The differential absorption properties of water vapor in the two channels enable one to determine the water vapor absorption correction without detailed knowledge of the vertical profiles of temperature and water vapor. The feasibility of determining the SST is demonstrated globally with Nimbus 3 data where cloud-free areas can be selected with the help of albedo data from the MRIR experiment on board the same satellite.

Validation of an automated fluorescein method for determining bromide in water

USGS Publications Warehouse

Fishman, M. J.; Schroder, L.J.; Friedman, L.C.

1985-01-01

Surface, atmospheric precipitation and deionized water samples were spiked with ??g l-1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0.015 to 0.5 mg l-1 of bromide. The correlation coefficient for the same sets of paired data is 0.9987. Recovery data, except for the surface water samples to which 0.005 mg l-1 of bromide was added, range from 89 to 112%. There appears to be no loss of bromide from solution in either type of container.Surface, atmospheric precipitation and deionized water samples were spiked with mu g l** minus **1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0. 015 to 0. 5 mg l** minus **1 of bromide. The correlation coefficient for the same sets of paired data is 0. 9987. Recovery data, except for the surface water samples to which 0. 005 mg l** minus **1 of bromide was added, range from 89 to 112%. Refs.

A nanosilver-based spectrophotometric method for determination of malachite green in surface water samples.

PubMed

Sahraei, R; Farmany, A; Mortazavi, S S; Noorizadeh, H

2013-07-01

A new spectrophotometric method is reported for the determination of nanomolar level of malachite green in surface water samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of malachite green by hexacyanoferrate (III) in acetate-acetic acid medium. The absorbance is measured at 610 nm with the fixed-time method. Under the optimum conditions, the linear range was 8.0 × 10(-9)-2.0 × 10(-7) mol L(-1) malachite green with a correlation coefficient of 0.996. The limit of detection (S/N = 3) was 2.0 × 10(-9) mol L(-1). Relative standard deviation for ten replicate determinations of 1.0 × 10(-8) mol L(-1) malachite green was 1.86%. The method is featured with good accuracy and reproducibility for malachite green determination in surface water samples without any pre-concentration and separation step.

Hydrogeochemical Processes Causing Persistent Low pH in Lakes within a Reclaimed Lignite Mine, East Texas

NASA Astrophysics Data System (ADS)

Paul, J. C.; Schwab, P.; Knappett, P.; Deng, Y.

2017-12-01

Surface water pH values ranging from 2.5 to 2.6 have been reported in three lakes at a reclaimed lignite mine located in the Wilcox Formation of East Texas (the site). Traditional neutralization processes using alkaline chemicals to neutralize the surface water were found to be temporary solutions at the site. Low pH conditions usually are caused by oxidation of pyritic materials in the original tailings, but that was not always apparent based on previous studies at this site. The objective of this study is to determine factors contributing to acid seepage to aid in developing pre- and post-mining strategies to mitigate persistent acidity in surface waters at this and other sites. Mineralogy, hydrogeology, and hydrogeochemical reactions were evaluated. A network of 30 wells was used to monitor the water table and chemistry of the shallow, unconfined aquifer surrounding the lakes. Pressure transducers were deployed in 18 of these wells and each of the lakes to measure high frequency water levels over approximately one year. These water levels were contoured to visualize changing hydraulic head over time and determine the correlation in time between ground water flow directions and local rainfall events. Boreholes at 15 of the monitoring wells were continuously cored, and samples were taken at selected depth intervals based on pH measurements. XRD, SEM, and TEM were used to determine the mineralogy of select soil samples. Ion chromatography was used to determine sulfate concentration, and ICP-MS was used to determine solute concentrations from water and digested soil samples. Framboidal and microcrystalline pyrite were identified in the vadose zone in silt and clay-sized fractions; these minerals have high surface area that is conducive to rapid oxidation and acidification as ground water permeates from the vadose into the saturated zone. Morphology in addition to quantity of weatherable pyrite plays a significant role in acidification. Computer models were used to evaluate the effect of dissolving and precipitating solid phases on water chemistry along identified subsurface flow pathways with a focus on metal sulfides and iron oxides as influential to acid mine seepage into the affected lakes.

Laboratory-based geoelectric monitoring of water infiltration in consolidated ground

NASA Astrophysics Data System (ADS)

Yang, Lining; Sun, Qiang; Yang, Haiping

2018-04-01

Infiltration usually plays a significant role in construction failures and transfer of contaminants. Therefore, it is very important to monitor underground water migration. In this study, a soil infiltration experiment was carried out using an indoor model test. The water infiltration characteristics were recorded and analyzed based on the response of the geoelectric field, including the primary field potential, self-potential, excitation current and apparent resistivity. The phreatic water surface and the infiltration velocity were determined. The inversion results were compared with direct observations. The results showed that the changes in the geoelectric field parameters explain the principles of groundwater flow. The infiltration velocity and the phreatic surface can be determined based on the primary field potential response and the excitation current. When the phreatic surface reached the location of the electrodes, the primary field potential and self-potential decreased rapidly whereas the excitation current increased rapidly. The height of the phreatic surface and the infiltration time exhibited a linear relationship for both the observation data and the calculations of the excitation current. The apparent resistivity described the infiltration status in the soil and tracked the phreatic surface accurately.

Experimental evaluation of theoretical sea surface reflectance factors relevant to above-water radiometry.

PubMed

Zibordi, Giuseppe

2016-03-21

Determination of the water-leaving radiance L_W through above-water radiometry requires knowledge of accurate reflectance factors ρ of the sea surface. Publicly available ρ relevant to above-water radiometry include theoretical data sets generated: i. by assuming a sky radiance distribution accounting for aerosols and multiple scattering, but neglecting polarization, and quantifying sea surface effects through Cox-Munk wave slope statistics; or differently ii. accounting for polarization, but assuming an ideal Rayleigh sky radiance distribution, and quantifying sea surface effects through modeled wave elevation and slope variance spectra. The impact on above-water data products of differences between those factors ρ was quantified through comparison of L_W from the Ocean Color component of the Aerosol Robotic Network (AERONET-OC) with collocated L_W from in-water radiometry. Results from the analysis of radiance measurements from the sea performed with 40 degrees viewing angle and 90 degrees azimuth offset with respect to the sun plane, indicated a slightly better agreement between above- and in-water L_W determined for wind speeds tentatively lower than 4 m s^-1 with ρ computed accounting for aerosols, multiple scattering and Cox-Munk surfaces. Nevertheless, analyses performed by partitioning the investigated data set also indicated that actual ρ values would exhibit dependence on sun zenith comprised between those characterizing the two sets of reflectance factors.

Radiolytic hydrogen generation at silicon carbide-water interfaces

NASA Astrophysics Data System (ADS)

Schofield, Jennifer; Reiff, Sarah C.; Pimblott, Simon M.; LaVerne, Jay A.

2016-02-01

While many of the proposed uses of SiC in the nuclear industry involve systems that are assumed to be dry, almost all materials have dissociated chemisorbed water associated with their surface, which can undergo chemistry in radiation fields. Silicon carbide α-phase and β-phase nanoparticles with water were irradiated with γ-rays and 5 MeV 4He ions followed by the determination of the production of molecular hydrogen, H2, and characterization of changes in the particle surface. The yields of H2 from SiC-water slurries were always greater than expected from a simple mixture rule indicating that the presence of SiC was influencing the production of H2 from water, probably through an energy transfer from the solid to liquid phase. Although the increase in H2 yields was modest, a decrease in the water mass percentage led to an increase in H2 yields, especially for very low amounts of water. Surface analysis techniques included diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), nitrogen absorption with the Brunauer - Emmett - Teller (BET) methodology for surface area determination, X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Little change in the SiC surface was observed following radiolysis except for some conversion of β-phase SiC to the α-phase and the formation of SiO2 with He ion radiolysis.

Open inlet conversion: Water quality benefits of two designs

USDA-ARS?s Scientific Manuscript database

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for movement of sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine the reduction in drainage effluent total suspended sediment (TSS) and phosphorus (P) concentr...

Quantum Chemical Study of Water Adsorption on the Surfaces of SrTiO3 Nanotubes.

PubMed

Bandura, Andrei V; Kuruch, Dmitry D; Evarestov, Robert A

2015-07-20

We have studied the adsorption of water molecules on the inner and outer surfaces of nanotubes generated by rolling (001) layers of SrTiO3 cubic crystals. The stability and the atomic and electronic structures of the adsorbed layers are determined by using hybrid density functional theory. The absorption energy and the preferred adsorbate structure are essentially governed by the nature of the surface of the nanotube. Dissociative adsorption prevails on the outer nanotube surfaces. The stability of the adsorbed layers on the inner surfaces is related to the possibility of the formation of hydrogen bonds between water molecules and surface oxygen atoms, and depends on the surface curvature. The presence of water molecules on the inner surface of the nanotubes leads to an increase of the electronic band gap. Externally TiO2 -terminated nanotubes could be used for the photocatalytic decomposition of water by ultraviolet radiation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of Two Spectrophotometric Techniques for Nutrients Analyses in Water Samples

NASA Astrophysics Data System (ADS)

Bartošová, Alica; Michalíková, Anna; Sirotiak, Maroš; Soldán, Maroš

2013-01-01

The aim of this contribution is to compare two common techniques for determining the concentrations of nitrate, nitrite, ammonium and phosphates in surface water and groundwater. Excess of these nutrients in water can directly affect human health (e.g. methemoglobinaemia) or indirectly through the products of secondary pollution - eutrophication (e.g. cyanotoxins, emanation of hydrogen sulphide, mercaptanes, methane...). Negative impact of nutrients excess in surface water often causes the destruction of water ecosystems, and therefore, common substances of these elements must be monitored and managed. For these experiments two spectrophotometric techniques - ultraviolet spectrophotometry and nutrient photometry were used. These techniques are commonly used for quick and simple analyses of nutrients in waste water. There are calibration curves for each nutrient and for determination of their concentration.

Preliminary studies leading toward the development of a LIDAR bathymetry mapping instrument

NASA Astrophysics Data System (ADS)

Hill, John M.; Krenek, Brendan D.; Kunz, Terry D.; Krabill, William; Stetina, Fran

1993-02-01

The National Aeronautics and Space Administration (NASA) at Goddard Space Flight Center (GSFC) has developed a laser ranging device (LIDAR) which provides accurate and timely data of earth features. NASA/GSFC recently modified the sensor to include a scanning capability to produce LIDAR swaths. They have also integrated a Global Positioning System (GPS) and an Inertial Navigation System (INS) to accurately determine the absolute aircraft location and aircraft attitude (pitch, yaw, and roll), respectively. The sensor has been flown in research mode by NASA for many years. The LIDAR has been used in different configurations or modes to acquire such data as altimetry (topography), bathymetry (water depth), laser-induced fluorosensing (tracer dye movements, oil spills and oil thickness, chlorophyll and plant stress identification), forestry, and wetland discrimination studies. NASA and HARC are developing a commercial version of the instrument for topographic mapping applications. The next phase of the commercialization project will be to investigate other applications such as wetlands mapping and coastal bathymetry. In this paper we report on preliminary laboratory measurements to determine the feasibility of making accurate depth measurements in relatively shallow water (approximately 2 to 6 feet deep) using a LIDAR system. The LIDAR bathymetry measurements are relatively simple in theory. The water depth is determined by measuring the time interval between the water surface reflection and the bottom surface reflection signals. Depth is then calculated by dividing by the index of refraction of water. However, the measurements are somewhat complicated due to the convolution of the water surface return signal with the bottom surface return signal. Therefore in addition to the laboratory experiments, computer simulations of the data were made to show these convolution effects in the return pulse waveform due to: (1) water depth, and (2) changes in bottom surface reflectivity.

Preliminary Studies Leading Toward the Development of a LIDAR Bathymetry Mapping Instrument

NASA Technical Reports Server (NTRS)

Hill, John M.; Krenek, Brendan D.; Kunz, Terry D.; Krabill, William; Stetina, Fran

1993-01-01

The National Aeronautics and Space Administration (NASA) at Goddard Space Flight Center (GSFC) has developed a laser ranging device (LIDAR) which provides accurate and timely data of earth features. NASA/GSFC recently modified the sensor to include a scanning capability to produce LIDAR swaths. They have also integrated a Global Positioning System (GPS) and an Inertial Navigation System (INS) to accurately determine the absolute aircraft location and aircraft attitude (pitch, yaw, and roll), respectively. The sensor has been flown in research mode by NASA for many years. The LIDAR has been used in different configurations or modes to acquire such data as altimetry (topography), bathymetry (water depth), laser-induced fluorosensing (tracer dye movements, oil spills and oil thickness, chlorophyll and plant stress identification), forestry, and wetland discrimination studies. NASA and HARC are developing a commercial version of the instrument for topographic mapping applications. The next phase of the commercialization project will be to investigate other applications such as wetlands mapping and coastal bathymetry. In this paper we report on preliminary laboratory measurements to determine the feasibility of making accurate depth measurements in relatively shallow water (approximately 2 to 6 feet deep) using a LIDAR system. The LIDAR bathymetry measurements are relatively simple in theory. The water depth is determined by measuring the time interval between the water surface reflection and the bottom surface reflection signals. Depth is then calculated by dividing by the index of refraction of water. However, the measurements are somewhat complicated due to the convolution of the water surface return signal with the bottom surface return signal. Therefore in addition to the laboratory experiments, computer simulations of the data were made to show these convolution effects in the return pulse waveform due to: (1) water depth, and (2) changes in bottom surface reflectivity.

Water-surface profile and flood boundaries for the computed 100-year flood, lower Salt River, Lincoln County, Wyoming

USGS Publications Warehouse

Miller, Kirk A.; Mason, John P.

2000-01-01

The water-surface profile and flood boundaries for the computed 100-year flood were determined for a part of the lower Salt River in Lincoln County, Wyoming. Channel cross-section data were provided by Lincoln County. Cross-section data for bridges and other structures were collected and compiled by the U.S. Geological Survey. Roughness coefficients ranged from 0.034 to 0.100. The 100-year flood was computed using standard methods, ranged from 5,170 to 4,120 cubic feet per second through the study reach, and was adjusted proportional to contributing drainage area. Water-surface elevations were determined by the standard step-backwater method. Flood boundaries were plotted on digital basemaps.

Determination of the Relative Uptake of Ground vs. Surface Water by Populus deltoides During Phytoremediation

Treesearch

Barton D. Clinton; James M. Vose; Don A. Vroblesky; Gregory J. Harvey

2004-01-01

The use of plants to remediate polluted groundwater is becoming an attractive alternative to more expensive traditional techniques. In order to adequately assess the effectiveness of the phytoremediation treatment, a clear understanding of water-use habits by the selected plant species is essential. We examined the relative uptake of surface water (i.e., precipitation...

On the existence and stability of liquid water on the surface of mars today.

PubMed

Kuznetz, L H; Gan, D C

2002-01-01

The recent discovery of high concentrations of hydrogen just below the surface of Mars' polar regions by Mars Odyssey has enlivened the debate about past or present life on Mars. The prevailing assumption prior to the discovery was that the liquid water essential for its existence is absent. That assumption was based largely on the calculation of heat and mass transfer coefficients or theoretical climate models. This research uses an experimental approach to determine the feasibility of liquid water under martian conditions, setting the stage for a more empirical approach to the question of life on Mars. Experiments were conducted in three parts: Liquid water's existence was confirmed by droplets observed under martian conditions in part 1; the evolution of frost melting on the surface of various rocks under martian conditions was observed in part 2; and the evaporation rate of water in Petri dishes under Mars-like conditions was determined and compared with the theoretical predictions of various investigators in part 3. The results led to the conclusion that liquid water can be stable for extended periods of time on the martian surface under present-day conditions.

On the existence and stability of liquid water on the surface of mars today

NASA Technical Reports Server (NTRS)

Kuznetz, L. H.; Gan, D. C.

2002-01-01

The recent discovery of high concentrations of hydrogen just below the surface of Mars' polar regions by Mars Odyssey has enlivened the debate about past or present life on Mars. The prevailing assumption prior to the discovery was that the liquid water essential for its existence is absent. That assumption was based largely on the calculation of heat and mass transfer coefficients or theoretical climate models. This research uses an experimental approach to determine the feasibility of liquid water under martian conditions, setting the stage for a more empirical approach to the question of life on Mars. Experiments were conducted in three parts: Liquid water's existence was confirmed by droplets observed under martian conditions in part 1; the evolution of frost melting on the surface of various rocks under martian conditions was observed in part 2; and the evaporation rate of water in Petri dishes under Mars-like conditions was determined and compared with the theoretical predictions of various investigators in part 3. The results led to the conclusion that liquid water can be stable for extended periods of time on the martian surface under present-day conditions.

Determination of pharmaceuticals, personal care products, and pesticides in surface and treated waters: method development and survey.

PubMed

Caldas, Sergiane Souza; Bolzan, Cátia Marian; Guilherme, Juliana Rocha; Silveira, Maria Angelis Kisner; Escarrone, Ana Laura Venquiaruti; Primel, Ednei Gilberto

2013-08-01

Water is fundamental to the existence of life since it is essential to a series of activities, such as agriculture, power generation, and public and industrial supplies. The residual water generated by these activities is released into the environment, reaches the water systems, and becomes a potential risk to nontarget organisms. This paper reports the development and validation of a quantitative method, based on solid-phase extraction and liquid chromatography tandem mass spectrometry, for the simultaneous analysis of 18 pharmaceuticals and personal care products (PPCPs) and 33 pesticides in surface and drinking waters. The accuracy of the method was determined by calculating the recoveries, which ranged from 70 to 120 % for most pesticides and PPCPs, whereas limits of quantification ranged from 0.8 to 40 ng/L. After the validation step, the method was applied to drinking and surface waters. Pesticides and PPCPs were found in concentrations lower than 135.5 ng/L. The evaluation of different water sources with regard to contamination by pesticides and PPCPs has been quite poor in southern Brazil.

Controlling Heterogeneous Catalysis of Water Dissociation Using Cu-Ni Bimetallic Alloy Surfaces: A Quantum Dynamics Study.

PubMed

Ray, Dhiman; Ghosh, Smita; Tiwari, Ashwani Kumar

2018-06-07

Copper-Nickel bimetallic alloys are emerging heterogeneous catalysts for water dissociation which is the rate determining step of industrially important Water Gas Shift (WGS) reaction. Yet, the detailed quantum dynamics studies of water-surface scattering in literature are limited to pure metal surfaces. We present here, a three dimensional wave-packet dynamics study of water dissociation on Cu-Ni alloy surfaces, using a pseudo diatomic model of water on a London-Eyring-Polanyi-Sato (LEPS) potential energy surface in order to study the effect of initial vibration, rotation and orientation of water molecule on reactivity. For all the chosen surfaces reactivity increases significantly with vibrational excitation. In general, for lower vibrational states the reactivity increases with increasing rotational excitation but it decreases in higher vibrational states. Molecular orientation strongly affects reactivity by helping the molecule to align along the reaction path at higher vibrational states. For different alloys, the reaction probability follows the trend of barrier heights and the surfaces having all Ni atoms in the uppermost layer are much more reactive than the ones with Cu atoms. Hence the nature of the alloy surface and initial quantum state of the incoming molecule significantly influence the reactivity in surface catalyzed water dissociation.

Vulnerability of drinking-water wells in La Crosse, Wisconsin, to enteric-virus contamination from surface water contributions.

PubMed

Borchardt, Mark A; Haas, Nathaniel L; Hunt, Randall J

2004-10-01

Human enteric viruses can contaminate municipal drinking-water wells, but few studies have examined the routes by which viruses enter these wells. In the present study, the objective was to monitor the municipal wells of La Crosse, Wisconsin, for enteric viruses and determine whether the amount of Mississippi River water infiltrating the wells was related to the frequency of virus detection. From March 2001 to February 2002, one river water site and four wells predicted by hydrogeological modeling to have variable degrees of surface water contributions were sampled monthly for enteric viruses, microbial indicators of sanitary quality, and oxygen and hydrogen isotopes. (18)O/(16)O and (2)H/(1)H ratios were used to determine the level of surface water contributions. All samples were collected prior to chlorination at the wellhead. By reverse transcription-PCR (RT-PCR), 24 of 48 municipal well water samples (50%) were positive for enteric viruses, including enteroviruses, rotavirus, hepatitis A virus (HAV), and noroviruses. Of 12 river water samples, 10 (83%) were virus positive by RT-PCR. Viable enteroviruses were not detected by cell culture in the well samples, although three well samples were positive for culturable HAV. Enteroviruses detected in the wells by RT-PCR were identified as several serotypes of echoviruses and group A and group B coxsackieviruses. None of the well water samples was positive for indicators of sanitary quality, namely male-specific and somatic coliphages, total coliform bacteria, Escherichia coli, and fecal enterococci. Contrary to expectations, viruses were found in all wells regardless of the level of surface water contributions. This result suggests that there were other unidentified sources, in addition to surface water, responsible for the contamination.

Vulnerability of Drinking-Water Wells in La Crosse, Wisconsin, to Enteric-Virus Contamination from Surface Water Contributions

PubMed Central

Borchardt, Mark A.; Haas, Nathaniel L.; Hunt, Randall J.

2004-01-01

Human enteric viruses can contaminate municipal drinking-water wells, but few studies have examined the routes by which viruses enter these wells. In the present study, the objective was to monitor the municipal wells of La Crosse, Wisconsin, for enteric viruses and determine whether the amount of Mississippi River water infiltrating the wells was related to the frequency of virus detection. From March 2001 to February 2002, one river water site and four wells predicted by hydrogeological modeling to have variable degrees of surface water contributions were sampled monthly for enteric viruses, microbial indicators of sanitary quality, and oxygen and hydrogen isotopes. 18O/16O and 2H/1H ratios were used to determine the level of surface water contributions. All samples were collected prior to chlorination at the wellhead. By reverse transcription-PCR (RT-PCR), 24 of 48 municipal well water samples (50%) were positive for enteric viruses, including enteroviruses, rotavirus, hepatitis A virus (HAV), and noroviruses. Of 12 river water samples, 10 (83%) were virus positive by RT-PCR. Viable enteroviruses were not detected by cell culture in the well samples, although three well samples were positive for culturable HAV. Enteroviruses detected in the wells by RT-PCR were identified as several serotypes of echoviruses and group A and group B coxsackieviruses. None of the well water samples was positive for indicators of sanitary quality, namely male-specific and somatic coliphages, total coliform bacteria, Escherichia coli, and fecal enterococci. Contrary to expectations, viruses were found in all wells regardless of the level of surface water contributions. This result suggests that there were other unidentified sources, in addition to surface water, responsible for the contamination. PMID:15466536

Vulnerability of drinking-water wells in La Crosse, Wisconsin, to enteric-virus contamination from surface water contributions

USGS Publications Warehouse

Borchardt, M. A.; Haas, N.L.; Hunt, R.J.

2004-01-01

Human enteric viruses can contaminate municipal drinking-water wells, but few studies have examined the routes by which viruses enter these wells. In the present study, the objective was to monitor the municipal wells of La Crosse, Wisconsin, for enteric viruses and determine whether the amount of Mississippi River water infiltrating the wells was related to the frequency of virus detection. From March 2001 to February 2002, one river water site and four wells predicted by hydrogeological modeling to have variable degrees of surface water contributions were sampled monthly for enteric viruses, microbial indicators of sanitary quality, and oxygen and hydrogen isotopes. 18O/ 16O and 2H/1H ratios were used to determine the level of surface water contributions. All samples were collected prior to chlorination at the wellhead. By reverse transcription-PCR (RT-PCR), 24 of 48 municipal well water samples (50%) were positive for enteric viruses, including enteroviruses, rotavirus, hepatitis A virus (HAV), and noroviruses. Of 12 river water samples, 10 (83%) were virus positive by RT-PCR. Viable enteroviruses were not detected by cell culture in the well samples, although three well samples were positive for culturable HAV. Enteroviruses detected in the wells by RT-PCR were identified as several serotypes of echoviruses and group A and group B coxsackieviruses. None of the well water samples was positive for indicators of sanitary quality, namely male-specific and somatic coliphages, total coliform bacteria, Escherichia coli, and fecal enterococci. Contrary to expectations, viruses were found in all wells regardless of the level of surface water contributions. This result suggests that there were other unidentified sources, in addition to surface water, responsible for the contamination.

Temperature of surface waters in the conterminous United States

USGS Publications Warehouse

Blakey, James F.

1966-01-01

Temperature is probably the most important, but least discussed, parameter in determining water quality. The purpose of this report is to present the average or most probable temperatures of surface waters in the conterminous United States and to cite factors that affect and are affected by water temperature. Temperature is related, usually directly, to all the chemical, physical, and biological properties of water. The ability of water to dissolve or precipitate materials is temperature dependent, the ability of water to transport or deposit suspended material is temperature dependent, and the aquatic life of a lake or stream may thrive or die because of the water temperature.Everyone is concerned, though often unknowingly, about water temperature. The amount and type of treatment necessary for a municipal supply are temperature dependent; therefore it affects the consumer cost. Temperature determines the volume of cooling water needed for industrial processes and steampower generation. Conservation and recreation practices are affected by water temperature, and the farmers' irrigation practices and livestock production may be affected by the water temperature.

Compatibility Study of Silver Biocide in Drinking Water with Candidate Metals for Crew Exploration Vehicle Potable Water System

NASA Technical Reports Server (NTRS)

Adam, Niklas M.

2009-01-01

The stability of silver biocide, used to keep drinking water on the CEV potable water sterile, is unknown as the system design is still in progress. Silver biocide in water can deplete rapidly when exposed to various metal surfaces. Additionally, silver depletion rates may be affected by the surface-area-to-volume (SA/V) ratios in the water system. Therefore, to facilitate the CEV water system design, it would be advantageous to know the biocide depletion rates in water exposed to the surfaces of these candidate metals at various SA/V ratios. Certain surface treatments can be employed to reduce the depletion rates of silver compared to the base metal. The purpose of this work is to determine the compatibility of specific spaceflight-certified metals that could used in the design of the CEV potable water system with silver biocide as well as understand the effect of surface are to volume ratios of metals used in the construction of the potable water system on the silver concentration.

Baseline risk assessment of ground water contamination at the uranium mill tailings site near Durango, Colorado. Revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-09-01

For the UMTRA Project site located near Durango, Colorado (the Durango site), the Surface Project cleanup occurred from 1986 to 1991. An evaluation was made to determine whether exposure to ground water contaminated by uranium processing could affect people`s health. Exposure could occur from drinking water pumped from a hypothetical well drilled in the contaminated ground water area. In addition, environmental risks may result if plants or animals are exposed to contaminated ground water, or surface water that has mixed with contaminated ground water. This risk assessment report is the first site-specific document prepared for the UMTRA Ground Water Projectmore » at the Durango site. The results of this report and further site characterization of the Durango site will be used to determine what is necessary to protect public health and the environment, and to comply with the EPA standards.« less

Multisample conversion of water to hydrogen by zinc for stable isotope determination

USGS Publications Warehouse

Kendall, C.; Coplen, T.B.

1985-01-01

Two techniques for the conversion of water to hydrogen for stable isotope ratio determination have been developed that are especially suited for automated multisample analysis. Both procedures involve reaction of zinc shot with a water sample at 450 ??C. in one method designed for water samples in bottles, the water is put in capillaries and is reduced by zinc in reaction vessels; overall savings in sample preparation labor of 75% have been realized over the standard uranium reduction technique. The second technique is for waters evolved under vacuum and is a sealed-tube method employing 9 mm o.d. quartz tubing. Problems inherent with zinc reduction include surface inhomogeneity of the zinc and exchange of hydrogen both with the zinc and with the glass walls of the vessels. For best results, water/zinc and water/glass surface area ratios of vessels should be kept as large as possible.

Removal of Surface-Reflected Light for the Measurement of Remote-Sensing Reflectance from an Above-Surface Platform

DTIC Science & Technology

2010-12-06

raw data). To remove surface-reflected light in field measurements of remote sensing reflectance, a spectral optimization approach was applied, with...results compared with those from remote - sensing models and from direct measurements. The agreement from different determinations suggests that...reasonable results for remote sensing reflectance of clear blue water to turbid brown water are obtainable from above-surface measurements, even under conditions of high waves.

Possibilities of surface waters monitoring at mining areas using UAV

NASA Astrophysics Data System (ADS)

Lisiecka, Ewa; Motyka, Barbara; Motyka, Zbigniew; Pierzchała, Łukasz; Szade, Adam

2018-04-01

The selected, remote measurement methods are discussed, useful for determining surface water properties using mobile unmanned aerial platforms (UAV). The possibilities of using this type of solutions in the scope of measuring spatial, physicochemical and biological parameters of both natural and anthropogenic water reservoirs, including flood polders, water-filled pits, settling tanks and mining sinks were analyzed. Methods of remote identification of the process of overgrowing this type of ecosystems with water and coastal plant formations have also been proposed.

REGIONAL RELATIONSHIPS BETWEEN GEOMORPHIC/HYDROLOGIC PARAMETERS AND SURFACE WATER CHEMISTRY RELATIVE TO ACIDIC DEPOSITION

EPA Science Inventory

We determined geomorphic and hydrologic parameters for 144 forested, lake watersheds in the Northeast (NE) of the United States based primarily on measurements from topographic maps. hese parameters were used to test for relationships with selected surface water chemistry relevan...

MICROBIOLOGICAL IMPACT OF CONCENTRATED ANIMAL FEED OPERATIONS (CAFOS) ON SURFACE AND GROUND WATER QUALITY

EPA Science Inventory

This investigation seeks to determine the microbiological impact of agricultural activities and confined animal feed operations (CAFOs) on surface and ground water in the Northwest Central Oklahoma. The first phase of the investigation will be carried on in collaboration with U...

Water adsorption on surface-modified cellulose nanocrystals

NASA Astrophysics Data System (ADS)

Wei, Zonghui; Sinko, Robert; Keten, Sinan; Luijten, Erik

Cellulose nanocrystals (CNCs) have attracted much attention as a filler phase for polymer nanocomposites due to their impressive mechanical properties, low cost, and environmental sustainability. Despite their promise for this application, there are still numerous obstacles that prevent optimal performance of CNC-polymer nanocomposites, such as poor filler dispersion and high levels of water absorption. One way to mitigate these negative effects is to modify CNC surfaces. Computational approaches can be utilized to obtain direct insight into the properties of modified CNC surfaces and probe the interactions of CNCs with other materials to facilitate the experimental design of nanocomposites. We use atomistic grand-canonical Monte Carlo simulations to study how surface modification of ion-exchanged sulfated cellulose nanocrystals (Na-CNCs) impacts water adsorption. We find that methyl(triphenyl)phosphonium-exchanged CNCs adsorb less water than Na-CNCs at the same relative humidity, supporting recent experimental dynamic vapor sorption measurements. By characterizing the distribution and configuration of water molecules near the modified CNC surfaces we determine how surface modifications disrupt CNC-water interactions.

Efficacy of electrolysed oxidizing water in inactivating Vibrio parahaemolyticus on kitchen cutting boards and food contact surfaces.

PubMed

Chiu, T-H; Duan, J; Liu, C; Su, Y-C

2006-12-01

To determine the efficacy of electrolysed oxidizing (EO) water in inactivating Vibrio parahaemolyticus on kitchen cutting boards and food contact surfaces. Cutting boards (bamboo, wood and plastic) and food contact surfaces (stainless steel and glazed ceramic tile) were inoculated with V. parahaemolyticus. Viable cells of V. parahaemolyticus were detected on all cutting boards and food contact surfaces after 10 and 30 min, respectively, at room temperatures. Soaking inoculated food contact surfaces and cutting boards in distilled water for 1 and 3 min, respectively, resulted in various reductions of V. parahaemolyticus, but failed to remove the organism completely from surfaces. However, the treatment of EO water [pH 2.7, chlorine 40 ppm, oxidation-reduction potential 1151 mV] for 30, 45, and 60 s, completely inactivated V. parahaemolyticus on stainless steel, ceramic tile, and plastic cutting boards, respectively. EO water could be used as a disinfecting agent for inactivating V. parahaemolyticus on plastic and wood cutting boards and food contact surfaces. Rinsing the food contact surfaces with EO water or soaking cutting boards in EO water for up to 5 min could be a simple strategy to reduce cross-contamination of V. parahaemolyticus during food preparation.

Inhibition of ice nucleation by slippery liquid-infused porous surfaces (SLIPS).

PubMed

Wilson, Peter W; Lu, Weizhe; Xu, Haojun; Kim, Philseok; Kreder, Michael J; Alvarenga, Jack; Aizenberg, Joanna

2013-01-14

Ice repellent coatings have been studied and keenly sought after for many years, where any advances in the durability of such coatings will result in huge energy savings across many fields. Progress in creating anti-ice and anti-frost surfaces has been particularly rapid since the discovery and development of slippery, liquid infused porous surfaces (SLIPS). Here we use SLIPS-coated differential scanning calorimeter (DSC) pans to investigate the effects of the surface modification on the nucleation of supercooled water. This investigation is inherently different from previous studies which looked at the adhesion of ice to SLIPS surfaces, or the formation of ice under high humidity conditions. Given the stochastic nature of nucleation of ice from supercooled water, multiple runs on the same sample are needed to determine if a given surface coating has a real and statistically significant effect on the nucleation temperature. We have cycled supercooling to freezing and then thawing of deionized water in hydrophilic (untreated aluminum), hydrophobic, superhydrophobic, and SLIPS-treated DSC pans multiple times to determine the effects of surface treatment on the nucleation and subsequent growth of ice. We find that SLIPS coatings lower the nucleation temperature of supercooled water in contact with statistical significance and show no deterioration or change in the coating performance even after 150 freeze-thaw cycles.

Thermodynamic properties of rhamnolipid micellization and adsorption.

PubMed

Mańko, Diana; Zdziennicka, Anna; Jańczuk, Bronisław

2014-07-01

of the surface tension, density, viscosity and conductivity of aqueous solutions of rhamnolipid at natural and controlled pH were made at 293 K. On the basis of the obtained results the critical micelle concentration of rhamnolipid and its Gibbs surface excess concentration at the water-air interface were determined. The maximal surface excess concentration was considered in the light of the size of rhamnolipid molecule. Next the Gibbs standard free energy of rhamnolipid adsorption at this interface was determined on the basis of the different approaches to this energy. The standard free energy of adsorption was also deduced on the basis of the surface tension of n-hexane and water-n-hexane interface tension. Standard free energy obtained in this way was close to those determined by using the Langmuir, Szyszkowski, Aronson and Rosen, Gu and Zhu as well as modified Gamboa and Olea equations. The standard free energy of rhamnolipid adsorption at the water-air interface was compared to its standard free energy of micellization which was determined from the Philips equation taking into account the degree of rhamnolipid dissociation in the micelles. Copyright © 2014 Elsevier B.V. All rights reserved.

Climate influences thermal balance and water use in African and Asian elephants: physiology can predict drivers of elephant distribution.

PubMed

Dunkin, Robin C; Wilson, Dinah; Way, Nicolas; Johnson, Kari; Williams, Terrie M

2013-08-01

Elephant movement patterns in relation to surface water demonstrate that they are a water-dependent species. Thus, there has been interest in using surface water management to mitigate problems associated with localized elephant overabundance. However, the physiological mechanisms underlying the elephant's water dependence remain unclear. Although thermoregulation is likely an important driver, the relationship between thermoregulation, water use and climate has not been quantified. We measured skin surface temperature of and cutaneous water loss from 13 elephants (seven African, 3768±642 kg; six Asian, 3834±498 kg) and determined the contribution of evaporative cooling to their thermal and water budgets across a range of air temperatures (8-33°C). We also measured respiratory evaporative water loss and resting metabolic heat production on a subset of elephants (N=7). The rate of cutaneous evaporative water loss ranged between 0.31 and 8.9 g min(-1) m(-2) for Asian elephants and 0.26 and 6.5 g min(-1) m(-2) for African elephants. Simulated thermal and water budgets using climate data from Port Elizabeth, South Africa, and Okaukuejo, Namibia, suggested that the 24-h evaporative cooling water debt incurred in warm climates can be more than 4.5 times that incurred in mesic climates. This study confirms elephants are obligate evaporative coolers but suggests that classification of elephants as water dependent is insufficient given the importance of climate in determining the magnitude of this dependence. These data highlight the potential for a physiological modeling approach to predicting the utility of surface water management for specific populations.

Numerical Investigation of Physicochemical Processes Occurring During Water Evaporation in the Surface Layer Pores of a Forest Combustible Material

NASA Astrophysics Data System (ADS)

Zhdanova, A. O.; Kuznetsov, G. V.; Strizhak, P. A.

2014-07-01

A numerical investigation of the physicochemical processes occurring during water evaporation from the pores of the surface layer of a forest combustible material has been carried out. The characteristic features of the suppression of the thermal decomposition reaction of a combustible material with water filling fullyits pores and formation of a water fi lm over its surface have been determined. The characteristic times of suppression of thermal decomposition reactions under various environmental conditions and the thickness and kinds of forest combustible material (birch leaves, pine and spruce needles, etc.) have been established.

Thermally decarboxylated sodium bicarbonate: Interactions with water vapour, calorimetric study

PubMed Central

Volkova, Natalia; Hansson, Henri; Ljunggren, Lennart

2012-01-01

Isothermal titration calorimetry (ITC) was used to study interactions between water vapour and the surface of thermally converted sodium bicarbonate (NaHCO3). The decarboxylation degree of the samples was varied from 3% to 35% and the humidity range was 54–100%. The obtained enthalpy values were all exothermic and showed a positive linear correlation with decarboxylation degrees for each humidity studied. The critical humidity, 75% (RHo), was determined as the inflection point on a plot of the mean−ΔH kJ/mole Na2CO3 against RH. Humidities above the critical humidity lead to complete surface dissolution. The water uptake (m) was determined after each calorimetric experiment, complementing the enthalpy data. A mechanism of water vapour interaction with decarboxylated samples, including the formation of trona and Wegscheider’s salt on the bicarbonate surface is proposed for humidities below RHo. PMID:29403816

Contamination levels of human pharmaceutical compounds in French surface and drinking water.

PubMed

Mompelat, S; Thomas, O; Le Bot, B

2011-10-01

The occurrence of 20 human pharmaceutical compounds and metabolites from 10 representative therapeutic classes was analysed from resource and drinking water in two catchment basins located in north-west France. 98 samples were analysed from 63 stations (surface water and drinking water produced from surface water). Of the 20 human pharmaceutical compounds selected, 16 were quantified in both the surface water and drinking water, with 22% of the values above the limit of quantification for surface water and 14% for drinking water). Psychostimulants, non-steroidal anti-inflammatory drugs, iodinated contrast media and anxiolytic drugs were the main therapeutic classes of human pharmaceutical compounds detected in the surface water and drinking water. The results for surface water were close to results from previous studies in spite of differences in prescription rates of human pharmaceutical compounds in different countries. The removal rate of human pharmaceutical compounds at 11 water treatment units was also determined. Only caffeine proved to be resistant to drinking water treatment processes (with a minimum rate of 5%). Other human pharmaceutical compounds seemed to be removed more efficiently (average elimination rate of over 50%) by adsorption onto activated carbon and oxidation/disinfection with ozone or chlorine (not taking account of the disinfection by-products). These results add to the increasing evidence of the occurrence of human pharmaceutical compounds in drinking water that may represent a threat to human beings exposed to a cocktail of human pharmaceutical compounds and related metabolites and by-products in drinking water.

Quality of surface water in the Suwannee River Basin, Florida, August 1968 through December 1977

USGS Publications Warehouse

Hull, Robert W.; Dysart, Joel E.; Mann, William B.

1981-01-01

In the 9,950-square mile area of the Suwannee River basin in Florida and Georgia, 17 surface-water stations on 9 streams and several springs were sampled for selected water-quality properties and constituents from August 1968 through December 1977. Analyses from these samples indicate that: (1) the water quality of tributary wetlands controls the water quality of the upper Suwannee River headwaters; (2) groundwater substantially affects the water quality of the Suwannee River basin streams below these headquarters; (3) the water quality of the Suwannee River, and many of its tributaries, is determined by several factors and is not simply related to discharge; and (4) development in the Suwannee River basin has had observable effects on the quality of surface waters. 

40 CFR 142.80 - Review procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that... determine, in accordance with § 141.71 of this chapter, if public water systems using surface water sources...

40 CFR 142.80 - Review procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that... determine, in accordance with § 141.71 of this chapter, if public water systems using surface water sources...

40 CFR 142.80 - Review procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that... determine, in accordance with § 141.71 of this chapter, if public water systems using surface water sources...

40 CFR 142.80 - Review procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that... determine, in accordance with § 141.71 of this chapter, if public water systems using surface water sources...

Nitrate retention in a sand plains stream and the importance of groundwater discharge

Treesearch

Robert S. Stelzer; Damion R. Drover; Susan L. Eggert; Maureen A. Muldoon

2011-01-01

We measured net nitrate retention by mass balance in a 700-m upwelling reach of a third-order sand plains stream, Emmons Creek, from January 2007 to November 2008. Surface water and ground-water fluxes of nitrate were determined from continuous records of discharge and from nitrate concentrations based on weekly and biweekly sampling at three surface water stations and...

Intermittent surface water connectivity: Fill and spill vs. fill and merge dynamics

USGS Publications Warehouse

Leibowitz, Scott G.; Mushet, David M.; Newton, Wesley E.

2016-01-01

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining differences in response was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes.

Flood recovery maps for the White River in Bethel, Stockbridge, and Rochester, Vermont, and the Tweed River in Stockbridge and Pittsfield, Vermont, 2014

USGS Publications Warehouse

Olson, Scott A.

2015-01-01

Eighteen high-water marks from Tropical Storm Irene were available along the studied reaches. The discharges in the Tropical Storm Irene HEC–RAS model were adjusted so that the resulting water-surface elevations matched the high-water mark elevations along the study reaches. This allowed for an estimation of the water-surface profile throughout the study area resulting from Tropical Storm Irene. From a comparison of the estimated water-surface profile of Tropical Storm Irene to the water-surface profiles of the 1- and 0.2-percent AEP floods, it was determined that the high-water elevations resulting from Tropical Storm Irene exceeded the estimated 1-percent AEP flood throughout the White River and Tweed River study reaches and exceeded the estimated 0.2-percent AEP flood in 16.7 of the 28.6 study reach miles. The simulated water-surface profiles were then combined with a geographic information system digital elevation model derived from light detection and ranging (lidar) data having a 18.2-centimeter vertical accuracy at the 95-percent confidence level and 1-meter horizontal resolution to delineate the area flooded for each water-surface profile.

Modifying the anti-wetting property of butterfly wings and water strider legs by atomic layer deposition coating: surface materials versus geometry.

PubMed

Ding, Yong; Xu, Sheng; Zhang, Yue; Wang, Aurelia C; Wang, Melissa H; Xiu, Yonghao; Wong, Ching Ping; Wang, Zhong Lin

2008-09-03

Although butterfly wings and water strider legs have an anti-wetting property, their working conditions are quite different. Water striders, for example, live in a wet environment and their legs need to support their weight and bear the high pressure during motion. In this work, we have focused on the importance of the surface geometrical structures in determining their performance. We have applied an atomic layer deposition technique to coat the surfaces of both butterfly wings and water strider legs with a uniform 30 nm thick hydrophilic Al(2)O(3) film. By keeping the surface material the same, we have studied the effect of different surface roughness/structure on their hydrophobic property. After the surface coating, the butterfly wings changed to become hydrophilic, while the water strider legs still remained super-hydrophobic. We suggest that the super-hydrophobic property of the water strider is due to the special shape of the long inclining spindly cone-shaped setae at the surface. The roughness in the surface can enhance the natural tendency to be hydrophobic or hydrophilic, while the roughness in the normal direction of the surface is favorable for forming a composite interface.

Antibiotic, Pharmaceutical, and Wastewater-Compound Data for Michigan, 1998-2005

USGS Publications Warehouse

Haack, Sheridan Kidd

2010-01-01

Beginning in the late 1990's, the U.S. Geological Survey began to develop analytical methods to detect, at concentrations less than 1 microgram per liter (ug/L), emerging water contaminants such as pharmaceuticals, personal-care chemicals, and a variety of other chemicals associated with various human and animal sources. During 1998-2005, the U.S. Geological Survey analyzed the following Michigan water samples: 41 samples for antibiotic compounds, 28 samples for pharmaceutical compounds, 46 unfiltered samples for wastewater compounds (dissolved and suspended compounds), and 113 filtered samples for wastewater compounds (dissolved constituents only). The purpose of this report is to summarize the status of emerging contaminants in Michigan waters based on data from several different project-specific sample-collection efforts in Michigan during an 8-year period. During the course of the 8-year sampling effort, antibiotics were determined at 20 surface-water sites and 2 groundwater sites, pharmaceuticals were determined at 11 surface-water sites, wastewater compounds in unfiltered water were determined at 31 surface-water sites, and wastewater compounds in filtered water were determined at 40 surface-water and 4 groundwater sites. Some sites were visited only once, but others were visited multiple times. A variety of quality-assurance samples also were collected. This report describes the analytical methods used, describes the variations in analytical methods and reporting levels during the 8-year period, and summarizes all data using current (2009) reporting criteria. Very few chemicals were detected at concentrations greater than current laboratory reporting levels, which currently vary from a low of 0.005 ug/L for some antibiotics to 5 ug/L for some wastewater compounds. Nevertheless, 10 of 51 chemicals in the antibiotics analysis, 9 of 14 chemicals in the pharmaceuticals analysis, 34 of 67 chemicals in the unfiltered-wastewater analysis, and 56 of 62 chemicals in the filtered-wastewater analysis were detected. Antibiotics were detected at 7 of 20 tested surface-water sites, but none were detected in 2 groundwater samples. Pharmaceuticals were detected at 7 of 11 surface-water sites. Wastewater compounds were detected at 25 of 31 sites for which unfiltered water samples were analyzed and at least once at all 40 surface-water sites and all 4 groundwater sites for which filtered water samples were analyzed. Overall, the chemicals detected most frequently in Michigan waters were similar to those reported frequently in other studies nationwide. Patterns of chemical detections were site specific and appear to be related to local sources, overall land use, and hydrologic conditions at the time of sampling. Field-blank results provide important information for the design of future sampling programs in Michigan and demonstrate the need for careful field-study design. Field-replicate results indicated substantial confidence regarding the presence or absence of the many chemicals tested. Overall, data reported herein indicate that a wide array of antibiotic, pharmaceutical, and organic wastewater compounds occur in Michigan waters. Patterns of occurrence, with respect to hydrologic, land use, and source variables, generally appear to be similar for Michigan as for other sampled waters across the United States. The data reported herein can serve as a basis for future studies in Michigan.

Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands: Pahranagat Valley, Nevada, USA

USGS Publications Warehouse

Paces, James B.; Wurster, Frederic C.

2014-01-01

Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge’s irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands - Pahranagat Valley, Nevada, USA

NASA Astrophysics Data System (ADS)

Paces, James B.; Wurster, Frederic C.

2014-09-01

Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable-isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge's irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate-aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

Removal of biofilms by impinging water droplets

NASA Astrophysics Data System (ADS)

Cense, A. W.; van Dongen, M. E. H.; Gottenbos, B.; Nuijs, A. M.; Shulepov, S. Y.

2006-12-01

The process of impinging water droplets on Streptococcus mutans biofilms was studied experimentally and numerically. Droplets were experimentally produced by natural breakup of a cylindrical liquid jet. Droplet diameter and velocity were varied between 20 and 200 μm and between 20 and 100 m/s, respectively. The resulting erosion process of the biofilm was determined experimentally with high-speed recording techniques and a quantitative relationship between the removal rate, droplet size, and velocity was determined. The shear stress and the pressure on the surface during droplet impact were determined by numerical simulations, and a qualitative agreement between the experiment and the simulation was obtained. Furthermore, it was shown that the stresses on the surface are strongly reduced when a water film is present.

Mars surface based factory. Phase 2, task 1C: Computer control of a water treatment system to support a space colony on Mars

NASA Technical Reports Server (NTRS)

Fuller, John; Ali, Warsame; Willis, Danette

1989-01-01

In a continued effort to design a surface based factory on Mars for the production of oxygen and water, a preliminary study was made of the surface and atmospheric composition on Mars and determined the mass densities of the various gases in the Martian atmosphere. Based on the initial studies, oxygen and water were determined to be the two products that could be produced economically under the Martian conditions. Studies were also made on present production techniques to obtain water and oxygen. Analyses were made to evaluate the current methods of production that were adaptable to the Martian conditions. Even though the initial effort was the production of oxygen and water, it was found necessary to produce some diluted gases that can be mixed with the oxygen produced to constitute 'breathable' air. The conceptual design of a breathable air manufacturing system, a means of drilling for underground water, and storage of water for future use were completed. The design objective was the conceptual design of an integrated system for the supply of quality water for biological consumption, farming, residential and industrial use.

Base of moderately saline ground water in the Uinta Basin, Utah, with an introductory section describing the methods used in determining its position

USGS Publications Warehouse

Howells, Lewis; Longson, M.S.; Hunt, Gilbert L.

1987-01-01

The base of the moderately saline water (water that contains from 3,000 to 10,000 milligrams per liter of dissolved solids) was mapped by using available water-quality data and by determining formation-water resistivities from geophysical well logs based on the resistivity-porosity, spontaneous potential, and resistivity-ratio methods. The contour map developed from these data showed a mound of very saline and briny water, mostly of sodium chloride and sodium bicarbonate type, in most of that part of the Uinta Basin that is underlain by either the Green River or Wasatch Formations. Along its northern edge, the mound rises steeply from below sea level to within 2,000 feet of the land surface and, locally, to land surface. Along its southern edge, the mound rises less steeply and is more complex in outline. This body of very saline to briny water may be a lens; many wells or test holes drilled within the area underlain by the mound re-entered fresh to moderately saline water at depths of 8,000 to 15,000 feet below lam surface.

Alumina Volatility in Water Vapor at Elevated Temperatures: Application to Combustion Environments

NASA Technical Reports Server (NTRS)

Opila, Elizabeth J.; Myers, Dwight L.

2003-01-01

The volatility of alumina in high temperature water vapor was determined by measuring weight loss of sapphire coupons at temperatures between 1250 and 1500 C, water vapor partial pressures between 0.15 and 0.68 atm in oxygen, at one atmosphere total pressure, and a gas velocity of 4.4 centimeters per second. The variation of the volatility with water vapor partial pressure was consistent with Al(OH)3(g) formation. The enthalpy of reaction to form Al(OH)3(g) from alumina and water vapor was found to be 210 plus or minus 20 kJ/mol. Surface rearrangement of ground sapphire surfaces increased with water vapor partial pressure, temperature and volatility rate. Recession rates of alumina due to volatility were determined as a function of water vapor partial pressure and temperature to evaluate limits for use of alumina in long term applications in combustion environments.

An appraisal of the quality of surface water in the Sevier Lake basin, Utah, 1964

USGS Publications Warehouse

Hahl, D.C.; Mundorff, J.C.

1968-01-01

The Sevier and Beaver River systems are the two major river systems in the Sevier Lake basin in Utah. This report contains an analysis of reconnaissance data collected during the 1964 water year regarding the quality of water in these rivers and their tributaries. The purpose of the reconnaissance was to obtain needed water-quality information for the basin. Corollary purposes were to (1) determine the suitability of surface water for specificuses, (2) determine the need and criteria for a water-quality network, and (3) locate sources of organic pollution to the rivers. Data concerning item 3 are mentioned only briefly in this report and will be discussed in a report to be prepared by the Utah Water Pollution and Control Board. Data collected in connection with the reconnaissance and resulting analyses were reported by Hahl and Cabell (1965).

Derivation of site-specific surface water quality criteria for the protection of aquatic ecosystems near a Korean military training facility.

PubMed

Jeong, Seung-Woo; An, Youn-Joo

2014-01-01

This study suggested the first Korean site-specific ecological surface water quality criteria for the protection of ecosystems near an artillery range at a Korean military training facility. Surface water quality (SWQ) criteria in Korea address human health protection but do not encompass ecological criteria such as limits for metals and explosives. The first objective of this study was to derive site-specific SWQ criteria for the protection of aquatic ecosystems in Hantan River, Korea. The second objective was to establish discharge criteria for the artillery range to protect the aquatic ecosystems of Hantan River. In this study, we first identified aquatic organisms living in the Hantan River, including fishes, reptiles, invertebrates, phytoplankton, zooplankton, and amphibians. Second, we collected ecotoxicity data for these aquatic organisms and constructed an ecotoxicity database for Cd, Cu, Zn, TNT, and RDX. This study determined the ecological maximum permissible concentrations for metals and explosives based on the ecotoxicity database and suggested ecological surface water quality criteria for the Hantan River by considering analytical detection limits. Discharge limit criteria for the shooting range were determined based on the ecological surface water quality criteria suggested for Hantan River with further consideration of the dilution of the contaminants discharged into the river.

Development and application of a sol-gel immunosorbent-based method for the determination of isoproturon in surface water.

PubMed

Zhang, Xiuli; Martens, Dieter; Krämer, Petra M; Kettrup, Antonius A; Liang, Xinmiao

2006-01-13

An immunosorbent was fabricated by encapsulation of monoclonal anti-isoproturon antibodies in sol-gel matrix. The immunosorbent-based loading, rinsing and eluting processes were optimized. Based on these optimizations, the sol-gel immunosorbent (SG-IS) selectively extracted isoproturon from an artificial mixture of 68 pesticides. In addition to this high selectivity, the SG-IS proved to be reusable. The SG-IS was combined with liquid chromatography-tandem mass spectrometry (LC-MS-MS) to determine isoproturon in surface water, and the linear range was up to 2.2 microg/l with correlation coefficient higher than 0.99 and relative standard deviation (RSD) lower than 5% (n=8). The limit of quantitation (LOQ) for 25-ml surface water sample was 5 ng/l.

Method of and device for detecting oil pollutions on water surfaces

DOEpatents

Belov, Michael Leonidovich [Moscow, RU; Gorodnichev, Victor Aleksandrovich [Moscow, RU; Kozintsev, Valentin Ivanovich [Moscow, RU; Smimova, Olga Alekseevna [Moscow, RU; Fedotov, Yurii Victorovich [Moscow, RU; Khroustaleva, Anastasiva Michailovnan [Moscow, RU

2008-08-26

Detection of oil pollution on water surfaces includes providing echo signals obtained from optical radiation of a clean water area at two wavelengths, optically radiating an investigated water area at two wavelengths and obtaining echo signals from the optical radiation of the investigated water area at the two wavelengths, comparing the echo signals obtained from the radiation of the investigated area at two wavelengths with the echo signals obtained from the radiation of the clean water area, and based on the comparison, determining presence or absence of oil pollution in the investigated water area.

Development of an Operational Land Water Mask for MODIS Collection 6, and Influence on Downstream Data Products

NASA Technical Reports Server (NTRS)

Carroll, M. L.; DiMiceli, C. M.; Townshend, J. R. G.; Sohlberg, R. A.; Elders, A. I.; Devadiga, S.; Sayer, A. M.; Levy, R. C.

2016-01-01

Data from the Moderate Resolution Imaging Spectro-radiometer (MODIS)on-board the Earth Observing System Terra and Aqua satellites are processed using a land water mask to determine when an algorithm no longer needs to be run or when an algorithm needs to follow a different pathway. Entering the fourth reprocessing (Collection 6 (C6)) the MODIS team replaced the 1 km water mask with a 500 m water mask for improved representation of the continental surfaces. The new water mask represents more small water bodies for an overall increase in water surface from 1 to 2 of the continental surface. While this is still a small fraction of the overall global surface area the increase is more dramatic in certain areas such as the Arctic and Boreal regions where there are dramatic increases in water surface area in the new mask. MODIS products generated by the on-going C6 reprocessing using the new land water mask show significant impact in areas with high concentrations of change in the land water mask. Here differences between the Collection 5 (C5) and C6 water masks and the impact of these differences on the MOD04 aerosol product and the MOD11 land surface temperature product are shown.

Airflow in Gravity Sewers - Determination of Wastewater Drag Coefficient.

PubMed

Bentzen, Thomas Ruby; Østertoft, Kristian Kilsgaard; Vollertsen, Jes; Fuglsang, Emil Dietz; Nielsen, Asbjørn Haaning

2016-03-01

Several experiments have been conducted in order to improve the understanding of the wastewater drag and the wall frictional force acting on the headspace air in gravity sewers. The aim of the study is to improve the data basis for a numerical model of natural sewer ventilation. The results of the study shows that by integrating the top/side wall shear stresses the log-law models for the air velocity distribution along the unwetted perimeter resulted in a good agreement with the friction forces calculated by use of the Colebrook-White formula for hydraulic smooth pipes. Secondly, the water surface drags were found by log-law models of the velocity distribution in turbulent flows to fit velocity profiles measured from the water surface and by integrating the water surface drags along the wetted perimeter, mean water surface drags were found and a measure of the water surface drag coefficient was found.

Surface properties and water treatment capacity of surface engineered silica coated with 3-(2-aminoethyl) aminopropyltrimethoxysilane

NASA Astrophysics Data System (ADS)

Majewski, Peter; Keegan, Alexandra

2012-01-01

This study's focus was on the water-based, one-pot preparation and characterisation of silica particles coated with 3-(2-aminoethyl)aminopropyltrimethoxysilane (Diamo) and the efficiency of the material in removing the pathogens Escherichia coli, Pseudomonas aeruginosa, Mycobacterium immunogenum, Vibrio cholerae, poliovirus, and Cryptosporidium parvum. The water-based processing resulted in Diamo coated silica particles with significantly increased positive surface charge as determined by zeta potential measurements. In addition, X-ray photoelectron spectrometry of pure and Diamo coated silica confirmed the presence of Diamo on the surface of the particles. Thermogravimetric measurements and chemical analysis of the silica indicated a surface concentration of amine groups of about 1 mmol/gsilica. Water treatment tests with the pathogens showed that a dose of about 10 g appeared to be sufficient to remove pathogens from pure water samples which were spiked with pathogen concentrations between about 102 and 104 cfu/mL.

Dynamic Heights in the Great Lakes using OPUS Projects

NASA Astrophysics Data System (ADS)

Roman, D. R.; Li, X.

2015-12-01

The U.S. will be implementing new geometric and vertical reference frames in 2022 to replace the North American Datum of 1983 (NAD 83) and the North American Vertical Datum of 1988 (NAVD 88), respectively. Less emphasized is the fact that a new dynamic height datum will also be defined about the same time to replace the International Great Lakes Datum of 1985 (IGLD 85). IGLD 85 was defined concurrent with NAVD 88 and used the same geopotential values. This paper focuses on the use of an existing tool for determining geometric coordinates and a developing geopotential model as a means of determining dynamic heights. The Online Positioning User Service (OPUS) Projects (OP) is an online tool available from the National Geodetic Survey (NGS) for use in developing geometric coordinates from simultaneous observations at multiple sites during multiple occupations. With observations performed at the water level gauges throughout the Great Lakes, the geometric coordinates of the mean water level surface can be determined. NGS has also developed the xGEOID15B model from satellite, airborne and surface gravity data. Using the input geometric coordinates determined through OP, the geopotential values for the water surface at the water level stations around the Great Lakes were determined using the xGEOID15B model. Comparisons were made between water level sites for each Lake as well as to existing IGLD 85 heights. A principal advantage to this approach is the ability to generate new water level control stations using OP, while maintaining the consistency between orthometric and dynamic heights by using the same gravity field model. Such a process may provide a means for determining dynamic heights for a future Great Lakes Datum.

Determination of color of turbid waters

USGS Publications Warehouse

Lamar, W.L.

1949-01-01

A convenient procedure for determining the color of turbid waters, using the principle of precipitation of turbidity by the electrolyte calcium chloride, is described. Because the stable turbidity of many surface waters cannot be completely precipitated by conventional centrifuging alone, this procedure presents a means of flocculating the turbidity without affecting the true color of the water. In the determination of true color of turbid samples one of the most prevalent errors is caused by the reading of color on samples not completely free of turbidity. Pertinent data are presented on color and turbidity of waters as related to the principles involved in the determination of color.

Distribution of polycyclic aromatic hydrocarbons in southern Chesapeake Bay surface water: Evaluation of three methods for determining freely dissolved water concentrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gustafson, K.E.; Dickhut, R.M.

1997-03-01

Gas sparging, semipermeable-membrane devices (SPMDs), and filtration with sorption of dissolved polycyclic aromatic hydrocarbons (PAHs) to XAD-2 resin were evaluated for determining the concentrations of freely dissolved PAHs in estuarine waters of southern Chesapeake Bay at sites ranging from rural to urban and highly industrialized. Gas sparging had significant sampling artifacts due to particle scavenging by rising bubbles, and SPMDs were kinetically limited for four-ring and larger PAHs relative to short-term temporal changes in water concentrations. Filtration with sorption of the dissolved contaminant fraction to XAD-2 resin was found to be the most accurate and feasible method for determining concentrationsmore » of freely dissolved PAHs in estuarine water. Concentrations and distribution coefficients of dissolved and particulate PAHs were measured using the filtration/XAD-2 method. Concentrations of PAHs in surface waters of southern Chesapeake Bay were higher than those reported for the northern bay; concentrations in the Elizabeth River were elevated relative to all other sites. A gradient for particulate PAHs was observed from urban to remote sites. No seasonal trends were observed in dissolved or particle-bound PAH fractions at any site. Distributions of dissolved and particulate PAHs in surface waters of the Chesapeake Bay are near equilibrium at all locations and during all seasons.« less

Variation of Water Quality Parameters with Siltation Depth for River Ichamati Along International Border with Bangladesh Using Multivariate Statistical Techniques

NASA Astrophysics Data System (ADS)

Roy, P. K.; Pal, S.; Banerjee, G.; Biswas Roy, M.; Ray, D.; Majumder, A.

2014-12-01

River is considered as one of the main sources of freshwater all over the world. Hence analysis and maintenance of this water resource is globally considered a matter of major concern. This paper deals with the assessment of surface water quality of the Ichamati river using multivariate statistical techniques. Eight distinct surface water quality observation stations were located and samples were collected. For the samples collected statistical techniques were applied to the physico-chemical parameters and depth of siltation. In this paper cluster analysis is done to determine the relations between surface water quality and siltation depth of river Ichamati. Multiple regressions and mathematical equation modeling have been done to characterize surface water quality of Ichamati river on the basis of physico-chemical parameters. It was found that surface water quality of the downstream river was different from the water quality of the upstream. The analysis of the water quality parameters of the Ichamati river clearly indicate high pollution load on the river water which can be accounted to agricultural discharge, tidal effect and soil erosion. The results further reveal that with the increase in depth of siltation, water quality degraded.

Permian paleoclimate data from fluid inclusions in halite

USGS Publications Warehouse

Benison, K.C.; Goldstein, R.H.

1999-01-01

This study has yielded surface water paleotemperatures from primary fluid inclusions in mid Permian Nippewalla Group halite from western Kansas. A 'cooling nucleation' method is used to generate vapor bubbles in originally all-liquid primary inclusions. Then, surface water paleotemperatures are obtained by measuring temperatures of homogenization to liquid. Homogenization temperatures ranged from 21??C to 50??C and are consistent along individual fluid inclusion assemblages, indicating that the fluid inclusions have not been altered by thermal reequilibration. Homogenization temperatures show a range of up to 26??C from base to top of individual cloudy chevron growth bands. Petrographic and fluid inclusion evidence indicate that no significant pressure correction is needed for the homogenization temperature data. We interpret these homogenization temperatures to represent shallow surface water paleotemperatures. The range in temperatures from base to top of single chevron bands may reflect daily temperatures variations. These Permian surface water temperatures fall within the same range as some modern evaporative surface waters, suggesting that this Permian environment may have been relatively similar to its modern counterparts. Shallow surface water temperatures in evaporative settings correspond closely to local air temperatures. Therefore, the Permian surface water temperatures determined in this study may be considered proxies for local Permian air temperatures.

Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction

USGS Publications Warehouse

Nelson, Jonathan M.; Kinzel, Paul J.; McDonald, Richard R.; Schmeeckle, Mark

2016-01-01

Recently developed optical and videographic methods for measuring water-surface properties in a noninvasive manner hold great promise for extracting river hydraulic and bathymetric information. This paper describes such a technique, concentrating on the method of infrared videog- raphy for measuring surface velocities and both acoustic (laboratory-based) and laser-scanning (field-based) techniques for measuring water-surface elevations. In ideal laboratory situations with simple flows, appropriate spatial and temporal averaging results in accurate water-surface elevations and water-surface velocities. In test cases, this accuracy is sufficient to allow direct inversion of the governing equations of motion to produce estimates of depth and discharge. Unlike other optical techniques for determining local depth that rely on transmissivity of the water column (bathymetric lidar, multi/hyperspectral correlation), this method uses only water-surface information, so even deep and/or turbid flows can be investigated. However, significant errors arise in areas of nonhydrostatic spatial accelerations, such as those associated with flow over bedforms or other relatively steep obstacles. Using laboratory measurements for test cases, the cause of these errors is examined and both a simple semi-empirical method and computational results are presented that can potentially reduce bathymetric inversion errors.

Soil water content and evaporation determined by thermal parameters obtained from ground-based and remote measurements

NASA Technical Reports Server (NTRS)

Reginato, R. J.; Idso, S. B.; Jackson, R. D.; Vedder, J. F.; Blanchard, M. B.; Goettelman, R.

1976-01-01

Soil water contents from both smooth and rough bare soil were estimated from remotely sensed surface soil and air temperatures. An inverse relationship between two thermal parameters and gravimetric soil water content was found for Avondale loam when its water content was between air-dry and field capacity. These parameters, daily maximum minus minimum surface soil temperature and daily maximum soil minus air temperature, appear to describe the relationship reasonably well. These two parameters also describe relative soil water evaporation (actual/potential). Surface soil temperatures showed good agreement among three measurement techniques: in situ thermocouples, a ground-based infrared radiation thermometer, and the thermal infrared band of an airborne multispectral scanner.

Flood Map for the Winooski River in Waterbury, Vermont, 2014

USGS Publications Warehouse

Olson, Scott A.

2015-01-01

High-water marks from Tropical Storm Irene were available for seven locations along the study reach. The highwater marks were used to estimate water-surface profiles and discharges resulting from Tropical Storm Irene throughout the study reach. From a comparison of the estimated water-surface profile for Tropical Storm Irene with the water-surface profiles for the 1- and 0.2-percent annual exceedance probability (AEP) floods, it was determined that the high-water elevations resulting from Tropical Storm Irene exceeded the estimated 1-percent AEP flood throughout the Winooski River study reach but did not exceed the estimated 0.2-percent AEP flood at any location within the study reach.

Optimization of the Use of Selected Non-Phosphate Water Retention Additives in Minced Beef Using Response Surface Methodology

NASA Astrophysics Data System (ADS)

Shang, Xiaolan; Qiao, Jie; Liu, Yujie

2017-12-01

This study looked to determine what the optimum cooking loss for minced beef was when three different non-phosphate water retention additives (L-Arginine, sodium carbonate, and sodium citrate) were combined; the optimum value was determined using a Box-Behnken response surface design method. The optimum value was found to be 8.26%, and it was obtained when 0.29% L-Arginine, 0.45% sodium carbonate, and 0.24% sodium citrate were added to the beef.

Airborne Lidar Measurements of Below-canopy Surface Water Height , Slope and Optical Properties in the Florida Everglades Shark River Slough

NASA Astrophysics Data System (ADS)

Dabney, P.; Harding, D. J.; Valett, S. R.; Yu, A. W.; Feliciano, E. A.; Neuenschwander, A. L.; Pitts, K.

2015-12-01

Determining the presence, persistence, optical properties and variation in height and slope of surface water beneath the dense canopies of flooded forests and mangrove stands could contribute to studies of the acquisition of water and nutrients by plant roots. NASA's airborne Slope Imaging Multi-polarization Photon-counting Lidar (SIMPL) provides unique capabilities that can identify below-canopy surface water, measure its height with respect to vegetation constituents with sub-decimeter precision and quantify its slope. It also provides information on canopy structure and closure, the water column extinction profile as a proxy for turbidity and water depth, with the penetration depth constrained by turbidity. It achieves this by using four laser beams operating at two wavelengths with measurements of water surface elevation at 1064 nm (near infrared) and water column properties at 532 nm (green), analogous to a bathymetric lidar. Importantly the instrument adds a polarimetry function, like some atmospheric lidars, which measures the amount of depolarization determined by the degree to which the plane-parallel transmitted laser pulse energy is converted to the perpendicular state. The degree of depolarization is sensitive to the number of photon multiple-scattering events. For the water surface, which is specular consisting only of single-scattering events, the near-infrared received signal retains the parallel polarization state. Absence of the perpendicular signal uniquely identifies surface water. Penetration of green light and the depth profile of photons converted to the perpendicular state compared to those in the parallel state is a measure of water-column multiple scattering, providing a relative measure of turbidity. The amount of photons reflected from the canopy versus the water provides a wavelength-dependent measure of canopy closure. By rapidly firing laser pulses (11,400 pulses per second) with a narrow width (1 nsec) and detecting single photons with 8 cm ranging precision, the surface altimetry data is acquired with very high spatial and vertical resolution. Examples of these capabilities will be shown using data collected in 2011 along and across the flow axis of the Florida Everglades Shark River Slough, targeting the slough's Long Term Ecology Research (LTER) field sites.

Hadean Oceanography: Experimental Constraints on the Development of the Terrestrial Hydrosphere and the Origin of Life on Earth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryerson, F J

The oxygen isotopic compositions of the world's oldest mineral grains, zircon, have recently been used to infer the compositions of the rocks from which they crystallized. The results appear to require a source that had once experienced isotopic fractionation between clay minerals and liquid water, thereby implying the presence of liquid water at the Earth's surface prior to 4.4 billion years ago, less than 2 million years after accretion. This observation has important implications for the development of the Earth's continental crust. The inferred composition of the zircon source rock is directly dependent upon the oxygen isotopic fractionation between zirconmore » and melt, and zircon and water. These fractionation factors have not been determined experimentally, however, constituting the weak link in this argument. A series of experiments to measure these fractionation factors has been conducted. The experiments consist of finely powdered quartz, a polished single crystal of zircon and isotopically-enriched or isotopically normal water to provide a range of isotopic compositions. The experiments will be run until quartz is in isotopic equilibrium with water. Zircon was expected to partially equilibrate producing an oxygen isotopic diffusion profile perpendicular to the surface. Ion probe spot analysis of quartz and depth profiling of zircon will determine the bulk and surface isotopic compositions of the phases, respectively. The well-known quartz-water isotopic fractionation factors can be used to calculate the oxygen isotopic composition of the fluid, and with the zircon surface composition, the zircon-water fractionation factor. Run at temperatures up to 1000 C for as long as 500 hours have not produced diffusion profiles longer than 50 nm. The steep isotopic gradient at the samples surface precludes use of the diffusion profile for estimation on the surface isotopic composition. The short profiles may be the result of surface dissolution, although such dissolution cannot be resolved in SEM images. The sluggish nature of diffusion in zircon may require that fractionation factors be determined by direct hydrothermal synthesis of zircon rather than by mineral-fluid exchange.« less

Application of new point measurement device to quantify groundwater-surface water interactions

NASA Astrophysics Data System (ADS)

Cremeans, M. M.; Devlin, J. F.; McKnight, U. S.; Bjerg, P. L.

2018-04-01

The streambed point velocity probe (SBPVP) measures in situ groundwater velocities at the groundwater-surface water interface without reliance on hydraulic conductivity, porosity, or hydraulic gradient information. The tool operates on the basis of a mini-tracer test that occurs on the probe surface. The SBPVP was used in a meander of the Grindsted Å (stream), Denmark, to determine the distribution of flow through the streambed. These data were used to calculate the contaminant mass discharge of chlorinated ethenes into the stream. SBPVP data were compared with velocities estimated from hydraulic head and temperature gradient data collected at similar scales. Spatial relationships of water flow through the streambed were found to be similar by all three methods, and indicated a heterogeneous pattern of groundwater-surface water exchange. The magnitudes of estimated flow varied to a greater degree. It was found that pollutants enter the stream in localized regions of high flow which do not always correspond to the locations of highest pollutant concentration. The results show the combined influence of flow and concentration on contaminant discharge and illustrate the advantages of adopting a flux-based approach to risk assessment at the groundwater-surface water interface. Chlorinated ethene mass discharges, expressed in PCE equivalents, were determined to be up to 444 kg/yr (with SBPVP data) which compared well with independent estimates of mass discharge up to 438 kg/yr (with mini-piezometer data from the streambed) and up to 372 kg/yr crossing a control plane on the streambank (as determined in a previous, independent study).

Bisphenol A and other bisphenol analogues including BPS and BPF in surface water samples from Japan, China, Korea and India.

PubMed

Yamazaki, Eriko; Yamashita, Nobuyoshi; Taniyasu, Sachi; Lam, James; Lam, Paul K S; Moon, Hyo-Bang; Jeong, Yunsun; Kannan, Pranav; Achyuthan, Hema; Munuswamy, Natesan; Kannan, Kurunthachalam

2015-12-01

Concentrations of eight bisphenol analogues (BPs) including BPA, BPS, and BPF were determined in surface waters collected from select rivers in Japan, Korea, China, and India. BPA was found at a concentration in the range of several tens to several hundreds of nanograms per liter in most of the rivers surveyed and some of the highest concentrations (54-1950 ng/L) were found in rivers in Chennai, India. Concentrations of BPF were one to two orders of magnitude higher than those of BPA in river and sea waters collected from Japan, Korea and China, which suggested that BPF is a major contaminant in surface waters in several Southeast Asian countries. BPF concentrations as high as 2850 ng/L were found in the Tamagawa River in Japan. The flux of BPs through riverine discharges into Tokyo Bay was calculated to be approximately 5.5 t per year. Based on the flux estimates and the mass of BPF found in water column and sediment in Tokyo Bay, it was found that BPF degrades faster than BPA in the environment. Elevated concentrations of BPF found in surface waters suggest the need for further studies to determine the fate and toxicity of this compound. Copyright © 2015 Elsevier Inc. All rights reserved.

Determination of bromine, chlorine and iodine in environmental aqueous samples by epithermal neutron activation analysis and Compton suppression

USGS Publications Warehouse

Landsberger, S.; O'Kelly, D. J.; Braisted, J.; Panno, S.

2006-01-01

Halides, particularly Br- and Cl-, have been used as indicators of potential sources of Na+ and Cl- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na+ and Cl- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using epithermal NAA in conjunction with Compton suppression. ?? 2006 Akade??miai Kiado??.

Intermittent Surface Water Connectivity: Fill and Spill vs. Fill ...

EPA Pesticide Factsheets

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

Intermittent Surface Water Connectivity: Fill and Spill Vs. Fill ...

EPA Pesticide Factsheets

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

Remote measurement of soil moisture over vegetation using infrared temperature measurements

NASA Technical Reports Server (NTRS)

Carlson, Toby N.

1991-01-01

Better methods for remote sensing of surface evapotranspiration, soil moisture, and fractional vegetation cover were developed. The objectives were to: (1) further develop a model of water movement through the soil/plant/atmosphere system; (2) use this model, in conjunction with measurements of infrared surface temperature and vegetation fraction; (3) determine the magnitude of radiometric temperature response to water stress in vegetation; (4) show at what point one can detect that sensitivity to water stress; and (5) determine the practical limits of the methods. A hydrological model that can be used to calculate soil water content versus depth given conventional meteorological records and observations of vegetation cover was developed. An outline of the results of these initiatives is presented.

POTENTIAL FOR NITROSAMINE FORMATION RESULTING FROM THE USE OF RHODAMINE WT FOR TIME-OF-TRAVEL STUDIES: A COMBINED LABORATORY AND FIELD INVESTIGATION.

USGS Publications Warehouse

Johnson, Sharon M.; Steinheimer, Thomas R.

1984-01-01

Rhodamine WT is used by surface water hydrologists for time of travel and dispersion studies in which flow characteristics of surface streams are determined. Surface water contamination by nitrosamines formed from Rhodamine WT and nitrite ion has been studied. A method for residue analysis of N-nitrosodiethylamine (NDEA) has been developed and evaluated using river samples spiked with Rhodamine WT and nitrite ion. It permits rapid and reliable determination of NDEA at a minimum concentration of 0. 03 mu g/L. The method uses solid-phase extraction and capillary gas chromatography.

Determination of benzotriazole corrosion inhibitors from aqueous environmental samples by liquid chromatography-electrospray ionization-tandem mass spectrometry.

PubMed

Weiss, Stefan; Reemtsma, Thorsten

2005-11-15

The first method for the determination of commonly used corrosion inhibitors in environmental water samples by liquid chromatography-electrospray ionization-tandem mass spectrometry is presented. Benzotriazole (BTri) and the two isomers of tolyltriazole (5- and 4-TTri) are separated in an isocratic run. By gradient elution, BTri, 4-TTri, 5-TTri, and xylyltriazole can be determined simultaneously with three benzothiazoles, but here TTri isomers coelute. The instrumental detection limit of 2 pg allows the determination of the three most important benzotriazoles from municipal wastewater and most surface waters by direct injection into the HPLC system without previous enrichment. When solid-phase extraction is employed with mean recovery rates of 95-113%, the limit of quantification for benzotriazoles range from 10 ng/L in groundwater to 25 ng/L in untreated wastewater. BTri and TTri were determined in municipal wastewater in microgram per liter concentrations. Elimination in wastewater treatment appears to be poor, and BTri and TTri can be followed through a water cycle from treated municipal wastewater through surface water to bank filtrate used for drinking water production. The TTri isomers show markedly different biodegradation behavior with 4-TTri being more stable.

DETERMINATION OF ECOLOGICALLY RELEVANT PHARMACEUTICALS AND THEIR SELECTED METABOLITES IN EFFLUENT AND SURFACE WATER USING UPLC/MS/MS

EPA Science Inventory

Objective is to develop analytical methods including SPE and UPLC/MS/MS needed to analyze over 60 human prescription pharamceuticals and metabolites belonging to a multitude of different classes in surface waters and wastewater effluent. The methods will be used in future studies...

Parent and conjugated estrogens and progestagens in surface water of the Santa Ana River: Determination, occurrence, and risk assessment

USDA-ARS?s Scientific Manuscript database

This study presents a sensitive analytical method using high performance liquid chromatography tandem mass spectrometry for the simultaneous monitoring of five estrogen conjugates, six estrogens and two progestagens in surface water of the Santa Ana River. Samples at ten representative sites along t...

Surface Water and Groundwater Nitrogen Dynamics in a Well Drained Riparian Forest within a Poorly Drained Agricultural Landscape

EPA Science Inventory

The effectiveness of riparian zones in mitigating nutrients in ground and surface water depends on the climate, management and hydrogeomorphology of a site. The purpose of this study was to determine the efficacy of a well-drained, mixed-deciduous riparian forest to buffer a ri...

RECOVERY OF SURFACE WATERS IN THE NORTHEASTERN U.S. FROM DECREASES IN ATMOSPHERIC DEPOSITION OF SULFUR

EPA Science Inventory

A simple mass flux model was developed to simulate the response of SO concentrations in surface waters to past and anticipated future changes in atmospheric deposition of SO . Values of bulk (or wet) SO deposition and dry deposition of S determined from measured air concentrat...

The Use of Bacterial Adherence to Hydrocarbons (BATH) Assay in Evaluation of the Hydrophobic Surface Characteristics of Potential Water Pathogens

EPA Science Inventory

Bacterial adherence to hydrocarbons, BATH, is a method for determining the hydrophobic surface characteristics of bacterial cells. The strain’s affinity for water is evaluated by thoroughly mixing a culture and hydrocarbon suspension and then evaluating the decrease in optical de...

Drainage water management

USDA-ARS?s Scientific Manuscript database

This article introduces a series of papers that report results of field studies to determine the effectiveness of drainage water management (DWM) on conserving drainage water and reducing losses of nitrogen (N) to surface waters. The series is focused on the performance of the DWM (also called contr...

Simple treatment of cotton textile to impart high water repellent properties

NASA Astrophysics Data System (ADS)

Ivanova, N. A.; Zaretskaya, A. K.

2010-12-01

We describe two methods to impart the water repellency for the surface of cotton fabric, using a commercially available and a laboratory synthesized fluoroalkylsiloxanes. To characterize the wettability and the durability of water repellent properties of hydrophobic coating produced, we have studied the advancing water contact angles, rolling angles and the evolution of water contact angle in time during a continuous contact of the surface with the water drop. The quality of the coatings was also assessed after the washing procedure. The analysis of the wettability of hydrophobized fabrics indicated that a better effect, leading to the superhydrophobic state of the surface, was observed when the surface relief of the fabric with the coating is determined by not only the structure and braiding of the fabric, but also the additional elements of texture created by the aggregates of molecules of hydrophobic agent.

Water-escape velocities in jumping blacktip sharks

PubMed Central

Brunnschweiler, Juerg M

2005-01-01

This paper describes the first determination of water-escape velocities in free-ranging sharks. Two approximations are used to estimate the final swimming speed at the moment of penetrating the water surface. Blacktip sharks were videotaped from below the surface and parameters were estimated by analysing the sequences frame by frame. Water-escape velocities averaged 6.3 m s−1. These velocities for blacktip sharks seem accurate and are similar to estimates obtained for other shark species of similar size. PMID:16849197

A method of determining surface runoff by

Treesearch

Donald E. Whelan; Lemuel E. Miller; John B. Cavallero

1952-01-01

To determine the effects of watershed management on flood runoff, one must make a reliable estimate of how much the surface runoff can be reduced by a land-use program. Since surface runoff is the difference between precipitation and the amount of water that soaks into the soil, such an estimate must be based on the infiltration capacity of the soil.

Does Personalized Water and Hand Quality Information Affect Attitudes, Behavior, and Health in Dar es Salaam, Tanzania?

NASA Astrophysics Data System (ADS)

Davis, J.; Pickering, A.; Horak, H.; Boehm, A.

2008-12-01

Tanzania (TZ) has one of the highest rates of child mortality due to enteric disease in the world. NGOs and local agencies have introduced numerous technologies (e.g., chlorine tablets, borewells) to increase the quantity and quality of water in Dar es Salaam, the capital of Tanzania, in hopes of reducing morbidity and mortality of waterborne disease. The objective of the present study is to determine if providing personalized information about water quality and hand surface quality, as determined by concentrations of enterococci and E. coli, results in improved health and water quality in households. A cohort study was completed in June-September 2008 in 3 communities ranging from urban to per-urban in Dar es Salaam, Tanzania to achieve our objective. The study consisted of 4 cohorts that were visited 4 times over the 3 month study. One cohort received no information about water and hand quality until the end of the summer, while the other groups received either just information on hand surface quality, just information on water quality, and information on both hand surface and water quality after the first (baseline) household visit. We report concentrations of enterococci and E. coli in water sources (surface waters and bore wells), water stored in households, and environmental waters were children and adults swim and bathe. In addition, we report concentrations of enterococci and E. coli on hands of caregivers and children in households. Preliminary results of surveys on health and perceptions of water quality and illness from the households are provided. Ongoing work will integrate the microbiological and sociological data sets to determine if personalized information interventions resulted in changes in health, water quality in the household, or perceptions of water quality, quantity and relation to human health. Future work will analyze DNA samples from hands and water for human-specific Bacteroides bacteria which are only present in human feces. Our study has the potential to provide empirical evidence to promote large scale monitoring and education campaigns in Africa to improve health and reduce the burden of waterborne disease.

Diversity and antibiotic resistance of Aeromonas spp. in drinking and waste water treatment plants.

PubMed

Figueira, Vânia; Vaz-Moreira, Ivone; Silva, Márcia; Manaia, Célia M

2011-11-01

The taxonomic diversity and antibiotic resistance phenotypes of aeromonads were examined in samples from drinking and waste water treatment plants (surface, ground and disinfected water in a drinking water treatment plant, and raw and treated waste water) and tap water. Bacteria identification and intra-species variation were determined based on the analysis of the 16S rRNA, gyrB and cpn60 gene sequences. Resistance phenotypes were determined using the disc diffusion method. Aeromonas veronii prevailed in raw surface water, Aeromonas hydrophyla in ozonated water, and Aeromonas media and Aeromonas puntacta in waste water. No aeromonads were detected in ground water, after the chlorination tank or in tap water. Resistance to ceftazidime or meropenem was detected in isolates from the drinking water treatment plant and waste water isolates were intrinsically resistant to nalidixic acid. Most of the times, quinolone resistance was associated with the gyrA mutation in serine 83. The gene qnrS, but not the genes qnrA, B, C, D or qepA, was detected in both surface and waste water isolates. The gene aac(6')-ib-cr was detected in different waste water strains isolated in the presence of ciprofloxacin. Both quinolone resistance genes were detected only in the species A. media. This is the first study tracking antimicrobial resistance in aeromonads in drinking, tap and waste water and the importance of these bacteria as vectors of resistance in aquatic environments is discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Surface Properties and Permeability of Poly(Vinylidene Fluoride)-Clays (PVDF/Clays) Composite Membranes

NASA Astrophysics Data System (ADS)

Pramono, E.; Ahdiat, M.; Simamora, A.; Pratiwi, W.; Radiman, C. L.; Wahyuningrum, D.

2017-07-01

Surface properties are important factors that determine the performance of ultrafiltration membranes. This study aimed to investigate the effects of clay addition on the surface properties and membrane permeability of PVDF (poly-vinylidene fluoride) membranes. Three types of clay with different particle size were used in this study, namely montmorillonite-MMT, bentonite-BNT and cloisite 15A-CLS. The PVDF-clay composite membranes were prepared by phase inversion method using PEG as additive. The hydrophobicity of membrane surface was characterized by contact angle. The membrane permeability was determined by dead- end ultrafiltration with a trans-membrane pressure of 2 bars. In contact angle measurement, water contact angle of composite membranes is higher than PVDF membrane. The addition of clays decreased water flux but increased of Dextran rejection. The PVDF-BNT composite membranes reach highest Dextran rejection value of about 93%. The type and particle size of clay affected the hydrophobicity of membrane surface and determined the resulting membrane structure as well as the membrane performance.

Influence of multi-industrial activities on trace metal contamination: an approach towards surface water body in the vicinity of Dhaka Export Processing Zone (DEPZ).

PubMed

Ahmed, Golam; Miah, M Arzu; Anawar, Hossain M; Chowdhury, Didarul A; Ahmad, Jasim U

2012-07-01

Industrial wastewater discharged into aquatic ecosystems either directly or because of inadequate treatment of process water can increase the concentrations of pollutants such as toxic metals and others, and subsequently deteriorate water quality, environmental ecology and human health in the Dhaka Export Processing Zone (DEPZ), the largest industrial belt of 6-EPZ in Bangladesh. Therefore, in order to monitor the contamination levels, this study collected water samples from composite effluent points inside DEPZ and the surrounding surface water body connected to effluent disposal sites and determined the environmental hazards by chemical analysis and statistical approach. The water samples were analysed by inductively coupled plasma mass spectrometry to determine 12 trace metals such as As, Ag, Cr, Co, Cu, Li, Ni, Pb, Se, Sr, V and Zn in order to assess the influence of multi-industrial activities on metal concentrations. The composite effluents and surface waters from lagoons were characterized by a strong colour and high concentrations of biochemical oxygen demand, chemical oxygen demand, electrical conductivity, pH, total alkalinity, total hardness, total organic carbon, Turb., Cl(-), total suspended solids and total dissolved solids, which were above the limit of Bangladesh industrial effluent standards, but dissolved oxygen concentration was lower than the standard value. The measurement of skewness and kurtosis values showed asymmetric and abnormal distribution of the elements in the respective phases. The mean trend of variation was found in a decreasing order: Zn > Cu > Sr > Pb > Ni > Cr > Li > Co > V > Se > As > Ag in composite industrial effluents and Zn > Cu > Sr > Pb > Ni > Cr > Li > V > As > Ag > Co > Se in surface waters near the DEPZ. The strong correlations between effluent and surface water metal contents indicate that industrial wastewaters discharged from DEPZ have a strong influence on the contamination of the surrounding water bodies by toxic metals. The average contamination factors were reported to be 0.70-96.57 and 2.85-1,462 for industrial effluents and surface waters, respectively. The results reveal that the surface water in the area is highly contaminated with very high concentrations of some heavy/toxic metals like Zn, Pb, Cu, Ni and Cr; their average contamination factors are 1,460, 860, 136, 74.71 and 4.9, respectively. The concentrations of the metals in effluent and surface water were much higher than the permissible limits for drinking water and the world average concentrations in surface water. Therefore, the discharged effluent and surface water may create health hazards especially for people working and living inside and in the surrounding area of DEPZ.

Landsat - What is operational in water resources

NASA Technical Reports Server (NTRS)

Middleton, E. M.; Munday, J. C., Jr.

1981-01-01

Applications of Landsat data in hydrology and water quality measurement were examined to determine which applications are operational. In hydrology, the principal applications have been surface water inventory, and land cover analysis for (1) runoff modeling and (2) abatement planning for non-point pollution and erosion. In water quality measurement, the principal applications have been: (1) trophic state assessment, and (2) measurement of turbidity and suspended sediment. The following applications were found to be operational: mapping of surface water, snow cover, and land cover (USGS Level 1) for watershed applications; measurement of turbidity, Secchi disk depth, suspended sediment concentration, and water depth.

Hydrogeologic characteristics of four public drinking-water supply springs in northern Arkansas

USGS Publications Warehouse

Galloway, Joel M.

2004-01-01

In October 2000, a study was undertaken by the U.S. Geological Survey (USGS) in cooperation with the Arkansas Department of Health to determine the hydrogeologic characteristics, including the extent of the recharge areas, for Hughes Spring, Stark Spring, Evening Shade Spring, and Roaring Spring, which are used for public-water supply in northern Arkansas. Information pertaining to each spring can be used to enable development of effective management plans to protect these water resources and public health. An integrated approach to determine the ground-water characteristics and the extent of the local recharge areas of the four springs incorporated tools and methods of hydrology, structural geology, geomorphology, geophysics, and geochemistry. Analyses of discharge, temperature, and water quality were completed to describe ground-water flow characteristics, source-water characteristics, and connectivity of the ground-water system with surface runoff. Water-level contour maps were constructed to determine ground-water flow directions and ground-water tracer tests were conducted to determine the extent of the recharge areas and ground-water flow velocities. Hughes Spring supplies water for the city of Marshall, Arkansas, and the surrounding area. The mean annual discharge for Hughes Spring was 2.9 and 5.2 cubic feet per second for water years 2001 and 2002, respectively. Recharge to the spring occurs mainly from the Boone Formation (Springfield Plateau aquifer). Ground-water tracer tests indicate the recharge area for Hughes Spring generally coincides with the surface drainage area (15.8 square miles) and that Hughes Spring is connected directly to the surface flow in Brush Creek. The geochemistry of Hughes Spring demonstrated variations with flow conditions and the influence of surface-runoff in the recharge area. Calcite saturation indices, total dissolved solids concentrations, and hardness demonstrate noticeable differences with flow conditions reflecting the reduced residence time and interaction of water with the source rock within the ground-water system at higher discharges for Hughes Spring. Concentrations of fecal indicator bacteria also demonstrated a substantial increase during high-flow conditions, suggesting that a non-point source of bacteria possibly from livestock may enter the system. Conversely, nutrient concentrations did not vary with flow and were similar to concentrations reported for undeveloped sites in the Springfield Plateau and Ozark aquifers in northern Arkansas and southern Missouri. Deuterium and oxygen-18 data show that the Hughes Spring discharge is representative of direct precipitation and not influenced by water enriched in oxygen-18 through evaporation. Discharge data show that Hughes Spring is dominated by conduit type ground-water flow, but a considerable component of diffuse flow also exists in the ground-water system. Carbon-13 data indicate a substantial component of the recharge water interacts with the surface material (soil and regolith) in the recharge area before entering the ground-water system for Hughes Spring. Tritium data for Hughes Spring indicate that the discharge water is a mixture of recent recharge and sub-modern water (recharged prior to 1952). Stark Spring supplies water for the city of Cushman, Arkansas, and the surrounding area. 2 Hydrogeologic Characteristics of Four Public Drinking-Water Supply Springs in Northern Arkansas The mean annual discharge for Stark Spring was 0.5 and 1.5 cubic feet per second for water years 2001 and 2002, respectively. The discharge and water-quality data show the ground-water system for Stark Spring is dominated by rapid recharge from surface runoff and mainly consists of a conduit- type flow system with little diffuse-type flow. Analyses of discharge data show that the estimated recharge area (0.79 square mile) is larger than the surface drainage area (0.34 square mile). Ground-water tracer tests and the outcrop of the

The calming effect of oil on water

NASA Astrophysics Data System (ADS)

Behroozi, Peter; Cordray, Kimberly; Griffin, William; Behroozi, Feredoon

2007-05-01

The calming effect of oil on water has been known since ancient times. Benjamin Franklin was the first to investigate the effect, but the underlying mechanism for this striking phenomenon remains elusive. We used a miniature laser interferometer to measure the amplitude of surface waves to a resolution of ±5nm, making it possible to determine the effect of an oil monolayer on the attenuation of capillary waves and the surface dilational modulus of the monolayer. We present attenuation data on pure water, water covered by olive oil, water covered by a fatty acid, and a water-acetone mixture for comparison. From the attenuation data at frequencies between 251 and 551Hz, we conclude that the calming effect of oil on surface waves is principally due to the dissipation of wave energy caused by the Gibbs surface elasticity of the monolayer, with only a secondary contribution from the reduction in surface tension. Our data also indicate that the surface-dilational viscosity of the oil monolayer is negligible and plays an insignificant role in calming the waves.

Determination of monthly mean humidity in the atmospheric surface layer over oceans from satellite data

NASA Technical Reports Server (NTRS)

Liu, W. T.; Niiler, P. P.

1984-01-01

A simple statistical technique is described to determine monthly mean marine surface-layer humidity, which is essential in the specification of surface latent heat flux, from total water vapor in the atmospheric column measured by space-borne sensors. Good correlation between the two quantities was found in examining the humidity soundings from radiosonde reports of mid-ocean island stations and weather ships. The relation agrees with that obtained from satellite (Seasat) data and ship reports averaged over 2 deg areas and a 92-day period in the North Atlantic and in the tropical Pacific. The results demonstrate that, by using a local regression in the tropical Pacific, total water vapor can be used to determine monthly mean surface layer humidity to an accuracy of 0.4 g/kg. With a global regression, determination to an accuracy of 0.8 g/kg is possible. These accuracies correspond to approximately 10 to 20 W/sq m in the determination of latent heat flux with the bulk parameterization method, provided that other required parameters are known.

Controllability of Surface Water Networks

NASA Astrophysics Data System (ADS)

Riasi, M. Sadegh; Yeghiazarian, Lilit

2017-12-01

To sustainably manage water resources, we must understand how to control complex networked systems. In this paper, we study surface water networks from the perspective of structural controllability, a concept that integrates classical control theory with graph-theoretic formalism. We present structural controllability theory and compute four metrics: full and target controllability, control centrality and control profile (FTCP) that collectively determine the structural boundaries of the system's control space. We use these metrics to answer the following questions: How does the structure of a surface water network affect its controllability? How to efficiently control a preselected subset of the network? Which nodes have the highest control power? What types of topological structures dominate controllability? Finally, we demonstrate the structural controllability theory in the analysis of a wide range of surface water networks, such as tributary, deltaic, and braided river systems.

Effect of surface roughness on droplet splashing

NASA Astrophysics Data System (ADS)

Hao, Jiguang

2017-12-01

It is well known that rough surfaces trigger prompt splashing and suppress corona splashing on droplet impact. Upon water droplet impact, we experimentally found that a slightly rough substrate triggers corona splashing which is suppressed to prompt splashing by both further increase and further decrease of surface roughness. The nonmonotonic effect of surface roughness on corona splashing weakens with decreasing droplet surface tension. The threshold velocities for prompt splashing and corona splashing are quantified under different conditions including surface roughness, droplet diameter, and droplet surface tension. It is determined that slight roughness significantly enhances both prompt splashing and corona splashing of a water droplet, whereas it weakly affects low-surface-tension droplet splashing. Consistent with previous studies, high roughness triggers prompt splashing and suppresses corona splashing. Further experiments on droplet spreading propose that the mechanism of slight roughness enhancing water droplet splashing is due to the decrease of the wetted area with increasing surface roughness.

Aqueous or solvent based surface modification: The influence of the combination solvent - organic functional group on the surface characteristics of titanium dioxide grafted with organophosphonic acids

NASA Astrophysics Data System (ADS)

Roevens, Annelore; Van Dijck, Jeroen G.; Geldof, Davy; Blockhuys, Frank; Prelot, Benedicte; Zajac, Jerzy; Meynen, Vera

2017-09-01

To alter the versatility of interactions at its surface, TiO2 is modified with organophosphonic acids (PA). A thorough understanding of the role of all synthesis conditions is necessary to achieve controlled functionalization. This study reports on the effect of using water, toluene and their mixtures when performing the modification of TiO2 with PA. Sorption and calorimetry measurements of surface interactions with various probing species clearly indicate that, by grafting PA in water, clear differences appear in the distribution of organic groups on the surface. Also the functional group of the PA determines the impact of using water as solvent. Modification in toluene results in a higher modification degree for propylphosphonic acid (3PA), as the solvent-solute interaction may hinder the grafting with phenylphosphonic acid (PhPA) in toluene. Water is preferred as solvent for PhPA modification as stabilizing π-OH interactions enhance surface grafting overcoming the competitive interaction of water at the surface as observed with 3PA. By using water in toluene mixtures for the functionalization of TiO2 with 3PA, the degree of functionalization is higher than when only water or toluene is used. Furthermore, adding small amounts of water leads to the formation of titanium propylphosphonates, next to surface grafting.

MCX based solid phase extraction combined with liquid chromatography tandem mass spectrometry for the simultaneous determination of 31 endocrine-disrupting compounds in surface water of Shanghai.

PubMed

Zhang, Hong-Chang; Yu, Xue-jun; Yang, Wen-chao; Peng, Jin-feng; Xu, Ting; Yin, Da-Qiang; Hu, Xia-lin

2011-10-15

A novel analytical method employing MCX (mixed-mode cationic exchange) based solid phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed to detect 31 endocrine-disrupting compounds (EDCs) in surface water samples simultaneously. The target EDCs belong to five classes, including seven estrogens, eight androgens, six progesterones, five adrenocortical hormones and five industrial compounds. In order to simultaneously concentrate the target EDCs and eliminate matrix interferences in the water samples, MCX SPE cartridges were employed for SPE, and then followed by a simple and highly efficient three-step sequential elution procedure. Two electrospray ionization (ESI) detection modes, positive (ESI+) and (ESI-), were optimized for HPLC-MS/MS analysis to obtain the highest sensitivity for all the EDCs. The limits of detection (LODs) were 0.02-1.9 ng L(-1), which are lower than or comparable to these reported in references. Wide linear ranges (LOD-100 ng L(-1) for ESI+ mode, and LOD-200 ng L(-1) for ESI- mode) were obtained with determination coefficients (R(2)) higher than 0.99 for all the compounds. With five internal standards, good recoveries (84.4-103.0%) of all the target compounds were obtained in selected surface water samples. The developed method was successfully applied to investigate the EDCs occurrence in the surface water of Shanghai by analyzing surface water samples from 11 sites. The results showed that nearly all the target compounds (30 in 31) were present in the surface water samples of Shanghai, of which three industrial compounds (4-t-OP, BPA, and BPF) showed the highest concentrations (median concentrations were 11.88-23.50 ng L(-1)), suggesting that industrial compounds were the dominating EDCs in the surface water of Shanghai, and much more attention should be paid on these compounds. Our present research demonstrated that SPE with MCX cartridges combined with HPLC-MS/MS was convenient, efficient and reliable for multiclass analysis of EDCs in surface water. Copyright © 2011 Elsevier B.V. All rights reserved.

Free energy of adhesion of lipid bilayers on silica surfaces

NASA Astrophysics Data System (ADS)

Schneemilch, M.; Quirke, N.

2018-05-01

The free energy of adhesion per unit area (hereafter referred to as the adhesion strength) of lipid arrays on surfaces is a key parameter that determines the nature of the interaction between materials and biological systems. Here we report classical molecular simulations of water and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers at model silica surfaces with a range of silanol densities and structures. We employ a novel technique that enables us to estimate the adhesion strength of supported lipid bilayers in the presence of water. We find that silanols on the silica surface form hydrogen bonds with water molecules and that the water immersion enthalpy for all surfaces varies linearly with the surface density of these hydrogen bonds. The adhesion strength of lipid bilayers is a linear function of the surface density of hydrogen bonds formed between silanols and the lipid molecules on crystalline surfaces. Approximately 20% of isolated silanols form such bonds but more than 99% of mutually interacting geminal silanols do not engage in hydrogen bonding with water. On amorphous silica, the bilayer displays much stronger adhesion than expected from the crystalline surface data. We discuss the implications of these results for nanoparticle toxicity.

Optical label-free and model-free probe of the surface potential of nanoscale and microscopic objects in aqueous solution

NASA Astrophysics Data System (ADS)

Lütgebaucks, Cornelis; Gonella, Grazia; Roke, Sylvie

2016-11-01

The electrostatic environment of aqueous systems is an essential ingredient for the function of any living system. To understand the electrostatic properties and their molecular foundation in soft, living, and three-dimensional systems, we developed a table-top model-free method to determine the surface potential of nano- and microscopic objects in aqueous solutions. Angle-resolved nonresonant second harmonic (SH) scattering measurements contain enough information to determine the surface potential unambiguously, without making assumptions on the structure of the interfacial region. The scattered SH light that is emitted from both the particle interface and the diffuse double layer can be detected in two different polarization states that have independent scattering patterns. The angular shape and intensity are determined by the surface potential and the second-order surface susceptibility. Calibrating the response with the SH intensity of bulk water, a single, unique surface potential value can be extracted. We demonstrate the method with 80 nm bare oil droplets in water and ˜50 nm dioleoylphosphatidylcholine (DOPC) and dioleoylphosphatidylserine (DOPS) liposomes at various ionic strengths.

Quality characterization and pollution source identification of surface water using multivariate statistical techniques, Nalagarh Valley, Himachal Pradesh, India

NASA Astrophysics Data System (ADS)

Herojeet, Rajkumar; Rishi, Madhuri S.; Lata, Renu; Dolma, Konchok

2017-09-01

Sirsa River flows through the central part of the Nalagarh valley, belongs to the rapid industrial belt of Baddi, Barotiwala and Nalagarh (BBN). The appraisal of surface water quality to ascertain its utility in such ecologically sensitive areas is need of the hour. The present study envisages the application of multivariate analysis, water utility class and conventional graphical representation to reveal the hidden factor responsible for deterioration of water quality and determine the hydrochemical facies and its evolution processes of water types in Nalagarh valley, India. The quality assessment is made by estimating pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness, major ions (Na+, K+, Ca2+, Mg2+, HCO3 -, Cl-, SO4 2-, NO3 - and PO4 3-), dissolved oxygen (DO), biological oxygen demand (BOD) and total coliform (TC) to determine its suitability for drinking and domestic purposes. The parameters like pH, TDS, TH, Ca2+, HCO3 -, Cl-, SO4 2-, NO3 - are within the desirable limit as per Bureau of Indian Standards (Indian Standard Drinking Water Specification (Second Edition) IS:10500. Indian Standard Institute, New Delhi, pp 1-18, 2012). Mg2+, Na+ and K+ ions for pre monsoon and EC during pre and post monsoon at few sites and approx 40% samples of BOD and TC for both seasons exceeds the permissible limits indicate organic contamination from human activities. Water quality classification for designated use indicates that maximum surface water samples are not suitable for drinking water source without conventional treatment. The result of piper trillinear and Chadha's diagram classified majority of surface water samples for both seasons fall in the fields of Ca2+-Mg2+-HCO3 - water type indicating temporary hardness. PCA and CA reveal that the surface water chemistry is influenced by natural factors such as weathering of minerals, ion exchange processes and anthropogenic factors. Thus, the present paper illustrates the importance of multivariate techniques for reliable quality characterization of surface water quality to develop effective pollution reduction strategies and maintain a fine balance between the industrialization and ecological integrity.

Operation of hydrologic data collection stations by the U.S. Geological Survey in 1987

USGS Publications Warehouse

Condes de la Torre, Alberto

1987-01-01

The U.S. Geological Survey operates hydrologic data collection stations nationwide which serve the needs of all levels of government, the private sector, and the general public, for water resources information. During fiscal year 1987, surface water discharge was determined at 10,624 stations; stage data on streams, reservoirs, and lakes were recorded at 1,806 stations; and various surface water quality characteristics were determined at 2,901 stations. In addition, groundwater levels were measured at 32,588 stations, and the quality of groundwater was determined at 9,120 stations. Data on sediment were collected daily at 174 stations and on a periodic basis at 878 stations. Information on precipitation quantity was collected at 909 stations, and the quality of precipitation was analyzed at 78 stations. Data collection platforms for satellite telemetry of hydrologic information were used at 2,292 Geological Survey stations. Funding for the hydrologic stations was derived, either solely or from a combination, from three major sources - the Geological Survey 's Federal Program appropriation, the Federal-State Cooperative Program, and reimbursements from other Federal agencies. The number of hydrologic stations operated by the Geological Survey declined from fiscal year 1983 to 1987. The number of surface water discharge stations were reduced by 452 stations; surface water quality stations declined by 925 stations; groundwater level stations declined by 1,051 stations; while groundwater quality stations increased by 1,472 stations. (Author 's abstract)

Water adsorption on TiO2 surfaces probed by soft X-ray spectroscopies: bulk materials vs. isolated nanoparticles

PubMed Central

Benkoula, Safia; Sublemontier, Olivier; Patanen, Minna; Nicolas, Christophe; Sirotti, Fausto; Naitabdi, Ahmed; Gaie-Levrel, François; Antonsson, Egill; Aureau, Damien; Ouf, François-Xavier; Wada, Shin-Ichi; Etcheberry, Arnaud; Ueda, Kiyoshi; Miron, Catalin

2015-01-01

We describe an experimental method to probe the adsorption of water at the surface of isolated, substrate-free TiO2 nanoparticles (NPs) based on soft X-ray spectroscopy in the gas phase using synchrotron radiation. To understand the interfacial properties between water and TiO2 surface, a water shell was adsorbed at the surface of TiO2 NPs. We used two different ways to control the hydration level of the NPs: in the first scheme, initially solvated NPs were dried and in the second one, dry NPs generated thanks to a commercial aerosol generator were exposed to water vapor. XPS was used to identify the signature of the water layer shell on the surface of the free TiO2 NPs and made it possible to follow the evolution of their hydration state. The results obtained allow the establishment of a qualitative determination of isolated NPs’ surface states, as well as to unravel water adsorption mechanisms. This method appears to be a unique approach to investigate the interface between an isolated nano-object and a solvent over-layer, paving the way towards new investigation methods in heterogeneous catalysis on nanomaterials. PMID:26462615

A 'first principles' potential energy surface for liquid water from VRT spectroscopy of water clusters.

PubMed

Goldman, Nir; Leforestier, Claude; Saykally, R J

2005-02-15

We present results of gas phase cluster and liquid water simulations from the recently determined VRT(ASP-W)III water dimer potential energy surface (the third fitting of the Anisotropic Site Potential with Woermer dispersion to vibration-rotation-tunnelling data). VRT(ASP-W)III is shown to not only be a model of high 'spectroscopic' accuracy for the water dimer, but also makes accurate predictions of vibrational ground-state properties for clusters up through the hexamer. Results of ambient liquid water simulations from VRT(ASP-W)III are compared with those from ab initio molecular dynamics, other potentials of 'spectroscopic' accuracy and with experiment. The results herein represent the first time to the authors' knowledge that a 'spectroscopic' potential surface is able to correctly model condensed phase properties of water.

Determination of methyl mercury by aqueous phase Eehylation, followed by gas chromatographic separation with cold vapor atomic fluorescence detection

USGS Publications Warehouse

De Wild, John F.; Olsen, Mark L.; Olund, Shane D.

2002-01-01

A recent national sampling of streams in the United States revealed low methyl mercury concentrations in surface waters. The resulting median and mean concentrations, calculated from 104 samples, were 0.06 nanograms per liter (ng/L) and 0.15 ng/L, respectively. This level of methyl mercury in surface water in the United States has created a need for analytical techniques capable of detecting sub-nanogram per liter concentrations. In an attempt to create a U.S. Geological Survey approved method, the Wisconsin District Mercury Laboratory has adapted a distillation/ethylation/ gas-phase separation method with cold vapor atomic fluorescence spectroscopy detection for the determination of methyl mercury in filtered and unfiltered waters. This method is described in this report. Based on multiple analyses of surface water and ground-water samples, a method detection limit of 0.04 ng/L was established. Precision and accuracy were evaluated for the method using both spiked and unspiked ground-water and surface-water samples. The percent relative standard deviations ranged from 10.2 to 15.6 for all analyses at all concentrations. Average recoveries obtained for the spiked matrices ranged from 88.8 to 117 percent. The precision and accuracy ranges are within the acceptable method-performance limits. Considering the demonstrated detection limit, precision, and accuracy, the method is an effective means to quantify methyl mercury in waters at or below environmentally relevant concentrations

Molecular dynamics simulations study of nano bubble attachment at hydrophobic surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Jiaqi; Dang, Liem X.; Miller, Jan D.

Bubble attachment phenomena are examined using Molecular Dynamics Simulations (MDS) for the first time. The simulation involves a nitrogen nano bubble containing 906 nitrogen molecules in a water phase with 74,000 water molecules at molybdenite surfaces. During a simulation period of 1 ns, film rupture and displacement occurs. The attached nanobubble at the hydrophobic molybdenite face surface results in a contact angle of about 90º. This spontaneous attachment is due to a “water exclusion zone” at the molybdenite face surface and can be explained by a van der Waals (vdW) attractive force, as discussed in the literature. In contrast, themore » film is stable at the hydrophilic quartz (001) surface and the bubble does not attach. Contact angles determined from MD simulations are reported, and these results agree well with experimental and MDS sessile drop results. In this way, film stability and bubble attachment are described with respect to interfacial water structure for surfaces of different polarity. Interfacial water molecules at the hydrophobic molybdenite face surface have relatively weak interactions with the surface when compared to the hydrophilic quartz (001) surface, as revealed by the presence of a 3 Å “water exclusion zone” at the molybdenite/water interface. The molybdenite armchair-edge and zigzag-edge surfaces show a comparably slow process for film rupture and displacement when compared to the molybdenite face surface, which is consistent with their relatively weak hydrophobic character.« less

Infrared photography and imagery in water resources research

USGS Publications Warehouse

Robinove, Charles J.

1965-01-01

Infrared photography has restricted usefulness in general water resources studies but is particularly useful in special problems such as shoreline mapping. Infrared imagery is beginning to be used in water resources studies for the identification of surface and sub surface thermal anomalies as expressed at the surface and the measurement of apparent water surface temperatures. It will attain its maximum usefulness only when interpretation criteria for infrared imagery are fully developed. Several important hydrologic problems to which infrared imagery may be applied are: (1) determination of circulation and cooling of water in power plant cooling ponds, (2) measurement of river temperature and temperature decline downstream from power plants discharging heated water, (3) identification of submarine springs along coasts, and (4) measurement of temperature differences along streams as indicators of effluent seepage of ground water. Although it is possible at this time to identify many features of importance to hydrology by the use of infrared imagery, the task remaining is to develop criteria to show the hydrologic significance of the features.

A review on the sources and spatial-temporal distributions of Pb in Jiaozhou Bay

NASA Astrophysics Data System (ADS)

Yang, Dongfang; Zhang, Jie; Wang, Ming; Zhu, Sixi; Wu, Yunjie

2017-12-01

This paper provided a review on the source, spatial-distribution, temporal variations of Pb in Jiaozhou Bay based on investigation of Pb in surface and waters in different seasons during 1979-1983. The source strengths of Pb sources in Jiaozhou Bay were showing increasing trends, and the pollution level of Pb in this bay was slight or moderate in the early stage of reform and opening-up. Pb contents in the marine bay were mainly determined by the strength and frequency of Pb inputs from human activities, and Pb could be moving from high content areas to low content areas in the ocean interior. Surface waters in the ocean was polluted by human activities, and bottom waters was polluted by means of vertical water’s effect. The process of spatial distribution of Pb in waters was including three steps, i.e., 1), Pb was transferring to surface waters in the bay, 2) Pb was transferring to surface waters, and 3) Pb was transferring to and accumulating in bottom waters.

The hydration structure at yttria-stabilized cubic zirconia (110)-water interface with sub-Ångström resolution

DOE PAGES

Hou, Binyang; Kim, Seunghyun; Kim, Taeho; ...

2016-06-15

The interfacial hydration structure of yttria-stabilized cubic zirconia (110) surface in contact with water was determined with ~0.5 Å resolution by high-resolution X-ray reflectivity measurement. The terminal layer shows a reduced electron density compared to the following substrate lattice layers, which indicates there are additional defects generated by metal depletion as well as intrinsic oxygen vacancies, both of which are apparently filled by water species. Above this top surface layer, two additional adsorbed layers are observed forming a characteristic interfacial hydration structure. The first adsorbed layer shows abnormally high density as pure water and likely includes metal species, whereas themore » second layer consists of pure water. The observed interfacial hydration structure seems responsible for local equilibration of the defective surface in water and eventually regulating the long-term degradation processes. As a result, the multitude of water interactions with the zirconia surface results in the complex but highly ordered interfacial structure constituting the reaction front.« less

The Assessment of Instruments for Detecting Surface Water Spills Associated with Oil and Gas Operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Aubrey E.; Hopkinson, Leslie; Soeder, Daniel

Surface water and groundwater risks associated with unconventional oil and gas development result from potential spills of the large volumes of chemicals stored on-site during drilling and hydraulic fracturing operations, and the return to the surface of significant quantities of saline water produced during oil or gas well production. To better identify and mitigate risks, watershed models and tools are needed to evaluate the dispersion of pollutants in possible spill scenarios. This information may be used to determine the placement of in-stream water-quality monitoring instruments and to develop early-warning systems and emergency plans. A chemical dispersion model has been usedmore » to estimate the contaminant signal for in-stream measurements. Spills associated with oil and gas operations were identified within the Susquehanna River Basin Commission’s Remote Water Quality Monitoring Network. The volume of some contaminants was found to be sufficient to affect the water quality of certain drainage areas. The most commonly spilled compounds and expected peak concentrations at monitoring stations were used in laboratory experiments to determine if a signal could be detected and positively identified using standard water-quality monitoring equipment. The results were compared to historical data and baseline observations of water quality parameters, and showed that the chemicals tested do commonly affect water quality parameters. This work is an effort to demonstrate that hydrologic and water quality models may be applied to improve the placement of in-stream water quality monitoring devices. This information may increase the capability of early-warning systems to alert community health and environmental agencies of surface water spills associated with unconventional oil and gas operations.« less

Study of dilution, height, and lateral spread of vertical dense jets in marine shallow water.

PubMed

Ahmad, Nadeem; Suzuki, Takayuki

2016-01-01

This study provides information for the design of sea outfalls to dispose of brine from desalination plants into shallow lagoons of the sea. The behavior of vertical dense jets was studied experimentally by discharging cold saline water vertically upward into a tank filled with hot freshwater under stagnant ambient conditions. The minimum return point dilution, μmin, was determined using thermocouples, and the maximum height, Z(m), and the lateral spread, R(sp), of the fountains were determined by observing shadowgraph pictures. The flow was turbulent and the densimetric Froude number Fr(0) varied from 9 to 18.8. Three mixing regimes were identified: deep, intermediate, and impinging mixing regimes. In the intermediate mixing regime, μ(min) and Z(m) were analyzed and compared with the results of deep water studies. The μ(min) and Z(m) values of fountains at an intermediate water depth were found to be higher than those of fountains at deep water depths. In the impinging regime, μ(min) decreases rapidly when a fountain starts to continuously impinge on the water surface, showing a noticeable disturbance in the water surface. Therefore, a good rule of thumb is to reduce the flow through multiport diffusers from desalination plants when the noticeable disturbance is observed from the top water surface.

Portable field kit for determining uranium in water

USGS Publications Warehouse

McHugh, John B.

1979-01-01

The pressing need for on-site field analyses of the uranium content of surface and ground waters has promoted the development of a simple, light-weight, relatively cheap, portable kit to make such determinations in the field. Forty to sixty water samples per day can be analyzed for uranium to less than 0.2 parts per billion. The kit was tested in the field with excellent results.

Low temperature self-cleaning properties of superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Wang, Fajun; Shen, Taohua; Li, Changquan; Li, Wen; Yan, Guilong

2014-10-01

Outdoor surfaces are usually dirty surfaces. Ice accretion on outdoor surfaces could lead to serious accidents. In the present work, the superhydrophobic surface based on 1H, 1H, 2H, 2H-Perfluorodecanethiol (PFDT) modified Ag/PDMS composite was prepared to investigate the anti-icing property and self-cleaning property at temperatures below freezing point. The superhydrophobic surface was deliberately polluted with activated carbon before testing. It was observed that water droplet picked up dusts on the cold superhydrophobic surface and took it away without freezing at a measuring temperature of -10 °C. While on a smooth PFDT surface and a rough surface base on Ag/PDMS composite without PFDT modification, water droplets accumulated and then froze quickly at the same temperature. However, at even lower temperature of -12 °C, the superhydrophobic surface could not prevent the surface water from icing. In addition, it was observed that the frost layer condensed from the moisture pay an important role in determining the low temperature self-cleaning properties of a superhydrophobic surface.

44 CFR 64.3 - Flood Insurance Maps.

Code of Federal Regulations, 2010 CFR

2010-10-01

... with water surface elevations determined A0 Area of special flood hazards having shallow water depths... insurance rating purposes AH Areas of special flood hazards having shallow water depths and/or unpredictable... of special flood hazards having shallow water depths and/or unpredictable flow paths between (1) and...

Phlogopite Decomposition, Water, and Venus

NASA Technical Reports Server (NTRS)

Johnson, N. M.; Fegley, B., Jr.

2005-01-01

Venus is a hot and dry planet with a surface temperature of 660 to 740 K and 30 parts per million by volume (ppmv) water vapor in its lower atmosphere. In contrast Earth has an average surface temperature of 288 K and 1-4% water vapor in its troposphere. The hot and dry conditions on Venus led many to speculate that hydrous minerals on the surface of Venus would not be there today even though they might have formed in a potentially wetter past. Thermodynamic calculations predict that many hydrous minerals are unstable under current Venusian conditions. Thermodynamics predicts whether a particular mineral is stable or not, but we need experimental data on the decomposition rate of hydrous minerals to determine if they survive on Venus today. Previously, we determined the decomposition rate of the amphibole tremolite, and found that it could exist for billions of years at current surface conditions. Here, we present our initial results on the decomposition of phlogopite mica, another common hydrous mineral on Earth.

Wettability, Polarity, and Water Absorption of Holm Oak Leaves: Effect of Leaf Side and Age1[OPEN

PubMed Central

Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

2014-01-01

Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. PMID:24913938

Drinking water treatment is not associated with an observed increase in neural tube defects in mice

PubMed Central

Melin, Vanessa E.; Johnstone, David W.; Etzkorn, Felicia A.

2018-01-01

Disinfection by-products (DBPs) arise when natural organic matter in source water reacts with disinfectants used in the water treatment process. Studies have suggested an association between DBPs and birth defects. Neural tube defects (NTDs) in embryos of untreated control mice were first observed in-house in May 2006 and have continued to date. The source of the NTD-inducing agent was previously determined to be a component of drinking water. Tap water samples from a variety of sources were analyzed for trihalomethanes (THMs) to determine if they were causing the malformations. NTDs were observed in CD-1 mice provided with treated and untreated surface water. Occurrence of NTDs varied by water source and treatment regimens. THMs were detected in tap water derived from surface water but not detected in tap water derived from a groundwater source. THMs were absent in untreated river water and laboratory purified waters, yet the percentage of NTDs in untreated river water were similar to the treated water counterpart. These findings indicate that THMs were not the primary cause of NTDs in the mice since the occurrence of NTDs was unrelated to drinking water disinfection. PMID:24497082

IMPERVIOUS SURFACES AND STREAMFLOW DISCHARGE: A HISTORICAL REMOTE SENSING PERSPECTIVE IN A NORTHERN VIRGINIA SUBWATERSHED

EPA Science Inventory

Impervious surfaces are a leading contributor to non-point-source water pollution in urban watersheds. These surfaces include such features as roads, parking lots, rooftops and driveways. Aerial photography provides a historical vehicle for determining impervious surface growth a...

Laboratory investigations of Mars - Chemical and spectroscopic characteristics of a suite of clays as Mars soil analogs

NASA Technical Reports Server (NTRS)

Banin, Amos; Carle, Glenn C.; Chang, Sherwood; Coyne, Lelia M.; Orenberg, James B.

1988-01-01

A model system of Mars soil analog materials (MSAMs) was prepared, and the properties of these clays, such as chemical composition, surface-ion composition, water adsorption isotherms, and reflectance spectra, were examined. The results of these studies, performed along with simulations of the Viking Labeled Release Experiement using MSAMs, indicate that surface iron and adsorbed water are important determinants of clay behavior, as evidenced by changes in reflectance, water absorption, and clay surface reactions. The paper discusses the relevance of these results to the two major questions raised by prior explorations of Mars: has there ever been abundant water on Mars, and why is the iron found in the Martian soil not readily seen in the reflectance spectra of the surface?

Field Techniques for Estimating Water Fluxes Between Surface Water and Ground Water

USGS Publications Warehouse

Rosenberry, Donald O.; LaBaugh, James W.

2008-01-01

This report focuses on measuring the flow of water across the interface between surface water and ground water, rather than the hydrogeological or geochemical processes that occur at or near this interface. The methods, however, that use hydrogeological and geochemical evidence to quantify water fluxes are described herein. This material is presented as a guide for those who have to examine the interaction of surface water and ground water. The intent here is that both the overview of the many available methods and the in-depth presentation of specific methods will enable the reader to choose those study approaches that will best meet the requirements of the environments and processes they are investigating, as well as to recognize the merits of using more than one approach. This report is designed to make the reader aware of the breadth of approaches available for the study of the exchange between surface and ground water. To accomplish this, the report is divided into four chapters. Chapter 1 describes many well-documented approaches for defining the flow between surface and ground waters. Subsequent chapters provide an in-depth presentation of particular methods. Chapter 2 focuses on three of the most commonly used methods to either calculate or directly measure flow of water between surface-water bodies and the ground-water domain: (1) measurement of water levels in well networks in combination with measurement of water level in nearby surface water to determine water-level gradients and flow; (2) use of portable piezometers (wells) or hydraulic potentiomanometers to measure hydraulic gradients; and (3) use of seepage meters to measure flow directly. Chapter 3 focuses on describing the techniques involved in conducting water-tracer tests using fluorescent dyes, a method commonly used in the hydrogeologic investigation and characterization of karst aquifers, and in the study of water fluxes in karst terranes. Chapter 4 focuses on heat as a tracer in hydrological investigations of the near-surface environment.

Velocity and stage data collected in a laboratory flume for water-surface slope determination using a pipe manometer

USGS Publications Warehouse

Lee, Jonathan K.; Visser, H.M.; Jenter, H.L.; Duff, M.P.

2000-01-01

U.S. Geological Survey (USGS) hydrologists and ecologist are conducting studies to quantify vegetative flow resistance in order to improve numerical models of surface-water flow in the Florida Everglades. Water-surface slope is perhaps the most difficult of the flow resistance parameters to measure in the Everglades due to the very low gradients of the topography and flow. In an effort to measure these very small slopes, a unique pipe manometer was developed for the local measurement of water-surface slopes on the order of 1 centimeter per kilometer (cm/km). According to theory, a very precise measurement of centerline velocity obtained inside the pipe manometer should serve as a unique proxy for water-surface slope in the direction of the pipe axis. In order to confirm this theoretical relationship and calibrate the pipe manometer, water-surface elevation and pipe centerline velocity data were simultaneously measured in a set of experiments carried out in the tilting flume at the USGS Hydraulic Laboratory Facility at Stennis Space Center, Mississippi. A description of the instrumentation and methods used to evaluate this technique for measuring water-surface slope as well as a summary of the entire data set is presented.

Structure and Dynamics of Forsterite-scCO2/H2O Interfaces as a Function of Water Content

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerisit, Sebastien N.; Weare, John H.; Felmy, Andrew R.

Molecular dynamics (MD) simulations of forsterite surfaces in contact with supercritical carbon dioxide (scCO2) fluids of varying water content were performed to determine the partition of water between the scCO2 fluid and the mineral surface, the nature of CO2 and H2O bonding at the interface, and the regions of the interface that may be conducive to HxCO3(2-x)- formation. Calculations of the free energy of the associative adsorption of water onto the (010) forsterite surface from the scCO2 phase indicated that the formation of a water film up to three-monolayer thick can be exothermic even for water contents below the watermore » saturation concentration of the scCO2 fluid. In MD simulations of scCO2/H2O mixtures in contact with the (010) forsterite surface, H2O was found to readily displace CO2 at the surface and, therefore, CO2 directly contacted the surface only for water coverages below two monolayers. For thicker water films, a two-monolayer hydration layer formed that CO2 could not penetrate. Simulations of the hydroxylated (010) surface and of the (011) surface suggested that this conclusion can be extended to forsterite surfaces with different surface structures and/or compositions. The density, diffusion, and degree of hydration of CO2 as well as the extent of CO2/H2O mixing at the interface were all predicted to depend strongly on the thickness of the water-rich film, i.e., on the water content of the scCO2 fluid.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oyola-Reynoso, S.; Tevis, I. D.; Chen, J.

Here, chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications. Reagents with multiple reactive sites have been used with the expectation that a monolayer will form. The step-growth polymerization mechanism, however, suggests the possibility of gel formation for hydrolyzable moieties in the presence of physisorbed water. In this report, we demonstrated that using alkyltrichlorosilanes (trivalent [i.e., 3 reactive sites]) in the surface modification of a cellulosic material (paper) does not yield a monolayer but rather gives surface-bound particles. We infer that the presencemore » of physisorbed (surface-bound) water allows for polymerization (or oligomerization) of the silane prior to its attachment on the surface. Surface energy mismatch between the hydrophobic tails of the growing polymer and any unreacted bound water leads to the assembly of the polymerizing material into spherical particles to minimize surface tension. By varying paper grammage (16.2–201.4 g m –2), we varied the accessible surface area and thus the amount of surface-adsorbed water, allowing us to control the ratio of the silane to the bound water. Using this approach, polymeric particles were formed on the surface of cellulose fibers ranging from ~70 nm to a film. The hydrophobicity of the surface, as determined by water contact angles, correlates with particle sizes (p < 0.001, Student's t-test), and, hence, the hydrophobicity can be tuned (contact angle between 94° and 149°). Using a model structure of a house, we demonstrated that as a result of this modification, paper-based houses can be rendered self-cleaning or tolerant to surface running water. In another application, we demonstrated that the felicitous choice of architectural design allows for the hydrophobic paper to be used for water harvesting.« less

Do root hydraulic properties change during the early vegetative stage of plant development in barley (Hordeum vulgare)?

PubMed Central

Suku, Shimi; Knipfer, Thorsten; Fricke, Wieland

2014-01-01

Background and Aims As annual crops develop, transpirational water loss increases substantially. This increase has to be matched by an increase in water uptake through the root system. The aim of this study was to assess the contributions of changes in intrinsic root hydraulic conductivity (Lp, water uptake per unit root surface area, driving force and time), driving force and root surface area to developmental increases in root water uptake. Methods Hydroponically grown barley plants were analysed during four windows of their vegetative stage of development, when they were 9–13, 14–18, 19–23 and 24–28 d old. Hydraulic conductivity was determined for individual roots (Lp) and for entire root systems (Lpr). Osmotic Lp of individual seminal and adventitious roots and osmotic Lpr of the root system were determined in exudation experiments. Hydrostatic Lp of individual roots was determined by root pressure probe analyses, and hydrostatic Lpr of the root system was derived from analyses of transpiring plants. Key Results Although osmotic and hydrostatic Lp and Lpr values increased initially during development and were correlated positively with plant transpiration rate, their overall developmental increases (about 2-fold) were small compared with increases in transpirational water loss and root surface area (about 10- to 40-fold). The water potential gradient driving water uptake in transpiring plants more than doubled during development, and potentially contributed to the increases in plant water flow. Osmotic Lpr of entire root systems and hydrostatic Lpr of transpiring plants were similar, suggesting that the main radial transport path in roots was the cell-to-cell path at all developmental stages. Conclusions Increase in the surface area of root system, and not changes in intrinsic root hydraulic properties, is the main means through which barley plants grown hydroponically sustain an increase in transpirational water loss during their vegetative development. PMID:24287810

Do root hydraulic properties change during the early vegetative stage of plant development in barley (Hordeum vulgare)?

PubMed

Suku, Shimi; Knipfer, Thorsten; Fricke, Wieland

2014-02-01

As annual crops develop, transpirational water loss increases substantially. This increase has to be matched by an increase in water uptake through the root system. The aim of this study was to assess the contributions of changes in intrinsic root hydraulic conductivity (Lp, water uptake per unit root surface area, driving force and time), driving force and root surface area to developmental increases in root water uptake. Hydroponically grown barley plants were analysed during four windows of their vegetative stage of development, when they were 9-13, 14-18, 19-23 and 24-28 d old. Hydraulic conductivity was determined for individual roots (Lp) and for entire root systems (Lp(r)). Osmotic Lp of individual seminal and adventitious roots and osmotic Lp(r) of the root system were determined in exudation experiments. Hydrostatic Lp of individual roots was determined by root pressure probe analyses, and hydrostatic Lp(r) of the root system was derived from analyses of transpiring plants. Although osmotic and hydrostatic Lp and Lp(r) values increased initially during development and were correlated positively with plant transpiration rate, their overall developmental increases (about 2-fold) were small compared with increases in transpirational water loss and root surface area (about 10- to 40-fold). The water potential gradient driving water uptake in transpiring plants more than doubled during development, and potentially contributed to the increases in plant water flow. Osmotic Lp(r) of entire root systems and hydrostatic Lp(r) of transpiring plants were similar, suggesting that the main radial transport path in roots was the cell-to-cell path at all developmental stages. Increase in the surface area of root system, and not changes in intrinsic root hydraulic properties, is the main means through which barley plants grown hydroponically sustain an increase in transpirational water loss during their vegetative development.

Occurrence and distribution of pesticides and volatile organic compounds in ground water and surface water in Central Arizona Basins, 1996-98, and their relation to land use

USGS Publications Warehouse

Gellenbeck, Dorinda J.; Anning, David W.

2002-01-01

Samples of ground water and surface water from the Sierra Vista subbasin, the Upper Santa Cruz Basin, and the West Salt River Valley were collected and analyzed to determine the occurrence and distribution of pesticides and volatile organic compounds in central Arizona. The study was done during 1996-98 within the Central Arizona Basins study unit of the National Water-Quality Assessment program. This study included 121 wells and 4 surface-water sites in the 3 basins and the analyses of samples from 4 sites along the Santa Cruz River that were part of a separate study. Samples were collected from 121 wells and 3 surface-water sites for pesticide analyses, and samples were collected from 109 wells and 3 surface-water sites for volatile organic compound analyses. Certain pesticides detected in ground water and surface water can be related specifically to agricultural or urban uses; others can be related to multiple land uses. Effects from historical agriculture are made evident by detections of DDE in ground-water and surface-water samples collected in the West Salt River Valley and detections of atrazine and deethylatrazine in the ground water in the Upper Santa Cruz Basin. Effects from present agriculture are evident in the seasonal variability in concentrations of pre-emergent pesticides in surface-water samples from the West Salt River Valley. Several detections of DDE and dieldrin in surface water were higher than established water-quality limits. Effects of urban land use are made evident by detections of volatile organic compounds in ground water and surface water from the West Salt River Valley. Detections of volatile organic compounds in surface water from the Santa Cruz River near Nogales, Arizona, also are indications of the effects of urban land use. One detection of tetrachloroethene in ground water was higher than established water-quality limits. Water reuse is an important conservation technique in the Southwest; however, the reuse of water provides a transport mechanism for pesticides and volatile organic compounds to reach areas that are not normally affected by manmade compounds from specific land-use activities. The most complex mixture of pesticides and volatile organic compounds is in the West Salt River Valley and is the result of water-management practices and the combination of land uses in this basin throughout history.

Spatial and Temporal Mapping of Distributed Surface and Groundwater Stable Isotopes Enables New insights into Hydrologic Processes Operating at the Catchment Scale

NASA Astrophysics Data System (ADS)

Cole, A.; Boutt, D. F.

2017-12-01

Isotopic analyses of d18O and d2H of water transiting the hydrologic cycle have allowed hydrologists to better understand the portioning of water between the different components of the water cycle. Isoscapes on a large spatial scale have been created to show isotopic variation in waters as a function of elevation, temperature, distance to coast and precipitation. This has not been done on a 10,000 sq mi area, sub-regional scale or for that matter exhaustively sampled the important components of the terrestrial hydrologic cycle (groundwater, surface water and soil waters). We present the spatial and temporal isotopic results of an ongoing study across Massachusetts, USA, to establish an isotopic baseline for the region. Our current database consists of water samples from 50 precipitation sites, 333 ground water sites and 421 surface water sites. The isotopic signature of d18O and d2H of the samples are measured by a wavelength scanned cavity ring-down spectrometry on un-acidified water samples by a Picarro Cavity Ring Down Spectrometer (L2120-I) analyzer. Our results show that groundwater ranges from -11 to -1 ‰ δ18O across Massachusetts. Wells show a correlation with elevation; at higher elevations groundwater is more depleted in the heavy isotopes than compared with wells located at a lower elevation. Surface, groundwater and precipitation depict a seasonal evaporative enrichment, with waters being lighter during the months and heavier during the summer months. Based on Massachusetts location relative to the coast, there is a large variability in the mean d18O of precipitation with rain being heavy near the coast and lighter with increasing distance from the coast. HYSPLIT trajectory models will be used to determine how source affects isotopic composition. Within Massachusetts the isotopic composition of groundwater in till, glacial fluvial and bedrock aquifers are distinct which indicates the potential for surface and groundwater interaction. Our data also indicates groundwater enrichment in the heavy isotopes. In order to further determine the interrelationship between surface and groundwater we will measure chloride on both surface and groundwater and relate the results. This dataset will become an important tool for water management and water resources.

Mapping of Temporal Surface-water Resources Availability and Agricultural Adaptability due to Climate Change and Anthropogenic Activity in a Hot Semi-arid Region of Maharashtra State, India

NASA Astrophysics Data System (ADS)

Roy, A.; Inamdar, A. B.

2016-12-01

Major part of Godavari River Basin is intensely drought prone and climate vulnerable in the Western Maharashtra State, India. The economy of the state depends on the agronomic productivity of this region. So, it is necessary to regulate the effects of existing and upcoming hydro-meteorological advances in various strata. This study investigates and maps the surface water resources availability and vegetation, their decadal deviations with multi-temporal LANDSAT images; and finally quantifies the agricultural adaptations. This work involves the utilization of Remote Sensing and GIS with Hydrological modeling. First, climatic trend analysis is carried out with NCEP dataset. Then, multi-temporal LANDSAT images are classified to determine the decadal LULC changes and correlated to the community level hydrological demand. Finally, NDVI, NDWI and SWAT model analysis are accomplished to determine irrigated and non-irrigated cropping area for identifying the agricultural adaptations. The analysis shows that the mean value of annual and monsoon rainfall is significantly decreasing, whereas the mean value of annual and summer temperature is increasing significantly and the winter temperature is decreasing. The analysis of LANDSAT images shows that the surface water availability is highly dependent on climatic conditions. Barren-lands are most dynamic during the study period followed by, vegetation, and water bodies. The spatial extent of barren-lands is increased drastically during the climate vulnerable years replacing the vegetation and surface water bodies. Hence, the barren lands are constantly increasing and the vegetation cover is linearly decreasing, whereas the water extent is changing either way in a random fashion. There appears a positive correlation between surface water and vegetation occurrence; as they are fluctuating in a similar fashion in all the years. The vegetation cover is densely replenished around the dams and natural water bodies which serve as the water supply stations for the irrigation purposes. Moreover, there is a shift to non-irrigated and less water demanding crops, from more water demanding crops, which is a conspicuous adaptation. Hence, the study shows there are alteration in meteorological predictors, land cover, agricultural practices and surface water availability.

Testing the performance of superhydrophobic aluminum surfaces.

PubMed

Ruiz-Cabello, F Javier Montes; Ibáñez-Ibáñez, Pablo F; Gómez-Lopera, J Francisco; Martínez-Aroza, José; Cabrerizo-Vílchez, Miguel; Rodríguez-Valverde, Miguel A

2017-12-15

The analysis of wetting properties of superhydrophobic surfaces may be a difficult task due to the restless behavior of drops on this type of surfaces and the limitations of goniometry for high contact angles. A method to validate the performance of superhydrophobic surfaces, rather than standard goniometry, is required. In this work, we used bouncing drop dynamics as a useful tool to predict the water repellency of different superhydrophobic surfaces. From bouncing drop experiments conducted over a wide range of superhydrophobic surfaces, we found that those surfaces with a proper roughness degree and homogeneous chemical composition showed higher water-repellency. We also conducted a drop condensation study at saturating conditions aimed to determine whether there is direct correlation between water repellency and condensation delay. We found that the drop condensation process is strongly related to the surface topography, as well as the intrinsic wettability. The condensation is promoted on rough surfaces but it is delayed on intrinsically hydrophobic surfaces. However, the differences found in condensation delay between the superhydrophobic surfaces explored in this study cannot be justified by their chemical homogeneity nor their efficiency as water repellent surfaces, separately. Copyright © 2017 Elsevier Inc. All rights reserved.

[Contamination and ecological risk assessment of polycyclic aromatic hydrocarbons in water and in Karst underground river catchment].

PubMed

Lan, Jia-Cheng; Sun, Yu-Chuan; Tian, Ping; Lu, Bing-Qing; Shi, Yang; Xu, Xin; Liang Zuo-Bing; Yang, Ping-Heng

2014-10-01

Water samples in Laolongdong underground river catchment were collected to determine the concentration, compositional profiles, and evaluate ecological risk of 16 priority polycyclic aromatic hydrocarbons (PAHs). PAHs were measured by GC/MS. The total concentrations of 16 PAH ranged from 81.5-8019 ng · L(-1) in underground river, 288.7-15,200 ng · L(-1) in karst springs, and 128.4-2,442 ng · L(-1) in surface water. Affected by waste water from Huangjueya town, concentrations of PAHs in underground river were higher than those in surface water and waste water from sinkhole. The PAHs profiles were dominated by 3 ring PAHs. There were differences of monthly variations of PAHs contents in the water, due to waste water, season and different characteristics of PAH. Surface water and waste water from sinkhole played an important role on contamination in the river. The levels of ecological risk were generally moderately polluted and heavily polluted according to all detected PAH compounds in the water.

Extratropical Influence of Sea Surface Temperature and Wind on Water Recycling Rate Over Oceans and Coastal Lands

NASA Technical Reports Server (NTRS)

Hu, Hua; Liu, W. Timothy

1999-01-01

Water vapor and precipitation are two important parameters confining the hydrological cycle in the atmosphere and over the ocean surface. In the extratropical areas, due to variations of midlatitude storm tracks and subtropical jetstreams, water vapor and precipitation have large variability. Recently, a concept of water recycling rate defined previously by Chahine et al. (GEWEX NEWS, August, 1997) has drawn increasing attention. The recycling rate of moisture is calculated as the ratio of precipitation to total precipitable water (its inverse is the water residence time). In this paper, using multi-sensor spacebased measurements we will study the role of sea surface temperature and ocean surface wind in determining the water recycling rate over oceans and coastal lands. Response of water recycling rate in midlatitudes to the El Nino event will also be discussed. Sea surface temperature data are derived from satellite observations from the Advanced Very High Resolution Radiometer (AVHRR) blended with in situ measurements, available for the period 1982-1998. Global sea surface wind observations are obtained from spaceborne scatterometers aboard on the European Remote-Sensing Satellite (ERS1 and 2), available for the period 1991-1998. Global total precipitable water provided by the NASA Water Vapor Project (NVAP) is available for the period 1988-1995. Global monthly mean precipitation provided by the Global Precipitation Climatology Project (GPCP) is available for the period 1987-1998.

Potentiometric surface, 2013, and water-level differences, 1991-2013, of the Carrizo-Wilcox aquifer in northwest Louisiana

USGS Publications Warehouse

Fendick, Robert B.; Carter, Kayla

2015-01-01

This report presents data and maps that illustrate the potentiometric surface of the Carrizo-Wilcox aquifer during March–May 2013 and water-level differences from 1991 to 2013. The potentiometric surface map can be used for determining the direction of groundwater flow, hydraulic gradients, and effects of withdrawals on the groundwater resource. The rate of groundwater movement also can be estimated from the gradient when the hydraulic conductivity is applied. Water-level data collected for this study are stored in the USGS National Water Information System (NWIS) (http://waterdata.usgs.gov/nwis) and are on file at the USGS office in Baton Rouge, La.

Altitude and configuration of the potentiometric surface in the Lower White Clay Creek and Upper Christina River Basins including portions of Franklin, London Britain, New Garden, and New London Townships, Chester County, Pennsylvania, June through September 2005

USGS Publications Warehouse

Hale, Lindsay B.

2006-01-01

Since 1984, the U.S. Geological Survey (USGS) has been mapping the altitude and configuration of the potentiometric surface in Chester County as part of an ongoing cooperative program to measure and describe the water resources of the county.  Areas where the potentiometric surface has been mapped are shown on figure 1.  These maps can be used to determine the general direction of ground-water flow and are frequently referenced by municipalities and developers to evaluate ground-water conditions for water supply and resource-protection requirements (Wood, 1998).

Application of new point measurement device to quantify groundwater-surface water interactions.

PubMed

Cremeans, M M; Devlin, J F; McKnight, U S; Bjerg, P L

2018-04-01

The streambed point velocity probe (SBPVP) measures in situ groundwater velocities at the groundwater-surface water interface without reliance on hydraulic conductivity, porosity, or hydraulic gradient information. The tool operates on the basis of a mini-tracer test that occurs on the probe surface. The SBPVP was used in a meander of the Grindsted Å (stream), Denmark, to determine the distribution of flow through the streambed. These data were used to calculate the contaminant mass discharge of chlorinated ethenes into the stream. SBPVP data were compared with velocities estimated from hydraulic head and temperature gradient data collected at similar scales. Spatial relationships of water flow through the streambed were found to be similar by all three methods, and indicated a heterogeneous pattern of groundwater-surface water exchange. The magnitudes of estimated flow varied to a greater degree. It was found that pollutants enter the stream in localized regions of high flow which do not always correspond to the locations of highest pollutant concentration. The results show the combined influence of flow and concentration on contaminant discharge and illustrate the advantages of adopting a flux-based approach to risk assessment at the groundwater-surface water interface. Chlorinated ethene mass discharges, expressed in PCE equivalents, were determined to be up to 444 kg/yr (with SBPVP data) which compared well with independent estimates of mass discharge up to 438 kg/yr (with mini-piezometer data from the streambed) and up to 372 kg/yr crossing a control plane on the streambank (as determined in a previous, independent study). Copyright © 2018 Elsevier B.V. All rights reserved.

Surface and Flow Field Measurements on the FAITH Hill Model

NASA Technical Reports Server (NTRS)

Bell, James H.; Heineck, James T.; Zilliac, Gregory; Mehta, Rabindra D.; Long, Kurtis R.

2012-01-01

A series of experimental tests, using both qualitative and quantitative techniques, were conducted to characterize both surface and off-surface flow characteristics of an axisymmetric, modified-cosine-shaped, wall-mounted hill named "FAITH" (Fundamental Aero Investigates The Hill). Two separate models were employed: a 6" high, 18" base diameter machined aluminum model that was used for wind tunnel tests and a smaller scale (2" high, 6" base diameter) sintered nylon version that was used in the water channel facility. Wind tunnel and water channel tests were conducted at mean test section speeds of 165 fps (Reynolds Number based on height = 500,000) and 0.1 fps (Reynolds Number of 1000), respectively. The ratio of model height to boundary later height was approximately 3 for both tests. Qualitative techniques that were employed to characterize the complex flow included surface oil flow visualization for the wind tunnel tests, and dye injection for the water channel tests. Quantitative techniques that were employed to characterize the flow included Cobra Probe to determine point-wise steady and unsteady 3D velocities, Particle Image Velocimetry (PIV) to determine 3D velocities and turbulence statistics along specified planes, Pressure Sensitive Paint (PSP) to determine mean surface pressures, and Fringe Imaging Skin Friction (FISF) to determine surface skin friction (magnitude and direction). This initial report summarizes the experimental set-up, techniques used, data acquired and describes some details of the dataset that is being constructed for use by other researchers, especially the CFD community. Subsequent reports will discuss the data and their interpretation in more detail

Effects of land use on surface-water quality in the East Everglades, Dade County, Florida

USGS Publications Warehouse

Waller, Bradley G.

1982-01-01

Water-quality characteristics were determined at five developed areas in the East Everglades, Dade County, Florida, during the 1978 wet season (June through October). These areas are designated as: Coopertown; Chekika Hammock State Park; residential area; rock-plowed tomato field; and Cracker Jack Slough agricultural area. Data from the developed areas were compared with data from four baseline sites in undeveloped areas to determine the effects of land use on the surface-water quality. The rock-plowed tomato field was the only area where surface-water quality was affected. Water quality at this field is affected by agricultural activities and chemical applications as indicated by increased concentrations of orthophosphate, organic nitrogen, organic carbon, copper, manganese, mercury, and potassium. The remaining four areas of land use had water-quality characteristics typical of baseline sites in nearby Northeast Shark River Slough or Taylor Slough. Chemical analyses of soil indicated chlorinated-hydrocarbon insecticide residues at Coopertown and the two agricultural areas, Cracker Jack Slough and the rock-plowed tomato field. Trace elements in concentrations greater than base level occurred at both agricultural areas (manganese), Chekika Hammock State Park (manganese), and at Coopertown (lead and zinc). (USGS)

Adsorption and structure of water on kaolinite surfaces: possible insight into ice nucleation from grand canonical monte carlo calculations.

PubMed

Croteau, T; Bertram, A K; Patey, G N

2008-10-30

Grand canonical Monte Carlo calculations are used to determine water adsorption and structure on defect-free kaolinite surfaces as a function of relative humidity at 235 K. This information is then used to gain insight into ice nucleation on kaolinite surfaces. Results for both the SPC/E and TIP5P-E water models are compared and demonstrate that the Al-surface [(001) plane] and both protonated and unprotonated edges [(100) plane] strongly adsorb at atmospherically relevant relative humidities. Adsorption on the Al-surface exhibits properties of a first-order process with evidence of collective behavior, whereas adsorption on the edges is essentially continuous and appears dominated by strong water lattice interactions. For the protonated and unprotonated edges no structure that matches hexagonal ice is observed. For the Al-surface some of the water molecules formed hexagonal rings. However, the a o lattice parameter for these rings is significantly different from the corresponding constant for hexagonal ice ( Ih). A misfit strain of 14.0% is calculated between the hexagonal pattern of water adsorbed on the Al-surface and the basal plane of ice Ih. Hence, the ring structures that form on the Al-surface are not expected to be good building-blocks for ice nucleation due to the large misfit strain.

Polydopamine-coated magnetic nanoparticles for isolation and enrichment of estrogenic compounds from surface water samples followed by liquid chromatography-tandem mass spectrometry determination.

PubMed

Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Piovesana, Susy; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

2016-06-01

Estrogens, phytoestrogens, and mycoestrogens may enter into the surface waters from different sources, such as effluents of municipal wastewater treatment plants, industrial plants, and animal farms and runoff from agricultural areas. In this work, a multiresidue analytical method for the determination of 17 natural estrogenic compounds, including four steroid estrogens, six mycoestrogens, and seven phytoestrogens, in river water samples has been developed. (Fe3O4)-based magnetic nanoparticles coated by polydopamine (Fe3O4@pDA) were used for dispersive solid-phase extraction, and the final extract was analyzed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry. The Fe3O4 magnetic nanoparticles were prepared by a co-precipitation procedure, coated by pDA, and characterized by scanning electron microscopy, infrared spectroscopy, and elemental analysis. The sample preparation method was optimized in terms of extraction recovery, matrix effect, selectivity, trueness, precision, method limits of detection, and method limits of quantification (MLOQs). For all the 17 analytes, recoveries were >70 % and matrix effects were below 30 % when 25 mL of river water sample was treated with 90 mg of Fe3O4@pDA nanoparticles. Selectivity was tested by spiking river water samples with 50 other compounds (mycotoxins, antibacterials, conjugated hormones, UV filters, alkylphenols, etc.), and only aflatoxins and some benzophenones showed recoveries >60 %. This method proved to be simple and robust and allowed the determination of natural estrogenic compounds belonging to different classes in surface waters with MLOQs ranging between 0.003 and 0.1 μg L(-1). Graphical Abstract Determination of natural estrogenic compounds in water by magnetic solid phase extraction followed by liquid chromatography-tandem mass spectrometry analysis.

Weakly bound water structure, bond valence saturation and water dynamics at the goethite (100) surface/aqueous interface: ab initio dynamical simulations.

PubMed

Chen, Ying; Bylaska, Eric J; Weare, John H

2017-03-31

Many important geochemical and biogeochemical reactions occur in the mineral/formation water interface of the highly abundant mineral, goethite [α-Fe(OOH)]. Ab initio molecular dynamics (AIMD) simulations of the goethite α-FeOOH (100) surface and the structure, water bond formation and dynamics of water molecules in the mineral/aqueous interface are presented. Several exchange correlation functionals were employed (PBE96, PBE96 + Grimme, and PBE0) in the simulations of a (3 × 2) goethite surface with 65 absorbed water molecules in a 3D-periodic supercell (a = 30 Å, FeOOH slab ~12 Å thick, solvation layer ~18 Å thick). The lowest energy goethite (100) surface termination model was determined to have an exposed surface Fe 3+ that was loosely capped by a water molecule and a shared hydroxide with a neighboring surface Fe 3+ . The water molecules capping surface Fe 3+ ions were found to be loosely bound at all DFT levels with and without Grimme corrections, indicative that each surface Fe 3+ was coordinated with only five neighbors. These long bonds were supported by bond valence theory calculations, which showed that the bond valence of the surface Fe 3+ was saturated and surface has a neutral charge. The polarization of the water layer adjacent to the surface was found to be small and affected only the nearest water. Analysis by density difference plots and localized Boys orbitals identified three types of water molecules: those loosely bound to the surface Fe 3+ , those hydrogen bonded to the surface hydroxyl, and bulk water with tetrahedral coordination. Boys orbital analysis showed that the spin down lone pair orbital of the weakly absorbed water interact more strongly with the spin up Fe 3+ ion. These weakly bound surface water molecules were found to rapidly exchange with the second water layer (~0.025 exchanges/ps) using a dissociative mechanism. Water molecules adjacent to the surface were found to only weakly interact with the surface and as a result were readily able to exchange with the bulk water. To account for the large surface Fe-OH 2 distances in the DFT calculations it was proposed that the surface Fe 3+ atoms, which already have their bond valence fully satisfied with only five neighbors, are under-coordinated with respect to the bulk coordination. Graphical abstract All first principle calculations, at all practically achievable levels, for the goethite 100 aqueous interface support a long bond and weak interaction between the exposed surface Fe 3+ and water molecules capping the surface. This result is supported by bond valence theory calculations and is indicative that each surface Fe 3+ is coordinated with only 5 neighbors.

Modulation of cell surface hydrophobicity and attachment of bacteria to abiotic surfaces and shrimp by Malaysian herb extracts.

PubMed

Hui, Yew Woh; Dykes, Gary A

2012-08-01

The use of simple crude water extracts of common herbs to reduce bacterial attachment may be a cost-effective way to control bacterial foodborne pathogens, particularly in developing countries. The ability of water extracts of three common Malaysian herbs (Andrographis paniculata, Eurycoma longifolia, and Garcinia atroviridis) to modulate hydrophobicity and attachment to surfaces of five food-related bacterial strains (Bacillus cereus ATCC 14576, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Salmonella Enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923) were determined. The bacterial attachment to hydrocarbon assay was used to determine bacterial hydrophobicity. Staining and direct microscopic counts were used to determine attachment of bacteria to glass and stainless steel. Plating on selective media was used to determine attachment of bacteria to shrimp. All extracts were capable of either significantly ( P < 0.05) increasing or decreasing bacterial surface hydrophobicity, depending on the herb extract and bacteria combination. Bacterial attachment to all surfaces was either significantly (P < 0.05) increased or decreased, depending on the herb extract and bacteria combination. Overall, hydrophobicity did not show a significant correlation (P > 0.05) to bacterial attachment. For specific combinations of bacteria, surface material, and plant extract, significant correlations (R > 0.80) between hydrophobicity and attachment were observed. The highest of these was observed for S. aureus attachment to stainless steel and glass after treatment with the E. longifolia extract (R = 0.99, P < 0.01). The crude water herb extracts in this study were shown to have the potential to modulate specific bacterial and surface interactions and may, with further work, be useful for the simple and practical control of foodborne pathogens.

Phoenix - the First Mars Scout Mission

NASA Technical Reports Server (NTRS)

Goldstein, Barry; Shotwell, Robert

2008-01-01

As the first of the new Mars Scouts missions, the Phoenix project was selected by NASA in August of 2003. Four years later, almost to the day, Phoenix was launched from Cape Canaveral Air Station and successfully injected into an interplanetary trajectory on its way to Mars. This paper will highlight some of the key changes since the 2006 IEEE paper of the same name, as well as activities, challenges and problems encountered on the way to the launch pad. Phoenix Follows the water responding directly to the recently published data from Dr. William Boynton, PI (and Phoenix co-I) of the Mars Odyssey Gamma Ray Spectrometer (GRS). GRS data indicate extremely large quantities of water ice (up to 50% by mass) within the upper 50 cm of the northern polar regolith. Phoenix will land within the north polar region at 68.2 N, 233.4 W identified by GRS to harbor near surface water ice and provide in-situ confirmation of this extraordinary find. Our mission will investigate water in all its phases, and will investigate the history of water as evidenced in the soil characteristics that will be carefully examined by the powerful suite of onboard instrumentation. Access to the critical subsurface region expected to contain this information is made possible by a third generation robotic arm capable of excavating the expected Martian regolith to a depth of 1m. Phoenix has four primary science objectives: 1) Determine the polar climate and weather, interaction with the surface, and composition of the lower atmosphere around 70 N for at least 90 sols focusing on water, ice, dust, noble gases, and CO2. Determine the atmospheric characteristics during descent through the atmosphere. 2) Characterize the geomorphology and active processes shaping the northern plains and the physical properties of the near surface regolith focusing on the role of water. 3) Determine the aqueous mineralogy and chemistry as well as the adsorbed gases and organic content of the regolith. Verify the Odyssey discovery of near-surface ice. 4) Characterize the history of water, ice, and the polar 1 1-4244-1488-1/08/$25.00 2008 IEEE 2 IEEEAC paper#1579, Version 1, Updated 2008:01:09 climate. Determine the past and present biological potential of the surface and subsurface environments.

A preliminary study of the tropical water cycle and its sensitivity to surface warming

NASA Technical Reports Server (NTRS)

Lau, K. M.; Sui, C. H.; Tao, W. K.

1993-01-01

The Goddard Cumulus Ensemble Model (GCEM) has been used to demonstrate that cumulus-scale dynamics and microphysics play a major role in determining the vertical distribution of water vapor and clouds in the tropical atmosphere. The GCEM is described and is the basic structure of cumulus convection. The long-term equilibrium response to tropical convection to surface warming is examined. A picture of the water cycle within tropical cumulus clusters is developed.

Installation Restoration Program for Richards-Gebaur AFB. Phase 2. Field Evaluation

DTIC Science & Technology

1983-12-01

of the Phase I--Records Search. "ýThe specific task was to determine whether environmental contamination of groundwater or surface water had resulted...concentrations (4 and 5 ug/L, respectively) which exceeded the Missouri Water Quality Standards for groundwater (I ug/L). A limited followup study was...contamination of groundwater and surface water had resulted from waste handling and disposal at two ’and- fills on Richards-Gebaur Air Force Base (AFB

PAHs behavior in surface water and groundwater of the Yellow River estuary: Evidence from isotopes and hydrochemistry.

PubMed

Li, Jing; Li, Fadong; Liu, Qiang

2017-07-01

Large-scale irrigation projects have impacted the regional surface-groundwater interactions in the North China Plain (NCP). Given this concern, the aim of this study is to evaluate levels of PAH pollution, identify the sources of the PAHs, analyze the influence of surface-groundwater interactions on PAH distribution, and propose urgent management strategies for PAHs in China's agricultural areas. PAH concentrations, hydrochemical indicators and stable isotopic compositions (δ 18 O and δ 2 H) were determined for surface water (SW) and groundwater (GW) samples. PAHs concentrations in surface water and groundwater varied from 11.84 to 393.12 ng/L and 8.51-402.84 ng/L, respectively, indicating mild pollution. The seasonal variations showed the following trend: PAHs in surface water at the low-water phase > PAHs in groundwater at the low-water phase > PAHs in surface water at the high-water phase > PAHs in groundwater at the high-water phase. Hydrochemical and δ 18 O value of most groundwater samples distributed between the Yellow River and seawater. The mean value of mixture ratio of the Yellow River water recharge to the groundwater was 65%, few anomalous sites can reach to 90%. Surface-groundwater interactions influence the spatial distribution of PAHs in the study area. In light of the ongoing serious pollution, management practices for source control, improved control technologies, and the construction of a monitoring network to warn of increased risk are urgently needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Theoretical study on the adsorption and relative stability of conformers of L-ascorbic acid on γ - alumina (100) surface

NASA Astrophysics Data System (ADS)

Mozaffari Majd, M.; Dabbagh, H. A.; Farrokhpour, H.; Najafi Chermahini, A.

2017-11-01

The adsorption energies (Eads) and relative stabilities of selected conformers of the most stable tautomer of L-ascorbic acid (vitamin C) on the dehydroxylated γ-alumina (100) surface were calculated in both gas phase and solvent (water) using the density functional theory (DFT) method. The selected conformers were related to the different rotational angles of OH groups of L-ascorbic acid. The conformational analysis of bare tautomer in both gas and water showed that the conformer No.20 (conf. 20) and 13 (conf. 13) with the dihedral angles of H15sbnd O10sbnd C11sbnd C9 (-73°) and H20sbnd O19sbnd C9sbnd C11 (-135°) were the most stable and unstable conformers, respectively. The performed calculations in the presence of surface showed that the interaction of the conformers with the surface changes their relative stabilities and structures in both gas phase and water. The Ead of each conformer was calculated and it was determined that conf. 8 and conf. 16 have the highest value of Ead in the gas phase (-62.56 kcal/mol) and water (-54.44 kcal/mol), respectively. The optimized structure of each conformer on the surface and the number of hydrogen bonds between it and surface along with their bond lengths were determined.

Water uptake depth analyses using stable water isotopes in rice-based cropping systems in Southeastern Asia

NASA Astrophysics Data System (ADS)

Mahindawansha, Amani; Kraft, Philipp; Orlowski, Natalie; Racela, Healthcliff S. U.; Breuer, Lutz

2017-04-01

Rice is one of the most water-consuming crop in the world. Understanding water source utilization of rice-based cropping systems will help to improve water use efficiency (WUE) in paddy management. The objectives of our study were to (1) determine the contributions of various water sources to plant growth in diversified rice-based production systems (wet rice, aerobic rice) (2) investigate water uptake depths at different maturity periods during wet and dry conditions, and (3) calculate WUE of the cropping systems. Our field experiment is based on changes of stable water isotope concentrations in the soil-plant-atmosphere continuum due to transpiration and evaporation. Soil samples were collected together with root sampling from nine different depths under vegetative, reproductive, and matured periods of plant growth together with stem samples. Soil and plant samples were extracted by cryogenic vacuum extraction. Groundwater, surface water, rain, and irrigation water were sampled weekly. All water samples were analyzed for hydrogen and oxygen isotope ratios (δ2H and δ18O) via a laser spectroscope (Los Gatos DLT100). The direct inference approach, which is based on comparing isotopic compositions between plant stem water and soil water, were used to determine water sources taken up by plant. Multiple-source mass balance assessment can provide the estimated range of potential contributions of water from each soil depth to root water uptake of a crop. These estimations were used to determine the proportion of water from upper soil horizons and deep horizons for rice in different maturity periods during wet and dry seasons. Shallow soil water has the higher evaporation than from deeper soil water where the highest evaporation effect is at 5 cm depth (drying front). Water uptake is mostly taking place from surface water in the vegetative and between 5-10 cm in the reproductive period, since roots have grown widely and deeper in the reproductive stage. This will be helpful to understand the WUE and identify the most efficient water management system and the influence of groundwater and surface water during both seasons in rice-based cropping ecosystems by using means of stable water isotope.

Surface-water-quality assessment of the upper Illinois River Basin in Illinois, Indiana, and Wisconsin; data on agricultural organic compounds, nutrients, and sediment in water, 1988-90

USGS Publications Warehouse

Sullivan, D.J.; Terrio, P.J.

1994-01-01

This report describes the sampling design and methods and presents data collected to determine the distribution of agricultural organic compounds, nutrients, and sediment in selected areas of the upper Illinois River Basin as part of the National Water-Quality Assessment program. Four stations in small watersheds (two urban, two agricultural) were sampled in 1988 and 1989. Seventeen stations in an agricultural subbasin were sampled in 1990. Samples were collected before, during, and after runoff events from late spring to midsummer to determine concentrations of agricultural organic compounds in surface waters resulting from storm runoff, as well as background concentrations. Over 200 water samples were analyzed for agricultural organic compound, nutrient, and suspended-sediment concentrations. The agricultural organic compounds included triazine and chlorophenoxy-acid herbicides, and organo-phosphorus insecticides.

Adsorption of humic acids and trace metals in natural waters

NASA Technical Reports Server (NTRS)

Leung, W. H.

1982-01-01

Studies concerning the interactions between suspended hydrous iron oxide and dissolved humic acids and trace metals are reported. As a major component of dissolved organic matters and its readiness for adsorption at the solid/water interface, humic acids may play a very important role in the organometallic geochemistry of suspended sediments and in determining the fate and distribution of trace metals, pesticides and anions in natural water systems. Most of the solid phases in natural waters contain oxides and hydroxides. The most simple promising theory to describe the interactions of hydrous iron oxide interface is the surface complex formation model. In this model, the adsorptions of humic acids on hydrous iron oxide may be interpreted as complex formation of the organic bases (humic acid oxyanions) with surface Fe ions. Measurements on adsorptions were made in both fresh water and seawater. Attempts have been made to fit our data to Langmuir adsorption isotherm. Adsorption equilibrium constants were determined.

Tritium migration to the surfaces of Type 316 stainless steel; aluminum 6061; and oxygen-free, high-conductivity copper

DOE PAGES

Sharpe, M.; Shmayda, W. T.; Schroder, W. U.

2016-05-25

The migration of tritium to the surfaces of aluminum 6061, oxygen-free, high-conductivity copper (OFHC), and stainless-steel 316 from the bulk metal was studied using low-pressure Tonks–Langmuir argon plasma. The plasma is shown to be effective at removing tritium from metal surfaces in a controlled manner. Tritium is removed in decreasing quantities with successive plasma exposures, which suggests a depletion of the surface and near-surface tritium inventories. A diffusion model was developed to predict tritium migration from the bulk and its accumulation in the water layers present on the metal surface. The model reproduces the rate of tritium re-growth on themore » surface for all three metals and can be used to calculate the triton solubility in the water layers present on metal surfaces. The ratio of surface-to-bulk solubilities at the water-layer/bulk-metal interface uniquely determines the concentration ratio between these two media. Removing the tritium-rich water layers induces tritium to migrate from the bulk to the surface. Furthermore, this process is driven by a concentration gradient that develops in the bulk because of the perturbation on the surface.« less

Uranium in the Surrounding of San Marcos-Sacramento River Environment (Chihuahua, Mexico)

PubMed Central

Rentería-Villalobos, Marusia; Cortés, Manuel Reyes; Mantero, Juan; Manjón, Guillermo; García-Tenorio, Rafael; Herrera, Eduardo; Montero-Cabrera, Maria Elena

2012-01-01

The main interest of this study is to assess whether uranium deposits located in the San Marcos outcrops (NW of Chihuahua City, Mexico) could be considered as a source of U-isotopes in its surrounding environment. Uranium activity concentrations were determined in biota, ground, and surface water by either alpha or liquid scintillation spectrometries. Major ions were analyzed by ICP-OES in surface water and its suspended matter. For determining uranium activity in biota, samples were divided in parts. The results have shown a possible lixiviation and infiltration of uranium from geological substrate into the ground and surface water, and consequently, a transfer to biota. Calculated annual effective doses by ingestion suggest that U-isotopes in biota could not negligibly contribute to the neighboring population dose. By all these considerations, it is concluded that in this zone there is natural enhancement of uranium in all environmental samples analyzed in the present work. PMID:22536148

Measurements of the dielectric properties of sea water at 1.43 GHz

NASA Technical Reports Server (NTRS)

Ho, W. W.; Love, A. W.; Vanmelle, M. J.

1974-01-01

Salinity and temperature of water surfaces of estuaries and bay regions are determined to accuracies of 1 ppt salinity and 0.3 kelvin surface temperature. L-band and S-band radiometers are used in combination as brightness temperature detectors. The determination of the brightness temperature versus salinity, with the water surface temperature as a parameter for 1.4 GHz, is performed with a capillary tube inserted into a resonance cavity. Detailed analysis of the results indicates that the measured values are accurate to better than 0.2 percent in the electric property epsilon' and 0.4 percent in epsilon''. The calculated brightness temperature as a function of temperature and salinity is better than 0.2 kelvin. Thus it is possible to reduce the measured data obtained with the two-frequency radiometer system with 1 ppt accuracy to values in the salinity range 5 to 40 ppt.

Determination of trace quaternary ammonium surfactants in water by combining solid-phase extraction with surface-assisted laser desorption/ionization mass spectrometry.

PubMed

Chen, Y C; Sun, M C

2001-01-01

This study demonstrates the feasibility of combining solid-phase extraction (SPE) with surface-assisted laser desorption/ionization (SALDI) mass spectrometry to determine trace quaternary ammonium surfactants in water. The trace surfactants in water were directly concentrated on the surface of activated carbon sorbent in SPE. The activated carbon sorbent was then mixed with the SALDI liquid for SALDI analysis. No SPE elution procedure was necessary. Experimental results indicate that the surfactants with longer chain alkyl groups exhibit higher sensitivities than those with shorter chain alkyl groups in SPE-SALDI analysis. The detection limit for hexadecyltrimethylammonium bromide is around 10 ppt in SPE-SALDI analysis by sampling 100 mL of aqueous solution, while that of tetradecyltrimethylammonium bromide is about 100 ppt. The detection limit for decyltrimethylammonium bromide and dodecyltrimethylammonium bromide is in the low-ppb range. Copyright 2001 John Wiley & Sons, Ltd.

Determining Regional Sensitivity to Energy-Related Water Withdrawals in Minnesota

NASA Astrophysics Data System (ADS)

McCulloch, A.; Brauman, K. A.

2015-12-01

Minnesota has abundant freshwater resources, yet concerns about water-impacts of energy and mining development are increasing. Statewide, total annual water withdrawals have increased, and, in some watersheds, withdrawals make up a large fraction of available water. The energy and mining sectors play a critical role in determining water availability, as water is used to irrigate biofuel feedstock crops, cool thermoelectric plants, and process and transport fuels and iron ore. We evaluated the Minnesota Department of Natural Resources (DNR) Water and Reporting System (MPARS) dataset (1988-2014) to identify regions where energy and mining-related water withdrawals are high or where they are increasing. The energy and mining sectors account for over 65 percent of total water extractions in Minnesota, but this percentage is greater in some regions. In certain southern and northeastern Minnesota watersheds, these extractions account for 90 percent of total water demand. Sensitivity to these demands is not dependent on total water demand alone, and is also not uniform among watersheds. We identified and evaluated factors influencing sensitivity, including population, extraction type (surface water or groundwater), percentage of increased demand, and whether withdrawals are consumptive or not. We determined that southern Minnesota is particularly sensitive to increased water demands, because of growing biofuel and sand extraction industries (the products of which are used in hydraulic fracturing). In the last ten years, ethanol production in Minnesota has increased by 440 percent, and over fifteen refineries (each with a capacity over 1.1 billion gallons), have been built. These users primarily extract from surface water bodies within a few watersheds, compromising local supplies. As these energy-related industries continue to grow, so will the demand for freshwater resources. Determining regional sensitivity to increased demands will allow policy-makers to manage the increased competition for Minnesota's future water supplies.

Modeling and optimization of trihalomethanes formation potential of surface water (a drinking water source) using Box-Behnken design.

PubMed

Singh, Kunwar P; Rai, Premanjali; Pandey, Priyanka; Sinha, Sarita

2012-01-01

The present research aims to investigate the individual and interactive effects of chlorine dose/dissolved organic carbon ratio, pH, temperature, bromide concentration, and reaction time on trihalomethanes (THMs) formation in surface water (a drinking water source) during disinfection by chlorination in a prototype laboratory-scale simulation and to develop a model for the prediction and optimization of THMs levels in chlorinated water for their effective control. A five-factor Box-Behnken experimental design combined with response surface and optimization modeling was used for predicting the THMs levels in chlorinated water. The adequacy of the selected model and statistical significance of the regression coefficients, independent variables, and their interactions were tested by the analysis of variance and t test statistics. The THMs levels predicted by the model were very close to the experimental values (R(2) = 0.95). Optimization modeling predicted maximum (192 μg/l) TMHs formation (highest risk) level in water during chlorination was very close to the experimental value (186.8 ± 1.72 μg/l) determined in laboratory experiments. The pH of water followed by reaction time and temperature were the most significant factors that affect the THMs formation during chlorination. The developed model can be used to determine the optimum characteristics of raw water and chlorination conditions for maintaining the THMs levels within the safe limit.

PHYSICAL AND BIOLOGICAL PARAMETERS THAT DETERMINE THE FATE OF 'P'-CHLOROPHENOL IN LABORATORY TEST SYSTEMS

EPA Science Inventory

Shake flask and microcosm studies were conducted to determine the fate of parachlorophenol (p-CP) in water and sediment systems and the role of sediment and nonsediment surfaces in the biodegradation process. Biodegradation of p-CP in estuarine water samples in shake flasks was s...

Estimation of sea surface temperature from remote sensing in the 11to 13-micron window region

NASA Technical Reports Server (NTRS)

Prabhakara, C.; Kunde, V. G.; Dalu, G.

1974-01-01

The Nimbus 3 and 4 Iris spectral data in the 11- to 13-micron water vapor window region are analyzed to determine the sea surface temperature (SST). The high spectral resolution data of Iris are averaged over approximately 1-micron-wide intervals to simulate channels of a radiometer to measure the SST. In the present exploratory study, three such channels in the 775- to 960-per cm (12.9-10.5 micron) region are utilized to measure the SST over cloud-free oceans. However, two of these channels are sufficient in routine SST determination. The differential absorption properties of water vapor in the two channels make it possible to determine the water vapor absorption correction without detailed knowledge of the vertical profiles of temperature and water vapor. The feasibility of determining the SST is demonstrated globally with Nimbus 3 data, where cloud-free areas can be selected with the help of albedo data from the medium-resolution infrared radiometer experiment on board the same satellite. The SST derived from this technique agrees with the measurements made by ships to about 1 C.-

No inter-gyre pathway for sea-surface temperature anomalies in the North Atlantic.

PubMed

Foukal, Nicholas P; Lozier, M Susan

2016-04-22

Recent Lagrangian analyses of surface drifters have questioned the existence of a surface current connecting the Gulf Stream (GS) to the subpolar gyre (SPG) and have cast doubt on the mechanism underlying an apparent pathway for sea-surface temperature (SST) anomalies between the two regions. Here we use modelled Lagrangian trajectories to determine the fate of surface GS water and satellite SST data to analyse pathways of GS SST anomalies. Our results show that only a small fraction of the surface GS water reaches the SPG, the water that does so mainly travels below the surface mixed layer, and GS SST anomalies do not propagate into the SPG on interannual timescales. Instead, the inter-gyre heat transport as part of the Atlantic Meridional Overturning Circulation must be accomplished via subsurface pathways. We conclude that the SST in the SPG cannot be predicted by tracking SST anomalies along the GS.

No inter-gyre pathway for sea-surface temperature anomalies in the North Atlantic

PubMed Central

Foukal, Nicholas P.; Lozier, M. Susan

2016-01-01

Recent Lagrangian analyses of surface drifters have questioned the existence of a surface current connecting the Gulf Stream (GS) to the subpolar gyre (SPG) and have cast doubt on the mechanism underlying an apparent pathway for sea-surface temperature (SST) anomalies between the two regions. Here we use modelled Lagrangian trajectories to determine the fate of surface GS water and satellite SST data to analyse pathways of GS SST anomalies. Our results show that only a small fraction of the surface GS water reaches the SPG, the water that does so mainly travels below the surface mixed layer, and GS SST anomalies do not propagate into the SPG on interannual timescales. Instead, the inter-gyre heat transport as part of the Atlantic Meridional Overturning Circulation must be accomplished via subsurface pathways. We conclude that the SST in the SPG cannot be predicted by tracking SST anomalies along the GS. PMID:27103496

New reagent for extraction photomeric determination of anionic surface-active substances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chernova, R.K.; Yastrebova, N.I.; Pankratov, A.N.

1995-02-01

The new reagent 2,6-diphenyl-4-(4-dimethylamino)styrylpyryl chloride is suggested for extraction photometric determination of anionic surface-active substances (SAS). This reagent possesses high sensitivity and selectivity, and can be used for the determination of both individual SAS of any kind and the total amount of anionic SAS. The reagent was used in analysis of highly mineralized statal waters and for the determination of sulfated products in polyoxyethylated alkylphenols.

Recruiting physisorbed water in surface polymerization for bio-inspired materials of tunable hydrophobicity

DOE PAGES

Oyola-Reynoso, S.; Tevis, I. D.; Chen, J.; ...

2016-08-18

Here, chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications. Reagents with multiple reactive sites have been used with the expectation that a monolayer will form. The step-growth polymerization mechanism, however, suggests the possibility of gel formation for hydrolyzable moieties in the presence of physisorbed water. In this report, we demonstrated that using alkyltrichlorosilanes (trivalent [i.e., 3 reactive sites]) in the surface modification of a cellulosic material (paper) does not yield a monolayer but rather gives surface-bound particles. We infer that the presencemore » of physisorbed (surface-bound) water allows for polymerization (or oligomerization) of the silane prior to its attachment on the surface. Surface energy mismatch between the hydrophobic tails of the growing polymer and any unreacted bound water leads to the assembly of the polymerizing material into spherical particles to minimize surface tension. By varying paper grammage (16.2–201.4 g m –2), we varied the accessible surface area and thus the amount of surface-adsorbed water, allowing us to control the ratio of the silane to the bound water. Using this approach, polymeric particles were formed on the surface of cellulose fibers ranging from ~70 nm to a film. The hydrophobicity of the surface, as determined by water contact angles, correlates with particle sizes (p < 0.001, Student's t-test), and, hence, the hydrophobicity can be tuned (contact angle between 94° and 149°). Using a model structure of a house, we demonstrated that as a result of this modification, paper-based houses can be rendered self-cleaning or tolerant to surface running water. In another application, we demonstrated that the felicitous choice of architectural design allows for the hydrophobic paper to be used for water harvesting.« less

Water dynamics: Gliding and trudging

NASA Astrophysics Data System (ADS)

Itoh, Yoshimitsu; Aida, Takuzo

2017-10-01

Water is increasingly recognized as being of paramount importance in biological processes, yet its exact role remains difficult to elucidate. Now, the motion of water molecules within and around a synthetic peptide-amphiphile nanofibre has been precisely determined, showing significant differences between its core and surface.

On the Hofmeister effect: fluctuations at the protein-water interface and the surface tension.

PubMed

Bogár, Ferenc; Bartha, Ferenc; Násztor, Zoltán; Fábián, László; Leitgeb, Balázs; Dér, András

2014-07-24

We performed molecular dynamics simulations on the tryptophane-cage miniprotein using a nonpolarizable force field, in order to model the effect of concentrated water solutions of neutral salts on protein conformation, which is a manifestation of Hofmeister effects. From the equilibrium values and the fluctuations of the solvent accessible surface area of the miniprotein, the salt-induced changes of the mean value of protein-water interfacial tension were determined. At 300 K, the chaotropic ClO4(-) and NO3(-) decreased the interfacial tension according to their position in the Hofmeister series (by approximately 5 and 2.7 mN/m, respectively), while the kosmotropic F(-) increased it (by 1 mN/m). These values were compared to those obtained from the Gibbs equation using the excess surface adsorption calculated from the probability distribution of the water molecules and ions around the miniprotein, and the two sets were found to be very close to each other. Our results present a direct evidence for the central role of interfacial tension and fluctuations at the protein-water interface in Hofmeister phenomena, and provide a computational method for the determination of the protein-water interfacial tension, establishing a link between the phenomenological and microscopic description of protein-water interfaces.

The efficiency of macroporous polystyrene ion-exchange resins in natural organic matter removal from surface water

NASA Astrophysics Data System (ADS)

Urbanowska, Agnieszka; Kabsch-Korbutowicz, Małgorzata

2017-11-01

Natural water sources used for water treatment contains various organic and inorganic compounds. Surface waters are commonly contaminated with natural organic matter (NOM). NOM removal from water is important e.g. due to lowering the risk of disinfection by-product formation during chlorination. Ion exchange with the use of synthetic ion-exchange resins is an alternative process to typical NOM removal approach (e.g. coagulation, adsorption or oxidation) as most NOM compounds have anionic character. Moreover, neutral fraction could be removed from water due to its adsorption on resin surface. In this study, applicability of two macroporous, polystyrene ion exchange resins (BD400FD and A100) in NOM removal from water was assessed including comparison of treatment efficiency in various process set-ups and conditions. Moreover, resin regeneration effectivity was determined. Obtained results shown that examined resins could be applied in NOM removal and it should be noticed that column set-up yielded better results (contrary to batch set-up). Among the examined resins A100 one possessed better properties. It was determined that increase of solution pH resulted in a slight decrease in treatment efficiency while higher temperature improved it. It was also observed that regeneration efficiency was comparable in both tested methods but batch set-up required less reagents.

Compositions of surface layers formed on amalgams in air, water, and saline.

PubMed

Hanawa, T; Gnade, B E; Ferracane, J L; Okabe, T; Watari, F

1993-12-01

The surface layers formed on both a zinc-free and a zinc-containing dental amalgam after polishing and aging in air, water, or saline, were characterized using x-ray photoelectron spectroscopy (XPS) to determine the compositions of the surface layers which might govern the release of mercury from amalgam. The XPS data revealed that the formation of the surface layer on the zinc-containing amalgam was affected by the environment in which the amalgam was polished and aged, whereas that on the zinc-free amalgam was not affected. In addition, among the elements contained in amalgam, zinc was the most reactive with the environment, and was preferentially dissolved from amalgam into water or saline. Mercury atoms existed in the metallic state in the surface layer.

Spectroscopic analyses of Fe and water in clays: A Martian surface weathering study

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Pieters, Carle M.; Edwards, J. O.; Coyne, L. M.; Chang, S.

1991-01-01

Martian surface morphology suggests the presence of liquid H2O on Mars in the past. Reflectance spectra of the Martian surface include features which correspond to the crystal field transitions of iron, as well as features supporting the presence of ice and minerals containing structural OH and surface water. Researchers initiated further spectroscopic studies of surface iron and water and structural OH in clays in order to determine what remotely obtained spectra can indicate about the presence of clays on Mars based on a clearer understanding of the factors influencing the spectral features. Current technology allows researchers to better correlate the low frequency fundamental stretching and bending vibrations of O-H bonds with the diagnostic near infrared overtone and combination bands used in mineral characterization and identification.

How well Can We Classify SWOT-derived Water Surface Profiles?

NASA Astrophysics Data System (ADS)

Frasson, R. P. M.; Wei, R.; Picamilh, C.; Durand, M. T.

2015-12-01

The upcoming Surface Water Ocean Topography (SWOT) mission will detect water bodies and measure water surface elevation throughout the globe. Within its continental high resolution mask, SWOT is expected to deliver measurements of river width, water elevation and slope of rivers wider than ~50 m. The definition of river reaches is an integral step of the computation of discharge based on SWOT's observables. As poorly defined reaches can negatively affect the accuracy of discharge estimations, we seek strategies to break up rivers into physically meaningful sections. In the present work, we investigate how accurately we can classify water surface profiles based on simulated SWOT observations. We assume that most river sections can be classified as either M1 (mild slope, with depth larger than the normal depth), or A1 (adverse slope with depth larger than the critical depth). This assumption allows the classification to be based solely on the second derivative of water surface profiles, with convex profiles being classified as A1 and concave profiles as M1. We consider a HEC-RAS model of the Sacramento River as a representation of the true state of the river. We employ the SWOT instrument simulator to generate a synthetic pass of the river, which includes our best estimates of height measurement noise and geolocation errors. We process the resulting point cloud of water surface heights with the RiverObs package, which delineates the river center line and draws the water surface profile. Next, we identify inflection points in the water surface profile and classify the sections between the inflection points. Finally, we compare our limited classification of simulated SWOT-derived water surface profile to the "exact" classification of the modeled Sacramento River. With this exercise, we expect to determine if SWOT observations can be used to find inflection points in water surface profiles, which would bring knowledge of flow regimes into the definition of river reaches.

Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 24. Seismic Refraction Tomography for Volume Analysis of Saturated Alluvium in the Straight Creek Drainage and Its Confluence With Red River, Taos County, New Mexico

USGS Publications Warehouse

Powers, Michael H.; Burton, Bethany L.

2007-01-01

As part of a research effort directed by the New Mexico Environment Department to determine pre-mining water quality of the Red River at a molybdenum mining site in northern New Mexico, we used seismic refraction tomography to create subsurface compressional-wave velocity images along six lines that crossed the Straight Creek drainage and three that crossed the valley of Red River. Field work was performed in June 2002 (lines 1-4) and September 2003 (lines 5-9). We interpreted the images to determine depths to the water table and to the top of bedrock. Depths to water and bedrock in boreholes near the lines correlate well with our interpretations based on seismic data. In general, the images suggest that the alluvium in this area has a trapezoidal cross section. Using a U.S. Geological Survey digital elevation model grid of surface elevations of this region and the interpreted elevations to water table and bedrock obtained from the seismic data, we generated new models of the shape of the buried bedrock surface and the water table through surface interpolation and extrapolation. Then, using elevation differences between the two grids, we calculated volumes of dry and wet alluvium in the two drainages. The Red River alluvium is about 51 percent saturated, whereas the much smaller volume of alluvium in the tributary Straight Creek is only about 18 percent saturated. When combined with average ground-water velocity values, the information we present can be used to determine discharge of Straight Creek into Red River relative to the total discharge of Red River moving past Straight Creek. This information will contribute to more accurate models of ground-water flow, which are needed to determine the pre-mining water quality in the Red River.

WATER QUALITY CHANGES IN HYPORHEIC FLOW PATHS BETWEEN A LARGE GRAVEL BED RIVER AND OFF-CHANNEL ALCOVES IN OREGON, USA

EPA Science Inventory

Changes in water quality that occur as water flows along hyporheic flow paths may have important effects on surface water quality and aquatic habitat, yet very few studies have examined these hyporheic processes along large gravel bed rivers. To determine water quality changes as...

Application of techniques to identify coal-mine and power-generation effects on surface-water quality, San Juan River basin, New Mexico and Colorado

USGS Publications Warehouse

Goetz, C.L.; Abeyta, Cynthia G.; Thomas, E.V.

1987-01-01

Numerous analytical techniques were applied to determine water quality changes in the San Juan River basin upstream of Shiprock , New Mexico. Eight techniques were used to analyze hydrologic data such as: precipitation, water quality, and streamflow. The eight methods used are: (1) Piper diagram, (2) time-series plot, (3) frequency distribution, (4) box-and-whisker plot, (5) seasonal Kendall test, (6) Wilcoxon rank-sum test, (7) SEASRS procedure, and (8) analysis of flow adjusted, specific conductance data and smoothing. Post-1963 changes in dissolved solids concentration, dissolved potassium concentration, specific conductance, suspended sediment concentration, or suspended sediment load in the San Juan River downstream from the surface coal mines were examined to determine if coal mining was having an effect on the quality of surface water. None of the analytical methods used to analyzed the data showed any increase in dissolved solids concentration, dissolved potassium concentration, or specific conductance in the river downstream from the mines; some of the analytical methods used showed a decrease in dissolved solids concentration and specific conductance. Chaco River, an ephemeral stream tributary to the San Juan River, undergoes changes in water quality due to effluent from a power generation facility. The discharge in the Chaco River contributes about 1.9% of the average annual discharge at the downstream station, San Juan River at Shiprock, NM. The changes in water quality detected at the Chaco River station were not detected at the downstream Shiprock station. It was not possible, with the available data, to identify any effects of the surface coal mines on water quality that were separable from those of urbanization, agriculture, and other cultural and natural changes. In order to determine the specific causes of changes in water quality, it would be necessary to collect additional data at strategically located stations. (Author 's abstract)

Observations on the nucleation of ice VII in compressed water

NASA Astrophysics Data System (ADS)

Stafford, Samuel J. P.; Chapman, David J.; Bland, Simon N.; Eakins, Daniel E.

2017-01-01

Water can freeze upon multiple shock compression, but the window material determines the pressure of the phase transition. Several plate impact experiments were conducted with liquid targets on a single-stage gas gun, diagnosed simultaneously using photonic doppler velocimetry (PDV) and high speed imaging through the water. The experiments investigated why silica windows instigate freezing above 2.5 GPa whilst sapphire windows do not until 7 GPa. We find that the nucleation of ice occurs on the surfaces of windows and can be affected by the surface coating suggesting the surface energy of fused silica, likely due to hydroxyl groups, encourages nucleation of ice VII crystallites. Aluminium coatings prevent nucleation and sapphire surfaces do not nucleate until approximately 6.5 GPa. This is believed to be the threshold pressure for the homogeneous nucleation of water.

Detection of the adsorption of water monolayers through the ion oscillation frequency in the magnesium oxide lattice by means of low energy electron diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guevara-Bertsch, M.; Avendaño, E.; Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José

We investigate the variation of the oscillation frequency of the Mg{sup 2+} and O{sup 2−} ions in the magnesium oxide lattice due to the interactions of the surface with water monolayers by means of Low Energy Electron Diffraction. Our key result is a new technique to determine the adsorbate vibrations produced by the water monolayers on the surface lattice as a consequence of their change in the surface Debye temperature and its chemical shift. The latter was systematically investigated for different annealing times and for a constant external thermal perturbation in the range of 110–300 K in order to accomplish adsorptionmore » or desorption of water monolayers in the surface lattice.« less

Pattern of dental caries experience on tooth surfaces in an adult population.

PubMed

Hopcraft, Matthew Scott; Morgan, Michael Vivian

2006-06-01

To determine the pattern of caries experience across teeth and surfaces in an adult population depending on age and exposure to water fluoridation. Between November 2002 and March 2003 a total of 973 subjects aged 17-51 years had a clinical examination using visual and tactile criteria. Subsequent to this examination, bitewing radiographs were taken and viewed separately. Approximal and occlusal surfaces of molars and premolars were examined on the radiographs. Caries experience was relatively low, with mean DMFS scores of 3.21, 5.12, 9.61, 13.04 and 24.35 for subjects aged 17-20, 21-25, 26-30, 31-35 and 36-51 years respectively. The first molar teeth had the greatest caries experience, and occlusal surfaces had more caries experience than approximal surfaces. Subjects with a lifetime exposure to fluoridated drinking water had significantly lower caries experience than those who had no exposure to fluoridated drinking water. This study showed that caries prevalence, although relatively low in the study population, was found predominantly in occlusal surfaces, with an increasing prevalence in approximal surfaces of posterior teeth in older subjects. Subjects with a lifetime exposure to fluoridated drinking water had a lower level of caries experience than those with no exposure to fluoridated drinking water, and this was more noticeable in approximal surfaces than occlusal surfaces.

Engineering tunable bio-inspired polymeric coatings for amphiphobic fibrous materials

NASA Astrophysics Data System (ADS)

Oyola-Reynoso, Stephanie

Chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications. Reagents with multiple reactive sites have been used with the expectation that a monolayer will form. The step-growth polymerization mechanism, however, suggests the possibility of gel formation for hydrolysable moieties in the presence of physisorbed water. In the following chapters, we demonstrate that using alkyltrichlorosilanes (trivalent [3 reactive sites]) in the surface modification of a cellulosic material (paper) does not yield a monolayer but rather gives surface-bound polymeric particles. We infer that the presence of physisorbed (surface-bound) water allows for polymerization (or oligomerization) of the silane, prior to its attachment on the surface. Surface energy mismatch between the hydrophobic tails of the growing polymer and any unreacted bound water leads to the assembly of the polymerizing material into spherical particles to minimize surface tension. By varying paper grammage (16.2-201.4 g/m2), we varied the accessible surface area and thus the amount of surface-adsorbed water, allowing us to control the ratio of the silane to the bound water. Using this approach, polymeric particles were formed on the surface of cellulose fibers ranging from 70 nm to a film. The hydrophobicity of the surface, as determined by water contact angles, correlates with particle sizes (p < 0.001, Student t-test), and, hence, the hydrophobicity can be tuned (contact angle between 94° and 149°). Using a model structure of a house, we demonstrated that as a result of this modification, cardboard houses can be rendered self-cleaning or tolerant to surface running water. Each of the chapters below supports the mechanism via a series of applications, material characterization, and/or, smart engineering.

Natural attenuation of chlorinated-hydrocarbon contamination at Fort Wainwright, Alaska; a hydrogeochemical and microbiological investigation workplan

USGS Publications Warehouse

McCarthy, Kathleen A.; Lilly, Michael R.; Braddock, Joan F.; Hinzman, Larry D.

1998-01-01

Natural attenuation processes include biological degradation, by which microorganisms break down contaminants into simpler product compounds; adsorption of contaminants to soil particles, which decreases the mass of contaminants dissolved in ground water; and dispersion, which decreases dissolved contaminant concentrations through dilution. The primary objectives of this study are to (1) assess the degree to which such natural processes are attenuating chlorinated-hydrocarbon contamination in ground water, and (2) evaluate the effects of ground-water/surface-water interactions on natural-attenuation processes in the area of the former East and West Quartermasters Fueling Systems for Fort Wainwright, Alaska. The study will include investigations of the hydrologic, geochemical, and microbiological processes occurring at this site that influence the transport and fate of chlorinated hydrocarbons in ground water. To accomplish these objectives, a data-collection program has been initiated that includes measurements of water-table elevations and the stage of the Chena River; measurements of vertical temperature profiles within the subsurface; characterization of moisture distribution and movement in the unsaturated zone; collection of ground-water samples for determination of both organic and inorganic chemical constituents; and collection of ground-water samples for enumeration of microorganisms and determination of their potential to mineralize contaminants. We will use results from the data-collection program described above to refine our conceptual model of hydrology and contaminant attenuation at this site. Measurements of water-table elevations and river stage will help us to understand the magnitude and direction of ground-water flow and how changes in the stage of the Chena River affect ground-water flow. Because ambient ground water and surface water typically have different temperature characteristics, temperature monitoring will likely provide further insight into ground-water/surface-water interactions in the subsurface. Characterization of the unsaturated zone will improve our understanding of interactions among ground water, the unsaturated zone, and the atmosphere. The interactions likely of importance to this study include the migration of water, dissolved contaminants, nutrients, and gases (oxygen, carbon dioxide, and methane) between the saturated and unsaturated zones. We will use the results of ground-water chemical analyses to determine the spatial and temporal distribution of (1) chlorinated-hydrocarbon contaminants and their degradation products, (2) oxidation-reduction indicators, (3) nutrients, and (4) major ground-water ions. These water-quality data will provide insight into ground-water flow directions, interactions between ground water and surface water, attenuation of contaminant concentrations caused by dispersion, and intrinsic microbiological processes. Microbiological analyses will indicate whether microorganisms at the site are capable of degrading the contaminants of interest, and will allow us to estimate their potential to attenuate existing contamination. Physical and chemical data interpreted as part of the analysis of ground water and surface water mixing will improve our understanding of the relationship between water quality and contaminant source mixing.

Wettability, polarity, and water absorption of holm oak leaves: effect of leaf side and age.

PubMed

Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

2014-09-01

Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. © 2014 American Society of Plant Biologists. All Rights Reserved.

The liquid-vapor equilibria of TIP4P/2005 and BLYPSP-4F water models determined through direct simulations of the liquid-vapor interface.

PubMed

Hu, Hongyi; Wang, Feng

2015-06-07

In this paper, the surface tension and critical properties for the TIP4P/2005 and BLYPSP-4F models are reported. A clear dependence of surface tension on the van der Waals cutoff radius (rvdw) is shown when van der Waals interactions are modeled with a simple cutoff scheme. A linear extrapolation formula is proposed that can be used to determine the infinite rvdw surface tension through a few simulations with finite rvdw. A procedure for determining liquid and vapor densities is proposed that does not require fitting to a profile function. Although the critical temperature of water is also found to depend on the choice of rvdw, the dependence is weaker. We argue that a rvdw of 1.75 nm is a good compromise for water simulations when long-range van der Waals correction is not applied. Since the majority of computational programs do not support rigorous treatment of long-range dispersion, the establishment of a minimal acceptable rvdw is important for the simulation of a variety of inhomogeneous systems, such as water bubbles, and water in confined environments. The BLYPSP-4F model predicts room temperature surface tension marginally better than TIP4P/2005 but overestimates the critical temperature. This is expected since only liquid configurations were fit during the development of the BLYPSP-4F potential. The potential is expected to underestimate the stability of vapor and thus overestimate the region of stability for the liquid.

Bioassays with caged hyalella azteca to determine in situ toxicity downstream of two Saskatchewan, Canada, uranium operations.

PubMed

Robertson, Erin L; Liber, Karsten

2007-11-01

The main objectives of this in situ study were to evaluate the usefulness of an in situ bioassay to determine if downstream water bodies at the Key Lake and Rabbit Lake uranium operations (Saskatchewan, Canada) were toxic to Hyalella azteca and, if toxicity was observed, to differentiate between the contribution of surface water and sediment contamination to in situ toxicity. These objectives were achieved by performing 4-d in situ bioassays with laboratory-reared H. azteca confined in specially designed, paired, surface water and sediment exposure chambers. Results from the in situ bioassays revealed significant mortality, relative to the respective reference site, at the exposure sites at both Key Lake (p

Effect of abrasive water jet on the structure of the surface layer of Al-Mg alloy

NASA Astrophysics Data System (ADS)

Tabatchikova, T. I.; Tereshchenko, N. A.; Yakovleva, I. L.; Gudnev, N. Z.

2017-09-01

Optical, scanning, and transmission electron microscopy methods, and X-ray diffraction analysis have been used to study the changes in the structure and the microhardness in the surface layer of the Al-Mg (5.8-6.8 wt %) alloy after water jet cutting. The dislocation density, the sizes of coherent scattering regions, and microdistortions have been determined. The transformation of the fine structure has been revealed in the displacement from the alloy volume to the abrasive-waterjet cutting surface.

Soil Water and Temperature System (SWATS) Instrument Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, David R.

2016-04-01

The soil water and temperature system (SWATS) provides vertical profiles of soil temperature, soil-water potential, and soil moisture as a function of depth below the ground surface at hourly intervals. The temperature profiles are measured directly by in situ sensors at the Central Facility and many of the extended facilities of the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) site. The soil-water potential and soil moisture profiles are derived from measurements of soil temperature rise in response to small inputs of heat. Atmospheric scientists use the data in climate models tomore » determine boundary conditions and to estimate the surface energy flux. The data are also useful to hydrologists, soil scientists, and agricultural scientists for determining the state of the soil.« less

Pathways for nitrate release from an alpine watershed: Determination using δ15N and δ18O

USGS Publications Warehouse

Campbell, Donald H.; Kendall, Carol; Chang, Cecily C.Y.; Silva, Steven R.; Tonnessen, Kathy A.

2002-01-01

Snowpack, snowmelt, precipitation, surface water, and groundwater samples from the Loch Vale watershed in Colorado were analyzed for δ15N and δ18O of nitrate to determine the processes controlling the release of atmospherically deposited nitrogen from alpine and subalpine ecosystems. Although overlap was found between the δ15N(NO3) values for all water types (−4 to +6‰), the δ18O(NO3) values for surface water and groundwater (+10 to +30‰) were usually distinct from snowpack, snowmelt, and rainfall values (+40 to +70‰). During snowmelt, δ18O(NO3) indicated that about half of the nitrate in stream water was the product of microbial nitrification; at other times that amount was greater than half. Springs emerging from talus deposits had high nitrate concentrations and a seasonal pattern in δ18O(NO3) that was similar to the pattern in the streams, indicating that shallow groundwater in talus deposits is a likely source of stream water nitrate. Only a few samples of surface water and groundwater collected during early snowmelt and large summer rain events had isotopic compositions that indicated most of the nitrate came directly from atmospheric deposition with no biological assimilation and release. This study demonstrates the value of the nitrate double‐isotope technique for determining nitrogen‐cycling processes and sources of nitrate in small, undisturbed watersheds that are enriched with inorganic nitrogen.

EVALUATION OF DRINKING WATER TREATMENT TECHNOLOGIES FOR REMOVAL OF ENDOCRINE DISRUPTING CHEMICALS (EDCS)

EPA Science Inventory

A number of the chemicals identified as potential EDCs have been observed in surface and ground waters leading to concern over the possible presence of EDCs in finished drinking waters. Although there has not yet been a determination of risks posed by EDCs in finished waters, it ...

Estimation of Missing Water-Level Data for the Everglades Depth Estimation Network (EDEN)

USGS Publications Warehouse

Conrads, Paul; Petkewich, Matthew D.

2009-01-01

The Everglades Depth Estimation Network (EDEN) is an integrated network of real-time water-level gaging stations, ground-elevation models, and water-surface elevation models designed to provide scientists, engineers, and water-resource managers with current (2000-2009) water-depth information for the entire freshwater portion of the greater Everglades. The U.S. Geological Survey Greater Everglades Priority Ecosystems Science provides support for EDEN and their goal of providing quality-assured monitoring data for the U.S. Army Corps of Engineers Comprehensive Everglades Restoration Plan. To increase the accuracy of the daily water-surface elevation model, water-level estimation equations were developed to fill missing data. To minimize the occurrences of no estimation of data due to missing data for an input station, a minimum of three linear regression equations were developed for each station using different input stations. Of the 726 water-level estimation equations developed to fill missing data at 239 stations, more than 60 percent of the equations have coefficients of determination greater than 0.90, and 92 percent have an coefficient of determination greater than 0.70.

Use of ICP/MS with ultrasonic nebulizer for routine determination of uranium activity ratios in natural water

USGS Publications Warehouse

Kraemer, T.F.; Doughten, M.W.; Bullen, T.D.

2002-01-01

A method is described that allows precise determination of 234U/238U activity ratios (UAR) in most natural waters using commonly available inductively coupled plasma/mass spectrometry (ICP/MS) instrumentation and accessories. The precision achieved by this technique (??0.5% RSD, 1 sigma) is intermediate between thermal ionization mass spectrometry (??0.25% RSID, 1 sigma) and alpha particle spectrometry (??5% RSD, 1 sigma). It is precise and rapid enough to allow analysis of a large number of samples in a short period of time at low cost using standard, commercially available quadrupole instrumentation with ultrasonic nebulizer and desolvator accessories. UARs have been analyzed successfully in fresh to moderately saline waters with U concentrations of from less than 1 ??g/L to nearly 100 ??g/L. An example of the uses of these data is shown for a study of surface-water mixing in the North Platte River in western Nebraska. This rapid and easy technique should encourage the wider use of uranium isotopes in surface-water and groundwater investigations, both for qualitative (e.g. identifying sources of water) and quantitative (e.g. determining end-member mixing ratios purposes.

On the influence of the intermolecular potential on the wetting properties of water on silica surfaces

NASA Astrophysics Data System (ADS)

Pafong, E.; Geske, J.; Drossel, B.

2016-09-01

We study the wetting properties of water on silica surfaces using molecular dynamics (MD) simulations. To describe the intermolecular interaction between water and silica atoms, two types of interaction potential models are used: the standard BródkA and Zerda (BZ) model and the Gulmen and Thompson (GT) model. We perform an in-depth analysis of the influence of the choice of the potential on the arrangement of the water molecules in partially filled pores and on top of silica slabs. We find that at moderate pore filling ratios, the GT silica surface is completely wetted by water molecules, which agrees well with experimental findings, while the commonly used BZ surface is less hydrophilic and is only partially wetted. We interpret our simulation results using an analytical calculation of the phase diagram of water in partially filled pores. Moreover, an evaluation of the contact angle of the water droplet on top of the silica slab reveals that the interaction becomes more hydrophilic with increasing slab thickness and saturates around 2.5-3 nm, in agreement with the experimentally found value. Our analysis also shows that the hydroaffinity of the surface is mainly determined by the electrostatic interaction, but the van der Waals interaction nevertheless is strong enough that it can turn a hydrophobic surface into a hydrophilic surface.

Results of borehole geophysical logging and hydraulic tests conducted in Area D supply wells, former U.S. Naval Air Warfare Center, Warminster, Pennsylvania

USGS Publications Warehouse

Sloto, Ronald A.; Grazul, Kevin E.

1998-01-01

Borehole geophysical logging, aquifer tests, and aquifer-isolation (packer) tests were conducted in four supply wells at the former U.S. Naval Air Warfare Center (NAWC) in Warminster, PA, to identify the depth and yield of water-bearing zones, occurrence of borehole flow, and effect of pumping on nearby wells. The study was conducted as part of an ongoing evaluation of ground-water contamination at the NAWC. Caliper, natural-gamma, single-point resistance, fluid resistivity, and fluid temperature logs and borehole television surveys were run in the supply wells, which range in depth from 242 to 560 ft (feet). Acoustic borehole televiewer and borehole deviation logs were run in two of the wells. The direction and rate of borehole-fluid movement under non-pumping conditions were measured with a high-resolution heatpulse flowmeter. The logs were used to locate water-bearing fractures, determine probable zones of vertical borehole-fluid movement, and determine the depth to set packers. An aquifer test was conducted in each well to determine open-hole specific capacity and the effect of pumping the open borehole on water levels in nearby wells. Specific capacities ranged from 0.21 to 1.7 (gal/min)/ft (gallons per minute per foot) of drawdown. Aquifer-isolation tests were conducted in each well to determine depth-discrete specific capacities and to determine the effect of pumping an individual fracture or fracture zone on water levels in nearby wells. Specific capacities of individual fractures and fracture zones ranged from 0 to 2.3 (gal/min)/ft. Most fractures identified as water-producing or water-receiving zones by borehole geophysical methods produced water when isolated and pumped. All hydrologically active fractures below 250 ft below land surface were identified as water-receiving zones and produced little water when isolated and pumped. In the two wells greater then 540 ft deep, downward borehole flow to the deep water-receiving fractures is caused by a large difference in head (as much as greater then 49 ft) between water-bearing fractured in the upper and lower part of the borehole. Vertical distribution of specific capacity between land surface and 250 ft below land surface is not related to depth.

Accurate determination of the charge transfer efficiency of photoanodes for solar water splitting.

PubMed

Klotz, Dino; Grave, Daniel A; Rothschild, Avner

2017-08-09

The oxygen evolution reaction (OER) at the surface of semiconductor photoanodes is critical for photoelectrochemical water splitting. This reaction involves photo-generated holes that oxidize water via charge transfer at the photoanode/electrolyte interface. However, a certain fraction of the holes that reach the surface recombine with electrons from the conduction band, giving rise to the surface recombination loss. The charge transfer efficiency, η t , defined as the ratio between the flux of holes that contribute to the water oxidation reaction and the total flux of holes that reach the surface, is an important parameter that helps to distinguish between bulk and surface recombination losses. However, accurate determination of η t by conventional voltammetry measurements is complicated because only the total current is measured and it is difficult to discern between different contributions to the current. Chopped light measurement (CLM) and hole scavenger measurement (HSM) techniques are widely employed to determine η t , but they often lead to errors resulting from instrumental as well as fundamental limitations. Intensity modulated photocurrent spectroscopy (IMPS) is better suited for accurate determination of η t because it provides direct information on both the total photocurrent and the surface recombination current. However, careful analysis of IMPS measurements at different light intensities is required to account for nonlinear effects. This work compares the η t values obtained by these methods using heteroepitaxial thin-film hematite photoanodes as a case study. We show that a wide spread of η t values is obtained by different analysis methods, and even within the same method different values may be obtained depending on instrumental and experimental conditions such as the light source and light intensity. Statistical analysis of the results obtained for our model hematite photoanode show good correlation between different methods for measurements carried out with the same light source, light intensity and potential. However, there is a considerable spread in the results obtained by different methods. For accurate determination of η t , we recommend IMPS measurements in operando with a bias light intensity such that the irradiance is as close as possible to the AM1.5 Global solar spectrum.

Understanding heterogeneity and data assimilation in karst groundwater surface water interactions: The role of geophysics and hydrologic models in a semi-confined aquifer

NASA Astrophysics Data System (ADS)

Meyerhoff, Steven B.

Groundwater and surface water historically have been treated as different entities. Due to this, planning and development of groundwater and surface water resources, both quantity and quality are often also treated separately. Recently, there has been work to characterize groundwater and surface water as a single system. Karstic systems are widely influenced by these interactions due to varying permeability, fracture geometry and porosity. Here, three different approaches are used to characterize groundwater surface water interactions in karstic environments. 1) A hydrologic model, ParFlow, is conditioned with known subsurface data to determine whether a reduction in subsurface uncertainty will enhance the prediction of surface water variables. A reduction in subsurface uncertainty resulted in substantial reductions in uncertainty in Hortonian runoff and less reductions in Dunne runoff. 2) Geophysical data is collected at a field site in O'leno State Park, Florida to visualize groundwater and surface water interactions in karstic environments. Significant changes in resistivity are seen through time at two locations. It is hypothesized that these changes are related to changing fluid source waters (e.g groundwater or surface water). 3). To confirm these observations an ensemble of synthetic forward models are simulated, inverted and compared directly with field observations and End-Member-Mixing-Analysis (EMMA). Field observations and synthetic models have comparable resistivity anomalies patterns and mixing fractions. This allows us to characterize and quantify subsurface mixing of groundwater and surface in karst environments. These three approaches (hydrologic models, field data and forward model experiments), (1) show the complexity and dynamics of groundwater and surface mixing in karstic environments in varying flow conditions, (2) showcase a novel geophysical technique to visualize groundwater and surface water interactions and (3) confirm hypothesis of flow and mixing in subsurface karst environments.

Fractal behavior of soil water storage at multiple depths

NASA Astrophysics Data System (ADS)

Ji, Wenjun; Lin, Mi; Biswas, Asim; Si, Bing C.; Chau, Henry W.; Cresswell, Hamish P.

2016-08-01

Spatiotemporal behavior of soil water is essential to understand the science of hydrodynamics. Data intensive measurement of surface soil water using remote sensing has established that the spatial variability of soil water can be described using the principle of self-similarity (scaling properties) or fractal theory. This information can be used in determining land management practices provided the surface scaling properties are kept at deep layers. The current study examined the scaling properties of sub-surface soil water and their relationship to surface soil water, thereby serving as supporting information for plant root and vadose zone models. Soil water storage (SWS) down to 1.4 m depth at seven equal intervals was measured along a transect of 576 m for 5 years in Saskatchewan. The surface SWS showed multifractal nature only during the wet period (from snowmelt until mid- to late June) indicating the need for multiple scaling indices in transferring soil water variability information over multiple scales. However, with increasing depth, the SWS became monofractal in nature indicating the need for a single scaling index to upscale/downscale soil water variability information. In contrast, all soil layers during the dry period (from late June to the end of the growing season in early November) were monofractal in nature, probably resulting from the high evapotranspirative demand of the growing vegetation that surpassed other effects. This strong similarity between the scaling properties at the surface layer and deep layers provides the possibility of inferring about the whole profile soil water dynamics using the scaling properties of the easy-to-measure surface SWS data.

Water-Surface Elevations, Discharge, and Water-Quality Data for Selected Sites in the Warm Springs Area near Moapa, Nevada

USGS Publications Warehouse

Beck, David A.; Ryan, Roslyn; Veley, Ronald J.; Harper, Donald P.; Tanko, Daron J.

2006-01-01

The U.S. Geological Survey, in cooperation with Southern Nevada Water Authority and the Nevada Division of Water Resources, operates and maintains a surface-water monitoring network of 6 continuous-record stream-flow gaging stations and 11 partial-record stations in the Warm Springs area near Moapa, Nevada. Permanent land-surface bench marks were installed within the Warm Springs area by the Las Vegas Valley Water District, the Southern Nevada Water Authority, and the U.S. Geological Survey to determine water-surface elevations at all network monitoring sites. Vertical datum elevation and horizontal coordinates were established for all bench marks through a series of Differential Global Positioning System surveys. Optical theodolite surveys were made to transfer Differential Global Positioning System vertical datums to reference marks installed at each monitoring site. The surveys were completed in June 2004 and water-surface elevations were measured on August 17, 2004. Water-surface elevations ranged from 1,810.33 feet above North American Vertical Datum of 1988 at a stream-gaging station in the Pederson Springs area to 1,706.31 feet at a station on the Muddy River near Moapa. Discharge and water-quality data were compiled for the Warm Springs area and include data provided by the U.S. Geological Survey, Nevada Division of Water Resources, U.S. Fish and Wildlife Service, Moapa Valley Water District, Desert Research Institute, and Converse Consultants. Historical and current hydrologic data-collection networks primarily are related to changes in land- and water-use activities in the Warm Springs area. These changes include declines in ranching and agricultural use, the exportation of water to other areas of Moapa Valley, and the creation of a national wildlife refuge. Water-surface elevations, discharge, and water-quality data compiled for the Warm Springs area will help identify (1) effects of changing vegetation within the former agricultural lands, (2) effects of restoration activities in the wildlife refuge, and (3) potential impacts of ground-water withdrawals.

Various nanoparticle morphologies and surface properties of waterborne polyurethane controlled by water

PubMed Central

Zhou, Xing; Fang, Changqing; Lei, Wanqing; Du, Jie; Huang, Tingyi; Li, Yan; Cheng, Youliang

2016-01-01

Water plays important roles in organic reactions such as polyurethane synthesis, and the aqueous solution environment affects polymer morphology and other properties. This paper focuses on the morphology and surface properties of waterborne polyurethane resulting from the organic reaction in water involving different forms (solid and liquid), temperatures and aqueous solutions. We provide evidence from TEM observations that the appearance of polyurethane nanoparticles in aqueous solutions presents diverse forms, including imperfect spheres, perfect spheres, perfect and homogenous spheres and tubes. Based on the results on FTIR, GPC, AFM and XRD experiments, we suggest that the shape of the nanoparticles may be decided by the crimp degree (i.e., the degree of polyurethane chains intertangling in the water environment) and order degree, which are determined by the molecular weight (Mn) and hydrogen bonds. Meanwhile, solid water and high-temperature water can both reduce hard segments that gather on the polyurethane film surface to reduce hydrophilic groups and produce a soft surface. Our findings show that water may play key roles in aqueous polymer formation and bring order to molecular chains. PMID:27687001

Experimental study on water content detection of traditional masonry based on infrared thermal image

NASA Astrophysics Data System (ADS)

Zhang, Baoqing; Lei, Zukang

2017-10-01

Based on infrared thermal imaging technology for seepage test of two kinds of brick masonry, find out the relationship between the distribution of one-dimensional two brick surface temperature distribution and one-dimensional surface moisture content were determined after seepage brick masonry minimum temperature zone and water content determination method of the highest point of the regression equation, the relationship between temperature and moisture content of the brick masonry reflected the quantitative and establish the initial wet masonry building disease analysis method, then the infrared technology is applied to the protection of historic buildings in.

Assessment of ground-water contamination near Lantana landfill, Southeast Florida

USGS Publications Warehouse

Russell, G.M.; Higer, A.L.

1988-01-01

The Lantana landfill located in Palm Beach County rises 40 to 50 feet above normal ground level and consists of about 250 acres of compacted garbage and trash, some below the water table. Surface-resistivity measurements and water-quality analyses indicate a contaminant plume along the eastern perimeter of the landfill that has migrated about 300 feet eastward toward an adjacent lake. Concentrations of chloride, ammonia, and nitrate were elevated within the plume. The surficial aquifer consists primarily of sand from 0 to about 68 feet, and sand interbedded with sandstone and limestone from 68 to 220 feet. A slight hydraulic gradient exists, indicating ground-water movement from the landfill toward a lake to the east. Analyses of geoelectric, lithologic, and water-quality data indicate that surface geophysical techniques were successful in determining the areal and vertical extent of leachate migration at this location.The Lantana landfill located in Palm Beach County rises 40 to 50 feet above normal ground level and consists of about 250 acres of compacted garbage and trash, some below the water table. Surface-resistivity measurements and water-quality analyses indicate a contaminant plume along the eastern perimeter of the landfill that has migrated about 300 feet eastward toward an adjacent lake. Concentrations of chloride, ammonia, and nitrate were elevated within the plume. The surficial aquifer consists primarily of sand from 0 to about 68 feet, and sand interbedded with sandstone and limestone from 68 to 220 feet. A slight hydraulic gradient exists, indicating ground-water movement from the landfill toward a lake to the east. Analyses of geoelectric, lithologic, and water-quality data indicate that surface geophysical techniques were successful in determining the areal and vertical extent of leachate migration at this location.

Analysis of pesticides in surface water, stemflow, and throughfall in an agricultural area in South Georgia, USA.

PubMed

Glinski, Donna A; Purucker, S Thomas; Van Meter, Robin J; Black, Marsha C; Henderson, W Matthew

2018-06-18

To study spray drift contributions to non-targeted habitats, pesticide concentrations in stemflow (water flowing down the trunk of a tree during a rain event), throughfall (water from tree canopy only), and surface water in an agriculturally impacted wetland area near Tifton, Georgia, USA were measured (2015-2016). Agricultural fields and sampling locations were on the University of Georgia's Gibbs Research Farm, Tifton, GA. Samples were screened for more than 160 pesticides, and cumulatively, 32 different pesticides were detected across matrices. Data indicate that herbicides and fungicides were present in all types of environmental samples analyzed while insecticides were only detected in surface water samples. The highest pesticide concentration observed was 10.50 μg/L of metolachlor in an August 2015 surface water sample. Metolachlor, tebuconazole, and fipronil were the most frequently detected herbicide, fungicide, and insecticide, respectively, regardless of sample origin. The most frequently detected pesticide in surface water and stemflow samples was metolachlor (0.09-10.5 μg/L), however, the most commonly detected pesticide in throughfall samples was biphenyl (0.02-0.07 μg/L). These data help determine the importance of indirect chemical exposures to non-targeted habitats by assessing inputs from stemflow and throughfall into surface waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development and evaluation of a culture-independent method for source determination of fecal wastes in surface and storm waters using reverse transcriptase-PCR detection of FRNA coliphage genogroup gene sequences.

EPA Science Inventory

A complete method, incorporating recently improved reverse transcriptase-PCR primer/probe assays and including controls for determining interferences to phage recoveries from water sample concentrates and for detecting interferences to their analysis, was developed for the direct...

Development and evaluation of a culture-independent method for source determination of fecal wastes in surface and storm waters using reverse transcriptase-PCR detection of FRNA coliphage genogroup gene sequences

EPA Science Inventory

A complete method, incorporating recently improved reverse transcriptase-PCR primer/probe assays and including controls for determining interferences to phage recoveries from water sample concentrates and for detecting interferences to their analysis, was developed for the direct...

Numerical Model of the Hoosic River Flood-Control Channel, Adams, MA

DTIC Science & Technology

2010-02-01

The model was then used to evaluate the flow conditions associated with the as-built channel configuration. The existing channel conditions were then...end as part of a channel restoration project. The model was to determine if restoration alterations would change water- surface elevations associated ...water-surface elevations associated with the initial design and construction. After as-built flow conditions were established, flow conditions

Designing a dynamic data driven application system for estimating real-time load of dissolved organic carbon in a river

Treesearch

Ying Ouyang

2012-01-01

Understanding the dynamics of naturally occurring dissolved organic carbon (DOC) in a river is central to estimating surface water quality, aquatic carbon cycling, and global climate change. Currently, determination of the DOC in surface water is primarily accomplished by manually collecting samples for laboratory analysis, which requires at least 24 h. In other words...

A Thermodynamic Description of the Adsorption of Simple Water-Soluble Peptoids to Silica.

PubMed

Calkins, Anna L; Yin, Jennifer; Rangel, Jacenda L; Landry, Madeleine R; Fuller, Amelia A; Stokes, Grace Y

2016-11-08

The first report of a water-soluble peptoid adsorbed to silica monitored by second harmonic generation (SHG) at the liquid/solid interface is presented here. The molecular insights gained from these studies will inform the design and preparation of novel peptoid coatings. Simple 6- and 15-residue peptoids were dissolved in phosphate buffered saline and adsorbed to bare silica surfaces. Equilibrium binding constants and relative surface concentrations of adsorbed peptoids were determined from fits to the Langmuir model. Complementary fluorescence spectroscopy studies were used to quantify the maximum surface excess. Binding constants, determined here by SHG, were comparable to those previously reported for cationic proteins and small molecules. Enthalpies and free energies of adsorption were determined to elucidate thermodynamic driving forces. Circular dichroism spectra confirm that minimal conformational changes occur when peptoids are adsorbed to silica while pH studies indicate that electrostatic interactions impact adsorption.

Use of borehole and surface geophysics to investigate ground-water quality near a road-deicing salt-storage facility, Valparaiso, Indiana

USGS Publications Warehouse

Risch, M.R.; Robinson, B.A.

2001-01-01

Two surface surveys of terrain electromagnetic conductivity were used to map the horizontal extent of the saltwater plume in areas without monitoring wells. Background values of terrain conductivity were measured in an area where water-quality and borehole geophysical data did not indicate saline or brackish water. Based on a guideline from previous case studies, the boundaries of the saltwater plume were mapped where terrain conductivity was 1.5 times background. The extent of the saltwater plume, based on terrain conductivity, generally was consistent with the available water-quality and borehole electromagnetic-conductivity data and with directions of ground-water flow determined from water-level altitudes.

Determination of the relative uptake of ground vs. surface water by Populus deltoides during phytoremediation

USGS Publications Warehouse

Clinton, B.D.; Vose, J.M.; Vroblesky, D.A.; Harvey, G.J.

2004-01-01

The use of plants to remediate polluted groundwater is becoming an attractive alternative to more expensive traditional techniques. In order to adequately assess the effectiveness of the phytoremediation treatment, a clear understanding of water-use habits by the selected plant species is essential. We examined the relative uptake of surface water (i.e., precipitation) vs. groundwater by mature Populus deltoides by applying irrigation water at a rate equivalent to a 5-cm rain event. We used stable isotopes of hydrogen (D) and oxygen (18O) to identify groundwater and surface water (irrigation water) in the xylem sap water. Pretreatment isotopic ratios of both deuterium and 18O, ranked from heaviest to lightest, were irrigation water > groundwater > xylem sap. The discrepancy in preirrigation isotopic signatures between groundwater and xylem sap suggests that in the absence of a surface source of water (i.e., between rain events) there is an unknown amount of water being extracted from sources other than groundwater (i.e., soil surface water). We examined changes in volumetric soil water content (%), total hourly sapflux rates, and trichloroethene (TCE) concentrations. Following the irrigation treatment, volumetric soil water increased by 86% and sapflux increased by as much as 61%. Isotopic signatures of the xylem sap became substantially heavier following irrigation, suggesting that the applied irrigation water was quickly taken up by the plants. TCE concentrations in the xylem sap were diluted by an average of 21% following irrigation; however, dilution was low relative to the increase in sapflux. Our results show that water use by Populus deltoides is variable. Hence, studies addressing phytoremediation effectiveness must account for the relative proportion of surface vs. groundwater uptake.

In Situ Determination of the Water Condensation Mechanisms on Superhydrophobic and Superhydrophilic Titanium Dioxide Nanotubes.

PubMed

Macias-Montero, Manuel; Lopez-Santos, Carmen; Filippin, A Nicolas; Rico, Victor J; Espinos, Juan P; Fraxedas, Jordi; Perez-Dieste, Virginia; Escudero, Carlos; Gonzalez-Elipe, Agustin R; Borras, Ana

2017-07-05

One-dimensional (1D) nanostructured surfaces based on high-density arrays of nanowires and nanotubes of photoactive titanium dioxide (TiO 2 ) present a tunable wetting behavior from superhydrophobic to superhydrophilic states. These situations are depicted in a reversible way by simply irradiating with ultraviolet light (superhydrophobic to superhydrophilic) and storage in dark. In this article, we combine in situ environmental scanning electron microscopy (ESEM) and near ambient pressure photoemission analysis (NAPP) to understand this transition. These experiments reveal complementary information at microscopic and atomic level reflecting the surface wettability and chemical state modifications experienced by these 1D surfaces upon irradiation. We pay special attention to the role of the water condensation mechanisms and try to elucidate the relationship between apparent water contact angles of sessile drops under ambient conditions at the macroscale with the formation of droplets by water condensation at low temperature and increasing humidity on the nanotubes' surfaces. Thus, for the as-grown nanotubes, we reveal a metastable and superhydrophobic Cassie state for sessile drops that tunes toward water dropwise condensation at the microscale compatible with a partial hydrophobic Wenzel state. For the UV-irradiated surfaces, a filmwise wetting behavior is observed for both condensed water and sessile droplets. NAPP analyses show a hydroxyl accumulation on the as-grown nanotubes surfaces during the exposure to water condensation conditions, whereas the water filmwise condensation on a previously hydroxyl enriched surface is proved for the superhydrophilic counterpart.

Determination of trace levels of herbicides and their degradation products in surface and ground waters by gas chromatography/ion-trap mass spectrometry

USGS Publications Warehouse

Pereira, W.E.; Rostad, C.E.; Leiker, T.J.

1990-01-01

A rapid, specific and highly sensitive method is described for the determination of several commonly used herbicides and their degradation products in surface and ground waters by using gas chromatography/ion-trap mass spectrometry. The compounds included atrazine, and its degradation products desethylatrazine and desisopropylatrazine; Simazine; Cyanazine; Metolachlor; and alachlor and its degradation products, 2-chloro-2', 6'-diethylacetanilide, 2-hydroxy-2', 6'-diethylacetanilide and 2,6-diethylaniline. The method was applied to surface-water samples collected from 16 different stations along the lower Mississippi River and its major tributaries, and ground-water samples beneath a cornfield in central Nebraska. Average recovery of a surrogate herbicide, terbuthylazine, was greater than 99%. Recoveries of the compounds of interest from river water spiked at environmental levels are also presented. Full-scan mass spectra of these compounds were obtained on 1 ng or less of analyte. Data were collected in the full-scan acquisition mode. Quantitation was based on a single characteristic ion for each compound. The detection limit was 60 pg with a signal-to-noise ratio of greater than 10:1.

Evaluation of borehole geophysical logs at the Sharon Steel Farrell Works Superfund site, Mercer County, Pennsylvania

USGS Publications Warehouse

McAuley, Steven D.

2004-01-01

On April 14?15, 2003, geophysical logging was conducted in five open-borehole wells in and adjacent to the Sharon Steel Farrell Works Superfund Site, Mercer County, Pa. Geophysical-logging tools used included caliper, natural gamma, single-point resistance, fluid temperature, and heatpulse flowmeter. The logs were used to determine casing depth, locate subsurface fractures, identify water-bearing fractures, and identify and measure direction and rate of vertical flow within the borehole. The results of the geophysical logging were used to determine the placement of borehole screens, which allows monitoring of water levels and sampling of water-bearing zones so that the U.S. Environmental Protection Agency can conduct an investigation of contaminant movement in the fractured bedrock. Water-bearing zones were identified in three of five boreholes at depths ranging from 46 to 119 feet below land surface. Borehole MR-3310 (MW03D) showed upward vertical flow from 71 to 74 feet below land surface to a receiving zone at 63-68 feet below land surface, permitting potential movement of ground water, and possibly contaminants, from deep to shallow zones. No vertical flow was measured in the other four boreholes.

WET DEMONSTRATION WORKSHOP ON THE IDENTIFICATION OF CRYPTOSPORIDIUM, MICROSPORIDIA, AND GIARDIA IN DRINKING WATER

EPA Science Inventory

This method is for determination of the identity and concentration of Cryptosporidium (CAS Registry number 137259-50-8) and Giardia (CAS Registry number 137259-49-5) in untreated surface water and in other waters by filtration, immunomagnetic separation (IMS), and immunofluoresce...

The Enterococcus QPCR Method for Recreational Water Quality Testing: Testing Background, Performance and Issues

EPA Science Inventory

Currently accepted culture-based monitoring methods for fecal indicator bacteria in surface waters take at least 24 hr to determine if unacceptable levels of fecal pollution have reached our recreational beaches. During this waiting period changing water conditions may result eit...

Coagulation effectiveness of graphene oxide for the removal of turbidity from raw surface water.

PubMed

Aboubaraka, Abdelmeguid E; Aboelfetoh, Eman F; Ebeid, El-Zeiny M

2017-08-01

This study presents the performance of graphene oxide (GO) as a coagulant in turbidity removal from naturally and artificially turbid raw surface water. GO is considered an excellent alternative to alum, the more common coagulant used in water treatment processes, to reduce the environmental release of aluminum. Effects of GO dosage, pH, and temperature on its coagulation ability were studied to determine the ideal turbidity removal conditions. The turbidity removal was ≥95% for all levels of turbid raw surface water (20, 100, and 200 NTU) at optimum conditions. The role of alkalinity in inducing turbidity removal by GO coagulation was much more pronounced upon using raw surface water samples compared with that using artificially turbid deionized water samples. Moreover, GO demonstrated high-performance removal of biological contaminants such as algae, heterotrophic bacteria, and fecal coliform bacteria by 99.0%, 98.8% and 96.0%, respectively, at a dosage of 40 mg/L. Concerning the possible environmental release of GO into the treated water following filtration process, there was no residual GO in a wide range of pH values. The outcomes of the study highlight the excellent coagulation performance of GO for the removal of turbidity and biological contaminants from raw surface water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogeologic and water-quality data for the main site, Naval Surface Warfare Center, Dahlgren Laboratory, Dahlgren, Virginia

USGS Publications Warehouse

Bell, Clifton F.; Bolles, Thomas P.; Harlow, George E.

1994-01-01

Hydrogeologic and water-quality data were collected at the Naval Surface Warfare Center, Dahlgren Laboratory at Dahlgren, Virginia, as part of a hydrogeologic assessment of the shallow aquifer system begun in 1992. The U.S. Geological Survey conducted this study to provide the Navy with hydrogeologic data to meet the requirements of a Spill Contingency Plan. This report describes the ground-water observation-well network, hydro- geologic, and water-quality data collected between August 1992 and September 1993. The report includes a description of the locations and con- struction of 35 observation wells on the Main Site. Hydrologic data include lithologic core samples, geophysical logs, and vertical hydraulic conductivity measurements of selected core intervals. Hydrologic data include synoptic and hourly measurements of ground-water levels, observation-well slug tests to determine horizontal hydraulic conductivity, and tide data. Water-quality data include analyses of major dissolved constituents in ground water and surface water.

Determining spatially discretized surface flow and baseflow in the context of climate change and water quality management

NASA Astrophysics Data System (ADS)

Raimonet, M.; Oudin, L.; Rabouille, C.; Garnier, J.; Silvestre, M.; Vautard, R.; Thieu, V.

2016-12-01

Water quality management of fresh and marine aquatic systems requires modelling tools along the land-ocean continuum in order to evaluate the effect of climate change on nutrient transfer and on potential ecosystem dysfonctioning (e.g. eutrophication, anoxia). In addition to direct effects of climate change on water temperature, it is essential to consider indirect effects of precipitation and temperature changes on hydrology since nutrient transfers are particularly sensitive to the partition of streamflow between surface flow and baseflow. Yet, the determination of surface flow and baseflow, their spatial repartition on drainage basins, and their relative potential evolution under climate change remains challenging. In this study, we developed a generic approach to determine 10-day surface flow and baseflow using a regionalized hydrological model applied at a high spatial resolution (unitary catchments of area circa 10km²). Streamflow data at gauged basins were used to calibrate hydrological model parameters that were then applied on neighbor ungauged basins to estimate streamflow at the scale of the French territory. The proposed methodology allowed representing spatialized surface flow and baseflow that are consistent with climatic and geomorphological settings. The methodology was then used to determine the effect of climate change on the spatial repartition of surface flow and baseflow on the Seine drainage bassin. Results showed large discrepancies of both the amount and the spatial repartition of changes of surface flow and baseflow according to the several GCM and RCM used to derive projected climatic forcing. Consequently, it is expected that the impact of climate change on nutrient transfer might also be quite heterogeneous for the Seine River. This methodology could be applied in any drainage basin where at least several gauged hydrometric stations are available. The estimated surface flow and baseflow can then be used in hydro-ecological models in order to evaluate direct and indirect impacts of climate change on nutrient transfers and potential ecosystem dysfunctioning along the land-ocean continuum.

Martian neutron leakage spectra

NASA Astrophysics Data System (ADS)

Drake, D. M.; Feldman, W. C.; Jakosky, B. M.

1988-06-01

A high-energy nucleon-meson transport code is used to calculate energy spectra of Martian leakage neutrons. Four calculations are used to simulate a uniform surface layer containing various amounts of water, different burial depths of a 50 percent water layer underneath a 1 percent water layer, changing atmospheric pressure, and a thick carbon dioxide ice sheet overlying a "dirty" water ice sheet. Calculated spectra at energies less than about 1000 eV were fitted by a superposition of thermal and epithermal functions having four free parameters, two of which (thermal and epithermal amplitudes) were found to vary systematically and to specify uniquely the configuration in each of the series. Parameter variations depend on the composition of the assumed surface layers through the average atomic mass and the macroscopic scattering and absorption cross sections. It is concluded that measurements of leakage neutron spectra should allow determination of the hydrogen content of surface layers buried to depths up to about 100 g/sq. cm and determination of the thickness of a polar dry ice cap up to a thickness of about 250 g/sq. cm.

Determination of dissolved-phase pesticides in surface water from the Yakima River basin, Washington, using the Goulden large-sample extractor and gas chromatography/mass spectrometer

USGS Publications Warehouse

Foster, Gregory D.; Gates, Paul M.; Foreman, William T.; McKenzie, Stuart W.; Rinella, Frank A.

1993-01-01

Concentrations of pesticides in the dissolved phase of surface water samples from the Yakima River basin, WA, were determined using preconcentration in the Goulden large-sample extractor (GLSE) and gas chromatography/mass spectrometry (GC/MS) analysis. Sample volumes ranging from 10 to 120 L were processed with the GLSE, and the results from the large-sample analyses were compared to those derived from 1-L continuous liquid-liquid extractions Few of the 40 target pesticides were detected in 1-L samples, whereas large-sample preconcentration in the GLSE provided detectable levels for many of the target pesticides. The number of pesticides detected in GLSE processed samples was usually directly proportional to sample volume, although the measured concentrations of the pesticides were generally lower at the larger sample volumes for the same water source. The GLSE can be used to provide lower detection levels relative to conventional liquid-liquid extraction in GC/MS analysis of pesticides in samples of surface water.

Relations of surface-water quality to streamflow in the Atlantic Coastal, lower Delaware River, and Delaware Bay basins, New Jersey, water years 1976-93

USGS Publications Warehouse

Hunchak-Kariouk, Kathryn; Buxton, Debra E.; Hickman, R. Edward

1999-01-01

Relations of water quality to streamflow were determined for 18 water-quality constituents at 28 surface-water-quality stations within the drainage area of the Atlantic Coastal, lower Delaware River, and Delaware Bay Basins for water years 1976-93. Surface-water-quality and streamflow data were evaluated for trends (through time) in constituent concentrations during high and low flows, and relations between constituent concentration and streamflow, and between constituent load and streamflow, were determined. Median concentrations were calculated for the entire period of study (water years 1976-93) and for the last 5 years of the period of study (water years 1989-93) to determine whether any large variation in concentration exists between the two periods. Medians also were used to determine the seasonal Kendall\\'s tau statistic, which was then used to evaluate trends in concentrations during high and low flows. Trends in constituent concentrations during high and low flows were evaluated to determine whether the distribution of the observations changes through time for intermittent (nonpoint storm runoff) and constant (point sources and ground water) sources, respectively. High- and low-flow trends in concentrations were determined for some constituents at 26 of the 28 water-quality stations. Seasonal effects on the relations of concentration to streamflow are evident for 10 constituents at 14 or more stations. Dissolved oxygen shows seasonal dependency at all stations. Negative slopes of relations of concentration to streamflow, which indicate a decrease in concentration at high flows, predominate over positive slopes because of dilution of instream concentrations from storm runoff. The slopes of the regression lines of load to streamflow were determined in order to show the relative contributions to the instream load from constant (point sources and ground water) and intermittent sources (storm runoff). Greater slope values indicate larger contributions from storm runoff to instream load, which most likely indicate an increased relative importance of nonpoint sources. Load-to-streamflow relations along a stream reach that tend to increase in a downstream direction indicate the increased relative importance of contributions from storm runoff. Likewise, load-to-streamflow relations along a stream reach that tend to decrease in a downstream direction indicate the increased relative importance of point sources and ground-water discharge. The magnitudes of the load slopes for five constituents increase in the downstream direction along the Great Egg Harbor River, indicating an increased relative importance of storm runoff for these constituents along the river. The magnitudes of the load slopes for 11 constituents decrease in the downstream direction along the Assunpink Creek and for 5 constituents along the Maurice River, indicating a decreased relative importance of storm runoff for these constituents along the rivers.

Filtration of water-sediment samples for the determination of organic compounds

USGS Publications Warehouse

Sandstrom, Mark W.

1995-01-01

This report describes the equipment and procedures used for on-site filtration of surface-water and ground-water samples for determination of organic compounds. Glass-fiber filters and a positive displacement pumping system are suitable for processing most samples for organic analyses. An optional system that uses disposable in-line membrane filters is suitable for a specific gas chromatography/mass spectrometry, selected-ion monitoring analytical method for determination of organonitrogen herbicides. General procedures to minimize contamination of the samples include preparing a clean workspace at the site, selecting appropriate sample-collection materials, and cleaning of the equipment with detergent, tap water, and methanol.

Protecting health from metal exposures in drinking water.

PubMed

Armour, Margaret-Ann

2016-03-01

Drinking water is essential to us as human beings. According to the World Health Organization "The quality of drinking-water is a powerful environmental determinant of health" (http://www.who.int/water_sanitation_health/dwq/en/), but clean drinking water is a precious commodity not always readily available. Surface and ground water are the major sources of drinking water. Both can be contaminated, surface water with bacteria while ground water frequently contains salts of metals that occur naturally or are introduced by human activity. This paper will briefly review the metallic salts found in drinking water in areas around the world, as well as list some of the methods used to reduce or remove them. It will then discuss our research on reducing the risk of pollution of drinking water by removal of metal ions from wastewater.

Constraining uncertainties in water supply reliability in a tropical data scarce basin

NASA Astrophysics Data System (ADS)

Kaune, Alexander; Werner, Micha; Rodriguez, Erasmo; de Fraiture, Charlotte

2015-04-01

Assessing the water supply reliability in river basins is essential for adequate planning and development of irrigated agriculture and urban water systems. In many cases hydrological models are applied to determine the surface water availability in river basins. However, surface water availability and variability is often not appropriately quantified due to epistemic uncertainties, leading to water supply insecurity. The objective of this research is to determine the water supply reliability in order to support planning and development of irrigated agriculture in a tropical, data scarce environment. The approach proposed uses a simple hydrological model, but explicitly includes model parameter uncertainty. A transboundary river basin in the tropical region of Colombia and Venezuela with an approximately area of 2100 km² was selected as a case study. The Budyko hydrological framework was extended to consider climatological input variability and model parameter uncertainty, and through this the surface water reliability to satisfy the irrigation and urban demand was estimated. This provides a spatial estimate of the water supply reliability across the basin. For the middle basin the reliability was found to be less than 30% for most of the months when the water is extracted from an upstream source. Conversely, the monthly water supply reliability was high (r>98%) in the lower basin irrigation areas when water was withdrawn from a source located further downstream. Including model parameter uncertainty provides a complete estimate of the water supply reliability, but that estimate is influenced by the uncertainty in the model. Reducing the uncertainty in the model through improved data and perhaps improved model structure will improve the estimate of the water supply reliability allowing better planning of irrigated agriculture and dependable water allocation decisions.

River water quality and pollution sources in the Pearl River Delta, China.

PubMed

Ouyang, Tingping; Zhu, Zhaoyu; Kuang, Yaoqiu

2005-07-01

Some physicochemical parameters were determined for thirty field water samples collected from different water channels in the Pearl River Delta Economic Zone river system. The analytical results were compared with the environmental quality standards for surface water. Using the SPSS software, statistical analyses were performed to determine the main pollutants of the river water. The main purpose of the present research is to investigate the river water quality and to determine the main pollutants and pollution sources. Furthermore, the research provides some approaches for protecting and improving river water quality. The results indicate that the predominant pollutants are ammonium, phosphorus, and organic compounds. The wastewater discharged from households in urban and rural areas, industrial facilities, and non-point sources from agricultural areas are the main sources of pollution in river water in the Pearl River Delta Economic Zone.

Spatiotemporal variation of the surface water effect on the groundwater recharge in a low-precipitation region: Application of the multi-tracer approach to the Taihang Mountains, North China

NASA Astrophysics Data System (ADS)

Sakakibara, Koichi; Tsujimura, Maki; Song, Xianfang; Zhang, Jie

2017-02-01

Groundwater recharge variations in time and space are crucial for effective water management, especially in low-precipitation regions. To determine comprehensive groundwater recharge processes in a catchment with large seasonal hydrological variations, intensive field surveys were conducted in the Wangkuai Reservoir watershed located in the Taihang Mountains, North China, during three different times of the year: beginning of the rainy season (June 2011), mid-rainy season (August 2012), and dry season (November 2012). Oxygen and hydrogen isotope and chemical analyses were conducted on the groundwater, spring water, stream water, and reservoir water of the Wangkuai Reservoir watershed. The results were processed using endmember mixing analysis to determine the amount of contribution of the groundwater recharging processes. Similar isotopic and chemical signatures between the surface water and groundwater in the target area indicate that the surface water in the mountain-plain transitional area and the Wangkuai Reservoir are the principal groundwater recharge sources, which result from the highly permeable geological structure of the target area and perennial large-scale surface water, respectively. Additionally, the widespread and significant effect of the diffuse groundwater recharge on the Wangkuai Reservoir was confirmed with the deuterium (d) excess indicator and the high contribution throughout the year, calculated using endmember mixing analysis. Conversely, the contribution of the stream water to the groundwater recharge in the mountain-plain transitional area clearly decreases from the beginning of the rainy season to the mid-rainy season, whereas that of the precipitation increases. This suggests that the main groundwater recharge source shifts from stream water to episodic/continuous heavy precipitation in the mid-rainy season. In other words, the surface water and precipitation commonly affect the groundwater recharge in the rainy season, whereas the reservoir and stream water play important roles in the groundwater recharge in the low-precipitation period. The results should contribute not only to the understanding of the mountain hydrology but also to groundwater resource management in the North China Plain.

Bacterial Communities of Surface Mixed Layer in the Pacific Sector of the Western Arctic Ocean during Sea-Ice Melting

PubMed Central

Ha, Ho Kyung; Kim, Hyun Cheol; Kim, Ok-Sun; Lee, Bang Yong; Cho, Jang-Cheon; Hur, Hor-Gil; Lee, Yoo Kyung

2014-01-01

From July to August 2010, the IBRV ARAON journeyed to the Pacific sector of the Arctic Ocean to monitor bacterial variation in Arctic summer surface-waters, and temperature, salinity, fluorescence, and nutrient concentrations were determined during the ice-melting season. Among the measured physicochemical parameters, we observed a strong negative correlation between temperature and salinity, and consequently hypothesized that the melting ice decreased water salinity. The bacterial community compositions of 15 samples, includicng seawater, sea-ice, and melting pond water, were determined using a pyrosequencing approach and were categorized into three habitats: (1) surface seawater, (2) ice core, and (3) melting pond. Analysis of these samples indicated the presence of local bacterial communities; a deduction that was further corroborated by the discovery of seawater- and ice-specific bacterial phylotypes. In all samples, the Alphaproteobacteria, Flavobacteria, and Gammaproteobacteria taxa composed the majority of the bacterial communities. Among these, Alphaproteobacteria was the most abundant and present in all samples, and its variation differed among the habitats studied. Linear regression analysis suggested that changes in salinity could affect the relative proportion of Alphaproteobacteria in the surface water. In addition, the species-sorting model was applied to evaluate the population dynamics and environmental heterogeneity in the bacterial communities of surface mixed layer in the Arctic Ocean during sea-ice melting. PMID:24497990

Bacterial communities of surface mixed layer in the Pacific sector of the western Arctic Ocean during sea-ice melting.

PubMed

Han, Dukki; Kang, Ilnam; Ha, Ho Kyung; Kim, Hyun Cheol; Kim, Ok-Sun; Lee, Bang Yong; Cho, Jang-Cheon; Hur, Hor-Gil; Lee, Yoo Kyung

2014-01-01

From July to August 2010, the IBRV ARAON journeyed to the Pacific sector of the Arctic Ocean to monitor bacterial variation in Arctic summer surface-waters, and temperature, salinity, fluorescence, and nutrient concentrations were determined during the ice-melting season. Among the measured physicochemical parameters, we observed a strong negative correlation between temperature and salinity, and consequently hypothesized that the melting ice decreased water salinity. The bacterial community compositions of 15 samples, includicng seawater, sea-ice, and melting pond water, were determined using a pyrosequencing approach and were categorized into three habitats: (1) surface seawater, (2) ice core, and (3) melting pond. Analysis of these samples indicated the presence of local bacterial communities; a deduction that was further corroborated by the discovery of seawater- and ice-specific bacterial phylotypes. In all samples, the Alphaproteobacteria, Flavobacteria, and Gammaproteobacteria taxa composed the majority of the bacterial communities. Among these, Alphaproteobacteria was the most abundant and present in all samples, and its variation differed among the habitats studied. Linear regression analysis suggested that changes in salinity could affect the relative proportion of Alphaproteobacteria in the surface water. In addition, the species-sorting model was applied to evaluate the population dynamics and environmental heterogeneity in the bacterial communities of surface mixed layer in the Arctic Ocean during sea-ice melting.

Assessment of water sources to plant growth in rice based cropping systems by stable water isotopes

NASA Astrophysics Data System (ADS)

Mahindawansha, Amani; Kraft, Philipp; Racela, Heathcliff; Breuer, Lutz

2016-04-01

Rice is one of the most water-consuming crops in the world. Understanding water source utilization of rice will help us to improve water use efficiency (WUE) in paddy management. The objectives of our study are to evaluate the isotopic compositions of surface ponded water, soil water, irrigation water, groundwater, rain water and plant water and based on stable water isotope signatures to evaluate the contributions of various water sources to plant growth (wet rice, aerobic rice and maize) together with investigating the contribution of water from different soil horizons for plant growth in different maturity periods during wet and dry seasons. Finally we will compare the water balances and crop yields in both crops during both seasons and calculate the water use efficiencies. This will help to identify the most efficient water management systems in rice based cropping ecosystems using stable water isotopes. Soil samples are collected from 9 different depths at up to 60 cm in vegetative, reproductive and matured periods of plant growth together with stem samples. Soil and plant samples are extracted by cryogenic vacuum extraction. Root samples are collected up to 60 cm depth from 10 cm intercepts leading calculation of root length density and dry weight. Groundwater, surface water, rain water and irrigation water are sampled weekly. All water samples are analyzed for hydrogen and oxygen isotope ratios (d18O and dD) using Los Gatos Research DLT100. Rainfall records, ground water level, surface water level fluctuations and the amount of water irrigated in each field will be measured during the sampling period. The direct inference approach which is based on comparing isotopic compositions (dD and d18O) between plant stem water and soil water will be used to determine water sources taken up by plant. Multiple-source mass balance assessment can provide the estimated range of potential contributions of water from each soil depth to root water uptake of a crop. These evaluations will be used to determine the proportion of water from upper soil horizons and deep horizons for rice and maize in different maturity periods during wet and dry seasons. Finally we will estimate the influence of groundwater and surface water by irrigation water and/or by precipitation. First results of the sampling during the wet season 2015 will be presented.

Perception of airborne odors by loggerhead sea turtles.

PubMed

Endres, C S; Putman, N F; Lohmann, K J

2009-12-01

Sea turtles are known to detect chemical cues, but in contrast to most marine animals, turtles surface to breathe and thus potentially have access to olfactory cues both in air and in water. To determine whether sea turtles can detect airborne chemical cues, captive loggerhead turtles (Caretta caretta) were placed into a circular, water-filled arena in which odorants could be introduced to the air above the water surface. Air that had passed across the surface of a cup containing food elicited increased activity, diving and other behavior normally associated with feeding. By contrast, air that had passed across the surface of an identical cup containing distilled water elicited no response. Increases in activity during food odor trials occurred only after turtles surfaced to breathe and peaked in the first post-breath minute, implying that the chemical cues eliciting the responses were unlikely to have been detected while the turtles were under water. These results provide the first direct evidence that sea turtles can detect airborne odors. Under natural conditions, this sensory ability might function in foraging, navigation or both.

Testing the effect of water in crevasses on a physically based calving model

USGS Publications Warehouse

Cook, S.; Zwinger, T.; Rutt, I.C.; O’Neel, S.; Murray, T.

2012-01-01

A new implementation of a calving model, using the finite-element code Elmer, is presented and used to investigate the effects of surface water within crevasses on calving rate. For this work, we use a two-dimensional flowline model of Columbia Glacier, Alaska. Using the glacier's 1993 geometry as a starting point, we apply a crevasse-depth calving criterion, which predicts calving at the location where surface crevasses cross the waterline. Crevasse depth is calculated using the Nye formulation. We find that calving rate in such a regime is highly dependent on the depth of water in surface crevasses, with a change of just a few meters in water depth causing the glacier to change from advancing at a rate of 3.5 km a-1 to retreating at a rate of 1.9 km a-1. These results highlight the potential for atmospheric warming and surface meltwater to trigger glacier retreat, but also the difficulty of modeling calving rates, as crevasse water depth is difficult to determine either by measurement in situ or surface mass-balance modelling.

The Relationship Between Microscopic Grain Surface Structure and the Dynamic Capillary-Driven Advance of Water Films over Individual Dry Natural Sand Grains

NASA Astrophysics Data System (ADS)

Kibbey, T. C. G.; Adegbule, A.; Yan, S.

2017-12-01

The movement of nonvolatile solutes in unsaturated porous media at low water contents depends on transport in surface-associated water films. The focus of the work described here was on studying solute movement in water films advancing by capillary forces over initially-dry grain surfaces, to understand how microscopic surface roughness features influence the initial velocity of water film advance. For this work, water containing a non-adsorbing conservative tracer was used to track the movement of advancing water films. A stainless steel capillary tube connected to an external reservoir a fixed distance below the grain surface was used to transmit solution to the grain surface under negative pressure (positive capillary pressure), consistent with conditions that might be expected in the unsaturated zone. The small internal diameter of the capillary prevents solution from draining out of the capillary back into the reservoir. When the capillary is contacted with a grain surface, capillary forces that result from contact between the fluid and the rough grain surface cause water films to wick across the grain surface. Multiple experiments were conducted on the same grain, rotating the grain and varying the capillary contact point around the circumference of the grain. Imaging was conducted at fixed intervals using an automated Extended Depth of Field (EDF) imaging system, and images were analyzed to determine initial velocity. Grain surfaces were then characterized through scanning electron microscope (SEM) imaging, using a hybrid stereoscopic reconstruction method designed to extract maximum detail in creating elevation maps of geologic surfaces from tilted pairs of SEM images. The resulting elevation maps were used to relate surface roughness profiles around the grain with initial velocities. Results suggest that velocity varies significant with contact point around an individual grain, and correlates quantitatively with the local grain surface structure. Preliminary simulation results will also be discussed.

Risk factors and monitoring for water quality to determine best management practices for splash parks.

PubMed

de Man, H; Leenen, E J T M; van Knapen, F; de Roda Husman, A M

2014-09-01

Splash parks have been associated with infectious disease outbreaks as a result of exposure to poor water quality. To be able to protect public health, risk factors were identified that determine poor water quality. Samples were taken at seven splash parks where operators were willing to participate in the study. Higher concentrations of Escherichia coli were measured in water of splash parks filled with rainwater or surface water as compared with sites filled with tap water, independent of routine inspection intervals and employed disinfection. Management practices to prevent fecal contamination and guarantee maintaining good water quality at splash parks should include selection of source water of acceptable quality.

The Association of Cryptosporidium parvum With Suspended Sediments: Implications for Transport in Surface Waters

NASA Astrophysics Data System (ADS)

Searcy, K. E.; Packman, A. I.; Atwill, E. R.; Harter, T.

2003-12-01

Understanding the transport and fate of microorganisms in surface waters is of vital concern in protecting the integrity and safety of municipal water supply systems. The human pathogen Cryptosporidium parvum is a particular public health interest, as it is ubiquitous in the surface waters of the United States, it can persist for long periods in the environment, and it is difficult to disinfect in water treatment plants. Due to its small size (5 um), low specific gravity (1.05 g/cm3), and negative surface charge, C. parvum oocysts are generally considered to move through watersheds from their source to drinking water reservoirs with little attenuation. However, the transport of the oocysts in surface waters may be mediated by interactions with suspended sediments. Batch experiments were conducted to determine the extent of C. parvum oocyst attachment to several inorganic and organic sediments under varying water chemical conditions, and settling column experiments were performed to demonstrate how these associations influence the effective settling velocity of C. parvum oocysts. Results from these experiments showed that C. parvum oocysts do associate with inorganic and organic sediments and often settle at the rate of the suspended sediment. The size and surface charge of the host suspended sediment influenced the extent of oocyst attachment as oocysts preferentially associated with particles greater than 3 um, and fewer oocysts associated with particles having a highly negative surface charge. Background water chemical conditions including ionic strength, ion composition, and pH did not have a significant effect on oocyst attachment to suspended sediments.

Relations of surface-water quality to streamflow in the Hackensack, Passaic, Elizabeth, and Rahway River basins, New Jersey, water years 1976-93

USGS Publications Warehouse

Buxton, Debra E.; Hunchak-Kariouk, Kathryn; Hickman, R. Edward

1998-01-01

Relations of water quality to streamflow were determined for 18 water-quality constituents at 19 surface-water-quality stations within the drainage basins of the Hackensack, Passaic, Elizabeth, and Rahway Rivers in New Jersey for water years 1976-93. Surface-waterquality and streamflow data were evaluated for trends (through time) in constituent concentrations during high and low flows, and relations between constituent concentration and streamflow, and constituent load and streamflow, were determined. Median concentrations were calculated for the entire period of study (water years 1976-93) and for the last 5 years of the period of study (water years 1989-93) to determine whether any large variation in concentration exists between the two periods. Medians also were used to determine the seasonal Kendall’s tau statistic, which was then used to evaluate trends in concentrations during high and low flows.Trends in constituent concentrations during high and low flows were evaluated to determine whether the distribution of the observations changes over time for intermittent (nonpoint storm runoff) or constant (point sources and ground water) sources, respectively. Highand low-flow concentration trends were determined for some constituents at 11 of the 19 waterquality stations; 8 stations have insufficient data to determine trends. Seasonal effects on the relations of concentration to streamflow are evident for 16 of the 18 constituents. Negative slopes of relations of concentration to streamflow, which indicate a decrease in concentration at high flows, predominate over positive slopes because of dilution of instream concentrations from storm runoff.The slopes of the regression lines of load to streamflow were determined in order to show the relative contributions to the instream load from constant (point sources and ground water) and intermittent sources (storm runoff). Greater slope values suggest larger contributions from storm runoff to instream load, which most likely indicate an increased relative importance of nonpoint sources. Load-to-streamflow relations along a stream reach that tend to increase in a downstream direction indicate the increased relative importance of contributions from storm runoff. Likewise, load-to-streamflow relations along a stream reach that tend to decrease in a downstream direction indicate the increased relative importance of point sources and ground-water discharge. For most of the 18 constituents, load-to-streamflow relations at stations along a river reach remain constant or decrease in a downstream direction. The slopes increase in the downstream direction for some or all of the nutrient species at the Ramapo, lower Passaic, and Rahway Rivers; for dissolved solids, dissolved sodium, and dissolved chloride at the lower Passaic River; and for alkalinity and hardness at the Rahway River.

Determination of Protein Surface Hydration by Systematic Charge Mutations

NASA Astrophysics Data System (ADS)

Yang, Jin; Jia, Menghui; Qin, Yangzhong; Wang, Dihao; Pan, Haifeng; Wang, Lijuan; Xu, Jianhua; Zhong, Dongping; Dongping Zhong Collaboration; Jianhua Xu Collaboration

Protein surface hydration is critical to its structural stability, flexibility, dynamics and function. Recent observations of surface solvation on picosecond time scales have evoked debate on the origin of such relatively slow motions, from hydration water or protein charged sidechains, especially with molecular dynamics simulations. Here, we used a unique nuclease with a single tryptophan as a local probe and systematically mutated neighboring three charged residues to differentiate the contributions from hydration water and charged sidechains. By mutations of alternative one and two and all three charged residues, we observed slight increases in the total tryptophan Stokes shifts with less neighboring charged residue(s) and found insensitivity of charged sidechains to the relaxation patterns. The dynamics is correlated with hydration water relaxation with the slowest time in a dense charged environment and the fastest time at a hydrophobic site. On such picosecond time scales, the protein surface motion is restricted. The total Stokes shifts are dominantly from hydration water relaxation and the slow dynamics is from water-driven relaxation, coupled with local protein fluctuations.

Calculating the Diffusive Flux of Persistent Organic Pollutants between Sediments and the Water Column on the Palos Verdes Shelf Superfund Site using Polymeric Passive Samplers

EPA Science Inventory

Passive samplers were used to determine water concentrations of persistent organic pollutants (POPs) in the surface sediments and near-bottom water of a marine Superfund site on the Palos Verdes Shelf, California, USA. Measured concentrations in the porewater and water column at...

Spatial and temporal variability of soil temperature, moisture and surface soil properties

NASA Technical Reports Server (NTRS)

Hajek, B. F.; Dane, J. H.

1993-01-01

The overall objectives of this research were to: (l) Relate in-situ measured soil-water content and temperature profiles to remotely sensed surface soil-water and temperature conditions; to model simultaneous heat and water movement for spatially and temporally changing soil conditions; (2) Determine the spatial and temporal variability of surface soil properties affecting emissivity, reflectance, and material and energy flux across the soil surface. This will include physical, chemical, and mineralogical characteristics of primary soil components and aggregate systems; and (3) Develop surface soil classes of naturally occurring and distributed soil property assemblages and group classes to be tested with respect to water content, emissivity and reflectivity. This document is a report of studies conducted during the period funded by NASA grants. The project was designed to be conducted over a five year period. Since funding was discontinued after three years, some of the research started was not completed. Additional publications are planned whenever funding can be obtained to finalize data analysis for both the arid and humid locations.

Process-based approach for the detection of CO2 injectate leakage

DOEpatents

Romanak, Katherine; Bennett, Philip C.

2017-11-14

The present invention includes a method for distinguishing between a natural source of deep gas and gas leaking from a CO.sub.2 storage reservoir at a near surface formation comprising: obtaining one or more surface or near surface geological samples; measuring a CO.sub.2, an O.sub.2, a CH.sub.4, and an N.sub.2 level from the surface or near surface geological sample; determining the water vapor content at or above the surface or near surface geological samples; normalizing the gas mixture of the CO.sub.2, the O.sub.2, the CH.sub.4, the N.sub.2 and the water vapor content to 100% by volume or 1 atmospheric total pressure; determining: a ratio of CO.sub.2 versus N.sub.2; and a ratio of CO.sub.2 to N.sub.2, wherein if the ratio is greater than that produced by a natural source of deep gas CO.sub.2 or deep gas methane oxidizing to CO.sub.2, the ratio is indicative of gas leaking from a CO.sub.2 storage reservoir.

Effectiveness of highway-drainage systems in preventing contamination of ground water by road salt, Route 25, southeastern Massachusetts; description of study area, data collection programs, and methodology

USGS Publications Warehouse

Church, P.E.; Armstrong, D.S.; Granato, G.E.; Stone, V.J.; Smith, K.P.; Provencher, P.L.

1996-01-01

Four test sites along a 7-mile section of Route 25 in southeastern Massachusetts, each representing a specific highway-drainage system, were instrumented to determine the effectiveness of the drainage systems in preventing contamination of ground water by road salt. One of the systems discharges highway runoff onsite through local drainpipes. The other systems use trunkline drainpipes through which runoff from highway surfaces, shoulders, and median strips is diverted and discharged into either a local stream or a coastal waterway. Route 25 was completed and opened to traffic in the summer of 1987. Road salt was first applied to the highway in the winter of 1987-88. The study area is on a thick outwash plain composed primarily of sand and gravel. Water-table depths range from 15 to 60 feet below land surface at the four test sites. Ground-water flow is in a general southerly direction, approximately perpendicular to the highway. Streamflow in the study area is controlled primarily by ground-water discharge. Background concentrations of dissolved chloride, sodium, and calcium-the primary constituents of road salt-are similar in ground water and surface water and range from 5 to 20, 5 to 10, and 1 to 5 milligrams per liter, respectively. Data-collection programs were developed for monitoring the application of road salt to the highway, the quantity of road-salt water entering the ground water, diverted through the highway-drainage systems, and entering a local stream. The Massachusetts Highway Department monitored road salt applied to the highway and reported these data to the U.S. Geological Survey. The U.S. Geological Survey designed and operated the ground-water, highway- drainage, and surface-water data-collection programs. A road-salt budget will be calculated for each test site so that the effectiveness of the different highway-drainage systems in preventing contamination of ground water by road salt can be determined.

THE PERSISTENCE OF MYCOBACTERIUM AVIUM IN A DRINKING WATER SYSTEM AFTER THE ADDITION OF FILTRATION

EPA Science Inventory

Drinking water is increasingly recognized as a major source of pathogenic nontuberculous mycobacteria (NTM) associated with human infection. Our goal was to determine if the prevalence of NTM would decrease after the addition of filtration treatment to an unfiltered surface water...

Concentration data for anthropogenic organic compounds in groundwater, surface water, and finished water of selected community water systems in the United States, 2002-10

USGS Publications Warehouse

Carter, Janet M.; Kingsbury, James A.; Hopple, Jessica A.; Delzer, Gregory C.

2010-01-01

The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used in SWQA studies, source water is the raw (ambient) water collected at the supply well before water treatment (for groundwater) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that has been treated and is ready to be delivered to consumers. Finished-water samples are collected before the water enters the distribution system. The primary objective of SWQAs is to determine the occurrence of more than 250 anthropogenic organic compounds in source water used by community water systems, many of which currently are unregulated in drinking water by the U.S. Environmental Protection Agency. A secondary objective is to understand recurrence patterns in source water and determine if these patterns also occur in finished water before distribution. SWQA studies were conducted in two phases for most studies completed by 2005, and in one phase for most studies completed since 2005. Analytical results are reported for a total of 295 different anthropogenic organic compounds monitored in source-water and finished-water samples collected during 2002-10. The 295 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and combustion-derived compounds; (10) personal-care and domestic-use products; (11) plant- or animal-derived biochemicals; (12) refrigerants and propellants; and (13) solvents. This report presents the analytical results of source- water samples from 448 community water system wells and 21 surface-water sites. This report also presents the analytical results of finished-water samples from 285 wells and 20 surface-water sites from community water systems. Results of quality-assurance/quality-control samples also are presented including data for equipment blanks, field blanks, source solution blanks, and replicate samples.

USING GIS AND AERIAL PHOTOGRAPHY TO DETERMINE A HISTORICAL IMPERVIOUS SURFACE/STREAMFLOW RELATIONSHIP

EPA Science Inventory

Impervious surfaces are a leading contributor to non-point-source water pollution in urban watersheds. These surfaces include such features as roads, parking lots, rooftops and driveways. Arcview GIS and the Image Analysis extension have been utilized to geo-register and map imp...

Phosphorus solubility of agricultural soils: a surface charge and phosphorus-31 NMR speciation study

USDA-ARS?s Scientific Manuscript database

We investigated ten soils from six states in United States to determine the relationship between potentiometric titration derived soil surface charge and Phosphorus-31 (P) nuclear magnetic resonance (NMR) speciation with the concentration of water-extractable P (WEP). The surface charge value at the...

Captive bubble and sessile drop surface characterization of a submerged aquatic plant, Hydrilla verticillata

USDA-ARS?s Scientific Manuscript database

The surface energy parameters of the invasive aquatic weed, Hydrilla verticillata, were determined using contact angle measurements using two different methods. The abaxial and adaxial surfaces of the leaves and stem were characterized for the weed while submerged in water using captive air and octa...

Validation of the REA bioassay to detect estrogenic activity in the water cycle.

PubMed

Nguyen, Mai Thao; van der Oost, Ron; Bovee, Toine F H

2011-12-01

Endocrine disrupting compounds (EDCs) with estrogenic potency contaminate water and might eventually cause adverse effects to the aquatic environment. Many estrogenic compounds are not completely removed by wastewater treatment systems and, together with the run-off from agricultural areas, they enter surface waters. Chemical analytical methods to determine these compounds are usually expensive and laborious. Therefore, screening bioassays which are able to detect compounds based on their effects offer a solution for prior selection of samples that need to be chemically analyzed. In this study, the REA (RIKILT yeast Estrogen bioAssay), which has been developed to detect estrogenic compounds in calf urine and animal feed at RIKILT, is validated at the Water Board Laboratory of Waterproef for water samples. According to EC Decision 2002/657, detection capability CCβ, specificity and stability have to be determined for the internal validation of a qualitative screening test. In addition, surface water and effluent samples were analyzed to further demonstrate the applicability of the validated test procedure. Results demonstrate that the REA assay is reproducible and specific for estrogenic compounds in water and meets the criteria as prescribed in EC Decision 2002/657. The assay was sensitive enough to detect estrogenic activity of pollutants in water with a limit of quantification (LOQ) below 1 ng EEQ/L. This means that samples can be compared with preliminary threshold levels for drinking water and surface waters (7 and 1 ng EEQ/L, respectively). The stability of estrogenic activity in water samples is at least 4 weeks, when stored at 4 °C. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mini-TES Observations of the Gusev and Meridiani Landing Sites

NASA Technical Reports Server (NTRS)

Christensen, Philip; Arvidson, Raymond; Bandfield, Joshua L.; Blaney, Diana; Budney, Charles; Calvin, Wendy; Ciccolella, Sandra; Fallacro, Alicia; Fergason, Robin; Glotch, Timothy

2004-01-01

The Miniature Thermal Emission Spectrometer (Mini-TES) has provided remote measurements of the mineralogy and thermophysical properties of the scene surrounding the Mars Exploration Rovers. The specific scientific objectives of this investigation are to: (1) determine the mineralogy of rocks and soils; (2) determine the thermophysical properties of surface materials; and (3) determine the temperature profile, dust and water-ice opacity, and water vapor abundance in the lower atmospheric boundary layer.

[Influence of microbiological quality of lactic acid cheese on water phase in conditions of hermetic packing].

PubMed

Steinka, Izabela

2005-01-01

Aim of research was to assess the influence of lactic acid cheese micro-flora on water phase fluctuation between surface of products and the packaging. Results of research showed that changes of water content could be expressed with the help of polynomial cubic equation. From linear correlation equations describing level of micro-flora in lactic acid cheese and water content it resulted micro-organisms had a significant influence on the water phase fluctuation. Values of determined coefficients of determination suggested that yeast, enterococci and staphylococci had a significant influence on water fluctuation between product and the packaging.

Environmental and Cultural Impact. Proposed Tennessee Colony Reservoir, Trinity River, Texas. Volume III. Appendices D and E.

DTIC Science & Technology

1972-01-01

daily dissolved oxygen concentration above 5 mg/l, assuming there are normal seasonal and daily variations above this concentration, (2) dissovled oxygen ... Oxygen Concentrations: Surface oxygen determinations were made at each col- lecting station at monthly intervals. Determinations were done using a...Yellow Springs Oxygen Analyzer Model 54. G. Phosphorus and nitrogen determinations : Water samples for chemical analysis were collected at the surface

Drop impact on inclined superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Choi, Wonjae; Leclear, Sani; Leclear, Johnathon; Abhijeet, .; Park, Kyoo-Chul

We report an empirical study and dimensional analysis on the impact patterns of water drops on inclined superhydrophobic surfaces. While the classic Weber number determines the spreading and recoiling dynamics of a water drop on a horizontal / smooth surface, for a superhydrophobic surface, the dynamics depends on two distinct Weber numbers, each calculated using the length scale of the drop or of the pores on the surface. Impact on an inclined superhydrophobic surface is even more complicated, as the velocity that determines the Weber number is not necessarily the absolute speed of the drop but the velocity components normal and tangential to the surface. We define six different Weber numbers, using three different velocities (absolute, normal and tangential velocities) and two different length scales (size of the drop and of the texture). We investigate the impact patterns on inclined superhydrophobic surfaces with three different types of surface texture: (i) posts, (ii) ridges aligned with and (iii) ridges perpendicular to the impact direction. Results suggest that all six Weber numbers matter, but affect different parts of the impact dynamics, ranging from the Cassie-Wenzel transition, maximum spreading, to anisotropic deformation. We acknowledge financial support from the Office of Naval Research (ONR) through Contract 3002453812.

Application of Tracer-Injection Techniques to Demonstrate Surface-Water and Ground-Water Interactions Between an Alpine Stream and the North Star Mine, Upper Animas River Watershed, Southwestern Colorado

USGS Publications Warehouse

Wright, Winfield G.; Moore, Bryan

2003-01-01

Tracer-injection studies were done in Belcher Gulch in the upper Animas River watershed, southwestern Colorado, to determine whether the alpine stream infiltrates into underground mine workings of the North Star Mine and other nearby mines in the area. The tracer-injection studies were designed to determine if and where along Belcher Gulch the stream infiltrates into the mine. Four separate tracer-injec-tion tests were done using lithium bromide (LiBr), optical brightener dye, and sodium chloride (NaCl) as tracer solu-tions. Two of the tracers (LiBr and dye) were injected con-tinuously for 24 hours, one of the NaCl tracers was injected continuously for 12 hours, and one of the NaCl tracers was injected over a period of 1 hour. Concentration increases of tracer constituents were detected in water discharging from the North Star Mine, substantiating a surface-water and ground-water connection between Belcher Gulch and the North Star Mine. Different timing and magnitude of tracer breakthroughs indicated multiple flow paths with different residence times from the stream to the mine. The Pittsburgh and Sultan Mines were thought to physically connect to the North Star Mine, but tracer breakthroughs were inconclusive in water from these mines. From the tracer-injection tests and synoptic measure-ments of streamflow discharge, a conceptual model was devel-oped for surface-water and ground-water interactions between Belcher Gulch and the North Star Mine. This information, combined with previous surface geophysical surveys indicat-ing the presence of subsurface voids, may assist with decision-making process for preventing infiltration and for the remedia-tion of mine drainage from these mines.

Use of satellite images to determine surface-water cover during the flood event of September 13, 2013, in Lyons and western Longmont, Colorado

USGS Publications Warehouse

Cole, Christopher J.; Friesen, Beverly A.; Wilson, Earl M.; Wilds, Stanley R.; Noble, Suzanne M.

2015-01-01

This surface-water cover dataset was created as a timely representation of post-flood ground conditions to support response efforts. This dataset and all processed imagery and derived products were uploaded to the USGS Hazards Data Distribution System (HDDS) website (http://hddsexplorer.usgs.gov/uplift/hdds/) for distribution to those responding to the flood event.

Stream profile analysis using a step backwater model for selected reaches in the Chippewa Creek basin in Medina, Wayne, and Summit Counties, Ohio

USGS Publications Warehouse

Straub, David E.; Ebner, Andrew D.

2011-01-01

The USGS, in cooperation with the Chippewa Subdistrict of the Muskingum Watershed Conservancy District, performed hydrologic and hydraulic analyses for selected reaches of three streams in Medina, Wayne, Stark, and Summit Counties in northeast Ohio: Chippewa Creek, Little Chippewa Creek, and River Styx. This study was done to facilitate assessment of various alternatives for mitigating flood hazards in the Chippewa Creek basin. StreamStats regional regression equations were used to estimate instantaneous peak discharges approximately corresponding to bankfull flows. Explanatory variables used in the regression equations were drainage area, main-channel slope, and storage area. Hydraulic models were developed to determine water-surface profiles along the three stream reaches studied for the bankfull discharges established in the hydrologic analyses. The HEC-RAS step-backwater hydraulic analysis model was used to determine water-surface profiles for the three streams. Starting water-surface elevations for all streams were established using normal depth computations in the HEC-RAS models. Cross-sectional elevation data, hydraulic-structure geometries, and roughness coefficients were collected in the field and (along with peak-discharge estimates) used as input for the models. Reach-averaged reductions in water-surface elevations ranged from 0.11 to 1.29 feet over the four roughness coefficient reduction scenarios.

Ultra-trace levels analysis of microcystins and nodularin in surface water by on-line solid-phase extraction with high-performance liquid chromatography tandem mass spectrometry.

PubMed

Balest, Lydia; Murgolo, Sapia; Sciancalepore, Lucia; Montemurro, Patrizia; Abis, Pier Paolo; Pastore, Carlo; Mascolo, Giuseppe

2016-06-01

An on-line solid phase extraction coupled with high-performance liquid chromatography in tandem with mass spectrometry (on-line SPE/HPLC/MS-MS) method for the determination of five microcystins and nodularin in surface waters at submicrogram per liter concentrations has been optimized. Maximum recoveries were achieved by carefully optimizing the extraction sample volume, loading solvent, wash solvent, and pH of the sample. The developed method was also validated according to both UNI EN ISO IEC 17025 and UNICHIM guidelines. Specifically, ten analytical runs were performed at three different concentration levels using a reference mix solution containing the six analytes. The method was applied for monitoring the concentrations of microcystins and nodularin in real surface water during a sampling campaign of 9 months in which the ELISA method was used as standard official method. The results of the two methods were compared showing good agreement when the highest concentration values of MCs were found. Graphical abstract An on-line SPE/HPLC/MS-MS method for the determination of five microcystins and nodularin in surface waters at sub μg L(-1) was optimized and compared with ELISA assay method for real samples.

Ultra-trace level determination of diquat and paraquat residues in surface and drinking water using ion-pair liquid chromatography with tandem mass spectrometry: a comparison of direct injection and solid-phase extraction methods.

PubMed

Oh, Jin-Aa; Lee, Jun-Bae; Lee, Soo-Hyung; Shin, Ho-Sang

2014-10-01

Direct injection and solid-phase extraction methods for the determination of diquat and paraquat in surface and drinking water were developed using liquid chromatography with tandem mass spectrometry. The signal intensities of analytes based on six ion-pairing reagents were compared with each other, and 12.5 mM nonafluoropentanoic acid was selected as the best suited amongst them. A clean-up method was developed using Oasis hydrophilic-lipophilic balance; this was compared to the direct injection method, with respect to limits of detection, interference, precision, and accuracy. Limits of quantification of diquat and paraquat were 0.03 and 0.01 μg/L using the direct injection method, and 0.002 and 0.001 μg/L using the hydrophilic-lipophilic balance method. When the hydrophilic-lipophilic balance method was used to analyze target compounds in 114 surface water and 30 drinking water samples, paraquat and diquat were detected within a concentration range of 0.001-0.12 and 0.002-0.038 μg/L in surface water, respectively. When the direct injection method was used to analyze target compounds in the same samples, the detected concentrations of paraquat and diquat were within 25% in samples being >0.015 μg/L using the hydrophilic-lipophilic balance method. The liquid chromatography with tandem mass spectrometry method using direct injection can thus be used for routine monitoring of paraquat and diquat in surface and drinking water. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling Phosphorous Losses from Seasonal Manure Application Schemes

NASA Astrophysics Data System (ADS)

Menzies, E.; Walter, M. T.

2015-12-01

Excess nutrient loading, especially nitrogen and phosphorus, to surface waters is a common and significant problem throughout the United States. While pollution remediation efforts are continuously improving, the most effective treatment remains to limit the source. Appropriate timing of fertilizer application to reduce nutrient losses is currently a hotly debated topic in the Northeastern United States; winter spreading of manure is under special scrutiny. We plan to evaluate the loss of phosphorous to surface waters from agricultural systems under varying seasonal fertilization schemes in an effort to determine the impacts of fertilizers applied throughout the year. The Cayuga Lake basin, located in the Finger Lakes region of New York State, is a watershed dominated by agriculture where a wide array of land management strategies can be found. The evaluation will be conducted on the Fall Creek Watershed, a large sub basin in the Cayuga Lake Watershed. The Fall Creek Watershed covers approximately 33,000 ha in central New York State with approximately 50% of this land being used for agriculture. We plan to use the Soil and Water Assessment Tool (SWAT) to model a number of seasonal fertilization regimes such as summer only spreading and year round spreading (including winter applications), as well as others. We will use the model to quantify the phosphorous load to surface waters from these different fertilization schemes and determine the impacts of manure applied at different times throughout the year. More detailed knowledge about how seasonal fertilization schemes impact phosphorous losses will provide more information to stakeholders concerning the impacts of agriculture on surface water quality. Our results will help farmers and extensionists make more informed decisions about appropriate timing of manure application for reduced phosphorous losses and surface water degradation as well as aid law makers in improving policy surrounding manure application.

Recovery of vancomycin-resistant enterococci on fingertips and environmental surfaces.

PubMed

Noskin, G A; Stosor, V; Cooper, I; Peterson, L R

1995-10-01

To determine the recovery of vancomycin-resistant enterococci (VRE) on fingertips, gloved fingertips, and environmental surfaces commonly encountered in the healthcare setting, and to examine the importance of handwashing on the removal of these organisms. Two clinical isolates of VRE (Enterococcus faecalis and Enterococcus faecium) were inoculated onto the hands of healthy human volunteers and the following environmental surfaces: countertops, bedrails, telephones, and stethoscopes. Following inoculation, samples were obtained at various time intervals to determine rates of recovery of organisms. To evaluate the effects of handwashing on enterococcal recovery, two different soap preparations were tested. Hands were washed with water alone or with one of the soaps and water. The soap and water studies were performed with a 5-second and a 30-second wash. Both enterococcal strains survived for at least 60 minutes on gloved and ungloved fingertips. The E faecalis was recoverable from countertops for 5 days; the E faecium persisted for 7 days. For bedrails, both enterococcal species survived for 24 hours without significant reduction in colony counts. The bacteria persisted for 60 minutes on the telephone handpiece and for 30 minutes on the diaphragmatic surface of the stethoscope. A 5-second wash with water alone resulted in virtually no change in recovery of enterococci; a 30-second wash with water plus either soap was necessary to eradicate the bacteria from hands completely. VRE are capable of prolonged survival on hands, gloves, and environmental surfaces. Hands should be washed thoroughly and gloves removed following contact with patients infected or colonized with these multidrug-resistant bacteria. Finally, environmental surfaces may serve as potential reservoirs for nosocomial transmission of VRE and need to be considered when formulating institutional infection control policies.

Organosolv-Water Cosolvent Phase Separation on Cellulose and its Influence on the Physical Deconstruction of Cellulose: A Molecular Dynamics Analysis.

PubMed

Smith, Micholas Dean; Cheng, Xiaolin; Petridis, Loukas; Mostofian, Barmak; Smith, Jeremy C

2017-11-03

Deconstruction of cellulose is crucial for the chemical conversion of lignocellulose into fuel/bioproduct precursors. Recently, a water-organosolv cosolvent system (THF-water) has been shown to both phase-separate on cellulose surfaces and partially deconstruct Avicel  (cellulose) in the absence of acid. Here we employ molecular dynamics simulations to determine whether other common water-organosolv cosolvent systems (acetone, ethanol, and γ-valerolactone) exhibit phase separation at cellulose surface and whether this alters a purely physical cellulose dissociation pathway. Despite finding varied degrees of phase-separation of organosolv on cellulose surfaces, physical dissociation is not enhanced. Interestingly, however, the total amount the median water-cellulose contact lifetimes increases for the cosolvent systems in the order of THF > acetone > ethanol > γ-valerolactone. Together our results indicate two points: a purely physical process for deconstruction of cellulose is unlikely for these cosolvents, and in THF-water, unlike γ-valerolactone- (and some concentrations of acetone and ethanol) water cosolvents, a significant fraction of surface water is slowed. This slowing may be of importance in enhancing chemical deconstruction of cellulose, as it permits an increase in potential THF-water-cellulose reactions, even while the amount of water near cellulose is decreased.

Organosolv-Water Cosolvent Phase Separation on Cellulose and its Influence on the Physical Deconstruction of Cellulose: A Molecular Dynamics Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Micholas Dean; Cheng, Xiaolin; Petridis, Loukas

Deconstruction of cellulose is crucial for the chemical conversion of lignocellulose into fuel/bioproduct precursors. Recently, a water-organosolv cosolvent system (THF-water) has been shown to both phase-separate on cellulose surfaces and partially deconstruct Avicel (cellulose) in the absence of acid. Here we employ molecular dynamics simulations to determine whether other common water-organosolv cosolvent systems (acetone, ethanol, and γ-valerolactone) exhibit phase separation at cellulose surface and whether this alters a purely physical cellulose dissociation pathway. Despite finding varied degrees of phase-separation of organosolv on cellulose surfaces, physical dissociation is not enhanced. Interestingly, however, the total amount the median water-cellulose contact lifetimes increasesmore » for the cosolvent systems in the order of THF > acetone > ethanol > γ-valerolactone. Together our results indicate two points: a purely physical process for deconstruction of cellulose is unlikely for these cosolvents, and in THF-water, unlike γ-valerolactone- (and some concentrations of acetone and ethanol) water cosolvents, a significant fraction of surface water is slowed. As a result, this slowing may be of importance in enhancing chemical deconstruction of cellulose, as it permits an increase in potential THF-water-cellulose reactions, even while the amount of water near cellulose is decreased.« less

Organosolv-Water Cosolvent Phase Separation on Cellulose and its Influence on the Physical Deconstruction of Cellulose: A Molecular Dynamics Analysis

DOE PAGES

Smith, Micholas Dean; Cheng, Xiaolin; Petridis, Loukas; ...

2017-11-03

Deconstruction of cellulose is crucial for the chemical conversion of lignocellulose into fuel/bioproduct precursors. Recently, a water-organosolv cosolvent system (THF-water) has been shown to both phase-separate on cellulose surfaces and partially deconstruct Avicel (cellulose) in the absence of acid. Here we employ molecular dynamics simulations to determine whether other common water-organosolv cosolvent systems (acetone, ethanol, and γ-valerolactone) exhibit phase separation at cellulose surface and whether this alters a purely physical cellulose dissociation pathway. Despite finding varied degrees of phase-separation of organosolv on cellulose surfaces, physical dissociation is not enhanced. Interestingly, however, the total amount the median water-cellulose contact lifetimes increasesmore » for the cosolvent systems in the order of THF > acetone > ethanol > γ-valerolactone. Together our results indicate two points: a purely physical process for deconstruction of cellulose is unlikely for these cosolvents, and in THF-water, unlike γ-valerolactone- (and some concentrations of acetone and ethanol) water cosolvents, a significant fraction of surface water is slowed. As a result, this slowing may be of importance in enhancing chemical deconstruction of cellulose, as it permits an increase in potential THF-water-cellulose reactions, even while the amount of water near cellulose is decreased.« less

The Verification of a Method for Detecting and Quantifying Diethylene Glycol, Triethylene Glycol, Tetraethylene Glycol, 2-Butoxyethanol and 2-Methoxyethanolin in Ground and Surface Waters

EPA Science Inventory

This verification study was a special project designed to determine the efficacy of a draft standard operating procedure (SOP) developed by US EPA Region 3 for the determination of selected glycols in drinking waters that may have been impacted by active unconventional oil and ga...

Water-quality assessment of south-central Texas: Occurrence and distribution of volatile organic compounds in surface water and ground water, 1983-94, and implications for future monitoring

USGS Publications Warehouse

Ging, P.B.; Judd, L.J.; Wynn, K.H.

1997-01-01

The study area of the South-Central Texas study unit of the National Water-Quality Assessment Program comprises the Edwards aquifer in the San Antonio region and its catchment area. The first phase of the assessment includes evaluation of existing water-quality data for surface water and ground water, including volatile organic compounds, to determine the scope of planned monitoring. Most analyses of volatile organic compounds in surface water are from the National Pollutant Discharge Elimination System sites in San Antonio, Texas. Nine volatile organic compounds were detected at the six sites. The three compounds with the most detections at National Pollutant Discharge Elimination System sites are 1,2,4-trimethylbenzene, toluene, and xylene. Analysis of volatile organic compounds in ground water was limited to Edwards aquifer wells. Twenty-eight volatile organic compounds were detected in samples from 89 wells. The five most commonly detected compounds in samples from wells, in descending order, are tetrachloroethene, trichloroethene, bromoform, chloroform, and dibromochloromethane. Detections of volatile organic compounds in surface water and ground water within the South-Central Texas study area are limited to site-specific sources associated with development; therefore, planned monitoring for possible detections of volatile organic compounds as part of the National Water-Quality Assessment Program will emphasize areas of expanding population and development. Monitoring of volatile organic compounds is planned at National Pollutant Discharge Elimination System sites, at basic fixed surface-water sites, and in the ground-water study-unit surveys.

A direct immunoassay for detecting diatoms in groundwater as an indicator of the direct influence of surface water

USGS Publications Warehouse

Walker, C.E.; Schrock, R.M.; Reilly, T.J.; Baehr, A.L.

2005-01-01

Groundwater under the direct influence of surface water (GWUDISW) is of concern in communities where growing public demand on groundwater resources has resulted in increased withdrawals and hydraulic stress near surface water bodies. Under these conditions, contaminants such as methyl-tert butyl ether (MTBE) and biological materials have been detected in domestic wells. Other contaminants and pathogens associated with surface water are not routinely tested for in groundwater-supplied systems. To address the need for methods to easily identify potentially vulnerable supplies, a direct immunoassay for the quantitative detection of diatoms in raw water samples was developed as a measure of surface water influence on groundwater. Cell wall preparations from Nitzschia palea Ku??tzing, a freshwater diatom found throughout North America, were used to produce a polyclonal antibody that was applied in a direct enzyme-linked immunosorbent assay (ELISA) developed to detect the presence of N. palea cell wall components. The direct immunoassay allows detection at 500 cells L-1, a level similar to diatom concentrations observed in samples of groundwater collected near the test site. This investigation was the first attempt to utilize an ELISA as an indicator of surface water influence on groundwater. Further research is needed to develop more specific diatom-based monoclonal antibodies, determine cross-reactivity, and optimize sample processing and ELISA procedures for development of a standardized method. ?? Springer 2005.

A direct immunoassay for detecting diatoms in groundwater as an indicator of the direct influence of surface water

USGS Publications Warehouse

Walker, C.E.; Schrock, R.M.; Reilly, T.J.; Baehr, A.L.

2005-01-01

Groundwater under the direct influence of surface water (GWUDISW) is of concern in communities where growing public demand on groundwater resources has resulted in increased withdrawals and hydraulic stress near surface water bodies. Under these conditions, contaminants such as methyl-tert butyl ether (MTBE) and biological materials have been detected in domestic wells. Other contaminants and pathogens associated with surface water are not routinely tested for in groundwater-supplied systems. To address the need for methods to easily identify potentially vulnerable supplies, a direct immunoassay for the quantitative detection of diatoms in raw water samples was developed as a measure of surface water influence on groundwater. Cell wall preparations from Nitzschia palea Kützing, a freshwater diatom found throughout North America, were used to produce a polyclonal antibody that was applied in a direct enzyme-linked immunosorbent assay (ELISA) developed to detect the presence of N. palea cell wall components. The direct immunoassay allows detection at 500 cells L−1, a level similar to diatom concentrations observed in samples of groundwater collected near the test site. This investigation was the first attempt to utilize an ELISA as an indicator of surface water influence on groundwater. Further research is needed to develop more specific diatom-based monoclonal antibodies, determine cross-reactivity, and optimize sample processing and ELISA procedures for development of a standardized method.

Defect-induced wetting on BaF 2(111) and CaF 2(111) at ambient conditions

NASA Astrophysics Data System (ADS)

Cardellach, M.; Verdaguer, A.; Fraxedas, J.

2011-12-01

The interaction of water with freshly cleaved (111) surfaces of isostructural BaF2 and CaF2 single crystals at ambient conditions (room temperature and under controlled humidity) has been studied using scanning force microscopy in different operation modes and optical microscopy. Such surfaces exhibit contrasting behaviors for both materials: while on BaF2(111) two-dimensional water layers are formed after accumulation at step edges, CaF2(111) does not promote the formation of such layers. We attribute such opposed behavior to lattice match (mismatch) between hexagonal water ice and the hexagonal (111) surfaces of BaF2(CaF2). Optical microscope images reveal that this behavior also determines the way the surfaces become wetted at a macroscopic level.

The paradoxical distribution of a shallow-rooted keystone species away from surface water, near the water-limited edge of its range in the Sonoran Desert: Seed-seedling conflicts

NASA Astrophysics Data System (ADS)

Drezner, Taly Dawn

2013-02-01

Species distributions reflect limiting factors, particularly near the margins of their range where density and abundance decrease as environmental factors decrease or increase to non-optimal conditions. I test whether the keystone saguaro cactus (Carnegiea gigantea), a shallow-rooted species, is indeed distributed disproportionately in areas of concentrated drainage (runnels) in a water-limited population. Carnegiea and a common nurse were sampled at a marginal site in and out of areas with concentrated surface water and chi-square analysis was used to determine the pattern of distribution. In this study I found that, surprisingly, near the hot, water-limited edge of their range, C. gigantea are found significantly less often in areas where more water would be available to them. For example, while only 20% of nurses were on interfluves, half of Carnegiea protégé were there. One possible explanation is that the subsequent redistribution of seeds by water away from preferred microsites may be important in shaping the final pattern of successful establishment. The shallow-rooted Carnegiea relies entirely on surface water for its moisture; it is thus paradoxical that the surface water so fundamentally essential to its survival throughout its life appears to hinder its establishment in precisely those sites where the greatest surface water would be available, particularly near the water-limited edge of its range.

Ground-water-level monitoring, basin boundaries, and potentiometric surfaces of the aquifer system at Edwards Air Force Base, California, 1992

USGS Publications Warehouse

Rewis, D.L.

1995-01-01

A ground-water-level monitoring program was implemented at Edwards Air Force Base, California, from January through December 1992 to monitor spatial and temporal changes in poten-tiometric surfaces that largely are affected by ground-water pumping. Potentiometric-surface maps are needed to determine the correlation between declining ground- water levels and the distribution of land subsidence. The monitoring program focused on areas of the base where pumping has occurred, especially near Rogers Lake, and involved three phases of data collection: (1) well canvassing and selection, (2) geodetic surveys, and (3) monthly ground-water-level measurements. Construction and historical water- level data were compiled for 118 wells and pi-ezometers on or near the base, and monthly ground-water-level measurements were made in 82 wells and piezometers on the base. The compiled water-level data were used in conjunction with previously collected geologic data to identify three types of no-flow boundaries in the aquifer system: structural boundaries, a principal-aquifer boundary, and ground-water divides. Heads were computed from ground-water-level measurements and land-surface altitudes and then were used to map seasonal potentiometric surfaces for the principal and deep aquifers underlying the base. Pumping has created a regional depression in the potentiometric surface of the deep aquifer in the South Track, South Base, and Branch Park well-field area. A 15-foot decline in the potentiometric surface from April to September 1992 and 20- to 30-foot drawdowns in the three production wells in the South Track well field caused locally unconfined conditions in the deep aquifer.

[Occurrence of bacteria of the Yersinia genus in surface water].

PubMed

Krogulska, B; Maleszewska, J

1992-01-01

The aim of the study was determination of the frequency of occurrence of Yersinia genus bacteria in surface waters polluted to various degrees with bacteria of the coliform and of fecal coli. For detection of Yersinia rods the previously elaborated medium Endo MLCe and the membrane filter method were applied. Samples of 42 surface waters were examined, including 26 from rivers and 16 from lakes, ponds and clay-pits. On the basis of sanitary bacteriological analysis 16 surface waters were classified to class I purity, 10 to class II, the remaining ones to class III or beyond classification. Yersinia rods were detected in 15 water bodies that is 35.7% of the examined waters. A total of 27 Yersinia strains were identified with dominance of Y. intermedia (14 strains) and Y. enterocolitica (10 strains). Three strains represented by the species Yersinia frederiksenii. Most of the Y. enterocolitica strains belonged to biotype 1, the particular strains being represented by various serotypes. Hence their different origin may be concluded. The pathogenic serotypes 0:3 and 0:9 of Yersinia enterocolitica were not detected.

Interaction of hydrogen chloride with alumina. [atmospheric effluent concentrations and interaction of solid rocket propellants used in space shuttle

NASA Technical Reports Server (NTRS)

Bailey, R. R.; Wightman, J. P.

1978-01-01

The influence of temperature, pressure, and outgas conditions on the absorption of hydrogen chloride and water vapor on both alpha and gamma alumina was studied. Characterization of the adsorbents was performed using X-ray powder diffraction, scanning electron microscopy (SEM), low temperature nitrogen adsorption desorption measurements, BET nitrogen surface area measurements and electron spectroscopy for chemical analysis (ESCA). Water vapor adsorption isotherms at 30, 40, and 50 C were measured on alpha and gamma alumina after outgassing at 80, 200, and 400 C. Both outgas temperature and adsorption temperature influenced the adsorption of water vapor on the aluminas. The water vapor adsorption was completely reversible. Alpha alumina absorbed more water per unit area than gamma alumina. Differences in the adsorption capacity for water vapor of the two aluminas were explained on the basis of ideal surface models of alpha and gamma alumina. Isosteric heats of adsorption for water vapor on the aluminas were determined over a limited range of surface coverage.

Microbial Survey of Pennsylvania Surface Water Used for Irrigating Produce Crops.

PubMed

Draper, Audrey D; Doores, Stephanie; Gourama, Hassan; LaBorde, Luke F

2016-06-01

Recent produce-associated foodborne illness outbreaks have been attributed to contaminated irrigation water. This study examined microbial levels in Pennsylvania surface waters used for irrigation, relationships between microbial indicator organisms and water physicochemical characteristics, and the potential use of indicators for predicting the presence of human pathogens. A total of 153 samples taken from surface water sources used for irrigation in southeastern Pennsylvania were collected from 39 farms over a 2-year period. Samples were analyzed for six microbial indicator organisms (aerobic plate count, Enterobacteriaceae, coliform, fecal coliforms, Escherichia coli, and enterococci), two human pathogens (Salmonella and E. coli O157), and seven physical and environmental characteristics (pH, conductivity, turbidity, air and water temperature, and sampling day and 3-day-accumulated precipitation levels). Indicator populations were highly variable and not predicted by water and environmental characteristics. Only five samples were confirmed positive for Salmonella, and no E. coli O157 was detected in any samples. Predictive relationships between microbial indicators and the occurrence of pathogens could therefore not be determined.

Chloride concentrations and stable isotopes of hydrogen and oxygen in surface water and groundwater in and near Fish Creek, Teton County, Wyoming, 2005-06

USGS Publications Warehouse

Eddy-Miller, Cheryl A.; Wheeler, Jerrod D.

2010-01-01

Fish Creek, an approximately 25-kilometer long tributary to the Snake River, is located in Teton County in western Wyoming near the town of Wilson. The U.S. Geological Survey, in cooperation with the Teton Conservation District, conducted a study to determine the interaction of local surface water and groundwater in and near Fish Creek. In conjunction with the surface water and groundwater interaction study, samples were collected for analysis of chloride and stable isotopes of hydrogen and oxygen in water. Chloride concentrations ranged from 2.9 to 26.4 milligrams per liter (mg/L) near Teton Village, 1.2 to 4.9 mg/L near Resor's Bridge, and 1.8 to 5.0 mg/L near Wilson. Stable isotope data for hydrogen and oxygen in water samples collected in and near the three cross sections on Fish Creek are shown in relation to the Global Meteoric Water Line and the Local Meteoric Water Line.

Development and evaluation of a gas chromatographic method for the determination of triazine herbicides in natural water samples

USGS Publications Warehouse

Steinheimer, T.R.; Brooks, M.G.

1984-01-01

A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0.1 ??g/L in a 1-litre sample. Three different natural water samples were used for error analysis via evaluation of recovery efficiencies and estimation of overall method precision. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0. 1 mu g/L in a 1-litre sample. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.

Hydrologic data for the Great and Denbow heaths in eastern Maine, October 1980 through September 1981

USGS Publications Warehouse

Nichols, Wallace J.; Smath, J.A.; Adamik, J.T.

1983-01-01

Hydrologic data collected on the Great and Denbow Heaths, Maine, include precipitation, pan evaporation, air temperatures, streamflow, groundwater levels, and water quality constituents. These data were collected for a peat bog hydrology study conducted in cooperation with the Maine Geological Survey. The data network consisted of climate information from three rain gages, an evaporation pan, and two maximum-minimum thermometers; surface water information from two continuous gaging stations and 19 partial record sites; groundwater information from an observation well equipped with a continuous recorder and 106 piezometers; and water quality information from 13 wells and seven surface water sites. Water quality constituents include: field determinations of pH, specific conductance, and temperature, and laboratory determinations of common inorganic cations and anions, trace elements, and selected organic compounds. Methods used for the collection and analyses of data included standard Survey techniques modified for the unique hydrologic environment of the study area. (Author 's abstract)

Radiological monitoring plan for the Oak Ridge Y-12 Plant: Surface Water

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-10-01

The Y-12 Plant conducts a surface water monitoring program in response to DOE Orders and state of Tennessee requirements under the National Pollutant Discharge Elimination System (NPDES). The anticipated codification of DOE Order 5400.5 for radiation protection of the public and the environment (10 CFR Part 834) will require an environmental radiation protection plan (ERPP). The NPDES permit issued by the state of Tennessee requires a radiological monitoring plan (RMP) for Y-12 Plant surface waters. In a May 4, 1995 memo, the state of Tennessee, Division of Water Pollution Control, stated their desired needs and goals regarding the content ofmore » RMPs, associated documentation, and data resulting from the RMPs required under the NPDES permitting system (L. Bunting, General Discussion, Radiological Monitoring Plans, Tennessee Division of Water Pollution Control, May 4,1995). Appendix A provides an overview of how the Y-12 Plant will begin to address these needs and goals. It provides a more complete, documented basis for the current Y-12 Plant surface water monitoring program and is intended to supplement documentation provided in the Annual Site Environmental Reports (ASERs), NPDES reports, Groundwater Quality Assessment Reports, and studies conducted under the Y-12 Plant Environmental Restoration (ER) Program. The purpose of this update to the Y-12 Plant RMP is to satisfy the requirements of the current NPDES permit, DOE Order 5400.5, and 10 CFR Part 834, as current proposed, by defining the radiological monitoring plan for surface water for the Y-12 Plant. This plan includes initial storm water monitoring and data analysis. Related activities such as sanitary sewer and sediment monitoring are also summarized. The plan discusses monitoring goals necessary to determine background concentrations of radionuclides, to quantify releases, determine trends, satisfy regulatory requirements, support consequence assessments, and meet requirements that releases be ``as low as reasonably achievable`` (ALARA).« less

Determination of endocrine disrupting chemicals and antiretroviral compounds in surface water: A disposable sorptive sampler with comprehensive gas chromatography - Time-of-flight mass spectrometry and large volume injection with ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Wooding, Madelien; Rohwer, Egmont R; Naudé, Yvette

2017-05-05

Many rural dwellers and inhabitants of informal settlements in South Africa are without access to treated water and collect untreated water from rivers and dams for personal use. Endocrine disrupting chemicals (EDCs) have been detected in surface water and wildlife of South Africa. EDCs are often present in complex environmental matrices at ultra-trace levels complicating detection thereof. We report a simplified multi-residue approach for the detection and quantification of EDCs, emerging EDCs, and antiretroviral drugs in surface water. A low cost (less than one US dollar), disposable, sorptive extraction sampler was prepared in-house. The disposable samplers consisted of polydimethylsiloxane (PDMS) tubing fashioned into a loop which was then placed in water samples to concentrate EDCs and emerging pollutants. The PDMS samplers were thermally desorbed directly in the inlet of a GC, thereby eliminating the need for expensive consumable cryogenics. Comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS) was used for compound separation and identification. Linear retention indices of EDCs and emerging pollutants were determined on a proprietary Crossbond ® phase Rtx ® -CLPesticides II GC capillary column. In addition, large volume injection of surface water into an ultra-performance liquid chromatograph tandem mass spectrometer (UPLC-MS/MS) was used as complementary methodology for the detection of less volatile compounds. Large volume injection reduced tedious and costly sample preparation steps. Limits of detection for the GC method ranged from 1 to 98pg/l and for the LC method from 2 to 135ng/l. Known and emerging EDCs such as pharmaceuticals, personal care products and pesticides, as well as the antiretroviral compounds, efavirenz and nevirapine, were detected in surface water from South Africa at concentration levels ranging from 0.16ng/l to 227ng/l. Copyright © 2017 Elsevier B.V. All rights reserved.

Habitability from the Surface to the Deep

NASA Astrophysics Data System (ADS)

Cox, A. D.; Schmidt, R.; Dahlquist, G. R.; Foster, J.; Dillard, M.

2016-12-01

Merging aqueous geochemical parameters of habitability with microbial identity and activity will help determine microbial contributions to observed water-rock reactions in surface to deep environments. To determine habitability for microbial life and decipher mechanisms by which microbes survive and perform chemical reactions, over one hundred sites in diverse geological and geochemical environs have been sampled for aqueous geochemistry, mineralogy, and microbial identity and activity. Sites ranged from surficial creeks and rivers to the flooded mine shafts beneath to hydrothermal features in the caldera of a supervolcano 250 km distant; these environments contain metal scarcity, extreme anoxia, and wide variations in metal, organic carbon, and oxygen scarcity, respectively. Aqueous geochemistry included in situ measurement of temperature, pH, conductivity, and dissolved oxygen by meters; field spectrophotometry for redox active species; and synchronous sample collection and preservation for water isotopes, major cations and anions, trace elements, and dissolved inorganic and organic carbon, and more. Concurrent collection and preservation of planktonic and sediment biomass at each site will allow for microbial community identification and assessment of microbial activity. DNA extraction and PCR amplification using universal, eukaryotic, bacterial, and archaeal small subunit ribosomal RNA gene primers yielded products for sequencing. For many of the aqueous geochemical parameters analyzed, including Li and B, concentrations in flooded mine shafts fell on a continuum directly between local surface waters and those resulting from hydrothermal alteration suggesting an intermediate level of water-rock interaction in flooded mine shaft habitats. Concentrations of Li and B ranged from low micromolal in surface waters to millimolal in thermal waters. Other elements - Fe, Mn, Zn, and As included - were enriched in anoxic mine shafts by three to four orders of magnitude, due to exposure to and reaction with minerals. Concentrations of Fe and Zn ranged up to tens of millimolal whereas millimolal Mn and submillimolal As concentrations were reached. The transition from mostly unreacted surface water to waters nearly in equilibrium with rock provides vast geochemical habitat for microbes to exploit.

Advanced oxidation kinetics of aqueous tri alkyl phosphate flame retardants and plasticizers

PubMed Central

Watts, Michael J.; Linden, Karl G.

2009-01-01

Tri alkyl phosphate esters are a class of anthropogenic organics commonly found in surface waters of Europe and North America, due to their frequent application as flame retardants, plasticizers, and solvents. Four tri alkyl phosphate esters were evaluated to determine second-order rates of reaction with ultraviolet- and ozone-generated •OH in water. In competition with nitrobenzene in UV irradiated hydrogen peroxide solutions tris(2-butoxyethyl) phosphate (TBEP) was fastest to react with •OH (kOH,TBEP=1.03×1010 M-1s-1), followed sequentially by tributyl phosphate (TBP), tris(2-chloroethyl) phosphate (TCEP), and tris(2-chloroisopropyl) phosphate (TCPP) (kOH,TBEP=6.40×109, kOH,TBEP=5.60×108, & kOH,TBEP=1.98×10 M-1s-1). A two-stage process was used to test the validity of the determined kOH for TBEP and the fastest reacting halogenated alkyl phosphate, TCEP. First, •OH oxidation of TCEP and TBEP, in competition with nitrobenzene, was measured in ozonated hydrogen peroxide solutions. Applying multiple regression analysis, it was determined that the UV-H2O2 and O3-H2O2 data sets were statistically identical for each compound. The subsequent validated kOH were used to predict TCEP and TBEP photodegradation in neutral pH, model surface water after chemical oxidant addition and UV irradiation (up to 1000 mJ/cm2). The insignificant difference, between the predicted TBEP and TCEP photodegradation and a best-fit of the first-order exponential decay function to the observed TBEP and TCEP concentrations with increasing UV fluence, was further evidence of the validity of the determined kOH. TBEP oxidation rates were similar in the surface waters tested. Substantial TCEP oxidation in the model surface water required a significant increase in H2O2. PMID:19475974

Determining temperature and thermal properties for heat-based studies of surface-water ground-water interactions: Appendix A of Heat as a tool for studying the movement of ground water near streams (Cir1260)

USGS Publications Warehouse

Stonestrom, David A.; Blasch, Kyle W.; Stonestrom, David A.; Constantz, Jim

2003-01-01

Advances in electronics leading to improved sensor technologies, large-scale circuit integration, and attendant miniaturization have created new opportunities to use heat as a tracer of subsurface flow. Because nature provides abundant thermal forcing at the land surface, heat is particularly useful in studying stream-groundwater interactions. This appendix describes methods for obtaining the thermal data needed in heat-based investigations of shallow subsurface flow.

Investigating Deliquescence of Mars-like Soils from the Atacama Desert and Implications for Liquid Water Near the Martian Surface

NASA Astrophysics Data System (ADS)

Van Alstyne, A. M.; Tolbert, M. A.; Gough, R. V.; Primm, K.

2017-12-01

Recent images obtained from orbiters have shown that the Martian surface is more dynamic than previously thought. These images, showing dark features that resemble flowing water near the surface, have called into question the habitability of the Mars today. Recurring slope lineae (RSL), or the dark features seen in these images, are characterized as narrow, dark streaks that form and grow in the warm season, fade in the cold season, and recur seasonally. It is widely hypothesized that the movement of liquid water near the surface is what causes the appearance of RSL. However, the origin of the water and the potential for water to be stable near the surface is a question of great debate. Here, we investigate the potential for stable or metastable liquid water via deliquescence and efflorescence. The deliquescent properties of salts from the Atacama Desert, a popular terrestrial analog for Martian environments, were investigated using a Raman microscope outfitted with an environmental cell. The salts were put under Mars-relevant conditions and spectra were obtained to determine the presence or absence of liquid phases. The appearance of liquid phases under Mars-relevant conditions would demonstrate that liquid water could be available to cause or play a role in the formations of RSL.

Development of the coastal zone color scanner for NIMBUS 7. Volume 1: Mission objectives and instrument description

NASA Technical Reports Server (NTRS)

1979-01-01

An Earth scanning six channel (detector) radiometer using a classical Cassegrain telescope and a Wadsworth type grating spectrometer was launched aboard Nimbus 7 in order to determine the abundance or density of chlorophyll at or near the sea surface in coastal waters. The instrument also measures the sediment or gelbstroffe (yellow stuff) in coastal waters, detects surface vegetation, and measures sea surface temperature. Block diagrams and schematics are presented, design features are discussed and each subsystem of the instrument is described. A mission overview is included.

Implementation of diverse tree hydraulics in a land surface model

NASA Astrophysics Data System (ADS)

Wolf, A.; Shevliakova, E.; Malyshev, S.; Weng, E.; Pacala, S. W.

2013-12-01

Increasing attention has been devoted to the occurence of drought kill in forests worldwide. These mortality events are significant disruptions to the terrestrial carbon cycle, but the mechanisms required to represent drought kill are not represented in terrestrial carbon cycle models. In part, this is due to the challenge of representing the diversity of hydraulic strategies, which include stomatal sensitivity to water deficit and woody tissue vulnerability to cavitation at low water potential. In part, this is due to the challenge of representing this boundary value problem numerically, because the hydraulic components determine water potential at the leaf, but the stomatal conductance on the leaf also determines the hydraulic gradients within the plant. This poster will describe the development of a land surface model parameterization of diverse tree hydraulic strategies.

The influence of irrigation water on the hydrology and lake water budgets of two small arid-climate lakes in Khorezm, Uzbekistan

USGS Publications Warehouse

Scott, J.; Rosen, Michael R.; Saito, L.; Decker, D.L.

2011-01-01

Little is known regarding the origins and hydrology of hundreds of small lakes located in the western Uzbekistan province of Khorezm, Central Asia. Situated in the Aral Sea Basin, Khorezm is a productive agricultural region, growing mainly cotton, wheat, and rice. Irrigation is provided by an extensive canal network that conveys water from the Amu Darya River (AD) throughout the province. The region receives on average 10 cm/year of precipitation, yet potential evapotranspiration exceeds this amount by about 15 times. It was hypothesized that the perennial existence of the lakes of interest depends on periodic input of excess irrigation water. This hypothesis was investigated by studying two small lakes in the region, Tuyrek and Khodjababa. In June and July 2008, surface water and shallow groundwater samples were collected at these lake systems and surrounding communities and analyzed for δ2H, δ18O, and major ion hydrochemistry to determine water sources. Water table and lake surface elevations were monitored, and the local aquifer characteristics were determined through aquifer tests. These data and climate data from a Class A evaporation pan and meteorological stations were used to estimate water budgets for both lakes. Lake evaporation was found to be about 0.7 cm/day during the study period. Results confirm that the waters sampled at both lake systems and throughout central Khorezm were evaporated from AD water to varying degrees. Together, the water budgets and stable isotope and major ion hydrochemistry data suggest that without surface water input from some source (i.e. excess irrigation water), these and other Khorezm lakes with similar hydrology may decrease in volume dramatically, potentially to the point of complete desiccation.

Determination of dominant sources of nitrate contamination in transboundary (Russian Federation/Ukraine) catchment with heterogeneous land use.

PubMed

Vystavna, Y; Diadin, D; Grynenko, V; Yakovlev, V; Vergeles, Y; Huneau, F; Rossi, P M; Hejzlar, J; Knöller, K

2017-09-18

Nitrate contamination of surface water and shallow groundwater was studied in transboundary (Russia/Ukraine) catchment with heterogeneous land use. Dominant sources of nitrate contamination were determined by applying a dual δ 15 N-NO 3 and δ 18 O-NO 3 isotope approach, multivariate statistics, and land use analysis. Nitrate concentration was highly variable from 0.25 to 22 mg L -1 in surface water and from 0.5 to 100 mg L -1 in groundwater. The applied method indicated that sewage to surface water and sewage and manure to groundwater were dominant sources of nitrate contamination. Nitrate/chloride molar ratio was added to support the dual isotope signature and indicated the contribution of fertilizers to the nitrate content in groundwater. Groundwater temperature was found to be an additional indicator of manure and sewerage leaks in the shallow aquifer which has limited protection and is vulnerable to groundwater pollution.

Evaluation of the possibility of using the water of the Bystrytsya-Nadvirnyans'ka River in Cherniiv (Ukraine) to supply the population with drinking water

NASA Astrophysics Data System (ADS)

Pietrzak, D.; Mandryk, O.; Wątor, K.; Kmiecik, E.; Zelmanowych, A.

2018-02-01

The article presents the results of the research carried out in order to assess the possibility of using surface water of the Bystrytsya-Nadvirnyans'ka River in Cherniiv (western Ukraine), for the public supply of water intended for human consumption. For this purpose an existing database that contains the results of analyses of surface water samples collected in 1999, 2002, 2005, 2008, 2011 and 2014 was used. Each year, from 8 to 13 samples were collected from the Bystrytsya-Nadvirnyans'ka River in Cherniiv. Physicochemical analyses of the samples taken included the determination of pH value, temperature, TDS, alkalinity, hardness, dissolved oxygen, BOD5, COD, suspended solids and ions: Ca2+, Mg2+, Na+, K+, Fe2+, NH4+, Cu2+, Cl-, SO42-, PO43-, HCO3-, NO2-, NO3-. These chemical analyses were verified by calculation of errors based on the ionic balance. The results of the analyses were referred to the polish applicable requirements for surface water used for public supply of water intended for human consumption and to the regulation regarding the classification of the surface water status and environmental quality standards for priority substances. The results indicate that water of the Bystrytsya-Nadvirnyans'ka River in the area of Cherniiv was out of the class in the years 1999 and 2002 due to exceeding the limit values for category A3 for Cu2+. On the basis of incomplete assessment of the status of the Bystrytsya-Nadvirnyans'ka River water (due to the tests limitation to the physical and chemical components) determined that the water has a bad status because it exceeded the limits for class II for Cl-, SO42-, NO3- and TDS. In the samples collected in 1999 and 2002 it is also observed exceeding the maximum limit concentrations for Cu2+.

A multi-residue method for the analysis of pesticides and pesticide degradates in water using HLB solid-phase extraction and gas chromatography-ion trap mass spectrometry

USGS Publications Warehouse

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

2008-01-01

A method was developed for the analysis of over 60 pesticides and degradates in water by HLB solid-phase extraction and gas-chromatography/mass spectrometry. Method recoveries and detection limits were determined using two surface waters with different dissolved organic carbon (DOC) concentrations. In the lower DOC water, recoveries and detection limits were 80%-108% and 1-12 ng/L, respectively. In the higher DOC water, the detection limits were slightly higher (1-15 ng/L). Additionally, surface water samples from four sites were analyzed and 14 pesticides were detected with concentrations ranging from 4 to 1,200 ng/L. ?? 2008 Springer Science+Business Media, LLC.

Pesticide exposure assessment for surface waters in the EU. Part 2: Determination of statistically based run-off and drainage scenarios for Germany.

PubMed

Bach, Martin; Diesner, Mirjam; Großmann, Dietlinde; Guerniche, Djamal; Hommen, Udo; Klein, Michael; Kubiak, Roland; Müller, Alexandra; Preuss, Thomas G; Priegnitz, Jan; Reichenberger, Stefan; Thomas, Kai; Trapp, Matthias

2017-05-01

In order to assess surface water exposure to active substances of plant protection products (PPPs) in the European Union (EU), the FOCUS (FOrum for the Co-ordination of pesticide fate models and their USe) surface water workgroup introduced four run-off and six drainage scenarios for Step 3 of the tiered FOCUSsw approach. These scenarios may not necessarily represent realistic worst-case situations for the different Member States of the EU. Hence, the suitability of the scenarios for risk assessment in the national authorisation procedures is not known. Using Germany as an example, the paper illustrates how national soil-climate scenarios can be developed to model entries of active substances into surface waters from run-off and erosion (using the model PRZM) and from drainage (using the model MACRO). In the authorisation procedure for PPPs on Member State level, such soil-climate scenarios can be used to determine exposure endpoints with a defined overall percentile. The approach allows the development of national specific soil-climate scenarios and to calculate percentile-based exposure endpoints. The scenarios have been integrated into a software tool analogous to FOCUS-SWASH which can be used in the future to assess surface water exposure in authorisation procedures of PPPs in Germany. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Surface pressure maps from scatterometer data

NASA Technical Reports Server (NTRS)

Brown, R. A.; Levy, Gad

1991-01-01

The ability to determine surface pressure fields from satellite scatterometer data was shown by Brown and Levy (1986). The surface winds are used to calculate the gradient winds above the planetary boundary layer, and these are directly related to the pressure gradients. There are corrections for variable stratification, variable surface roughness, horizontal inhomogeneity, humidity and baroclinity. The Seasat-A Satellite Scatterometer (SASS) data have been used in a systematic study of 50 synoptic weather events (regions of approximately 1000 X 1000 km). The preliminary statistics of agreement with national weather service surface pressure maps are calculated. The resulting surface pressure maps can be used together with SASS winds and Scanning Multichannel Microwave Radiometer (SMMR) water vapor and liquid water analyses to provide good front and storm system analyses.

Low-level (PPB) determination of cisplatin in cleaning validation (rinse water) samples. II. A high-performance liquid chromatographic method.

PubMed

Raghavan, R; Burchett, M; Loffredo, D; Mulligan, J A

2000-04-01

A high-performance liquid chromatographic (HPLC) method is described for the determination of residual levels of cisplatin from extracts of surfaces with very low surface area; from extracts of surfaces of coupons made of Teflon (polytetrafluoroethylene, PTFE), stainless steel, and glass; and in aqueous solution collected after rinsing equipment and parts. Initially, the method was developed to determine cisplatin at concentrations ranging from 20 to 200 ng/ml by direct injection. Retaining the same method conditions, the scope of the method was expanded by the addition of a sample preconcentration step, allowing analyses at levels ranging from 0.5 ng to 20 ng/ml. Preconcentration is necessary for the determination of cisplatin in rinse waters at a quantifiable concentration of about 2 PPB. Under these conditions, the detection limit is about 0.2 to 0.3 ng/ml. Residual cisplatin on different types of surfaces, including surfaces with very low surface area, can be determined by swabbing each test surface with a derivatizing solution. The cisplatin recovered in the swabbing solution can be analyzed by HPLC using direct injection or preconcentration, depending on the expected level of cisplatin in the sample. Initial methods were developed to quantitate at a cisplatin concentration of about 100 PPB or higher in solution extracted from surfaces. However, when surface areas are limited because of the size of the parts, solution concentration becomes very low as a result of the minimum volume required for extraction. To support the application of swabbing techniques to surface analysis, stainless steel, Teflon, and glass surfaces were spiked with cisplatin at 2.5 to 20 ng/cm2. Satisfactory overall recoveries of 90% +/- 10% were obtained from all surfaces. Cisplatin has no ultraviolet/visible (UV/Vis) spectral-active functional group that can be used to detect low levels of cisplatin. Hence, diethyldithiocarbamate (DDTC) was used as a derivatizing agent to increase sensitivity to UV absorption at 340 nm. Diethyldithiocarbamate forms complexes with the platinum in cisplatin to yield a platinum-DDTC (Pt-DDTC) complex with a high molar-extinction coefficient. The Pt(DDTC)2 complex thus formed was chromatographically separated and the quantitated by comparison of its detector response to that of a similarly derivatized standard preparation. DDTC also has application as a cleaning agent for cisplatin (e.g., for production equipment cleaning, spill cleanup). Destruction of cisplatin can be affected by the reaction of cisplatin with this cleaning agent. Derivatization of cisplatin will convert active cisplatin to platinum-DDTC on surfaces or in solution. Final cleaning can be accomplished using a water-for-injection rinse. After such a cleaning process, the rinse water, when collected and analyzed, showed levels of free cisplatin less than the detection concentration of 0.2 PPB and a total platinum concentration less than 10 PPB as Pt-DDTC complex.

Method to identify wells that yield water that will be replaced by water from the Colorado River downstream from Laguna Dam in Arizona and California

USGS Publications Warehouse

Owen-Joyce, Sandra J.; Wilson, Richard P.; Carpenter, Michael C.; Fink, James B.

2000-01-01

Accounting for the use of Colorado River water is required by the U.S. Supreme Court decree, 1964, Arizona v. California. Water pumped from wells on the flood plain and from certain wells on alluvial slopes outside the flood plain is presumed to be river water and is accounted for as Colorado River water. The accounting-surface method developed for the area upstream from Laguna Dam was modified for use downstream from Laguna Dam to identify wells outside the flood plain of the lower Colorado River that yield water that will be replaced by water from the river. Use of the same method provides a uniform criterion of identification for all users pumping water from wells by determining if the static water-level elevation in the well is above or below the elevation of the accounting surface. Wells that have a static water-level elevation equal to or below the accounting surface are presumed to yield water that will be replaced by water from the Colorado River. Wells that have a static water-level elevation above the accounting surface are presumed to yield river water stored above river level. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The river aquifer consists of permeable sediments and sedimentary rocks that are hydraulically connected to the Colorado River so that water can move between the river and the aquifer in response to withdrawal of water from the aquifer or differences in water-level elevations between the river and the aquifer. The subsurface limit of the river aquifer is the nearly impermeable bedrock of the bottom and sides of the basins that underlie the Yuma area and adjacent valleys. The accounting surface represents the elevation and slope of the unconfined static water table in the river aquifer outside the flood plain of the Colorado River that would exist if the river were the only source of water to the river aquifer. The accounting surface was generated by using water-surface profiles of the Colorado River from Laguna Dam to about the downstream limit of perennial flow at Morelos Dam. The accounting surface extends outward from the edges of the flood plain to the subsurface boundary of the river aquifer. Maps at a scale of 1:100,000 show the extent of the river aquifer and elevation of the accounting surface downstream from Laguna Dam in Arizona and California.

Application of a Groundwater Modeling Tool for Managing Hydrologically Connected Area in State of Nebraska, US

NASA Astrophysics Data System (ADS)

Li, R.; Flyr, B.; Bradley, J.; Pun, M.; Schneider, J.; Wietjes, J.; Chinta, S.

2014-12-01

Determination of the nature and degree of hydrologically connected groundwater and surface water resources is of paramount importance to integrated water management within the State of Nebraska to understand the impact of water uses on available supplies, such as depletion of streams and aquifers caused by groundwater pumping. The ability to quantify effects of surface water-groundwater hydrologic connection and interactions, is regarded as one of the most important steps towards effectively managing water resources in Nebraska and provides the basis for designating management areas. Designation of management areas allows the state and other management entities to focus various efforts and resources towards those projects that have the greatest impact to water users. Nebraska Department of Natural Resources (NDNR) developed a groundwater modeling tool, Cycle Well Analysis, to determine the areas defined to have a high degree of connectivity between groundwater and surface water (in accordance with the state regulations). This tool features two graphic user interfaces to allow the analysis to be fully compatible with most MODFLOW-based numerical groundwater models currently utilized by NDNR. Case studies showed that the tool, in combination of Geographic Information Systems (GIS), can be used to quantify the degree of stream depletion and delineate the boundary of hydrologically connected areas within different political boundaries and subbasins in Nebraska. This approach may be applied to other regions with similar background and need for integrated water management.

Determination of ethephon residues in water by gas chromatography with cubic mass spectrometry after ion-exchange purification and derivatisation with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide.

PubMed

Royer, A; Laporte, F; Bouchonnet, S; Communal, P-Y

2006-03-03

An analytical method has been developed for the determination of residues of ethephon (2-chloroethyl phosphonic acid) in drinking and surface water. The procedure is based on de-ionisation with an anion/cation-exchange resin, solid phase extraction by means of anion-exchange polystyrene-divinylbenzene extraction disks, elution with a mixture of methanol and 10 M hydrochloric acid (98/2, v/v), redisolution into acetonitrile after evaporation and silylation with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA). Quantification is performed by gas chromatography with ion-trap cubic mass spectrometric detection in the electron impact mode (GC-EI-MS3). Method validation was conducted using samples of mineral, tap, and river water that were fortified with ethephon at concentration levels ranging from 0.1 to 1.0 microg/L. The mean recovery from all the fortified samples (n = 36) amounted to 88% with a relative standard deviation of 17%. The method, therefore, was shown to allow accurate determination of ethephon residues in drinking and surface water with a limit of quantification of 0.1 microg/L.

Surface velocity divergence model of air/water interfacial gas transfer in open-channel flows

NASA Astrophysics Data System (ADS)

Sanjou, M.; Nezu, I.; Okamoto, T.

2017-04-01

Air/water interfacial gas transfer through a free surface plays a significant role in preserving and restoring water quality in creeks and rivers. However, direct measurements of the gas transfer velocity and reaeration coefficient are still difficult, and therefore a reliable prediction model needs to be developed. Varying systematically the bulk-mean velocity and water depth, laboratory flume experiments were conducted and we measured surface velocities and dissolved oxygen (DO) concentrations in open-channel flows to reveal the relationship between DO transfer velocity and surface divergence (SD). Horizontal particle image velocimetry measurements provide the time-variations of surface velocity divergence. Positive and negative regions of surface velocity divergence are transferred downstream in time, as occurs in boil phenomenon on natural river free-surfaces. The result implies that interfacial gas transfer is related to bottom-situated turbulence motion and vertical mass transfer. The original SD model focuses mainly on small-scale viscous motion, and this model strongly depends on the water depth. Therefore, we modify the SD model theoretically to accommodate the effects of the water depth on gas transfer, introducing a non-dimensional parameter that includes contributions of depth-scale large-vortex motion, such as secondary currents, to surface renewal events related to DO transport. The modified SD model proved effective and reasonable without any dependence on the bulk mean velocity and water depth, and has a larger coefficient of determination than the original SD model. Furthermore, modeling of friction velocity with the Reynolds number improves the practicality of a new formula that is expected to be used in studies of natural rivers.

Ordered water structure at hydrophobic graphite interfaces observed by 4D, ultrafast electron crystallography

PubMed Central

Yang, Ding-Shyue; Zewail, Ahmed H.

2009-01-01

Interfacial water has unique properties in various functions. Here, using 4-dimensional (4D), ultrafast electron crystallography with atomic-scale spatial and temporal resolution, we report study of structure and dynamics of interfacial water assembly on a hydrophobic surface. Structurally, vertically stacked bilayers on highly oriented pyrolytic graphite surface were determined to be ordered, contrary to the expectation that the strong hydrogen bonding of water on hydrophobic surfaces would dominate with suppressed interfacial order. Because of its terrace morphology, graphite plays the role of a template. The dynamics is also surprising. After the excitation of graphite by an ultrafast infrared pulse, the interfacial ice structure undergoes nonequilibrium “phase transformation” identified in the hydrogen-bond network through the observation of structural isosbestic point. We provide the time scales involved, the nature of ice-graphite structural dynamics, and relevance to properties related to confined water. PMID:19246378

Remote sensing of ephemeral water bodies in western Niger

USGS Publications Warehouse

Verdin, J.P.

1996-01-01

Research was undertaken to evaluate the feasibility of monitoring the small ephemeral water bodies of the Sahel with the 1.1 km resolution data of the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR). Twenty-one lakes of western Niger with good ground observation records were selected for examination. Thematic Mapper images from 1988 were first analysed to determine surface areas and temperature differences between water and adjacent land. Six AVHRR scenes from the 1988-89 dry season were then studied. It was found that a lake can be monitored until its surface area drops below 10 ha, in most cases. Furthermore, with prior knowledge of the location and shape of a water body, its surface area can be estimated from AVHRR band 5 data to within about 10 ha. These results are explained by the sharp temperature contrast between water and land, on the order of 13?? C.

Mechanism of Cohesion of Monomolecular Water Film with the β-AgI Crystal Surface under Thermal Fluctuations

NASA Astrophysics Data System (ADS)

Shevkunov, S. V.

2018-07-01

The growth of liquid phase nuclei on the surface of some crystals was shown to differ from that described in the classic theory of capillarity. The surface of the base face of a silver iodide crystal is completely covered with a monomolecular water film already in unsaturated vapors, and the wetting conditions of the substrate are determined by the hydrophobic properties of the film surface, but not the crystal surface itself. The mechanism by which the monomolecular film is held on the surface of crystalline silver iodide was studied by the Monte Carlo method at the molecular level. It was found that the adhesion of the film to the surface of the base face of the crystal was by hydrogen bonding with the ions of the second crystallographic layer of the substrate, and the film was thermodynamically stable even in unsaturated water vapor. The film hydrophobicity is due to the deficiency of hydrogen bond donors on its surface. The nanostructural elements on the surface of the aerosol particle can neutralize the hydrophobic properties of the film and thus serve as nucleation centers.

Zirconium fluoride glass - Surface crystals formed by reaction with water

NASA Technical Reports Server (NTRS)

Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

1984-01-01

The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

Improvement in surface hydrophilicity and resistance to deformation of natural leather through O2/H2O low-temperature plasma treatment

NASA Astrophysics Data System (ADS)

You, Xuewei; Gou, Li; Tong, Xingye

2016-01-01

The natural leather was modified through O2/H2O low-temperature plasma treatment. Surface morphology was characterized by scanning electron microscopy (SEM) and the results showed that the pores on the leather surface became deeper and larger with enhanced permeability of water and vapor. XPS and FTIR-ATR was performed to determine the chemical composition of natural leather surface. Oxygen-containing groups were successfully grafted onto the surface of natural leather and oxygen content increased with longer treatment time. After O2/H2O plasma treatment, initial water contact angle was about 21° and water contact angles were not beyond 55° after being stored for 3 days. Furthermore, the tensile test indicated that the resistance to deformation had a prominent transform without sacrificing the tensile strength.

Interaction of Strong Turbulence With Free Surfaces

NASA Astrophysics Data System (ADS)

Dalrymple, Robert A.

Spray from a nozzle, spilling breakers, and “rooster tails” from speeding boats are all examples of a turbulent flow with a free surface. In many cases like these, the free surface is difficult to discern as the volume of air in the fluid can exceed that of the water.In traditional studies, the free surface is simply defined as a continuous surface separating the fluid from air. The pressure at the surface is assumed to be atmospheric pressure and the fluid comprising the surface moves with the surface. While these conditions are sufficient for non-turbulent flows, such as nonbreaking water waves, and lead to the (albeit non-linear) dynamic and kinematic free surface boundary conditions that serve to provide sufficient conditions to determine the surface, they are not valid descriptions for a bubbly free surface in a highly turbulent regime, such as the roller in front of a spilling breaker or the propeller wash behind a ship.

Study design and percent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve water samples containing free chlorine, 2004-06

USGS Publications Warehouse

Valder, Joshua F.; Delzer, Gregory C.; Price, Curtis V.; Sandstrom, Mark W.

2008-01-01

The National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS) began implementing Source Water-Quality Assessments (SWQAs) in 2002 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used for SWQA studies, source water is the raw (ambient) water collected at the supply well prior to water treatment (for ground water) or the raw (ambient) water collected from the river near the intake (for surface water). Finished water is the water that is treated, which typically involves, in part, the addition of chlorine or other disinfection chemicals to remove pathogens, and is ready to be delivered to consumers. Finished water is collected before the water enters the distribution system. This report describes the study design and percent recoveries of anthropogenic organic compounds (AOCs) with and without the addition of ascorbic acid to preserve water samples containing free chlorine. The percent recoveries were determined by using analytical results from a laboratory study conducted in 2004 by the USGS's National Water Quality Laboratory (NWQL) and from data collected during 2004-06 for a field study currently (2008) being conducted by the USGS's NAWQA Program. The laboratory study was designed to determine if preserving samples with ascorbic acid (quenching samples) adversely affects analytical performance under controlled conditions. During the laboratory study, eight samples of reagent water were spiked for each of five analytical schedules evaluated. Percent recoveries from these samples were then compared in two ways: (1) four quenched reagent spiked samples analyzed on day 0 were compared with four quenched reagent spiked samples analyzed on day 7 or 14, and (2) the combined eight quenched reagent spiked samples analyzed on day 0, 7, or 14 were compared with eight laboratory reagent spikes (LRSs). Percent recoveries from the quenched reagent spiked samples that were analyzed at two different times (day 0 and day 7 or 14) can be used to determine the stability of the quenched samples held for an amount of time representative of the normal amount of time between sample collection and analysis. The comparison between the quenched reagent spiked samples and the LRSs can be used to determine if quenching samples adversely affects the analytical performance under controlled conditions. The field study began in 2004 and is continuing today (February 2008) to characterize the effect of quenching on field-matrix spike recoveries and to better understand the potential oxidation and transformation of 277 AOCs. Three types of samples were collected from 11 NAWQA Study Units across the Nation: (1) quenched finished-water samples (not spiked), (2) quenched finished-water spiked samples, and (3) nonquenched finished-water spiked samples. Percent recoveries of AOCs in quenched and nonquenched finished-water spiked samples collected during 2004-06 are presented. Comparisons of percent recoveries between quenched and nonquenched spiked samples can be used to show how quenching affects finished-water samples. A maximum of 6 surface-water and 7 ground-water quenched finished-water spiked samples paired with nonquenched finished-water spiked samples were analyzed. Analytical results for the field study are presented in two ways: (1) by surface-water supplies or ground-water supplies, and (2) by use (or source) group category for surface-water and ground-water supplies. Graphical representations of percent recoveries for the quenched and nonquenched finished-water spiked samples also are presented.

Influent of Borax Decahydrate Composition as Additional Flux into Stoneware Bodies

NASA Astrophysics Data System (ADS)

Bakil, Siti Natrah Abd; Hussin, Rosniza; Bakar Aramjat, Abu

2017-08-01

Stoneware is vitrified, has less porosity and requires high sintering temperature. The influent of borax decahydrate composition at sintering temperature 1050°C and 1150°C on the thermal analysis, fracture surface, linear shrinkage, water absorption and modular of rapture (MOR) were investigated. Rectangular sample were produced by uniaxially pressing at 40MPa. The thermal behavior was determined by thermogravimetric and different thermal analysis (TGA-DTA). The Scanning electron microscopy (SEM) was used for fracture surface analysis. The water absorption (%) of the sample were determined using Archimedes’ method. The experimental result showed that content of borax decahydrate have influent the properties of stoneware bodies.

Rapid Detection of Melamine in Tap Water and Milk Using Conjugated "One-Step" Molecularly Imprinted Polymers-Surface Enhanced Raman Spectroscopic Sensor.

PubMed

Hu, Yaxi; Lu, Xiaonan

2016-05-01

An innovative "one-step" sensor conjugating molecularly imprinted polymers and surface enhanced Raman spectroscopic-active substrate (MIPs-SERS) was investigated for simultaneous extraction and determination of melamine in tap water and milk. This sensor was fabricated by integrating silver nanoparticles (AgNPs) with MIPs synthesized by bulk polymerization of melamine (template), methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linking agent), and 2,2'-azobisisobutyronitrile (initiator). Static and kinetic adsorption tests validated the specific affinity of MIPs-AgNPs to melamine and the rapid adsorption equilibration rate. Principal component analysis segregated SERS spectral features of tap water and milk samples with different melamine concentrations. Partial least squares regression models correlated melamine concentrations in tap water and skim milk with SERS spectral features. The limit of detection (LOD) and limit of quantification (LOQ) of melamine in tap water were determined as 0.0019 and 0.0064 mmol/L, while the LOD and LOQ were 0.0165 and 0.055 mmol/L for the determination of melamine in skim milk. However, this sensor is not ideal to quantify melamine in tap water and skim milk. By conjugating MIPs with SERS-active substrate (that is, AgNPs), reproducibility of SERS spectral features was increased, resulting in more accurate detection. The time required to determine melamine in tap water and milk were 6 and 25 min, respectively. The low LOD, LOQ, and rapid detection confirm the potential of applying this sensor for accurate and high-throughput detection of melamine in tap water and milk. © 2016 Institute of Food Technologists®

Base-flow characteristics of streams in the Valley and Ridge, the Blue Ridge, and the Piedmont physiographic provinces of Virginia

USGS Publications Warehouse

Nelms, David L.; Harlow, George E.; Hayes, Donald C.

1997-01-01

Growth within the Valley and Ridge, Blue Ridge, and Piedmont physiographic provinces of Virginia has focused concern about allocation of surface-water flow and increased demands on the ground-water resources. Potential surface-water yield was determined from statistical analysis of base-flow characteristics of streams. Base-flow characteristics also may provide a relative indication of the potential ground-water yield for areas that lack sufficient specific capacity or will-yield data; however, other factors need to be considered, such as geologic structure, lithology, precipitation, relief, and the degree of hydraulic interconnection between the regolith and bedrock.

Batch and column adsorption of herbicide fluroxypyr on different types of activated carbons from water with varied degrees of hardness and alkalinity.

PubMed

Pastrana-Martínez, L M; López-Ramón, M V; Fontecha-Cámara, M A; Moreno-Castilla, C

2010-02-01

There has been little research into the effects of the water hardness and alkalinity of surface waters on the adsorption of herbicides on activated carbons. The aim of this study was to determine the influence of these water characteristics on fluroxypyr adsorption on different activated carbons. At low fluroxypyr surface concentrations, the amount adsorbed from distilled water was related to the surface hydrophobicity. Surface area of carbons covered by fluroxypyr molecules ranged from 60 to 65%. Variations in fluroxypyr solubility with water hardness and alkalinity showed a salting-in effect. Calcium, magnesium and bicarbonate ions were adsorbed to a varied extent on the activated carbons. The presence of fluroxypyr in solution decreased their adsorption due to a competition effect. K(F) from the Freundlich equation linearly increased with water hardness due to salt-screened electrostatic repulsions between charged fluroxypyr molecules. The amount adsorbed from distilled water was largest at high fluroxypyr solution concentrations, because there was no competition between inorganic ions and fluroxypyr molecules. The column breakthrough volume and the amount adsorbed at breakthrough were smaller in tap versus distilled water. Carbon consumption was lower with activated carbon cloth than with the use of granular activated carbon. (c) 2009 Elsevier Ltd. All rights reserved.

Investigating surface water-well interaction using stable isotope ratios of water

USGS Publications Warehouse

Hunt, R.J.; Coplen, T.B.; Haas, N.L.; Saad, D.A.; Borchardt, M. A.

2005-01-01

Because surface water can be a source of undesirable water quality in a drinking water well, an understanding of the amount of surface water and its travel time to the well is needed to assess a well's vulnerability. Stable isotope ratios of oxygen in river water at the City of La Crosse, Wisconsin, show peak-to-peak seasonal variation greater than 4??? in 2001 and 2002. This seasonal signal was identified in 7 of 13 city municipal wells, indicating that these 7 wells have appreciable surface water contributions and are potentially vulnerable to contaminants in the surface water. When looking at wells with more than 6 sampling events, a larger variation in ??18O compositions correlated with a larger fraction of surface water, suggesting that samples collected for oxygen isotopic composition over time may be useful for identifying the vulnerability to surface water influence even if a local meteoric water line is not available. A time series of ??18O from one of the municipal wells and from a piezometer located between the river and the municipal well showed that the travel time of flood water to the municipal well was approximately 2 months; non-flood arrival times were on the order of 9 months. Four independent methods were also used to assess time of travel. Three methods (groundwater temperature arrival times at the intermediate piezometer, virus-culture results, and particle tracking using a numerical groundwater-flow model) yielded flood and non-flood travel times of less than 1 year for this site. Age dating of one groundwater sample using 3H-3He methods estimated an age longer than 1 year, but was likely confounded by deviations from piston flow as noted by others. Chlorofluorocarbons and SF6 analyses were not useful at this site due to degradation and contamination, respectively. This work illustrates the utility of stable hydrogen and oxygen isotope ratios of water to determine the contribution and travel time of surface water in groundwater, and demonstrates the importance of using multiple methods to improve estimates for time of travel of 1 year or less. ?? 2004 Elsevier B.V. All rights reserved.

Mercury exchange at the air-water-soil interface: an overview of methods.

PubMed

Fang, Fengman; Wang, Qichao; Liu, Ruhai

2002-06-12

An attempt is made to assess the present knowledge about the methods of determining mercury (Hg) exchange at the air-water-soil interface during the past 20 years. Methods determining processes of wet and dry removal/deposition of atmospheric Hg to aquatic and terrestrial ecosystems, as well as methods determining Hg emission fluxes to the atmosphere from natural surfaces (soil and water) are discussed. On the basis of the impressive advances that have been made in the areas relating to Hg exchange among air-soil-water interfaces, we analyzed existing problems and shortcomings in our current knowledge. In addition, some important fields worth further research are discussed and proposed.

Surface force and vibrational spectroscopic analyses of interfacial water molecules in the vicinity of methoxy-tri(ethylene glycol)-terminated monolayers: mechanisms underlying the effect of lateral packing density on bioinertness.

PubMed

Sekine, Taito; Asatyas, Syifa; Sato, Chikako; Morita, Shigeaki; Tanaka, Masaru; Hayashi, Tomohiro

Unequivocal dependence of bioinertness of self-assembled monolayers of methoxy-tri(ethylene glycol)-terminated alkanethiol (EG3-OMe SAMs) on their packing density has been a mystery for more than two decades. We tackled this long-standing question by performing surface force and surface-enhanced infrared absorption (SEIRA) spectroscopic measurements. Our surface force measurements revealed a physical barrier of interfacial water in the vicinity of the Au-supported EG3-OMe SAM (low packing density), whereas the Ag-supported one (high packing density) did not possess such interfacial water. In addition, the results of SEIRA measurements clearly exhibited that hydrogen bonding states of the interfacial water differ depending on the substrates. We also characterized the bioinertness of these SAMs by protein adsorption tests and adhesion assays of platelet and human umbilical vein endothelial cells. The hydrogen bonding states of the interfacial water and water-induced interaction clearly correlated with the bioinertness of the SAMs, suggesting that the interfacial water plays an important role determining the interaction of the SAMs with biomolecules and cells.

Willamette Basin Surface Water Isoscape (18O and 2H): Interpreting Temporal Changes of Source Water within the River

EPA Science Inventory

Determining how water sources for rivers vary over time can greatly enhance our understanding and management of land use and climate change impacts on rivers. Because the stable isotope composition of precipitation can vary geographically, variation in the stable isotope composi...

75 FR 69435 - Public Water System Supervision Program Revision for the State of North Dakota

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-12

... Water System Supervision (PWSS) Primacy Program by adopting federal regulations for the Groundwater Rule, Long Term 2 Enhanced Surface Water Treatment Rule and Stage 2 Disinfection By-Product Rule which.... DATES: Any member of the public may request a public hearing on this determination by December 13, 2010...

75 FR 69436 - Public Water System Supervision Program Revision for the State of South Dakota

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-12

... Water System Supervision (PWSS) Primacy Program by adopting federal regulations for the Long Term 2 Enhanced Surface Water Treatment Rule, Stage 2 Disinfection By-Product Rule, Groundwater Rule, and the Lead... public hearing on this determination by December 13, 2010. Please see SUPPLEMENTARY INFORMATION, Item C...

The influence of lithology on surface water sources | Science ...

EPA Pesticide Factsheets

Understanding the temporal and spatial variability of surface water sources within a basin is vital to our ability to manage the impacts of climate variability and land cover change. Water stable isotopes can be used as a tool to determine geographic and seasonal sources of water at the basin scale. Previous studies in the Coastal Range of Oregon reported that the variation in the isotopic signatures of surface water does not conform to the commonly observed “rainout effect”, which exhibits a trend of increasing isotopic depletion with rising elevation. The primary purpose of this research is to investigate the mechanisms governing seasonal and spatial variations in the isotopic signature of surface waters within the Marys River Basin, located in the leeward side of the Oregon Coastal Range. Surface water and precipitation samples were collected every 2-3 weeks for isotopic analysis of δ18O and δ2H for one year. Results indicate a significant difference in isotopic signature between watersheds underlain by basalt and sandstone. The degree of separation was the most distinct during the summer when low flows reflect deeper groundwater sources, whereas isotopic signatures during the rainy season (fall and winter) showed a greater degree of similarity between the two lithologies. This indicates that baseflow within streams drained by sandstone versus basalt is being supplied from two distinctly separate water sources. In addition, Marys River flow at the outle

GC13I-0860: An Assessment of Surface Water Detection Methods for the Tahoua Region, Niger

NASA Technical Reports Server (NTRS)

Herndon, Kelsey E.; Muench, Rebekke; Cherrington, Emil; Griffin, Robert

2017-01-01

The recent release of several global surface water datasets derived from remotely sensed data has allowed for unprecedented analysis of the earth's hydrologic processes at a global scale. However, some of these datasets fail to identify important sources of surface water, especially small ponds, in the Sahel, an arid region of Africa that forms a border zone between the Sahara Desert to the north, and the savannah to the south. These ponds may seem insignificant in the context of wider, global-scale hydrologic processes, but smaller sources of water are important for local and regional hydrologic assessments. Particularly, these smaller water bodies are significant sources of hydration and irrigation for nomadic pastoralists and smallholder farmers throughout the Sahel. For this study, several methods of identifying surface water from Landsat 8 OLI, Sentinel 1 SAR, Sentinel 2 MSI, and Planet Dove data were compared to determine the most effective means of delineating these features in the Tahoua Region of Niger. The Automated Water Extraction Index (AWEInsh) had the best performance when validated against very high resolution Digital Globe imagery, with an overall accuracy of 98.6%. This study reiterates the importance of region-specific algorithms and suggests that the AWEInsh method may be the best for delineating surface water in the Sahelian ecozone, likely due to the nature of the exposed geology and lack of dense green vegetation.

An Assessment of Surface Water Detection Algorithms for the Tahoua Region, Niger

NASA Astrophysics Data System (ADS)

Herndon, K. E.; Muench, R.; Cherrington, E. A.; Griffin, R.

2017-12-01

The recent release of several global surface water datasets derived from remotely sensed data has allowed for unprecedented analysis of the earth's hydrologic processes at a global scale. However, some of these datasets fail to identify important sources of surface water, especially small ponds, in the Sahel, an arid region of Africa that forms a border zone between the Sahara Desert to the north, and the savannah to the south. These ponds may seem insignificant in the context of wider, global-scale hydrologic processes, but smaller sources of water are important for local and regional assessments. Particularly, these smaller water bodies are significant sources of hydration and irrigation for nomadic pastoralists and smallholder farmers throughout the Sahel. For this study, several methods of identifying surface water from Landsat 8 OLI and Sentinel 1 SAR data were compared to determine the most effective means of delineating these features in the Tahoua Region of Niger. The Modified Normalized Difference Water Index (MNDWI) had the best performance when validated against very high resolution World View 3 imagery, with an overall accuracy of 99.48%. This study reiterates the importance of region-specific algorithms and suggests that the MNDWI method may be the best for delineating surface water in the Sahelian ecozone, likely due to the nature of the exposed geology and lack of dense green vegetation.

Estimation of open water evaporation using land-based meteorological data

NASA Astrophysics Data System (ADS)

Li, Fawen; Zhao, Yong

2017-10-01

Water surface evaporation is an important process in the hydrologic and energy cycles. Accurate simulation of water evaporation is important for the evaluation of water resources. In this paper, using meteorological data from the Aixinzhuang reservoir, the main factors affecting water surface evaporation were determined by the principal component analysis method. To illustrate the influence of these factors on water surface evaporation, the paper first adopted the Dalton model to simulate water surface evaporation. The results showed that the simulation precision was poor for the peak value zone. To improve the model simulation's precision, a modified Dalton model considering relative humidity was proposed. The results show that the 10-day average relative error is 17.2%, assessed as qualified; the monthly average relative error is 12.5%, assessed as qualified; and the yearly average relative error is 3.4%, assessed as excellent. To validate its applicability, the meteorological data of Kuancheng station in the Luan River basin were selected to test the modified model. The results show that the 10-day average relative error is 15.4%, assessed as qualified; the monthly average relative error is 13.3%, assessed as qualified; and the yearly average relative error is 6.0%, assessed as good. These results showed that the modified model had good applicability and versatility. The research results can provide technical support for the calculation of water surface evaporation in northern China or similar regions.

Effect of alternative surface inlet designs on sediment and phosphorus drainage losses

USDA-ARS?s Scientific Manuscript database

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

Bulk water freezing dynamics on superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Chavan, S.; Carpenter, J.; Nallapaneni, M.; Chen, J. Y.; Miljkovic, N.

2017-01-01

In this study, we elucidate the mechanisms governing the heat-transfer mediated, non-thermodynamic limited, freezing delay on non-wetting surfaces for a variety of characteristic length scales, Lc (volume/surface area, 3 mm < Lc < 6 mm) using carefully designed freezing experiments in a temperature-controlled, zero-humidity environment on thin water slabs. To probe the effect of surface wettability, we investigated the total time for room temperature water to completely freeze into ice on superhydrophilic ( θaapp→ 0°), hydrophilic (0° < θa < 90°), hydrophobic (90° < θa < 125°), and superhydrophobic ( θaapp→ 180°) surfaces. Our results show that at macroscopic length scales, heat conduction through the bulk water/ice layer dominates the freezing process when compared to heat conduction through the functional coatings or nanoscale gaps at the superhydrophobic substrate-water/ice interface. In order to verify our findings, and to determine when the surface structure thermal resistance approaches the water/ice resistance, we fabricated and tested the additional substrates coated with commercial superhydrophobic spray coatings, showing a monotonic increase in freezing time with coating thickness. The added thermal resistance of thicker coatings was much larger than that of the nanoscale superhydrophobic features, which reduced the droplet heat transfer and increased the total freezing time. Transient finite element method heat transfer simulations of the water slab freezing process were performed to calculate the overall heat transfer coefficient at the substrate-water/ice interface during freezing, and shown to be in the range of 1-2.5 kW/m2K for these experiments. The results shown here suggest that in order to exploit the heat-transfer mediated freezing delay, thicker superhydrophobic coatings must be deposited on the surface, where the coating resistance is comparable to the bulk water/ice conduction resistance.

Pesticides in near-surface aquifers: An assessment using highly sensitive analytical methods and tritium

USGS Publications Warehouse

Kolpin, D.W.; Goolsby, D.A.; Thurman, E.M.

1995-01-01

In 1992, the U.S. Geological Survey (USGS) determined the distribution of pesticides in near-surface aquifers of the midwestern USA to be much more widespread than originally determined during a 1991 USGS study. The frequency of pesticide detection increased from 28.4% during the 1991 study to 59.0% during the 1992 study. This increase in pesticide detection was primarily the result of a more sensitive analytical method that used reporting limits as much as 20 times lower than previously available and a threefold increase in the number of pesticide metabolites analyzed. No pesticide concentrations exceeded the U.S. Environmental Protection Agency's (USEPAs) maximum contaminant levels or health advisory levels for drinking water. However, five of the six most frequently detected compounds during 1992 were pesticide metabolites that currently do not have drinking water standards determined. The frequent presence of pesticide metabolites for this study documents the importance of obtaining information on these compounds to understand the fate and transport of pesticides in the hydrologic system. It appears that the 56 parent compounds analyzed follow similar pathways through the hydrologic system as atrazine. When atrazine was detected by routine or sensitive analytical methods, there was an increased likelihood of detecting additional parent compounds. As expected, the frequency of pesticide detection was highly dependent on the analytical reporting limit. The number of atrazine detections more than doubled as the reporting limit decreased from 0.10 to 0.01 µg/L. The 1992 data provided no indication that the frequency of pesticide detection would level off as improved analytical methods provide concentrations below 0.003 µg/L. A relation was determined between groundwater age and the frequency of pesticide detection, with 15.8% of the samples composed of pre-1953 water and 70.3% of the samples of post-1953 water having a detection of at least one pesticide or metabolite. Pre-1953 water is less likely to contain pesticides because it tends to predate the use of pesticides to increase crop production in the Midwest. Pre-1953 water was more likely to occur in the near-surface bedrock aquifers (50.0%) than in the near-surface unconsolidated aquifers (9.1%) sampled.

Variation of surface water spectral response as a function of in situ sampling technique

NASA Technical Reports Server (NTRS)

Davis, Bruce A.; Hodgson, Michael E.

1988-01-01

Tests were carried out to determine the spectral variation contributed by a particular sampling technique. A portable radiometer was used to measure the surface water spectral response. Variation due to the reflectance of objects near the radiometer (i.e., the boat side) during data acquisition was studied. Consideration was also given to the variation due to the temporal nature of the phenomena (i.e., wave activity).

The Nature of Surface Oxides on Corrosion-Resistant Nickel Alloy Covered by Alkaline Water

PubMed Central

2010-01-01

A nickel alloy with high chrome and molybdenum content was found to form a highly resistive and passive oxide layer. The donor density and mobility of ions in the oxide layer has been determined as a function of the electrical potential when alkaline water layers are on the alloy surface in order to account for the relative inertness of the nickel alloy in corrosive environments. PMID:20672134

Water management practices in rural and urban homes: a case study from Bangladesh on ingestion of polluted water.

PubMed

Ahmed, S A; Hoque, B A; Mahmud, A

1998-09-01

Although Bangladesh has achieved remarkable success in extending the availability of hand pumped and piped water, unsafe water is still ingested. This brief study attempted to assess water management practices in rural and urban homes in Bangladesh so as to establish the routes by which unsafe water is ingested, to examine methods of collection and storage, and determine why unsafe water sources are used when unsafe supplies are available. Forty-eight rural and forty-five urban slum households were studied. Observations, interviews and water quality investigations were conducted. The results show that the respondents were aware that hand pump/tap water is safe and took care to use these safe sources for drinking purposes. However, they continued to use surface water for non-drinking activities such as bathing, washing and rinsing their mouths. Reasons were given that it was a traditional practice to bathe in surface water and was more enjoyable. One of the reasons given for not using hand pumped water to wash clothing and food was that such groundwater caused staining. Bacteriological results from such ingested water showed the quality, especially in rural areas, to be poor. Results also showed the internal surfaces of the base of storage containers to be heavily contaminated with bacteria. This showed that water that was safe when it was first drawn would became contaminated during storage. This study had a limited scope; much further research is needed to find what determines and how water becomes contaminated in containers. These factors include how to reduce contamination of water, in particular the relationship between growth of bacteria in stored water and the material from which the container is made and how to improve the overall quality of water. On the management side, studies could be conducted as to how to improve people's understanding of the use of water for domestic purposes and its safe management.

Ground- and Surface-Water Chemistry of Handcart Gulch, Park County, Colorado, 2003-2006

USGS Publications Warehouse

Verplanck, Philip L.; Manning, Andrew H.; Kimball, Briant A.; McCleskey, R. Blaine; Runkel, Robert L.; Caine, Jonathan S.; Adams, Monique; Gemery-Hill, Pamela A.; Fey, David L.

2008-01-01

As part of a multidisciplinary project to determine the processes that control ground-water chemistry and flow in mineralized alpine environments, ground- and surface-water samples from Handcart Gulch, Colorado were collected for analysis of inorganic solutes and water and dissolved sulfate stable isotopes in selected samples. The primary aim of this study was to document variations in ground-water chemistry in Handcart Gulch and to identify changes in water chemistry along the receiving stream of Handcart Gulch. Water analyses are reported for ground-water samples collected from 12 wells in Handcart Gulch, Colorado. Samples were collected between August 2003 and October 2005. Water analyses for surface-water samples are reported for 50 samples collected from Handcart Gulch and its inflows during a low-flow tracer injection on August 6, 2003. In addition, water analyses are reported for three other Handcart Gulch stream samples collected in September 2005 and March 2006. Reported analyses include field parameters (pH, specific conductance, temperature, dissolved oxygen, and Eh), major and trace constituents, oxygen and hydrogen isotopic composition of water and oxygen and sulfur isotopic composition of dissolved sulfate. Ground-water samples from this study are Ca-SO4 type and range in pH from 2.5 to 6.8. Most of the samples (75 percent) have pH values between 3.3 and 4.3. Surface water samples are also Ca-SO4 type and have a narrower range in pH (2.7?4.0). Ground- and surface-water samples vary from relatively dilute (specific conductance of 68 ?S/cm) to concentrated (specific conductance of 2,000 ?S/cm).

The Influence of a Sandy Substrate, Seagrass, or Highly Turbid Water on Albedo and Surface Heat Flux

NASA Astrophysics Data System (ADS)

Fogarty, M. C.; Fewings, M. R.; Paget, A. C.; Dierssen, H. M.

2018-01-01

Sea-surface albedo is a combination of surface-reflected and water-leaving irradiance, but water-leaving irradiance typically contributes less than 15% of the total albedo in open-ocean conditions. In coastal systems, however, the bottom substrate or suspended particulate matter can increase the amount of backscattered light, thereby increasing albedo and decreasing net shortwave surface heat flux. Here a sensitivity analysis using observations and models predicts the effect of light scattering on albedo and the net shortwave heat flux for three test cases: a bright sand bottom, a seagrass canopy, and turbid water. After scaling to the full solar shortwave spectrum, daytime average albedo for the test cases is up to 0.20 and exceeds the value of 0.05 predicted using a commonly applied parameterization. Daytime net shortwave heat flux into the water is significantly reduced, particularly for waters with bright sediments, dense horizontal seagrass canopies < 0.25 m from the sea surface, or highly turbid waters with suspended particulate matter concentration ≥ 50 g m-3. Observations of a more vertical seagrass canopy within 0.2 and 1 m of the surface indicate the increase in albedo compared to the common parameterization is negligible. Therefore, we suggest that the commonly applied albedo lookup table can be used in coastal heat flux estimates in water as shallow as 1 m unless the bottom substrate is highly reflective or the water is highly turbid. Our model results provide guidance to researchers who need to determine albedo in highly reflective or highly turbid conditions but have no direct observations.

Physicochemical controls on absorbed water film thickness in unsaturated geological media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokunaga, T.

2011-06-14

Adsorbed water films commonly coat mineral surfaces in unsaturated soils and rocks, reducing flow and transport rates. Therefore, it is important to understand how adsorbed film thickness depends on matric potential, surface chemistry, and solution chemistry. Here, the problem of adsorbed water film thickness is examined through combining capillary scaling with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Novel aspects of this analysis include determining capillary influences on film thicknesses, and incorporating solution chemistry-dependent electrostatic potential at air-water interfaces. Capillary analysis of monodisperse packings of spherical grains provided estimated ranges of matric potentials where adsorbed films are stable, and showed that pendular ringsmore » within drained porous media retain most of the 'residual' water except under very low matric potentials. Within drained pores, capillary contributions to thinning of adsorbed films on spherical grains are shown to be small, such that DLVO calculations for flat surfaces are suitable approximations. Hamaker constants of common soil minerals were obtained to determine ranges of the dispersion component to matric potential-dependent film thickness. The pressure component associated with electrical double layer forces was estimated using the compression and linear superposition approximations. The pH-dependent electrical double layer pressure component is the dominant contribution to film thicknesses at intermediate values of matric potential, especially in lower ionic strength solutions (< 10 mol m{sup -3}) on surfaces with higher magnitude electrostatic potentials (more negative than - 50 mV). Adsorbed water films are predicted to usually range in thickness from 1 to 20 nm in drained pores and fractures of unsaturated environments.« less

Physicochemical controls on adsorbed water film thickness in unsaturated geological media

NASA Astrophysics Data System (ADS)

Tokunaga, Tetsu K.

2011-08-01

Adsorbed water films commonly coat mineral surfaces in unsaturated soils and rocks, reducing flow and transport rates. Therefore, it is important to understand how adsorbed film thickness depends on matric potential, surface chemistry, and solution chemistry. Here the problem of adsorbed water film thickness is examined by combining capillary scaling with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Novel aspects of this analysis include determining capillary influences on film thicknesses and incorporating solution chemistry-dependent electrostatic potential at air-water interfaces. Capillary analysis of monodisperse packings of spherical grains provided estimated ranges of matric potentials where adsorbed films are stable and showed that pendular rings within drained porous media retain most of the "residual" water except under very low matric potentials. Within drained pores, capillary contributions to thinning of adsorbed films on spherical grains are shown to be small, such that DLVO calculations for flat surfaces are suitable approximations. Hamaker constants of common soil minerals were obtained to determine ranges of the dispersion component to matric potential-dependent film thickness. The pressure component associated with electrical double-layer forces was estimated using the compression and linear superposition approximations. The pH-dependent electrical double-layer pressure component is the dominant contribution to film thicknesses at intermediate values of matric potential, especially in lower ionic strength solutions (<10 mol m-3) on surfaces with higher-magnitude electrostatic potentials (more negative than ≈-50 mV). Adsorbed water films are predicted to usually range in thickness from ≈1 to 20 nm in drained pores and fractures of unsaturated environments.

Monte Carlo investigation of backscatter factors for skin dose determination in interventional neuroradiology procedures

NASA Astrophysics Data System (ADS)

Omar, Artur; Benmakhlouf, Hamza; Marteinsdottir, Maria; Bujila, Robert; Nowik, Patrik; Andreo, Pedro

2014-03-01

Complex interventional and diagnostic x-ray angiographic (XA) procedures may yield patient skin doses exceeding the threshold for radiation induced skin injuries. Skin dose is conventionally determined by converting the incident air kerma free-in-air into entrance surface air kerma, a process that requires the use of backscatter factors. Subsequently, the entrance surface air kerma is converted into skin kerma using mass energy-absorption coefficient ratios tissue-to-air, which for the photon energies used in XA is identical to the skin dose. The purpose of this work was to investigate how the cranial bone affects backscatter factors for the dosimetry of interventional neuroradiology procedures. The PENELOPE Monte Carlo system was used to calculate backscatter factors at the entrance surface of a spherical and a cubic water phantom that includes a cranial bone layer. The simulations were performed for different clinical x-ray spectra, field sizes, and thicknesses of the bone layer. The results show a reduction of up to 15% when a cranial bone layer is included in the simulations, compared with conventional backscatter factors calculated for a homogeneous water phantom. The reduction increases for thicker bone layers, softer incident beam qualities, and larger field sizes, indicating that, due to the increased photoelectric crosssection of cranial bone compared to water, the bone layer acts primarily as an absorber of low-energy photons. For neurointerventional radiology procedures, backscatter factors calculated at the entrance surface of a water phantom containing a cranial bone layer increase the accuracy of the skin dose determination.

Technical note: Examining ozone deposition over seawater

EPA Science Inventory

Surface layer resistance plays an important role in determining ozone deposition velocity over sea-water and can be influenced by chemical interactions at the air-water interface. Here, we examine the effect of chemical interactions of iodide, dimethylsulfide, dissolved organic c...

Determination of glyphosate and AMPA in surface and waste water using high-performance ion chromatography coupled to inductively coupled plasma dynamic reaction cell mass spectrometry (HPIC-ICP-DRC-MS).

PubMed

Popp, Maximilian; Hann, Stephan; Mentler, Axel; Fuerhacker, Maria; Stingeder, Gerhard; Koellensperger, Gunda

2008-05-01

A novel method employing high-performance cation chromatography in combination with inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS) for the simultaneous determination of the herbicide glyphosate (N-phosphonomethylglycine) and its main metabolite aminomethyl phosphonic acid (AMPA) is presented. P was measured as (31)P(16)O(+) using oxygen as reaction gas. For monitoring the stringent target value of 0.1 μg L(-1) for glyphosate, applicable for drinking and surface water within the EU, a two-step enrichment procedure employing Chelex 100 and AG1-X8 resins was applied prior to HPIC-ICP-MS analysis. The presented approach was validated for surface water, revealing concentrations of 0.67 μg L(-1) glyphosate and 2.8 μg L(-1) AMPA in selected Austrian river water samples. Moreover, investigations at three waste water-treatment plants showed that elimination of the compounds at the present concentration levels was not straightforward. On the contrary, all investigated plant effluents showed significant amounts of both compounds. Concentration levels ranged from 0.5-2 μg L(-1) and 4-14 μg L(-1) for glyphosate and AMPA, respectively.

On-Line Derivatization Gas Chromatography Ion Trap Mass Spectrometry for Determination of Endocrine Disruptors in Surface Water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tzing, Shin-Hwa; Chang, Jia-Yaw; Ling, Yong-Chien

2004-03-31

A method has been developed for the determination of endocrine disruptors (EDs) (containing hydroxyl groups) in surface water from different sources. The surface water samples from different sites including school and local dormitory sewage effluents, lake water and river water were collected and analyzed. In this method, the pretreated sample is directly analyzed by GC-MS using on-line derivatization, where tetramethylammonium hydroxide (TMA-OH) was used as the derivatizing agent. Use of large-volume direct sample introduction (DSI) and co-injection of the sample and TMAOH avoids external contaminations as observed in conventional derivatization protocols. Additionally, the use of chemical ionization (CI) and CI-MS/MSmore » could enable detection of EDs at lower concentrations and reduce the matrices' interference thereby enhancing detection sensitivity of EDs for quantification. In this work, the use of dichloromethane as CI reagent for EDs is reported for the first time and could detect EDs to concentrations as low as 0.5 pg/mL. The recovery ranged from 74 to 112 % and the relative standard derivations for replicate analyses ranged from 5 to 17 %. We hope that this method will be applicable for routine analysis of EDs with hydroxyl functional groups.« less

Surface Properties of Al-Functionalized Mesoporous MCM-41 and the Melting Behavior of Water in Al-MCM-41 Nanopores.

PubMed

Sterczyńska, Angelina; Deryło-Marczewska, Anna; Zienkiewicz-Strzałka, Małgorzata; Śliwińska-Bartkowiak, Małgorzata; Domin, Kamila

2017-10-24

We report an experimental investigation of structural and adhesive properties for Al-containing mesoporous MCM-41 and MCM-41 surfaces. In this work, highly ordered hexagonal mesoporous structures of aluminosilica with two different Si/Al molar ratios equal to 50 and 80 and silica samples were studied; Al was incorporated into the MCM-41 structures using the direct synthesis method, with CTAB as a surfactant. The incorporation of aluminum was evidenced simultaneously without any change in the hexagonal arrangement of cylindrical mesopores. The porous materials were examined by techniques such as low-temperature nitrogen sorption, energy-dispersive spectroscopy, and scanning and transmission electron microscopy. Surface properties were determined through X-ray photoelectron spectroscopy, potentiometric titration, and static contact angle measurements. It was shown that an increase in surface acidity leads to an increase in the wetting energy of the surface. To investigate the influence of acidity on the confinement effects, the melting behavior of water in Al-MCM-41 and MCM-41 with the same pore size was determined by using dielectric relaxation spectroscopy and differential scanning calorimetry methods. We found that the melting-point depression of water in pores is larger in the functionalized pores than in pure silica pores of the same pore diameter.

Hydraulic visibility and effective cross sections based on hydrodynamical modeling of flow lines gained by satellite altimetry

NASA Astrophysics Data System (ADS)

Biancamaria, S.; Garambois, P. A.; Calmant, S.; Roux, H.; Paris, A.; Monnier, J.; Santos da Silva, J.

2015-12-01

Hydrodynamic laws predict that irregularities in a river bed geometry produce spatial and temporal variations in the water level, hence in its slope. Conversely, observation of these changes is a goal of the SWOT mission with the determination of the discharge as a final objective. In this study, we analyse the relationship between river bed undulations and water surface for an ungauged reach of the Xingu river, a first order tributary of the Amazon river. It is crosscut more than 10 times by a single ENVISAT track over a hundred of km. We have determined time series of water levelsat each of these crossings, called virtual stations (VS), hence slopes of the flow line. Using the discharge series computed by Paiva et al. (2013) between 1998 and 2009, Paris et al. (submitted) determined at each VS a rating curve relating these simulated discharge with the ENVISAT height series. One parameter of these rating curves is the zero-flow depth Z 0 . We show that it is possible to explain the spatial and temporal variations of the water surface slope in terms of hydrodynamical response of the longitudinal changes of the river bed geometry given by the successive values of Z 0 . Our experiment is based on an effective, single thread representation of a braided river, realistic values for the Manning coefficient and river widths picked up on JERS images. This study confirms that simulated flow lines are consistent with water surface elevations (WSE) and slopes gained by satellite altimetry. Hydrodynamical signatures are more visible where the river bed geometry varies significantly, and for reaches with a strong downstream control. Therefore, this study suggests that the longitudinal variations of the slope might be an interesting criteria for the question of river segmentation into elementary reaches for the SWOT mission which will provide continuous measurements of the water surface elevation, the slope and the reach width.

Modelling of surface-water temperature for the estimation of the Czech fishery productivity under the climate change

NASA Astrophysics Data System (ADS)

Svobodová, Eva; Trnka, Miroslav; Kopp, Radovan; Mareš, Jan; Dubrovský, Martin; Spurný, Petr; Žalud, Zděněk

2015-04-01

Freshwater fish production is significantly correlated with water temperature which is expected to increase under the climate change. This study is dealing with the estimation of the change of water temperature in productive ponds and its impact on the fishery in the Czech Republic. Calculation of surface-water temperature which was based on three-day mean of the air temperature was developed and tested in several ponds in three main fish production areas. Output of surface-water temperature model was compared with measured data and showed that the lower range of model accuracy is surface-water temperature 3°C, under this temperature threshold the model loses its predictive competence. In the expecting of surface-water temperature above the temperature 3°C the model has proved the well consistence between observed and modelled surface-water temperature (R 0.79 - 0.96). Verified model was applied in the conditions of climate change determined by the pattern scaling method, in which standardised scenarios were derived from five global circulation models MPEH5, CSMK3, IPCM4, GFCM21 and HADGEM. Results were evaluated with regard to thresholds which characterise the fish species requirements on water temperature. Used thresholds involved the upper temperature threshold for fish survival and the tolerable number of days in continual period with mentioned threshold surface-water temperature. Target fish species were Common carp (Cyprinus carpio), Maraene whitefish (Coregonus maraena), Northern whitefish (Coregonus peled) and Rainbow trout (Oncorhynchus mykis). Results indicated the limitation of the Czech fish-farming in terms of i) the increase of the length of continual periods with surface-water temperature above the threshold appropriate to given fish species toleration, ii) the increase of the number of continual periods with surface-water temperature above the threshold, both appropriate to given fish species toleration, and iii) the increase of overall number of days within the continual period with temperature above the threshold tolerated by given fish species. ACKNOWLEDGEMENTS: This study was funded by project "Building up a multidisciplinary scientific team focused on drought" No. CZ.1.07/2.3.00/20.0248.

Human health impacts of drinking water (surface and ground) pollution Dakahlyia Governorate, Egypt

NASA Astrophysics Data System (ADS)

Mandour, R. A.

2012-09-01

This study was done on 30 drinking tap water samples (surface and ground) and 30 urine samples taken from patients who attended some of Dakahlyia governorate hospitals. These patients were complaining of poor-quality tap water in their houses, which was confirmed by this study that drinking water is contaminated with trace elements in some of the studied areas. The aim of this study was to determine the relationship between the contaminant drinking water (surface and ground) in Dakahlyia governorate and its impact on human health. This study reports the relationship between nickel and hair loss, obviously shown in water and urine samples. Renal failure cases were related to lead and cadmium contaminated drinking water, where compatibilities in results of water and urine samples were observed. Also, liver cirrhosis cases were related to iron-contaminated drinking water. Studies of these diseases suggest that abnormal incidence in specific areas is related to industrial wastes and agricultural activities that have released hazardous and toxic materials in the drinking water and thereby led to its contamination in these areas. We conclude that trace elements should be removed from drinking water for human safety.

The herbicide glyphosate and its metabolite AMPA in the Lavaux vineyard area, western Switzerland: proof of widespread export to surface waters. Part II: the role of infiltration and surface runoff.

PubMed

Daouk, Silwan; De Alencastro, Luiz F; Pfeifer, Hans-Rudolf

2013-01-01

Two parcels of the Lavaux vineyard area, western Switzerland, were studied to assess to which extent the widely used herbicide, glyphosate, and its metabolite aminomethylphosphonic acid (AMPA) were retained in the soil or exported to surface waters. They were equipped at their bottom with porous ceramic cups and runoff collectors, which allowed retrieving water samples for the growing seasons 2010 and 2011. The role of slope, soil properties and rainfall regime in their export was examined and the surface runoff/throughflows ratio was determined with a mass balance. Our results revealed elevated glyphosate and AMPA concentrations at 60 and 80 cm depth at parcel bottoms, suggesting their infiltration in the upper parts of the parcels and the presence of preferential flows in the studied parcels. Indeed, the succession of rainy days induced the gradual saturation of the soil porosity, leading to rapid infiltration through macropores, as well as surface runoff formation. Furthermore, the presence of more impervious weathered marls at 100 cm depth induced throughflows, the importance of which in the lateral transport of the herbicide molecules was determined by the slope steepness. Mobility of glyphosate and AMPA into the unsaturated zone was thus likely driven by precipitation regime and soil characteristics, such as slope, porosity structure and layer permeability discrepancy. Important rainfall events (>10 mm/day) were clearly exporting molecules from the soil top layer, as indicated by important concentrations in runoff samples. The mass balance showed that total loss (10-20%) mainly occurred through surface runoff (96%) and, to a minor extent, by throughflows in soils (4%), with subsequent exfiltration to surface waters.

A sensitive multi-residue method for the determination of 35 micropollutants including pharmaceuticals, iodinated contrast media and pesticides in water.

PubMed

Valls-Cantenys, Carme; Scheurer, Marco; Iglesias, Mònica; Sacher, Frank; Brauch, Heinz-Jürgen; Salvadó, Victoria

2016-09-01

A sensitive, multi-residue method using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed to determine a representative group of 35 analytes, including corrosion inhibitors, pesticides and pharmaceuticals such as analgesic and anti-inflammatory drugs, five iodinated contrast media, β-blockers and some of their metabolites and transformation products in water samples. Few other methods are capable of determining such a broad range of contrast media together with other analytes. We studied the parameters affecting the extraction of the target analytes, including sorbent selection and extraction conditions, their chromatographic separation (mobile phase composition and column) and detection conditions using two ionisation sources: electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI). In order to correct matrix effects, a total of 20 surrogate/internal standards were used. ESI was found to have better sensitivity than APCI. Recoveries ranging from 79 to 134 % for tap water and 66 to 144 % for surface water were obtained. Intra-day precision, calculated as relative standard deviation, was below 34 % for tap water and below 21 % for surface water, groundwater and effluent wastewater. Method quantification limits (MQL) were in the low ng L(-1) range, except for the contrast agents iomeprol, amidotrizoic acid and iohexol (22, 25.5 and 17.9 ng L(-1), respectively). Finally, the method was applied to the analysis of 56 real water samples as part of the validation procedure. All of the compounds were detected in at least some of the water samples analysed. Graphical Abstract Multi-residue method for the determination of micropollutants including pharmaceuticals, iodinated contrast media and pesticides in waters by LC-MS/MS.

Acid-base accounting to predict post-mining drainage quality on surface mines.

PubMed

Skousen, J; Simmons, J; McDonald, L M; Ziemkiewicz, P

2002-01-01

Acid-base accounting (ABA) is an analytical procedure that provides values to help assess the acid-producing and acid-neutralizing potential of overburden rocks prior to coal mining and other large-scale excavations. This procedure was developed by West Virginia University scientists during the 1960s. After the passage of laws requiring an assessment of surface mining on water quality, ABA became a preferred method to predict post-mining water quality, and permitting decisions for surface mines are largely based on the values determined by ABA. To predict the post-mining water quality, the amount of acid-producing rock is compared with the amount of acid-neutralizing rock, and a prediction of the water quality at the site (whether acid or alkaline) is obtained. We gathered geologic and geographic data for 56 mined sites in West Virginia, which allowed us to estimate total overburden amounts, and values were determined for maximum potential acidity (MPA), neutralization potential (NP), net neutralization potential (NNP), and NP to MPA ratios for each site based on ABA. These values were correlated to post-mining water quality from springs or seeps on the mined property. Overburden mass was determined by three methods, with the method used by Pennsylvania researchers showing the most accurate results for overburden mass. A poor relationship existed between MPA and post-mining water quality, NP was intermediate, and NNP and the NP to MPA ratio showed the best prediction accuracy. In this study, NNP and the NP to MPA ratio gave identical water quality prediction results. Therefore, with NP to MPA ratios, values were separated into categories: <1 should produce acid drainage, between 1 and 2 can produce either acid or alkaline water conditions, and >2 should produce alkaline water. On our 56 surface mined sites, NP to MPA ratios varied from 0.1 to 31, and six sites (11%) did not fit the expected pattern using this category approach. Two sites with ratios <1 did not produce acid drainage as predicted (the drainage was neutral), and four sites with a ratio >2 produced acid drainage when they should not have. These latter four sites were either mined very slowly, had nonrepresentative ABA data, received water from an adjacent underground mine, or had a surface mining practice that degraded the water. In general, an NP to MPA ratio of <1 produced mostly acid drainage sites, between 1 and 2 produced mostly alkaline drainage sites, while NP to MPA ratios >2 produced alkaline drainage with a few exceptions. Using these values, ABA is a good tool to assess overburden quality before surface mining and to predict post-mining drainage quality after mining. The interpretation from ABA values was correct in 50 out of 52 cases (96%), excluding the four anomalous sites, which had acid water for reasons other than overburden quality.

Comparison of a vertically-averaged and a vertically-resolved model for hyporheic flow beneath a pool-riffle bedform

NASA Astrophysics Data System (ADS)

Ibrahim, Ahmad; Steffler, Peter; She, Yuntong

2018-02-01

The interaction between surface water and groundwater through the hyporheic zone is recognized to be important as it impacts the water quantity and quality in both flow systems. Three-dimensional (3D) modeling is the most complete representation of a real-world hyporheic zone. However, 3D modeling requires extreme computational power and efforts; the sophistication is often significantly compromised by not being able to obtain the required input data accurately. Simplifications are therefore often needed. The objective of this study was to assess the accuracy of the vertically-averaged approximation compared to a more complete vertically-resolved model of the hyporheic zone. The groundwater flow was modeled by either a simple one-dimensional (1D) Dupuit approach or a two-dimensional (2D) horizontal/vertical model in boundary fitted coordinates, with the latter considered as a reference model. Both groundwater models were coupled with a 1D surface water model via the surface water depth. Applying the two models to an idealized pool-riffle sequence showed that the 1D Dupuit approximation gave comparable results in determining the characteristics of the hyporheic zone to the reference model when the stratum thickness is not very large compared to the surface water depth. Conditions under which the 1D model can provide reliable estimate of the seepage discharge, upwelling/downwelling discharges and locations, the hyporheic flow, and the residence time were determined.

Fluxes of Ethanol Between the Atmosphere and Oceanic Surface Waters; Implications for the Fate of Biofuel Ethanol Released into the Environment

NASA Astrophysics Data System (ADS)

Avery, G. B., Jr.; Shimizu, M. S.; Willey, J. D.; Mead, R. N.; Skrabal, S. A.; Kieber, R. J.; Lathrop, T. E.; Felix, J. D. D.

2017-12-01

The use of ethanol as a transportation fuel has increased significantly during the past decade in the US. Some ethanol escapes the combustion process in internal combustion engines resulting in its release to the atmosphere. Ethanol can be oxidized photochemically to acetaldehyde and then converted to peroxyacetyl nitrate contributing to air pollution. Therefore it is important to determine the fate ethanol released to the atmosphere. Because of its high water solubility the oceans may act as a sink for ethanol depending on its state of saturation with respect to the gas phase. The purpose of the current study was to determine the relative saturation of oceanic surface waters by making simultaneous measurements of gas phase and surface water concentrations. Data were obtained from four separate cruises ranging from estuarine to open ocean locations in the coast of North Carolina, USA. The majority of estuarine sites were under saturated in ethanol with respect to the gas phase (11-50% saturated) representing a potential sink. Coastal surface waters tended to be supersaturated (135 - 317%) representing a net flux of ethanol to the atmosphere. Open ocean samples were generally at saturation or slightly below saturation (76-99%) indicating equilibrium between the gas and aqueous phases. The results of this study underscore to variable role the oceans play in mitigating the increases in atmospheric ethanol from increased biofuel usage and their impact on air quality.

Adsorption of Eu(III) onto roots of water hyacinth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelley, C.; Mielke, R.E.; Dimaquibo, D.

1999-05-01

The water hyacinth (Eichhornia crassipes) has drawn attention as a plant capable of removing pollutants, including toxic metals, from water. The authors are interested in the capacity of the water hyacinth to remediate aquatic environments that have been contaminated with the lanthanide metal, europium Eu(III). Using scanning electron microscopy (SEM) they have been able to determine that Eu(III) is adsorbed onto the surface of the roots from water and that the highest concentration of Eu(III) is on the root hairs. X-ray absorption spectroscopy (XAS) techniques were used to speciate the Eu(III) adsorbed onto the surface of the roots. The XASmore » data for Eu-contaminated water hyacinth roots provides evidence of a Eu-oxygen environment and establishes that Eu(III) is coordinated to 10--11 oxygen atoms at a distance of 2.44 {angstrom}. This likely involves binding of Eu(III) to the root via carboxylate groups and hydration of Eu(III) at the root surface.« less

Slowly biodegradable organic compounds impact the biostability of non-chlorinated drinking water produced from surface water.

PubMed

Hijnen, W A M; Schurer, R; Bahlman, J A; Ketelaars, H A M; Italiaander, R; van der Wal, A; van der Wielen, P W J J

2018-02-01

It is possible to distribute drinking water without a disinfectant residual when the treated water is biologically stable. The objective of this study was to determine the impact of easily and slowly biodegradable compounds on the biostability of the drinking water at three full-scale production plants which use the same surface water, and on the regrowth conditions in the related distribution systems. Easily biodegradable compounds in the drinking water were determined with AOC-P17/Nox during 2012-2015. Slowly biodegradable organic compounds measured as particulate and/or high-molecular organic carbon (PHMOC), were monitored at the inlet and after the different treatment stages of the three treatments during the same period. The results show that PHMOC (300-470 μg C L -1 ) was approximately 10% of the TOC in the surface water and was removed to 50-100 μg C L -1 . The PHMOC in the water consisted of 40-60% of carbohydrates and 10% of proteins. A significant and strong positive correlation was observed for PHMOC concentrations and two recently introduced bioassay methods for slowly biodegradable compounds (AOC-A3 and biomass production potential, BPC 14 ). Moreover, these three parameters in the biological active carbon effluent (BACF) of the three plants showed a positive correlation with regrowth in the drinking water distribution system, which was assessed with Aeromonas, heterotrophic plate counts, coliforms and large invertebrates. In contrast, the AOC-P17/Nox concentrations did not correlate with these regrowth parameters. We therefore conclude that slowly biodegradable compounds in the treated water from these treatment plants seem to have a greater impact on regrowth in the distribution system than easily biodegradable compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of Gas Potential in the Niobrara Formation, Rosebud Reservation, South Dakota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Aubrey E.; Hopkinson, Leslie; Soeder, Daniel

2016-01-23

Surface water and groundwater risks associated with unconventional oil and gas development result from potential spills of the large volumes of chemicals stored on-site during drilling and hydraulic fracturing operations, and the return to the surface of significant quantities of saline water produced during oil or gas well production. To better identify and mitigate risks, watershed models and tools are needed to evaluate the dispersion of pollutants in possible spill scenarios. This information may be used to determine the placement of in-stream water-quality monitoring instruments and to develop early-warning systems and emergency plans. A chemical dispersion model has been usedmore » to estimate the contaminant signal for in-stream measurements. Spills associated with oil and gas operations were identified within the Susquehanna River Basin Commission’s Remote Water Quality Monitoring Network. The volume of some contaminants was found to be sufficient to affect the water quality of certain drainage areas. The most commonly spilled compounds and expected peak concentrations at monitoring stations were used in laboratory experiments to determine if a signal could be detected and positively identified using standard water-quality monitoring equipment. The results were compared to historical data and baseline observations of water quality parameters, and showed that the chemicals tested do commonly affect water quality parameters. This work is an effort to demonstrate that hydrologic and water quality models may be applied to improve the placement of in-stream water quality monitoring devices. This information may increase the capability of early-warning systems to alert community health and environmental agencies of surface water spills associated with unconventional oil and gas operations.« less

Removal of surface-reflected light for the measurement of remote-sensing reflectance from an above-surface platform.

PubMed

Lee, Zhongping; Ahn, Yu-Hwan; Mobley, Curtis; Arnone, Robert

2010-12-06

Using hyperspectral measurements made in the field, we show that the effective sea-surface reflectance ρ (defined as the ratio of the surface-reflected radiance at the specular direction corresponding to the downwelling sky radiance from one direction) varies not only for different measurement scans, but also can differ by a factor of 8 between 400 nm and 800 nm for the same scan. This means that the derived water-leaving radiance (or remote-sensing reflectance) can be highly inaccurate if a spectrally constant ρ value is applied (although errors can be reduced by carefully filtering measured raw data). To remove surface-reflected light in field measurements of remote sensing reflectance, a spectral optimization approach was applied, with results compared with those from remote-sensing models and from direct measurements. The agreement from different determinations suggests that reasonable results for remote sensing reflectance of clear blue water to turbid brown water are obtainable from above-surface measurements, even under conditions of high waves.

Remotely Sensed Based Lake/Reservoir Routing in Congo River Basin

NASA Astrophysics Data System (ADS)

Raoufi, R.; Beighley, E.; Lee, H.

2017-12-01

Lake and reservoir dynamics can influence local to regional water cycles but are often not well represented in hydrologic models. One challenge that limits their inclusion in models is the need for detailed storage-discharge behavior that can be further complicated in reservoirs where specific operation rules are employed. Here, the Hillslope River Routing (HRR) model is combined with a remotely sensed based Reservoir Routing (RR) method and applied to the Congo River Basin. Given that topographic data are often continuous over the entire terrestrial surface (i.e., does not differentiate between land and open water), the HRR-RR model integrates topographic derived river networks and catchment boundaries (e.g., HydroSHEDs) with water boundary extents (e.g., Global Lakes and Wetlands Database) to develop the computational framework. The catchments bordering lakes and reservoirs are partitioned into water and land portions, where representative flowpath characteristics are determined and vertical water balance and lateral routings is performed separately on each partition based on applicable process models (e.g., open water evaporation vs. evapotranspiration). To enable reservoir routing, remotely sensed water surface elevations and extents are combined to determine the storage change time series. Based on the available time series, representative storage change patterns are determined. Lake/reservoir routing is performed by combining inflows from the HRR-RR model and the representative storage change patterns to determine outflows. In this study, a suite of storage change patterns derived from remotely sensed measurements are determined representative patterns for wet, dry and average conditions. The HRR-RR model dynamically selects and uses the optimal storage change pattern for the routing process based on these hydrologic conditions. The HRR-RR model results are presented to highlight the importance of lake attenuation/routing in the Congo Basin.

GC/MS analysis of pesticides in the Ferrara area (Italy) surface water: a chemometric study.

PubMed

Pasti, Luisa; Nava, Elisabetta; Morelli, Marco; Bignami, Silvia; Dondi, Francesco

2007-01-01

The development of a network to monitor surface waters is a critical element in the assessment, restoration and protection of water quality. In this study, concentrations of 42 pesticides--determined by GC-MS on samples from 11 points along the Ferrara area rivers--have been analyzed by chemometric tools. The data were collected over a three-year period (2002-2004). Principal component analysis of the detected pesticides was carried out in order to define the best spatial locations for the sampling points. The results obtained have been interpreted in view of agricultural land use. Time series data regarding pesticide contents in surface waters has been analyzed using the Autocorrelation function. This chemometric tool allows for seasonal trends and makes it possible to optimize sampling frequency in order to detect the effective maximum pesticide content.

Method for estimating potential wetland extent by utilizing streamflow statistics and flood-inundation mapping techniques: Pilot study for land along the Wabash River near Terre Haute, Indiana

USGS Publications Warehouse

Kim, Moon H.; Ritz, Christian T.; Arvin, Donald V.

2012-01-01

Potential wetland extents were estimated for a 14-mile reach of the Wabash River near Terre Haute, Indiana. This pilot study was completed by the U.S. Geological Survey in cooperation with the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS). The study showed that potential wetland extents can be estimated by analyzing streamflow statistics with the available streamgage data, calculating the approximate water-surface elevation along the river, and generating maps by use of flood-inundation mapping techniques. Planning successful restorations for Wetland Reserve Program (WRP) easements requires a determination of areas that show evidence of being in a zone prone to sustained or frequent flooding. Zone determinations of this type are used by WRP planners to define the actively inundated area and make decisions on restoration-practice installation. According to WRP planning guidelines, a site needs to show evidence of being in an "inundation zone" that is prone to sustained or frequent flooding for a period of 7 consecutive days at least once every 2 years on average in order to meet the planning criteria for determining a wetland for a restoration in agricultural land. By calculating the annual highest 7-consecutive-day mean discharge with a 2-year recurrence interval (7MQ2) at a streamgage on the basis of available streamflow data, one can determine the water-surface elevation corresponding to the calculated flow that defines the estimated inundation zone along the river. By using the estimated water-surface elevation ("inundation elevation") along the river, an approximate extent of potential wetland for a restoration in agricultural land can be mapped. As part of the pilot study, a set of maps representing the estimated potential wetland extents was generated in a geographic information system (GIS) application by combining (1) a digital water-surface plane representing the surface of inundation elevation that sloped in the downstream direction of flow and (2) land-surface elevation data. These map products from the pilot study will aid the NRCS and its partners with the onsite inundation-zone verification in agricultural land for a potential restoration and will assist in determining at what elevation to plant hardwood trees for increased survivability on ground above frequently flooded terraces.

Semi-permeable surface analytical reversed-phase column for the improved trace analysis of acidic pesticides in water with coupled-column reversed-phase liquid chromatography with UV detection. Determination of bromoxynil and bentazone in surface water.

PubMed

Hogendoorn, E A; Westhuis, K; Dijkman, E; Heusinkveld, H A; den Boer, A C; Evers, E A; Baumann, R A

1999-10-08

The coupled-column (LC-LC) configuration consisting of a 3 microm C18 column (50 x 4.6 mm I.D.) as the first column and a 5 microm C18 semi-permeable-surface (SPS) column (150 x 4.6 mm I.D.) as the second column appeared to be successful for the screening of acidic pesticides in surface water samples. In comparison to LC-LC employing two C18 columns, the combination of C18/SPS-C18 significantly decreased the baseline deviation caused by the hump of the co-extracted humic substances when using UV detection (217 nm). The developed LC-LC procedure allowed the simultaneous determination of the target analytes bentazone and bromoxynil in uncleaned extracts of surface water samples to a level of 0.05 microg/l in less than 15 min. In combination with a simple solid-phase extraction step (200 ml of water on a 500 mg C18-bonded silica) the analytical procedure provides a high sample throughput. During a period of about five months more than 200 ditch-water samples originating from agricultural locations were analyzed with the developed procedure. Validation of the method was performed by randomly analyzing recoveries of water samples spiked at levels of 0.1 microg/l (n=10), 0.5 microg/l (n=7) and 2.5 microg/l (n=4). Weighted regression of the recovery data showed that the method provides overall recoveries of 95 and 100% for bentazone and bromoxynil, respectively, with corresponding intra-laboratory reproducibilities of 10 and 11%, respectively. Confirmation of the analytes in part of the samples extracts was carried out with GC-negative ion chemical ionization MS involving a derivatization step with bis(trifluoromethyl)benzyl bromide. No false negatives or positives were observed.

Adsorption and solvation of ethanol at the water liquid-vapor interface: a molecular dynamics study

NASA Technical Reports Server (NTRS)

Wilson, M. A.; Pohorille, A.

1997-01-01

The free energy profiles of methanol and ethanol at the water liquid-vapor interface at 310K were calculated using molecular dynamics computer simulations. Both alcohols exhibit a pronounced free energy minimum at the interface and, therefore, have positive adsorption at this interface. The surface excess was computed from the Gibbs adsorption isotherm and was found to be in good agreement with experimental results. Neither compound exhibits a free energy barrier between the bulk and the surface adsorbed state. Scattering calculations of ethanol molecules from a gas phase thermal distribution indicate that the mass accommodation coefficient is 0.98, and the molecules become thermalized within 10 ps of striking the interface. It was determined that the formation of the solvation structure around the ethanol molecule at the interface is not the rate-determining step in its uptake into water droplets. The motion of an ethanol molecule in a water lamella was followed for 30 ns. The time evolution of the probability distribution of finding an ethanol molecule that was initially located at the interface is very well described by the diffusion equation on the free energy surface.

Molecular origins of fluorocarbon hydrophobicity

PubMed Central

Dalvi, Vishwanath H.; Rossky, Peter J.

2010-01-01

We have undertaken atomistic molecular simulations to systematically determine the structural contributions to the hydrophobicity of fluorinated solutes and surfaces compared to the corresponding hydrocarbon, yielding a unified explanation for these phenomena. We have transformed a short chain alkane, n-octane, to n-perfluorooctane in stages. The free-energy changes and the entropic components calculated for each transformation stage yield considerable insight into the relevant physics. To evaluate the effect of a surface, we have also conducted contact-angle simulations of water on self-assembled monolayers of hydrocarbon and fluorocarbon thiols. Our results, which are consistent with experimental observations, indicate that the hydrophobicity of the fluorocarbon, whether the interaction with water is as solute or as surface, is due to its “fatness.” In solution, the extra work of cavity formation to accommodate a fluorocarbon, compared to a hydrocarbon, is not offset by enhanced energetic interactions with water. The enhanced hydrophobicity of fluorinated surfaces arises because fluorocarbons pack less densely on surfaces leading to poorer van der Waals interactions with water. We find that interaction of water with a hydrophobic solute/surface is primarily a function of van der Waals interactions and is substantially independent of electrostatic interactions. This independence is primarily due to the strong tendency of water at room temperature to maintain its hydrogen bonding network structure at an interface lacking hydrophilic sites. PMID:20643968

Water-Use Estimates for West Virginia, 2004

USGS Publications Warehouse

Atkins, John T.

2007-01-01

This study estimates the quantity of surface water and ground water used within West Virginia. About 4,787 million gallons per day (Mgal/d) of water were withdrawn from West Virginia surface-water and ground-water sources in 2004, with about 4,641 Mgal/d (97 percent) from surface-water sources and about 146 Mgal/d (3 percent) from ground water sources. The largest surface-water withdrawals were in Grant and Mason Counties and were about 1,156 and 1,090 Mgal/d, respectively. The largest ground-water withdrawals were in Berkeley and Wood Counties and were about 12.0 and 12.8 Mgal/d, respectively. Estimates were determined for surface-water and ground-water withdrawals in seven water-use categories: public supply, domestic, thermoelectric power, industrial, irrigation, commercial, and mining. Instream water uses, including hydroelectric power generation, were not considered. Total withdrawals for public supply were 189 Mgal/d, of which 152 Mgal/d were from surface-water sources and 37 Mgal/d were from ground-water sources. Kanawha County withdrew 34 Mgal/d of surface water for public supply, which is more than any other county in the state. Wood County withdrew more ground water for public supply than any other county in the state, about 7.59 Mgal/d. The total domestic (non-publicly supplied) water withdrawal was estimated at 33.5 Mgal/d, with 98 percent from ground water and 2 percent from surface water. There were 17 fossil-fuel, steam-generating thermoelectric power plants operated in the state, 10 plants with once-through cooling systems and 7 plants with recirculation cooling systems. Thermoelectric power used the greatest amount of water compared to the other water-use categories, and water withdrawal from surface-water sources was about 3,406 Mgal/d for plants with once-through cooling systems and about 145 Mgal/d for plants with recirculation cooling systems. Only a trace of water was withdrawn from ground-water sources for plants with once-through cooling systems and about 0.20 Mgal/d for plants with recirculation cooling systems. Water withdrawal by industries was about 911 Mgal/d from surface-water sources and about 54 Mgal/d from ground-water sources. West Virginia had the lowest estimated irrigation of any state or territory of the United States, with only about 0.036 Mgal/d withdrawn from surface-water sources and 0.036 Mgal/d withdrawn from ground-water sources. Water withdrawal for commercial use was about 16.7 Mgal/d from surface-water sources and about 16.0 Mgal/d from ground-water sources. Water withdrawal for mining was about 9.78 Mgal/d from surface-water sources and about 4.89 Mgal/d from ground-water sources. The proportions of surface-water and ground-water withdrawals were similar in 1995 and 2004 (at about 3 percent ground water). Public-supply withdrawal for 2004 was about the same as for 2000 and 7 percent greater than the 1995 estimate. Domestic withdrawal for 2004 was about 18 percent less than the 1995 estimate. Withdrawal for thermoelectric power for 2004 was about 10 percent less than the 2000 estimate and about 18 percent greater than the 1995 estimate. Industrial withdrawal for 2004 was about 27 percent less than the estimate for 1995 and about the same as the estimate for 2000. Irrigation withdrawal for 2004 was about double that estimated for 2000. Commercial withdrawal for 2004 was down 28 percent from 1995. Mining withdrawals for 2004 were about 31 and 32 percent greater for surface and ground water, respectively, than estimates for 1995.

The polarization of light in coastal and open oceans: Reflection and transmission by the air-sea interface and application for the retrieval of water optical properties

NASA Astrophysics Data System (ADS)

Foster, Robert

For decades, traditional remote sensing retrieval methods that rely solely on the spectral intensity of the water-leaving light have provided indicators of aquatic ecosystem health. With the increasing demand for new water quality indicators and improved accuracy of existing ones, the limits of traditional remote sensing approaches are becoming apparent. Use of the additional information intrinsic to the polarization state of light is therefore receiving more attention. One of the major challenges inherent in any above-surface determination of the water-leaving radiance, scalar or vector, is the removal of extraneous light which has not interacted with the water body and is therefore not useful for remote sensing of the water itself. Due in-part to the lack of a proven alternative, existing polarimeter installations have thus far assumed that such light was reflected by a flat sea surface, which can lead to large inaccuracies in the water-leaving polarization signal. This dissertation rigorously determines the full Mueller matrices for both surface-reflected skylight and upwardly transmitted light by a wind-driven ocean surface. A Monte Carlo code models the surface in 3D and performs polarized ray-tracing, while a vector radiative transfer (VRT) simulation generates polarized light distributions from which the initial Stokes vector for each ray is inferred. Matrices are computed for the observable range of surface wind speeds, viewing and solar geometries, and atmospheric aerosol loads. Radiometer field-of-view effects are also assessed. Validation of the results is achieved using comprehensive VRT simulations of the atmosphere-ocean system based on several oceanographic research cruises and specially designed polarimeters developed by the City College of New York: one submerged beneath the surface and one mounted on a research vessel. When available, additional comparisons are made at 9 km altitude with the NASA Research Scanning Polarimeter (RSP). Excellent agreement is achieved between all instrumentation, demonstrating the accuracy of the modeling approach and validating the computed Mueller matrices. Further, the results are used to demonstrate the feasibility for polarimetric retrieval of the total attenuation coefficient for Case II waters, a feat which is not possible using scalar remote sensing methods.

Interaction of poly(ethylene-glycols) with air-water interfaces and lipid monolayers: investigations on surface pressure and surface potential.

PubMed Central

Winterhalter, M; Bürner, H; Marzinka, S; Benz, R; Kasianowicz, J J

1995-01-01

We have characterized the surface activity of different-sized poly(ethylene-glycols) (PEG; M(r) 200-100,000 Da) in the presence or absence of lipid monolayers and over a wide range of bulk PEG concentrations (10(-8)-10% w/v). Measurements of the surface potential and surface pressure demonstrate that PEGs interact with the air-water and lipid-water interfaces. Without lipid, PEG added either to the subphase or to the air-water interface forms relatively stable monolayers. Except for very low molecular weight polymers (PEGs < 1000 Da), low concentrations of PEG in the subphase (between 10(-5) and 10(-4)% w/v) increase the surface potential from zero (with respect to the potential of a pure air-water interface) to a plateau value of approximately 440 mV. At much higher polymer concentrations, > 10(-1)% (w/v), depending on the molecular weight of the PEG and corresponding to the concentration at which the polymers in solution are likely to overlap, the surface potential decreases. High concentrations of PEG in the subphase cause a similar decrease in the surface potential of densely packed lipid monolayers spread from either diphytanoyl phosphatidylcholine (DPhPC), dipalmitoyl phosphatidylcholine (DPPC), or dioleoyl phosphatidylserine (DOPS). Adding PEG as a monolayer at the air-water interface also affects the surface activity of DPhPC or DPPC monolayers. At low lipid concentration, the surface pressure and potential are determined by the polymer. For intermediate lipid concentrations, the surface pressure-area and surface potential-area isotherms show that the effects due to lipid and PEG are not always additive and that the polymer's effect is distinct for the two lipids. When PEG-lipid-mixed monolayers are compressed to surface pressures greater than the collapse pressure for a PEG monolayer, the surface pressure-area and surface potential-area isotherms approach that of the lipid alone, suggesting that for this experimental condition PEG is expelled from the interface. PMID:8534807

Simulation of hydraulic characteristics in the white sturgeon spawning habitat of the Kootenai River near Bonners Ferry, Idaho

USGS Publications Warehouse

Berenbrock, Charles

2005-01-01

Hydraulic characterization of the Kootenai River, especially in the white sturgeon spawning habitat reach, is needed by the Kootenai River White Sturgeon Recovery Team to promote hydraulic conditions that improve spawning conditions for the white sturgeon (Acipenser transmontanus) in the Kootenai River. The decreasing population and spawning failure of white sturgeon has led to much concern. Few wild juvenile sturgeons are found in the river today. Determining the location of the transition between backwater and free-flowing water in the Kootenai River is a primary focus for biologists who believe that hydraulic changes at the transition affect the location where the sturgeon choose to spawn. The Kootenai River begins in British Columbia, Canada, and flows through Montana, Idaho, and back into British Columbia. The 65.6-mile reach of the Kootenai River in Idaho was studied. The study area encompasses the white sturgeon spawning reach that has been designated as a critical habitat. A one-dimensional hydraulic-flow model of the study reach was developed, calibrated, and used to develop relations between hydraulic characteristics and water-surface elevation, discharge, velocity, and backwater extent. The model used 164 cross sections, most of which came from a previous river survey conducted in 2002-03. The model was calibrated to water-surface elevations at specific discharges at five gaging stations. Calibrated water-surface elevations ranged from about 1,743 to about 1,759 feet, and discharges used in calibration ranged from 5,000 to 47,500 cubic feet per second. Model calibration was considered acceptable when the difference between measured and simulated water-surface elevations was ?0.15 foot or less. Measured and simulated average velocities also were compared. These comparisons indicated agreement between measured and simulated values. The location of the transition between backwater and free-flowing water was determined using the calibrated model. The model was used to simulate hydraulic characteristics for a range of water-surface elevations from 1,741 to 1,762 feet and discharges from 4,000 to 75,000 cubic feet per second. These simulated hydraulic characteristics were used to develop a three-parameter relation-discharge in the study reach, water-surface elevation at Kootenai River at Porthill gaging station (12322000), and the location of the transition between backwater and free-flowing water. Simulated hydraulic characteristics produced backwater locations ranging from river mile (RM) 105.6 (Porthill) to RM 158 (near Crossport), a span of about 52 miles. However, backwater locations from measured data ranged primarily from RM 152 to RM 157, a 5-mile span. The average backwater location from measured data was at about RM 154. Three-parameter relations also were developed for determining the amount of discharge in the Shorty Island side channel and average velocity at selected cross sections in the study reach. Simulated discharge for the side channel relative to measured data ranged from 0 to about 5,500 cubic feet per second, and simulated average velocity relative to measured data ranged from 0 to about 3.5 feet per second. Relations using other hydraulic, sediment/incipient motion, ecological, and biological characteristics also could be developed. The relations also can be used in real time by accessing data from the Web. Discharge and stage data for two gaging stations, Tribal Hatchery (12310100) and Porthill (12322500), are available from the Idaho U.S. Geological Survey web page (URL: http://waterdata.usgs.gov/id/nwis/current/?type=flow). Because the coordinate axes of the three-parameter relations use discharge from the Tribal Hatchery gaging station and water-surface elevation from the Porthill gaging station, the location of the transition between backwater and free-flowing water can be determined for current conditions using the real-time data. Similarly, discharge in the Shorty Island side channel and (or) average velocity at selected cross sections also can be determined for current conditions.

Northern Regions of Russia as Alternative Sources of Pure Water for Sustainable Development: Challenges and Solutions

NASA Astrophysics Data System (ADS)

Tsukerman, V. A.; Gudkov, A. V.; Ivanov, S. V.

The paper discusses problems associated with the existing crisis of water scarcity in the modern conditions of the global water use. Available alternative sources of fresh water may be underground and surface waters of the North and the Arctic. Investigated the current situation and condition of fresh water resources in the technological and industrial development of the North and Arctic. The necessity of developing and using green technologies and measures to prevent pollution of surface and ground water from industrial sectors of the Northern regions is shown. Studied modern technologies and techniques for monitoring groundwater and determination of their age in order to avoid and prevent the effects of environmental contaminants. The ways of use of innovative production technologies of fresh and clean water of north Russia for sustainable development, and delivery of water in the needy regions of the world are investigated.

Road impacts on the Baca National Wildlife Refuge, Colorado, with emphasis on effects to surface- and shallow ground-water hydrology - A literature review

USGS Publications Warehouse

Andersen, Douglas C.

2007-01-01

A review of published research on unpaved road effects on surface-water and shallow ground-water hydrology was undertaken to assist the Baca National Wildlife Refuge, Colorado, in understanding factors potentially influencing refuge ecology. Few studies were found that addressed hydrological effects of roads on a comparable area of shallow slope in a semiarid region. No study dealt with road effects on surface- and ground-water supplies to ephemeral wetlands, which on the refuge are sustained by seasonal snowmelt in neighboring mountains. Road surfaces increase runoff, reduce infiltration, and serve as a sediment source. Roadbeds can interfere with normal surface- and ground-water flows and thereby influence the quantity, timing, and duration of water movement both across landscapes and through the soil. Hydrologic effects can be localized near the road as well as widespread and distant. The number, arrangement, and effectiveness of road-drainage structures (culverts and other devices) largely determine the level of hydrologic alteration produced by a road. Undesirable changes to natural hydrologic patterns can be minimized by considering potential impacts during road design, construction, and maintenance. Road removal as a means to restore desirable hydrologic conditions to landscapes adversely affected by roads has yet to be rigorously evaluated.

Radiolytic stability of gibbsite and boehmite with adsorbed water

NASA Astrophysics Data System (ADS)

Huestis, Patricia; Pearce, Carolyn I.; Zhang, X.; N'Diaye, Alpha T.; Rosso, Kevin M.; LaVerne, Jay A.

2018-04-01

Aluminum oxyhydroxide (boehmite, AlOOH) and aluminum hydroxide (gibbsite, Al(OH)3) powders with adsorbed water were irradiated with γ-rays and 5 MeV He ions (α-particles) in order to determine overall radiation stability and chemical modification to the surface. No variation in overall phase or crystallinity due to radiolysis was observed with X-ray diffraction (XRD) and Raman spectroscopy for doses up to 2 MGy with γ-rays and 175 MGy with α-particles. Temperature programed desorption (TPD) of the water from the surface to the gas phase indicated that the water was chemisorbed and strongly bound. Water adsorption sites are of similar energy for both gibbsite and boehmite. Observation of the water adsorbed on the surface of gibbsite and boehmite with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed broad peaks at 3100-3600 cm-1 due to OH stretching that slowly decreased on heating to 500 °C, which corresponds well with the water vapor evolution observed with TPD. Both materials were found to be amorphous following heating to 500 °C. X-ray photoelectron spectroscopy (XPS) indicated surface reduction of Al(III) to Al metal on radiolysis with α-particles. Complete loss of chemisorbed water and the formation of bulk O atoms was observed following radiolysis with α-particles.

Radiolytic stability of gibbsite and boehmite with adsorbed water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huestis, Patricia; Pearce, Carolyn I.; Zhang, X.

Aluminum oxyhydroxide (boehmite, AlOOH) and aluminum hydroxide (gibbsite, Al(OH)3) powders with adsorbed water were irradiated with -rays and 5 MeV He ions (α-particles) in order to determine overall radiation stability and chemical modification to the surface. No variation in overall phase or crystallinity due to radiolysis was observed with X-ray diffraction (XRD) and Raman spectroscopy for doses up to 2 MGy with -rays and 175 MGy with α-particles. Temperature programed desorption (TPD) of the water from the surface to the gas phase indicated that the water was chemisorbed and strongly bound. Water adsorption sites are of similar energy for bothmore » gibbsite and boehmite. Observation of the water adsorbed on the surface of gibbsite and boehmite with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed broad peaks at 3100-3600 cm-1 due to OH stretching that slowly decreased on heating to 500oC, which corresponds well with the water vapor evolution observed with TPD. Both materials were found to be amorphous following heating to 500oC. X-ray photoelectron spectroscopy (XPS) indicated surface reduction of Al(III) to Al metal on radiolysis with α-particles. Complete loss of chemisorbed water and the formation of bulk O atoms was observed following radiolysis with α-particles.« less

High-resolution mapping of global surface water and its long-term changes

NASA Astrophysics Data System (ADS)

Pekel, J. F.; Cottam, A.; Gorelick, N.; Belward, A.

2016-12-01

The location and persistence of surface water is both affected by climate and human activity and affects climate, biological diversity and human wellbeing. Global datasets documenting surface water location and seasonality have been produced but measuring long-term changes at high resolution remains a challenge.To address the dynamic nature of water, the European Commission's Joint Research Centre (JRC), working with the Google Earth Engine (GEE) team has processed each single pixel acquired by Landsat 5, 7, and 8 between 16th March 1984 to 10th October 2015 (> 3.000.000 Landsat scenes, representing > 1823 Terabytes of data).The produced dataset record months and years when water was present across 32 year, were occurrence changed and what form changes took in terms of seasonality and persistence, and document intra-annual persistence, inter-annual variability, and trends.This validated dataset shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered showing how surface water is altered by human activities.Freely available, we anticipate that this dataset will provide valuable information to those working in areas linked to security of water supply for agriculture, industry and human consumption, for assessing water-related disaster reduction and recovery and for the study of waterborne pollution and disease spread. The maps will also improve surface boundary condition setting in climate and weather models, improve carbon emissions estimates, inform regional climate change impact studies, delimit wetlands for biodiversity and determine desertification trends. Issues such as dam building (and less widespread dam removal), disappearing rivers, the geopolitics of water distribution and coastal erosion are also addressed.

Polarization optics of the Brewster's dark patch visible on water surfaces versus solar height and sky conditions: theory, computer modeling, photography, and painting.

PubMed

Takács, Péter; Barta, András; Pye, David; Horváth, Gábor

2017-10-20

When the sun is near the horizon, a circular band with approximately vertically polarized skylight is formed at 90° from the sun, and this skylight is only weakly reflected from the region of the water surface around the Brewster's angle (53° from the nadir). Thus, at low solar heights under a clear sky, an extended dark patch is visible on the water surface when one looks toward the north or south quarter perpendicular to the solar vertical. In this work, we study the radiance distribution of this so-called Brewster's dark patch (BDP) in still water as functions of the solar height and sky conditions. We calculate the pattern of reflectivity R of a water surface for a clear sky and obtain from this idealized situation the shape of the BDP. From three full-sky polarimetric pictures taken about a clear, a partly cloudy, and an overcast sky, we determine the R pattern and compose from that synthetic color pictures showing how the radiance distribution of skylight reflected at the water surface and the BDPs would look under these sky conditions. We also present photographs taken without a linearly polarizing filter about the BDP. Finally, we show a 19th century painting on which a river is seen with a dark region of the water surface, which can be interpreted as an artistic illustration of the BDP.

Reuse of spent granular activated carbon for organic micro-pollutant removal from treated wastewater.

PubMed

Hu, Jingyi; Shang, Ran; Heijman, Bas; Rietveld, Luuk

2015-09-01

Spent granular activated carbons (sGACs) for drinking water treatments were reused via pulverizing as low-cost adsorbents for micro-pollutant adsorption from a secondary treated wastewater effluent. The changes of physicochemical characteristics of the spent carbons in relation to the fresh carbons were determined and were correlated to the molecular properties of the respective GAC influents (i.e. a surface water and a groundwater). Pore size distribution analysis showed that the carbon pore volume decreased over a wider size range due to preloading by surface water, which contains a broader molecular weight distribution of organic matter in contrast to the groundwater. However, there was still considerable capacity available on the pulverized sGACs for atrazine adsorption in demineralized water and secondary effluent, and this was particularly the case for the groundwater spent GAC. However, as compared to the fresh counterparts, the decreased surface area and the induced surface acidic groups on the pulverized sGACs contributed both to the lower uptake and the more impeded adsorption kinetic of atrazine in the demineralized water. Nonetheless, the pulverized sGACs, especially the one preloaded by surface water, was less susceptible to adsorption competition in the secondary effluent, due to its negatively charged surface which can repulse the accessibility of the co-present organic matter. This suggests the reusability of the drinking water spent GACs for micro-pollutant adsorption in the treated wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

Photochemical influences on the air-water exchange of mercury

NASA Astrophysics Data System (ADS)

Vette, Alan Frederic

The formation of dissolved gaseous mercury (DGM) in natural waters is an important component in the biogeochemical cycle of mercury (Hg). The predominate form of DGM in natural waters, gaseous elemental Hg (Hg0), may be transferred from the water to the atmosphere. Gas exchange may reduce the amount of Hg available for methyl-Hg formation, the most toxic form of Hg that bioaccumulates in the food chain. Determining the mechanisms and rates of DGM formation is essential in understanding the fate and cycling of Hg in aquatic ecosystems. Field and laboratory experiments were conducted to evaluate the effect of light on DGM formation in surface waters containing different levels of dissolved organic carbon (DOC). Water samples collected from the Tahqwamenon River and Whitefish Bay on Lake Superior were amended with divalent Hg (Hg2+) and irradiated under a variety of reaction conditions to determine rates of DGM formation. The water samples were also analyzed for various Hg species (total, filtered, easily reducible and dissolved gaseous Hg), DOC and light attenuation. Additional field studies were conducted on Lake Michigan to measure gaseous Hg in air and water. These data were used to develop a mechanistic model to estimate air-water exchange of gaseous Hg. This research found that photochemical formation of DGM was affected by penetration of UV A radiation (320-400 nm). Formation of DGM was enhanced at higher DOC concentrations, indicating DOC photosensitized the reduction of Hg2+ to Hg0. Wavelength studies determined that formation of DGM was significantly reduced in the absence of UV A. Field studies showed DGM concentrations were highest near the water surface and peaked at mid-day, indicating a photo-induced source of DGM. The conversion of reducible Hg2+ to Hg0 was suppressed in high DOC waters where UV A penetration was limited. The mechanistic model predicted similar DGM concentrations to the observed values and demonstrated that deposition and emission fluxes of gaseous Hg were similar in Lake Michigan. In addition, deposition and emission fluxes of gaseous Hg were similar to Hg loadings by precipitation. The formation and emission of DGM from surface waters represents a significant contribution to the Hg cycle in aquatic ecosystems.

Comparison of MTI Satellite-Derived Surface Water Temperatures and In-Situ Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurzeja, R.

2001-07-26

Temperatures of the water surface of a cold, mid-latitude lake and the tropical Pacific Ocean were determined from MTI images and from in situ concurrent measurements. In situ measurements were obtained at the time of the MTI image with a floating, anchored platform, which measured the surface and bulk water temperatures and relevant meteorological variables, and also from a boat moving across the target area. Atmospheric profiles were obtained from concurrent radiosonde soundings. Radiances at the satellite were calculated with the Modtran radiative transfer model. The MTI infrared radiances were within 1 percent of the calculated values at the Pacificmore » Ocean site but were 1-2 percent different over the mid-latitude lake.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jenner, Elliot; Barbier, Charlotte N; D'Urso, Brian R

Robust and easily produced Superhydrophobic surfaces are of great interest for mechanical applications, including drag reduction and MEMS. We produce novel superhydrophobic surfaces with several different coatings and tested the durability of each of these coatings with respect to long term immersion in water in order to determine the most long-lasting surface preparation. A pair of combinations of spin on polymers, surface features, and adhesion promoters was found that provide long term durability.

Surface truth measurements of optical properties of the waters in the northern Gulf of California

NASA Technical Reports Server (NTRS)

Austin, R. W.

1972-01-01

Gemini and Apollo flight photographs of the southwestern United States and northwestern Mexico, and especially of the Colorado River delta and the northwestern Gulf of California, are considered. The clearly discernible water coloration in the imagery led to the suggestion that remote sensing techniques may be usefully applied in such areas to determine bathymetric information. Measurements of the optical properties of the water in this region obtained in March 1971 showed that generally low transmissivities prevailed and at no station did the beam transmittance for the total water column exceed 2.5 x 10 to the -8th power. It was concluded that any correlation between water depth and spectral radiance at the surface must result from secondarily related phenomena.

Topography and surface free energy of DPPC layers deposited on a glass, mica, or PMMA support.

PubMed

Jurak, Malgorzata; Chibowski, Emil

2006-08-15

An investigation of energetic properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) layers deposited on glass, mica, and PMMA (poly(methyl methacrylate)) surfaces was carried out by means of contact angles measurements (advancing and receding) for three probe liquids (diiodomethane, water, and formamide). DPPC was deposited on the surfaces from water (on glass and mica) or methanol (on PMMA) solutions. The topography of the tested surfaces was determined with a help of scanning electron microscopy (SEM) and atomic force microscopy (AFM). Using the measured contact angles, the total apparent surface free energy and its components of the studied layers were determined from van Oss et al.'s (Lifshitz-van der Waals and acid-base components, LWAB) and contact angle hysteresis (CAH) approaches. It allowed us to learn about changes in the surface free energy of the layers (hydrophobicity/hydrophilicity) depending on their number and kind of support. It was found that the changes in the energy greatly depended on the surface properties of the substrate as well as the statistical number of monolayers of DPPC. However, principal changes took place for first three monolayers.

Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean and the Hawaiian Islands

NASA Technical Reports Server (NTRS)

Carlson, P. R. (Principal Investigator); Conomos, T. J.; Janda, R. J.; Peterson, D. H.

1973-01-01

The author has identified the following significant results. ERTS-1 multispectral scanner imagery of the nearshore surface waters of the Northeast Pacific Ocean is proving to be a useful tool for determining source and dispersal of suspended particulate matter. The principal sources of the turbid water, seen best on the green and red bands, are river and stream effluents and actively eroding coastlines; secondary sources are waste effluents and production of planktonic organisms, but these may sometimes be masked by the very turbid plumes of suspended sediment being discharged into the nearshore zone during times of high river discharge. The configuration and distribution of the plumes of turbid water also can be used to infer near-surface current directions. Comparison of imagery of the nearshore water off the northern California coast from October 1972 and January 1973 shows a reversal of the near-surface currents, from predominantly south-setting in the fall (California Current) to north-setting in the winter (Davidson Current).

Organic Pollution in Surface Waters from the Fuglebekken Basin in Svalbard, Norwegian Arctic

PubMed Central

Polkowska, Żaneta; Cichała-Kamrowska, Katarzyna; Ruman, Marek; Kozioł, Krystyna; Krawczyk, Wiesława Ewa; Namieśnik, Jacek

2011-01-01

The Fuglebekken basin is situated in the southern part of the island of Spitsbergen (Norwegian Arctic), on the Hornsund fjord (Wedel Jarlsberg Land). Surface water was collected from 24 tributaries (B1–B24) and from the main stream water in the Fuglebekken basin (25) between 10 July 2009 and 30 July 2009. The present investigation reveals the results of the analysis of these samples for their PAH and PCB content. Twelve of 16 PAHs and seven PCBs were determined in the surface waters from 24 tributaries and the main stream. Total PAH and PCB concentrations in the surface waters ranged from 4 to 600 ng/L and from 2 to 400 ng/L respectively. The highest concentrations of an individual PCB (138–308 ng/L and 123 ng/L) were found in samples from tributaries B9 and B5. The presence in the basin (thousands of kilometres distant from industrial centres) of PAHs and PCBs is testimony to the fact that these compounds are transported over vast distances with air masses and deposited in regions devoid of any human pressure. PMID:22164112

Seasonality of Cryptosporidium oocyst detection in surface waters of Meru, Kenya as determined by two isolation methods followed by PCR

PubMed Central

Muchiri, John M.; Ascolillo, Luke; Mugambi, Mutuma; Mutwiri, Titus; Ward, Honorine D.; Naumova, Elena N.; Egorov, Andrey I.; Cohen, Seth; Else, James G.; Griffiths, Jeffrey K.

2009-01-01

Meru, Kenya has watersheds which are shared by wildlife, humans and domesticated animals. These surface waters can be contaminated by the waterborne pathogen Cryptosporidium. To quantify the seasonality and prevalence of Cryptosporidium in Meru regional surface waters, we used a calcium carbonate flocculation (CCF) and sucrose floatation method, and a filtration and immunomagnetic bead separation method, each of which used PCR for Cryptosporidium detection and genotyping. Monthly water samples were collected from January through June in 2003 and 2004, bracketing two April-May rainy seasons. We detected significant seasonality with 8 of 9 positive samples from May and June (p < 0.0014), which followed peak rainy season precipitation and includes some of the subsequent dry season. Six of 9 positive samples revealed C. parvum, and 3 contained C. andersoni. None contained C. hominis. Our results indicate that Meru surface waters are Cryptosporidium-contaminated at the end of rainy seasons, consistent with the timing of human infections reported by others from East Africa and contrasting with the onset of rainy season peak incidence reported from West Africa. PMID:18957776

Flying fish accelerate at 5 G to leap from the water surface

NASA Astrophysics Data System (ADS)

Yang, Patricia; Phonekeo, Sulisay; Xu, Ke; Chang, Shui-Kai; Hu, David

2013-11-01

Flying fish can both swim underwater and glide in air. Transitioning from swimming to gliding requires penetration of the air-water interface, or breaking the ``surface tension barrier,'' a formidable task for juvenile flying fish measuring 1 to 5 cm in length. In this experimental investigation, we use high-speed videography to characterize the kinematics of juvenile flying fish as they leap from the water surface. During this process, which lasts 0.05 seconds, flying fish achieve body accelerations of 5 times earth's gravity and gliding speeds of 1.3 m/s, an order of magnitude higher than their steady swimming speed. We rationalize this anomalously high speed on the basis of the hydrodynamic and surface tension forces and torques experienced by the fish. Specifically, leaping fish experience skin friction forces only on the submerged part of their body, permitting them to achieve much higher speeds than in steady underwater swimming. We also perform experiments using a towed flying fish mimc to determine optimality of various parameters in this process, including body angle and start position with respect to the water surface.

Streambed-material characteristics and surface-water quality, Green Pond Brook and tributaries, Picatinny Arsenal, New Jersey, 1983-90

USGS Publications Warehouse

Storck, D.A.; Lacombe, Pierre

1996-01-01

This report presents the results of a study designed to determine whether Green Pond Brook and its tributaries contain contaminated streambed sediments and to characterize the quaity of water in the brook. Results of previous investigations at Picatinny Arsenal, Morris County, New Jersey, indicate that significant contamination of ground water, surface water, and soil is present at the arsenal. Forty-five streambed-material samples were collected for analysis to determine whether contaminants have migrated to the brook from the surrounding area. Samples were analyzed for trace elements, base/neutral- and acid-etractable compounds, insecticides, and other constituents. Results of an electromagnetic-conductivity and natural-gamma-ray survey were used to describe the distribution of particle sizes in streambed and substreambed sediments. Historical results of analyses of streambed-material and surface-water samples also are presented. Samples of streambed material from three areas in Green Pond Brook and its tributaries contained organic and (or) inorganic constituents in concentrations greater than those typically found at the arsenal. These areas are Green Pond Brook, from the area near the outflow of Picatinny Lake downstream to Farley Avenue; Bear Swamp Brook, from the area near building 241 downstream to the confluence with Green Pond Brook; and Green Pond Brook, from the open burning area downstream to the dam near building 1178. Contaminants identified include trace elements, polynuclear aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine insecticides. Surface water in Green Pond Brook contained several volatile organic compounds, including trichloroethylene, tetrachloroethylene, and 1,2-dichloroethylene, at maximum concen- trations of 3.8, 4.6, and 11 micrograms per liter, respectively. Volatilization is expected to remove volatile organic compounds in the steep, fast- flowing reaches of the brook. No organic or inorganic constituents were detected in surface- water samples in concentrations greater than the U.S. Environmental Protection Agency primary drinking-water regulations. Only two constituents, iron and manganese, were detected in concen- trations greater than the U.S. Environmental Protection Agency secondary drinking-water regulations.

Analysis of the sorption properties of different soils using water vapour adsorption and potentiometric titration methods

NASA Astrophysics Data System (ADS)

Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

2016-07-01

Parameters of specific surface area as well as surface charge were used to determine and compare sorption properties of soils with different physicochemical characteristics. The gravimetric method was used to obtain water vapour isotherms and then specific surface areas, whereas surface charge was estimated from potentiometric titration curves. The specific surface area varied from 12.55 to 132.69 m2 g-1 for Haplic Cambisol and Mollic Gleysol soil, respectively, and generally decreased with pH (R=0.835; α = 0.05) and when bulk density (R=-0.736; α = 0.05) as well as ash content (R=-0.751; α = 0.05) increased. In the case of surface charge, the values ranged from 63.00 to 844.67 μmol g-1 Haplic Fluvisol and Mollic Gleysol, respecively. Organic matter gave significant contributions to the specific surface area and cation exchange capacity due to the large surface area and numerous surface functional groups, containing adsorption sites for water vapour molecules and for ions. The values of cation exchange capacity and specific surface area correlated linearly at the level of R=0.985; α = 0.05.

Probing equilibrium of molecular and deprotonated water on TiO 2 (110)

DOE PAGES

Wang, Zhi-Tao; Wang, Yang-Gang; Mu, Rentao; ...

2017-02-06

Understanding water structure and its deprotonation dynamics on oxide surfaces is key to understanding many physical and chemical processes. In this study, we directly measure the energy barriers associated with the protonation equilibrium of water on the prototypical oxide surface, rutile-TiO2(110) by a combination of a supersonic molecular beam, scanning tunneling microscopy, and ab initio molecular dynamics simulations. We show that long-range electrostatic fields emanating from the oxide lead to steering and reorientation of the molecules approaching the surface, activating the O-H bonds and inducing deprotonation. The incident energy dependent studies allow for a direct determination of the dissociation barrier.more » Temperature dependent imaging yields the reverse barrier and the equilibrium constant. Molecularly bound water is preferred by 0.035 eV over the surface-bound hydroxyls. The techniques developed in this work are readily extended to other systems where the understanding of bond-activation processes is critical.« less

Probing equilibrium of molecular and deprotonated water on TiO 2(110)

DOE PAGES

Wang, Zhi -Tao; Wang, Yang -Gang; Mu, Rentao; ...

2017-02-06

Understanding water structure and its deprotonation dynamics on oxide surfaces is key to understanding many physical and chemical processes. In this study, we directly measure the energy barriers associated with the protonation equilibrium of water on the prototypical oxide surface, rutile-TiO 2(110) by a combination of a supersonic molecular beam, scanning tunneling microscopy, and ab initio molecular dynamics simulations. We show that long-range electrostatic fields emanating from the oxide lead to steering and reorientation of the molecules approaching the surface, activating the O-H bonds and inducing deprotonation. The incident energy dependent studies allow for a direct determination of the dissociationmore » barrier. Temperature dependent imaging yields the reverse barrier and the equilibrium constant. Molecularly bound water is preferred by 0.035 eV over the surface-bound hydroxyls. In conclusion, the techniques developed in this work are readily extended to other systems where the understanding of bond-activation processes is critical.« less

Surface Protonation at the Rutile (110) Interface: Explicit Incorporation of Solvation Structure within the Refined MUSIC Model Framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machesky, Michael L.; Predota, M.; Wesolowski, David J

The detailed solvation structure at the (110) surface of rutile ({alpha}-TiO{sub 2}) in contact with bulk liquid water has been obtained primarily from experimentally verified classical molecular dynamics (CMD) simulations of the ab initio-optimized surface in contact with SPC/E water. The results are used to explicitly quantify H-bonding interactions, which are then used within the refined MUSIC model framework to predict surface oxygen protonation constants. Quantum mechanical molecular dynamics (QMD) simulations in the presence of freely dissociable water molecules produced H-bond distributions around deprotonated surface oxygens very similar to those obtained by CMD with nondissociable SPC/E water, thereby confirming thatmore » the less computationally intensive CMD simulations provide accurate H-bond information. Utilizing this H-bond information within the refined MUSIC model, along with manually adjusted Ti-O surface bond lengths that are nonetheless within 0.05 {angstrom} of those obtained from static density functional theory (DFT) calculations and measured in X-ray reflectivity experiments (as well as bulk crystal values), give surface protonation constants that result in a calculated zero net proton charge pH value (pHznpc) at 25 C that agrees quantitatively with the experimentally determined value (5.4 {+-} 0.2) for a specific rutile powder dominated by the (110) crystal face. Moreover, the predicted pH{sub znpc} values agree to within 0.1 pH unit with those measured at all temperatures between 10 and 250 C. A slightly smaller manual adjustment of the DFT-derived Ti-O surface bond lengths was sufficient to bring the predicted pH{sub znpc} value of the rutile (110) surface at 25 C into quantitative agreement with the experimental value (4.8 {+-} 0.3) obtained from a polished and annealed rutile (110) single crystal surface in contact with dilute sodium nitrate solutions using second harmonic generation (SHG) intensity measurements as a function of ionic strength. Additionally, the H-bond interactions between protolyzable surface oxygen groups and water were found to be stronger than those between bulk water molecules at all temperatures investigated in our CMD simulations (25, 150 and 250 C). Comparison with the protonation scheme previously determined for the (110) surface of isostructural cassiterite ({alpha}-SnO{sub 2}) reveals that the greater extent of H-bonding on the latter surface, and in particular between water and the terminal hydroxyl group (Sn-OH) results in the predicted protonation constant for that group being lower than for the bridged oxygen (Sn-O-Sn), while the reverse is true for the rutile (110) surface. These results demonstrate the importance of H-bond structure in dictating surface protonation behavior, and that explicit use of this solvation structure within the refined MUSIC model framework results in predicted surface protonation constants that are also consistent with a variety of other experimental and computational data.« less

Surface protonation at the rutile (110) interface: explicit incorporation of solvation structure within the refined MUSIC model framework.

PubMed

Machesky, Michael L; Predota, Milan; Wesolowski, David J; Vlcek, Lukas; Cummings, Peter T; Rosenqvist, Jörgen; Ridley, Moira K; Kubicki, James D; Bandura, Andrei V; Kumar, Nitin; Sofo, Jorge O

2008-11-04

The detailed solvation structure at the (110) surface of rutile (alpha-TiO2) in contact with bulk liquid water has been obtained primarily from experimentally verified classical molecular dynamics (CMD) simulations of the ab initio-optimized surface in contact with SPC/E water. The results are used to explicitly quantify H-bonding interactions, which are then used within the refined MUSIC model framework to predict surface oxygen protonation constants. Quantum mechanical molecular dynamics (QMD) simulations in the presence of freely dissociable water molecules produced H-bond distributions around deprotonated surface oxygens very similar to those obtained by CMD with nondissociable SPC/E water, thereby confirming that the less computationally intensive CMD simulations provide accurate H-bond information. Utilizing this H-bond information within the refined MUSIC model, along with manually adjusted Ti-O surface bond lengths that are nonetheless within 0.05 A of those obtained from static density functional theory (DFT) calculations and measured in X-ray reflectivity experiments (as well as bulk crystal values), give surface protonation constants that result in a calculated zero net proton charge pH value (pHznpc) at 25 degrees C that agrees quantitatively with the experimentally determined value (5.4+/-0.2) for a specific rutile powder dominated by the (110) crystal face. Moreover, the predicted pHznpc values agree to within 0.1 pH unit with those measured at all temperatures between 10 and 250 degrees C. A slightly smaller manual adjustment of the DFT-derived Ti-O surface bond lengths was sufficient to bring the predicted pHznpcvalue of the rutile (110) surface at 25 degrees C into quantitative agreement with the experimental value (4.8+/-0.3) obtained from a polished and annealed rutile (110) single crystal surface in contact with dilute sodium nitrate solutions using second harmonic generation (SHG) intensity measurements as a function of ionic strength. Additionally, the H-bond interactions between protolyzable surface oxygen groups and water were found to be stronger than those between bulk water molecules at all temperatures investigated in our CMD simulations (25, 150 and 250 degrees C). Comparison with the protonation scheme previously determined for the (110) surface of isostructural cassiterite (alpha-SnO2) reveals that the greater extent of H-bonding on the latter surface, and in particular between water and the terminal hydroxyl group (Sn-OH) results in the predicted protonation constant for that group being lower than for the bridged oxygen (Sn-O-Sn), while the reverse is true for the rutile (110) surface. These results demonstrate the importance of H-bond structure in dictating surface protonation behavior, and that explicit use of this solvation structure within the refined MUSIC model framework results in predicted surface protonation constants that are also consistent with a variety of other experimental and computational data.

An upscaled rate law for magnesite dissolution in heterogeneous porous media

NASA Astrophysics Data System (ADS)

Wen, Hang; Li, Li

2017-08-01

Spatial heterogeneity in natural subsurface systems governs water fluxes and residence time in reactive zones and therefore determines effective rates of mineral dissolution. Extensive studies have documented mineral dissolution rates in natural systems, although a general rate law has remain elusive. Here we fill this gap by answering two questions: (1) how and to what extent does spatial heterogeneity affect water residence time and effectively-dissolving surface area? (2) what is the upscaled rate law that quantifies effective dissolution rates in natural, heterogeneous media? With data constraints from experimental work, 240 Monte-Carlo numerical experiments of magnesite dissolution within quartz matrix were run with spatial distributions characterized by a range of permeability variance σ2lnκ (0.5-6.0) and correlation length (2-50 cm). Although the total surface area and global residence time (τa) are the same in all experiments, the water fluxes through reactive magnesite zones varies between 0.7 and 72.8% of the total water fluxes. Highly heterogeneous media with large σ2lnκ and long λ divert water mostly into non-reactive preferential flow paths, therefore bypassing and minimizing flow in low permeability magnesite zones. As a result, the water residence time in magnesite zones (i.e., reactive residence time τa,r) is long and magnesite dissolution quickly reaches local equilibrium, which leads to small effective surface area and low dissolution rates. Magnesite dissolution rates in heterogeneous media vary from 2.7 to 100% of the rates in the equivalent homogeneous media, with effectively-dissolving surface area varying from 0.18 to 6.83 m2 (out of 51.71 m2 total magnesite surface area). Based on 240 numerical experiments and 45 column experiments, a general upscaled rate law in heterogeneous media, RMgCO3,ht =kAe,hm(1 - exp(-τa/τa,r))α, was derived to quantify effective dissolution rates. The dissolution rates in heterogeneous media are a function of the rate constants k being those measured under well-mixed conditions, effective surface area in equivalent homogeneous media Ae,hm, and the heterogeneity factor (1 - exp(-τa/τa,r))α. The heterogeneity factor quantify heterogeneity effects and depends on the relative magnitude of global residence time (τa) and reactive residence time (τa,r), as well as the shape factor α(= 5 σlnκ2) of the gamma distribution for reactive residence times. Exponential forms of rate laws have been used at the micro-scale describing direct interactions among water and mineral surface, and at the catchment scale describing weathering rates and concentration-discharge relationships. These observations highlight the key role of mineral-water contact time in determining dissolution rates at different scales. This work also emphasizes the importance of critical interfaces between reactive and non-reactive zones as determined by the details of spatial patterns and effective surface area as a scaling factor that quantifies dissolution rates in heterogeneous media across scales.

Surface-water investigations at Barrow, Alaska

USGS Publications Warehouse

Jones, Stanley H.

1972-01-01

The U.S. Public Health Service is currently developing plans for a long-term water supply and sewage treatment system for the village of Barrow, Alaska. To assist in planning, the U.S. Geological Survey was requested to initiate a cooperative streamflow data-collection program with the U.S. Public Health Service in June 1972 to determine the availability of surface water and the areal distribution of runoff in the Barrow area. This basic-data report summarizes the streamflow data collected from June 1 through July 10, 1972, at three gaging stations in the Barrow area (fig. 1) and discusses the future data-collection program.

The Amateur Scientist: Funny Things Happen When Drops of Oil or Other Substances Are Placed on Water.

ERIC Educational Resources Information Center

Walker, Jearl

1983-01-01

Discusses solubility interactions of various oils placed on the surface of water and other liquids, explained using the basic forces of gravity, electrical attraction, and quantum mechanics (non-mathematical). Hydrogen and ionic bonding between oleic acid/water is analyzed. An experiment to determine physical properties of the oleic acid molecule…

77 FR 8865 - Public Water System Supervision Program Approval for the State of Illinois; Tentative Approval

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-15

... By-products Regulations to all Illinois community and noncommunity water systems that add and/or... for Long-Term 2 Enhanced Surface Water Treatment and Stage 2 Disinfectants and Disinfection By-product... determined that the state regulations and procedures submitted by the State to EPA for review are no less...

Surface tension measurements of aqueous ammonium chloride (NH4Cl) in air

NASA Technical Reports Server (NTRS)

Lowry, S. A.; Mccay, M. H.; Mccay, T. D.; Gray, P. A.

1989-01-01

Aqueous NH4Cl's solidification is often used to model metal alloy solidification processes. The present determinations of the magnitude of the variation of aqueous NH4Cl's surface tension as a function of both temperature and solutal concentration were conducted at 3, 24, and 40 C over the 72-100 wt pct water solutal range. In general, the surface tension increases 0.31 dyn/cm per percent decrease in wt pct of water, and decreases 0.13 dyn/cm for each increase in deg C. Attention is given to the experimental apparatus employed.

Impact of water-vending kiosks and hygiene education on household drinking water quality in rural Ghana.

PubMed

Opryszko, Melissa C; Guo, Yayi; MacDonald, Luke; MacDonald, Laura; Kiihl, Samara; Schwab, Kellogg J

2013-04-01

Innovative solutions are essential to improving global access to potable water for nearly 1 billion people. This study presents an independent investigation of one alternative by examining for-profit water-vending kiosks, WaterHealth Centers (WHCs), in rural Ghana to determine their association with household drinking water quality. WHCs' design includes surface water treatment using filtration and ultraviolet light disinfection along with community-based hygiene education. Analyses of water samples for Escherichia coli and household surveys from 49 households across five villages collected one time per year for 3 years indicate that households using WHCs had improved water quality compared with households using untreated surface water (adjusted incidence rate ratio = 0.07, 95% confidence interval = 0.02, 0.21). However, only 38% of households used WHCs by the third year, and 60% of those households had E. coli in their water. Recontamination during water transport and storage is an obstacle to maintaining WHC-vended water quality.

Impact of Water-Vending Kiosks and Hygiene Education on Household Drinking Water Quality in Rural Ghana

PubMed Central

Opryszko, Melissa C.; Guo, Yayi; MacDonald, Luke; MacDonald, Laura; Kiihl, Samara; Schwab, Kellogg J.

2013-01-01

Innovative solutions are essential to improving global access to potable water for nearly 1 billion people. This study presents an independent investigation of one alternative by examining for-profit water-vending kiosks, WaterHealth Centers (WHCs), in rural Ghana to determine their association with household drinking water quality. WHCs' design includes surface water treatment using filtration and ultraviolet light disinfection along with community-based hygiene education. Analyses of water samples for Escherichia coli and household surveys from 49 households across five villages collected one time per year for 3 years indicate that households using WHCs had improved water quality compared with households using untreated surface water (adjusted incidence rate ratio = 0.07, 95% confidence interval = 0.02, 0.21). However, only 38% of households used WHCs by the third year, and 60% of those households had E. coli in their water. Recontamination during water transport and storage is an obstacle to maintaining WHC-vended water quality. PMID:23382168

Direct water decomposition on transition metal surfaces: Structural dependence and catalytic screening

DOE PAGES

Tsai, Charlie; Lee, Kyoungjin; Yoo, Jong Suk; ...

2016-02-16

Density functional theory calculations are used to investigate thermal water decomposition over the close-packed (111), stepped (211), and open (100) facets of transition metal surfaces. A descriptor-based approach is used to determine that the (211) facet leads to the highest possible rates. As a result, a range of 96 binary alloys were screened for their potential activity and a rate control analysis was performed to assess how the overall rate could be improved.

Effect of replacing surface inlets with blind or gravel inlets on sediment and phosphorus subsurface drainage losses

USDA-ARS?s Scientific Manuscript database

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine whether modifying open inlets by burying them in gravel capped with 30 cm of sandy clay loam soil or in ve...

Summary of Organic Wastewater Compounds and Other Water-Quality Data in Charles County, Maryland, October 2007 through August 2008

USGS Publications Warehouse

Lorah, Michelle M.; Soeder, Daniel J.; Teunis, Jessica A.

2010-01-01

The U.S. Geological Survey, in cooperation with the government of Charles County, Maryland, and the Port Tobacco River Conservancy, Inc., conducted a water-quality reconnaissance and sampling investigation of the Port Tobacco River and Nanjemoy Creek watersheds in Charles County during October 2007 and June-August 2008. Samples were collected and analyzed for major ions, nutrients, organic wastewater compounds, and other selected constituents from 17 surface-water sites and 11 well sites (5 of which were screened in streambed sediments to obtain porewater samples). Most of the surface-water sites were relatively widely spaced throughout the Port Tobacco River and Nanjemoy Creek watersheds, although the well sites and some associated surface-water sites were concentrated in one residential community along the Port Tobacco River that has domestic septic systems. Sampling for enterococci bacteria was conducted by the Port Tobacco River Conservancy, Inc., at each site to coordinate with the sampling for chemical constituents. The purpose of the coordinated sampling was to determine correlations between historically high, in-stream bacteria counts and human wastewater inputs. Chemical data for the groundwater, porewater, and surface-water samples are presented in this report.

Chapter A6. Section 6.1. Temperature

USGS Publications Warehouse

Revised by Wilde, Franceska D.

2006-01-01

Accurate temperature measurements are required for accurate determinations of important environmental parameters such as pH, specific electrical conductance, and dissolved oxygen, and to the determination of chemical reaction rates and equilibria, biological activity, and physical fluid properties. This section of the National Field Manual (NFM) describes U.S. Geological Survey (USGS) guidance and protocols for measurement of temperature in air, ground water, and surface water and calibration of the equipment used.

Detecting surface runoff location in a small catchment using distributed and simple observation method

NASA Astrophysics Data System (ADS)

Dehotin, Judicaël; Breil, Pascal; Braud, Isabelle; de Lavenne, Alban; Lagouy, Mickaël; Sarrazin, Benoît

2015-06-01

Surface runoff is one of the hydrological processes involved in floods, pollution transfer, soil erosion and mudslide. Many models allow the simulation and the mapping of surface runoff and erosion hazards. Field observations of this hydrological process are not common although they are crucial to evaluate surface runoff models and to investigate or assess different kinds of hazards linked to this process. In this study, a simple field monitoring network is implemented to assess the relevance of a surface runoff susceptibility mapping method. The network is based on spatially distributed observations (nine different locations in the catchment) of soil water content and rainfall events. These data are analyzed to determine if surface runoff occurs. Two surface runoff mechanisms are considered: surface runoff by saturation of the soil surface horizon and surface runoff by infiltration excess (also called hortonian runoff). The monitoring strategy includes continuous records of soil surface water content and rainfall with a 5 min time step. Soil infiltration capacity time series are calculated using field soil water content and in situ measurements of soil hydraulic conductivity. Comparison of soil infiltration capacity and rainfall intensity time series allows detecting the occurrence of surface runoff by infiltration-excess. Comparison of surface soil water content with saturated water content values allows detecting the occurrence of surface runoff by saturation of the soil surface horizon. Automatic records were complemented with direct field observations of surface runoff in the experimental catchment after each significant rainfall event. The presented observation method allows the identification of fast and short-lived surface runoff processes at a small spatial and temporal resolution in natural conditions. The results also highlight the relationship between surface runoff and factors usually integrated in surface runoff mapping such as topography, rainfall parameters, soil or land cover. This study opens interesting prospects for the use of spatially distributed measurement for surface runoff detection, spatially distributed hydrological models implementation and validation at a reasonable cost.

Estimating the susceptibility of surface water in Texas to nonpoint-source contamination by use of logistic regression modeling

USGS Publications Warehouse

Battaglin, William A.; Ulery, Randy L.; Winterstein, Thomas; Welborn, Toby

2003-01-01

In the State of Texas, surface water (streams, canals, and reservoirs) and ground water are used as sources of public water supply. Surface-water sources of public water supply are susceptible to contamination from point and nonpoint sources. To help protect sources of drinking water and to aid water managers in designing protective yet cost-effective and risk-mitigated monitoring strategies, the Texas Commission on Environmental Quality and the U.S. Geological Survey developed procedures to assess the susceptibility of public water-supply source waters in Texas to the occurrence of 227 contaminants. One component of the assessments is the determination of susceptibility of surface-water sources to nonpoint-source contamination. To accomplish this, water-quality data at 323 monitoring sites were matched with geographic information system-derived watershed- characteristic data for the watersheds upstream from the sites. Logistic regression models then were developed to estimate the probability that a particular contaminant will exceed a threshold concentration specified by the Texas Commission on Environmental Quality. Logistic regression models were developed for 63 of the 227 contaminants. Of the remaining contaminants, 106 were not modeled because monitoring data were available at less than 10 percent of the monitoring sites; 29 were not modeled because there were less than 15 percent detections of the contaminant in the monitoring data; 27 were not modeled because of the lack of any monitoring data; and 2 were not modeled because threshold values were not specified.

Surface Adsorption in Nonpolarizable Atomic Models.

PubMed

Whitmer, Jonathan K; Joshi, Abhijeet A; Carlton, Rebecca J; Abbott, Nicholas L; de Pablo, Juan J

2014-12-09

Many ionic solutions exhibit species-dependent properties, including surface tension and the salting-out of proteins. These effects may be loosely quantified in terms of the Hofmeister series, first identified in the context of protein solubility. Here, our interest is to develop atomistic models capable of capturing Hofmeister effects rigorously. Importantly, we aim to capture this dependence in computationally cheap "hard" ionic models, which do not exhibit dynamic polarization. To do this, we have performed an investigation detailing the effects of the water model on these properties. Though incredibly important, the role of water models in simulation of ionic solutions and biological systems is essentially unexplored. We quantify this via the ion-dependent surface attraction of the halide series (Cl, Br, I) and, in so doing, determine the relative importance of various hypothesized contributions to ionic surface free energies. Importantly, we demonstrate surface adsorption can result in hard ionic models combined with a thermodynamically accurate representation of the water molecule (TIP4Q). The effect observed in simulations of iodide is commensurate with previous calculations of the surface potential of mean force in rigid molecular dynamics and polarizable density-functional models. Our calculations are direct simulation evidence of the subtle but sensitive role of water thermodynamics in atomistic simulations.

Surface microstructures of daisy florets (Asteraceae) and characterization of their anisotropic wetting.

PubMed

Koch, Kerstin; Bennemann, Michael; Bohn, Holger F; Albach, Dirk C; Barthlott, Wilhelm

2013-09-01

The surface microstructures on ray florets of 62 species were characterized and compared with modern phylogenetic data of species affiliation in Asteraceae to determine sculptural patterns and their occurrence in the tribes of Asteraceae. Their wettability was studied to identify structural-induced droplet adhesion, which can be used for the development of artificial surfaces for water harvesting and passive surface water transport. The wettability was characterized by contact angle (CA) and tilt angle measurements, performed on fresh ray florets and their epoxy resin replica. The CAs on ray florets varied between 104° and 156°, but water droplets did not roll off when surface was tilted at 90°. Elongated cell structures and cuticle folding orientated in the same direction as the cell elongation caused capillary forces, leading to anisotropic wetting, with extension of water droplets along the length axis of epidermis cells. The strongest elongation of the droplets was also supported by a parallel, cell-overlapping cuticle striation. In artificial surfaces made of epoxy replica of ray florets, this effect was enhanced. The distribution of the identified four structural types exhibits a strong phylogenetic signal and allows the inference of an evolutionary trend in the modification of floret epidermal cells.

Recent spectroscopic findings concerning clay/water interactions at low humidity: Possible applications to models of Martian surface reactivity

NASA Technical Reports Server (NTRS)

Coyne, L.; Bishop, J.; Howard, L.; Scattergood, T. W.

1991-01-01

A feasibility study assessing the utility of the adaptation of near infrared correlation spectroscopy to quantifying iron and adsorbed water in some clay-based Mars soil analog materials (MarSAM's). The work was intended to constitute Phase 1 of an approach to identifying optical analytical wavelength regions, not only for important mineral classes, but for chemically active centers within them. Many of these centers are common to unrelated mineral classes and of disproportionate influence relative to the mineral structure as a whole in determining the surface reactivity of mineral surfaces. We previously reported linearity between reflectance and total iron and total moisture over a large range of both key variables. We also discovered interesting relationships between the intensity of iron bands and the relative humidity of the systems. These relationships were confirmed. We also show that, in the low humidity range, reflectance is linearly dependent on a different kind of water from that best representing the full humidity range (the kind of water associated, in clays, with surface acidity). These relationships and the sensitivity and capability of quantitation of near infrared data indicate high promise with the production of reactive surface intermediates of products of surface reactions.

Water resources of Bannock Creek basin, southeastern Idaho

USGS Publications Warehouse

Spinazola, Joseph M.; Higgs, B.D.

1997-01-01

The potential for development of water resources in the Bannock Creek Basin is limited by water supply. Bannock Creek Basin covers 475 square miles in southeastern Idaho. Shoshone-Bannock tribal lands on the Fort Hall Indian Reservation occupy the northern part of the basin; the remainder of the basin is privately owned. Only a small amount of information on the hydrologic and water-quality characteristics of Bannock Creek Basin is available, and two previous estimates of water yield from the basin ranged widely from 45,000 to 132,500 acre-feet per year. The Shoshone-Bannock Tribes need an accurate determination of water yield and baseline water-quality characteristics to plan and implement a sustainable level of water use in the basin. Geologic setting, quantities of precipitation, evapotranspiration, surface-water runoff, recharge, and ground-water underflow were used to determine water yield in the basin. Water yield is the annual amount of surface and ground water available in excess of evapotranspiration by crops and native vegetation. Water yield from Bannock Creek Basin was affected by completion of irrigation projects in 1964. Average 1965-89 water yield from five subbasins in Bannock Creek Basin determined from water budgets was 60,600 acre-feet per year. Water yield from the Fort Hall Indian Reservation part of Bannock Creek Basin was estimated to be 37,700 acre-feet per year. Water from wells, springs, and streams is a calcium bicarbonate type. Concentrations of dissolved nitrite plus nitrate as nitrogen and fluoride were less than Maximum Contaminant Levels for public drinking-water supplies established by the U.S. Environmental Protection Agency. Large concentrations of chloride and nitrogen in water from several wells, springs, and streams likely are due to waste from septic tanks or stock animals. Estimated suspended-sediment load near the mouth of Bannock Creek was 13,300 tons from December 1988 through July 1989. Suspended-sediment discharge was greatest during periods of high streamflow.

Effects of Holding Time, Storage, and the Preservation of ...

EPA Pesticide Factsheets

The purpose of this project was to answer questions related to storage of samples to be analyzed by the quantitative polymerase chain reaction (qPCR)-based assays for fecal indicator bacteria. The project was divided into two parts. The first part was to determine if filters that were used to collect fecal indicators could be stored frozen and analyzed at a later date and the second part was to determine if refrigerated water samples could be held for 24 to 48 hours prior to analysis by qPCR. Both of these studies answer questions that were important in the analysis of fresh and marine surface water samples for beach monitoring purposes. 1) Develop and evaluate qPCR assays and test methods for the detection and quantification of genetic markers from indicator bacteria that are associated with human fecal waste and from two new groups of general fecal indicator bacteria (E. coli and Clostridia) that historically have been widely used or are favored in specific regions 2) Determine the occurrence and densities of genetic markers detected by new qPCR assays developed under objective 1 and compare with occurrence and densities of genetic markers detected by previously developed qPCR assays for enterococci and total Bacterioidalesin waste waters and fecal material from different animal sources. 3) Determine stability of fecal indicator bacteria target DNA sequences in freezer archived filter retentates of ambient surface water samples 4) Determine the densitie

HCMM/soil moisture experiment. [relationship between surface minus air temperature differential and available water according to crop type in Canada

NASA Technical Reports Server (NTRS)

Cihlar, J. (Principal Investigator)

1980-01-01

Progress in the compilation and analysis of airborne and ground data to determine the relationship between the maximum surface minus maximum air temperature differential (delta Tsa) and available water (PAW) is reported. Also, results of an analysis of HCMM images to determine the effect of cloud cover on the availability of HCMM-type data are presented. An inverse relationship between delta Tsa and PAW is indicated along with stable delta Tsa vs. PAW distributions for fully developed canopies. Large variations, both geographical and diurnal, in the cloud cover images are reported. The average monthly daytime cloud cover fluctuated between 40 and 60 percent.

Combining Remotely Sensed Environmental Characteristics with Social and Behavioral Conditions that Affect Surface Water Use in Spatiotemporal Modelling of Schistosomiasis in Ghana

NASA Astrophysics Data System (ADS)

Kulinkina, A. V.; Walz, Y.; Liss, A.; Kosinski, K. C.; Biritwum, N. K.; Naumova, E. N.

2016-06-01

Schistosoma haematobium transmission is influenced by environmental conditions that determine the suitability of the parasite and intermediate host snail habitats, as well as by socioeconomic conditions, access to water and sanitation infrastructure, and human behaviors. Remote sensing is a demonstrated valuable tool to characterize environmental conditions that support schistosomiasis transmission. Socioeconomic and behavioral conditions that propagate repeated domestic and recreational surface water contact are more difficult to quantify at large spatial scales. We present a mixed-methods approach that builds on the remotely sensed ecological variables by exploring water and sanitation related community characteristics as independent risk factors of schistosomiasis transmission.

Direct photolysis of polycyclic aromatic hydrocarbons in drinking water sources.

PubMed

Sanches, S; Leitão, C; Penetra, A; Cardoso, V V; Ferreira, E; Benoliel, M J; Crespo, M T Barreto; Pereira, V J

2011-09-15

The widely used low pressure lamps were tested in terms of their efficiency to degrade polycyclic aromatic hydrocarbons listed as priority pollutants by the European Water Framework Directive and the U.S. Environmental Protection Agency, in water matrices with very different compositions (laboratory grade water, groundwater, and surface water). Using a UV fluence of 1500 mJ/cm(2), anthracene and benzo(a)pyrene were efficiently degraded, with much higher percent removals obtained when present in groundwater (83-93%) compared to surface water (36-48%). The removal percentages obtained for fluoranthene were lower and ranged from 13 to 54% in the different water matrices tested. Several parameters that influence the direct photolysis of polycyclic aromatic hydrocarbons were determined and their photolysis by-products were identified by mass spectrometry. The formation of photolysis by-products was found to be highly dependent on the source waters tested. Copyright © 2011 Elsevier B.V. All rights reserved.

Activated carbon oxygen content influence on water and surfactant adsorption.

PubMed

Pendleton, Phillip; Wu, Sophie Hua; Badalyan, Alexander

2002-02-15

This research investigates the adsorption properties of three activated carbons (AC) derived from coconut, coal, and wood origin. Each carbon demonstrates different levels of resistance to 2 M NaOH treatment. The coconut AC offers the greatest and wood AC the least resistance. The influence of base treatment is mapped in terms of its effects on specific surface area, micropore volume, water adsorption, and dodecanoic acid adsorption from both water and 2 M NaOH solution. A linear relationship exists between the number of water molecules adsorbed at the B-point of the water adsorption isotherm and the oxygen content determined from elemental analysis. Surfactant adsorption isotherms from water and 2 M NaOH indicate that the AC oxygen content effects a greater dependence on affinity for surfactant than specific surface area and micropore volume. We show a linear relationship between the plateau amount of surfactant adsorbed and the AC oxygen content in both water and NaOH phases. The higher the AC oxygen content, the lower the amount of surfactant adsorbed. In contrast, no obvious relationship could be drawn between the surfactant amount adsorbed and the surface area.

Estimating soil water content from ground penetrating radar coarse root reflections

NASA Astrophysics Data System (ADS)

Liu, X.; Cui, X.; Chen, J.; Li, W.; Cao, X.

2016-12-01

Soil water content (SWC) is an indispensable variable for understanding the organization of natural ecosystems and biodiversity. Especially in semiarid and arid regions, soil moisture is the plants primary source of water and largely determine their strategies for growth and survival, such as root depth, distribution and competition between them. Ground penetrating radar (GPR), a kind of noninvasive geophysical technique, has been regarded as an accurate tool for measuring soil water content at intermediate scale in past decades. For soil water content estimation with surface GPR, fixed antenna offset reflection method has been considered to have potential to obtain average soil water content between land surface and reflectors, and provide high resolution and few measurement time. In this study, 900MHz surface GPR antenna was used to estimate SWC with fixed offset reflection method; plant coarse roots (with diameters greater than 5 mm) were regarded as reflectors; a kind of advanced GPR data interpretation method, HADA (hyperbola automatic detection algorithm), was introduced to automatically obtain average velocity by recognizing coarse root hyperbolic reflection signals on GPR radargrams during estimating SWC. In addition, a formula was deduced to determine interval average SWC between two roots at different depths as well. We examined the performance of proposed method on a dataset simulated under different scenarios. Results showed that HADA could provide a reasonable average velocity to estimate SWC without knowledge of root depth and interval average SWC also be determined. When the proposed method was applied to estimation of SWC on a real-field measurement dataset, a very small soil water content vertical variation gradient about 0.006 with depth was captured as well. Therefore, the proposed method could be used to estimate average soil water content from ground penetrating radar coarse root reflections and obtain interval average SWC between two roots at different depths. It is very promising for measuring root-zone-soil-moisture and mapping soil moisture distribution around a shrub or even in field plot scale.

Field and laboratory arsenic speciation methods and their application to natural-water analysis

USGS Publications Warehouse

Bednar, A.J.; Garbarino, J.R.; Burkhardt, M.R.; Ranville, J.F.; Wildeman, T.R.

2004-01-01

The toxic and carcinogenic properties of inorganic and organic arsenic species make their determination in natural water vitally important. Determination of individual inorganic and organic arsenic species is critical because the toxicology, mobility, and adsorptivity vary substantially. Several methods for the speciation of arsenic in groundwater, surface-water, and acid mine drainage sample matrices using field and laboratory techniques are presented. The methods provide quantitative determination of arsenite [As(III)], arsenate [As(V)], monomethylarsonate (MMA), dimethylarsinate (DMA), and roxarsone in 2-8min at detection limits of less than 1??g arsenic per liter (??g AsL-1). All the methods use anion exchange chromatography to separate the arsenic species and inductively coupled plasma-mass spectrometry as an arsenic-specific detector. Different methods were needed because some sample matrices did not have all arsenic species present or were incompatible with particular high-performance liquid chromatography (HPLC) mobile phases. The bias and variability of the methods were evaluated using total arsenic, As(III), As(V), DMA, and MMA results from more than 100 surface-water, groundwater, and acid mine drainage samples, and reference materials. Concentrations in test samples were as much as 13,000??g AsL-1 for As(III) and 3700??g AsL-1 for As(V). Methylated arsenic species were less than 100??g AsL-1 and were found only in certain surface-water samples, and roxarsone was not detected in any of the water samples tested. The distribution of inorganic arsenic species in the test samples ranged from 0% to 90% As(III). Laboratory-speciation method variability for As(III), As(V), MMA, and DMA in reagent water at 0.5??g AsL-1 was 8-13% (n=7). Field-speciation method variability for As(III) and As(V) at 1??g AsL-1 in reagent water was 3-4% (n=3). ?? 2003 Elsevier Ltd. All rights reserved.

Incorporating human-water dynamics in a hyper-resolution land surface model

NASA Astrophysics Data System (ADS)

Vergopolan, N.; Chaney, N.; Wanders, N.; Sheffield, J.; Wood, E. F.

2017-12-01

The increasing demand for water, energy, and food is leading to unsustainable groundwater and surface water exploitation. As a result, the human interactions with the environment, through alteration of land and water resources dynamics, need to be reflected in hydrologic and land surface models (LSMs). Advancements in representing human-water dynamics still leave challenges related to the lack of water use data, water allocation algorithms, and modeling scales. This leads to an over-simplistic representation of human water use in large-scale models; this is in turn leads to an inability to capture extreme events signatures and to provide reliable information at stakeholder-level spatial scales. The emergence of hyper-resolution models allows one to address these challenges by simulating the hydrological processes and interactions with the human impacts at field scales. We integrated human-water dynamics into HydroBlocks - a hyper-resolution, field-scale resolving LSM. HydroBlocks explicitly solves the field-scale spatial heterogeneity of land surface processes through interacting hydrologic response units (HRUs); and its HRU-based model parallelization allows computationally efficient long-term simulations as well as ensemble predictions. The implemented human-water dynamics include groundwater and surface water abstraction to meet agricultural, domestic and industrial water demands. Furthermore, a supply-demand water allocation scheme based on relative costs helps to determine sectoral water use requirements and tradeoffs. A set of HydroBlocks simulations over the Midwest United States (daily, at 30-m spatial resolution for 30 years) are used to quantify the irrigation impacts on water availability. The model captures large reductions in total soil moisture and water table levels, as well as spatiotemporal changes in evapotranspiration and runoff peaks, with their intensity related to the adopted water management strategy. By incorporating human-water dynamics in a hyper-resolution LSM this work allows for progress on hydrological monitoring and predictions, as well as drought preparedness and water impact assessments at relevant decision-making scales.

Determination of infiltration and percolation rates along a reach of the Santa Fe River near La Bajada, New Mexico

USGS Publications Warehouse

Thomas, Carole L.; Stewart, Amy E.; Constantz, Jim E.

2000-01-01

Two methods, one a surface-water method and the second a ground-water method, were used to determine infiltration and percolation rates along a 2.5-kilometer reach of the Santa Fe River near La Bajada, New Mexico. The surface-water method uses streamflow measurements and their differences along a stream reach, streamflow-loss rates, stream surface area, and evaporation rates to determine infiltration rates. The ground-water method uses heat as a tracer to monitor percolation through shallow streambed sediments. Data collection began in October 1996 and continued through December 1997. During that period the stream reach was instrumented with three streamflow gages, and temperature profiles were monitored from the stream-sediment interface to about 3 meters below the streambed at four sites along the reach. Infiltration is the downward flow of water through the stream- sediment interface. Infiltration rates ranged from 92 to 267 millimeters per day for an intense measurement period during June 26- 28, 1997, and from 69 to 256 millimeters per day during September 27-October 6, 1997. Investigators calculated infiltration rates from streamflow loss, stream surface-area measurements, and evaporation-rate estimates. Infiltration rates may be affected by unmeasured irrigation-return flow in the study reach. Although the amount of irrigation-return flow was none to very small, it may result in underestimation of infiltration rates. The infiltration portion of streamflow loss was much greater than the evaporation portion. Infiltration accounted for about 92 to 98 percent of streamflow loss. Evaporation-rate estimates ranged from 3.4 to 7.6 millimeters per day based on pan-evaporation data collected at Cochiti Dam, New Mexico, and accounted for about 2 to 8 percent of streamflow loss. Percolation is the movement of water through saturated or unsaturated sediments below the stream-sediment interface. Percolation rates ranged from 40 to 109 millimeters per day during June 26-28, 1997. Percolation rates were not calculated for the September 27-October 6, 1997, period because a late summer flood removed the temperature sensors from the streambed. Investigators used a heat-and-water flow model, VS2DH (variably saturated, two- dimensional heat), to calculate near-surface streambed infiltration and percolation rates from temperatures measured in the stream and streambed. Near the stream-sediment interface, infiltration and percolation rates are comparable. Comparison of infiltration and percolation rates showed that infiltration rates were greater than percolation rates. The method used to calculate infiltration rates accounted for net loss or gain over the entire stream reach, whereas the method used to calculate percolation was dependent on point measurements and, as applied in this study, neglected the nonvertical component of heat and water fluxes. In general, using the ground-water method was less labor intensive than making a series of streamflow measurements and relied on temperature, an easily measured property. The ground-water method also eliminated the difficulty of measuring or estimating evaporation from the water surface and was therefore more direct. Both methods are difficult to use during periods of flood flow. The ground-water method has problems with the thermocouple-wire temperature sensors washing out during flood events. The surface- water method often cannot be used because of safety concerns for personnel making wading streamflow measurements.

Closed depression topography Harps soil, revisited

USDA-ARS?s Scientific Manuscript database

Accumulation of carbonates around depressions indicates past or present water and solute flow paths out and up from the depressions. The purpose of this study was to determine the pattern of surface carbonates in relation to landscape parameters, depressions, and original Harps map units. Surface ca...

Generation of Hot Water from Hot-Dry for Heavy-Oil Recovery in Northern Alberta, Canada

NASA Astrophysics Data System (ADS)

Pathak, V.; Babadagli, T.; Majorowicz, J. A.; Unsworth, M. J.

2011-12-01

The focus of prior applications of hot-dry-rock (HDR) technology was mostly aimed at generating electricity. In northern Alberta, the thermal gradient is low and, therefore, this technology is not suitable for electricity generation. On the other hand, the cost of steam and hot water, and environmental impacts, are becoming critical issues in heavy-oil and bitumen recovery in Alberta. Surface generation of steam or hot-water accounts for six percent of Canada's natural gas consumption and about 50 million tons of CO2 emission. Lowered cost and environmental impacts are critical in the widespread use of steam (for in-situ recovery) and hot-water (for surface extraction of bitumen) in this region. This paper provides an extensive analysis of hot-water generation to be used in heavy-oil/bitumen recovery. We tested different modeling approaches used to determine the amount of energy produced during HDR by history matching to example field data. The most suitable numerical and analytical models were used to apply the data obtained from different regions containing heavy-oil/bitumen deposits in northern Alberta. The heat generation capacity of different regions was determined and the use of this energy (in the form of hot-water) for surface extraction processes was evaluated. Original temperature gradients were applied as well as realistic basement formation characteristics through an extensive hydro thermal analysis in the region including an experimental well drilled to the depth of 2,500m. Existing natural fractures and possible hydraulic fracturing scenarios were evaluated from the heat generation capacity and the economics points of view. The main problem was modeling difficulties, especially determination and representation of fracture network characteristics. A sensitivity analysis was performed for the selected high temperature gradient regions in Alberta. In this practice, the characteristics of hydraulic fractures, injection rate, depth, the distance between injection and production wells and formation thickness were used as variables and an optimization study was carried out based on these variables. The results showed that the hot water (50 C at surface) needed in Fort McMurray for extraction could be obtained at lower costs than the generation of it using natural gas.

Perfluorinated Surfactant Chain-Length Effects on Sonochemical Kinetics

NASA Astrophysics Data System (ADS)

Campbell, Tammy Y.; Vecitis, Chad D.; Mader, Brian T.; Hoffmann, Michael R.

2009-08-01

The sonochemical degradation kinetics of the aqueous perfluorochemicals (PFCs) perfluorobutanoate (PFBA), perfluorobutanesulfonate (PFBS), perfluorohexanoate (PFHA), and perfluorohexanesulfonate (PFHS) have been investigated. Surface tension measurements were used to evaluate chain-length effects on equilibrium air-water interface partitioning. The PFC air-water interface partitioning coefficients, KeqPF, and maximum surface concentrations, ΓmaxPF, were determined from the surface pressure equation of state for PFBA, PFBS, PFHA, and PFHS. Relative KeqPF values were dependent upon chain length KeqPFHS ≅ 2.1KeqPFHA ≅ 3.9KeqPFBS ≅ 5.0KeqPFBA, whereas relative ΓmaxPF values had minimal chain length dependence ΓmaxPFHS ≅ ΓmaxPFHA ≅ ΓmaxPFBS ≅ 2.2ΓmaxPFBA. The rates of sonolytic degradation were determined over a range of frequencies from 202 to 1060 kHz at dilute (<1 μM) initial PFC concentrations and are compared to previously reported results for their C8 analogs: perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA). Under all conditions, the time-dependent PFC sonolytic degradation was observed to follow pseudo-first-order kinetics, i.e., below kinetic saturation, suggesting bubble-water interface populations were significantly below the adsorption maximum. The PFHX (where X = A or S) sonolysis rate constant was observed to peak at an ultrasonic frequency of 358 kHz, similar to that for PFOX. In contrast, the PFBX degradation rate constants had an apparent maximum at 610 kHz. Degradation rates observed for PFHX are similar to previously determined PFOX rates, kapp,358PFOX ≅ kapp,358PFHX. PFOX is sonolytically pyrolyzed at the transiently cavitating bubble-water interface, suggesting that rates should be proportional to equilibrium interfacial partitioning. However, relative equilibrium air-water interfacial partitioning predicts that KeqPFOX ≅ 5KeqPFHX. This suggests that at dilute PFC concentrations, adsorption to the bubble-water interface is ultrasonically enhanced due to high-velocity radial bubble oscillations. PFC sonochemical kinetics are slower for PFBS and further diminished for PFBA as compared to longer analogs, suggesting that PFBX surface films are of lower stability due to their greater water solubility.

Determination of water-soluble ions in soils from the dry valleys of Antarctica

NASA Technical Reports Server (NTRS)

Bustin, R.

1981-01-01

The soil chemistry of the dry valleys of Antarctica was studied. These valleys furnish a terrestrial analog for the surface of Mars. The abundance of the water-soluble ions magnesium, calcium, potassium, sodium chloride, and nitrate in soil samples was determined. All samples examined contained water-soluble salts reflecting the aridity of the area. Movement of salts to low-lying areas was verified. Upward ionic migration was evident in all core samples. Of all cations observed, sodium showed the greatest degree of migration.

Determination of Perfluorinated Compounds in the Upper Mississippi River Basin

EPA Science Inventory

Despite ongoing efforts to develop robust analytical methods for the determination of perfluorinated compounds (PFCs) such as perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) in surface water, comparatively little has been published on method performance, and the...

Hydrologic processes governing near surface saturation of alpine wetlands in the Canadian Rockies

NASA Astrophysics Data System (ADS)

Westbrook, C.; Mercer, J.

2016-12-01

Alpine wetlands are vital for habitat, biodiversity, carbon cycling and water storage, but little is known about their hydrologic condition. Climate trends toward smaller mountain snowpacks that melt earlier are thought to pose a threat to the continued provision of alpine wetland ecological functions, and their existence, as it is believed they derive their water mainly from snowmelt. Our objective was to determine the hydrologic processes governing near surface saturation in alpine wetlands. We monitored the water table dynamics of three alpine wetlands in contrasting hydrogeomorphic landscape positions for two summers in Banff National Park, Canada. We concurrently monitored water balance components, and analyzed soil properties and source water geochemistry. Despite very different snow conditions between the two study years, water tables remained near the surface and relatively stable in both years, indicating wetlands are more hydrologically buffered from snowpack variations than expected. We did not find convincing evidence of hydrogeomorphic position influencing wetland water table dynamics. Instead, peat thickness seemed to be critical in regulating water table as the wetland with the thickest peat soil (>1 m) maintained water tables closest to the ground surface for the longest period of time. Thicker peat deposits may develop under convergent hydrologic flow path conditions. Our results indicate that alpine wetlands are more resilient to shifting environmental conditions than previously reported.

Diminished mercury emission from waters with duckweed cover

NASA Astrophysics Data System (ADS)

Wollenberg, Jennifer L.; Peters, Stephen C.

2009-06-01

Duckweeds (Lemnaceae) are a widely distributed type of floating vegetation in freshwater systems. Under suitable conditions, duckweeds form a dense vegetative mat on the water surface, which reduces light penetration into the water column and limits gas exchange at the water-air interface by decreasing the area of open water surface. Experiments were conducted to determine whether duckweed decreases mercury emission by limiting gas diffusion across the water-air interface and attenuating light, or, conversely, enhances emission via transpiration of mercury vapor. Microcosm flux chamber experiments indicate that duckweed decreases mercury emission from the water surface compared to open water controls. Fluxes under duckweed were 17-67% lower than in controls, with lower fluxes occurring at higher percent cover. The decrease in mercury emission suggests that duckweed may limit emission through one of several mechanisms, including limited gas transport across the air-water interface, decreased photoreactions due to light attenuation, and plant-mercury interactions. The results of this experiment were applied to a model lake system to illustrate the magnitude of potential effects on mercury cycling. The mercury retained in the lake as a result of hindered emission may increase bioaccumulation potential in lakes with duckweed cover.

Water Bouncing Balls: how material stiffness affects water entry

NASA Astrophysics Data System (ADS)

Truscott, Tadd

2014-03-01

It is well known that one can skip a stone across the water surface, but less well known that a ball can also be skipped on water. Even though 17th century ship gunners were aware that cannonballs could be skipped on the water surface, they did not know that using elastic spheres rather than rigid ones could greatly improve skipping performance (yet would have made for more peaceful volleys). The water bouncing ball (Waboba®) is an elastic ball used in a game of aquatic keep away in which players pass the ball by skipping it along the water surface. The ball skips easily along the surface creating a sense that breaking the world record for number of skips could easily be achieved (51 rock skips Russell Byers 2007). We investigate the physics of skipping elastic balls to elucidate the mechanisms by which they bounce off of the water. High-speed video reveals that, upon impact with the water, the balls create a cavity and deform significantly due to the extreme elasticity; the flattened spheres resemble skipping stones. With an increased wetted surface area, a large hydrodynamic lift force is generated causing the ball to launch back into the air. Unlike stone skipping, the elasticity of the ball plays an important roll in determining the success of the skip. Through experimentation, we demonstrate that the deformation timescale during impact must be longer than the collision time in order to achieve a successful skip. Further, several material deformation modes can be excited upon free surface impact. The effect of impact velocity and angle on the two governing timescales and material wave modes are also experimentally investigated. Scaling for the deformation and collision times are derived and used to establish criteria for skipping in terms of relevant physical parameters.

Determination of acidic herbicides in surface water by solid-phase extraction followed by capillary zone electrophoresis.

PubMed

Qin, Weidong; Wei, Hongping; Li, Sam Fong Yau

2002-08-01

A rapid solid-phase extraction-capillary zone electrophoresis (CZE) method for determining 2,4-dichlorophenoxyacetic acid, 4-(2,4-dichlorophenoxy) butyric acid, and 2,4,5-trichlorophenoxyacetic acid in real water samples is described. Factors affecting the recoveries and detection of the targets are investigated. With samples being acidified to pH 2 and salted by sodium sulfate to 2% (w/w), an average recovery of greater than 85% is obtained using ethyl acetate as the eluent on an octadecylsilane-bonded silica cartridge. A running buffer of 5 mM sodium tetraborate in a water-acetonitrile mixture (70:30, v/v) adjusted to pH 9 is employed in the CZE analysis, and the targets can be analyzed within 7 min with good reproducibility and acceptable sensitivity. The method is suitable for detecting herbicide residues of sub-parts-per-billion levels in surface water. A local pond water is analyzed, and the concentrations of 2,4-dichlorophenoxyacetic acid and 4-(2,4-dichlorophenoxy) butyric acid are detected to be 0.27 +/- 0.03 ppb and 0.61 +/- 0.08 ppb, respectively.

A Scale-up Approach for Film Coating Process Based on Surface Roughness as the Critical Quality Attribute.

PubMed

Yoshino, Hiroyuki; Hara, Yuko; Dohi, Masafumi; Yamashita, Kazunari; Hakomori, Tadashi; Kimura, Shin-Ichiro; Iwao, Yasunori; Itai, Shigeru

2018-04-01

Scale-up approaches for film coating process have been established for each type of film coating equipment from thermodynamic and mechanical analyses for several decades. The objective of the present study was to establish a versatile scale-up approach for film coating process applicable to commercial production that is based on critical quality attribute (CQA) using the Quality by Design (QbD) approach and is independent of the equipment used. Experiments on a pilot scale using the Design of Experiment (DoE) approach were performed to find a suitable CQA from surface roughness, contact angle, color difference, and coating film properties by terahertz spectroscopy. Surface roughness was determined to be a suitable CQA from a quantitative appearance evaluation. When surface roughness was fixed as the CQA, the water content of the film-coated tablets was determined to be the critical material attribute (CMA), a parameter that does not depend on scale or equipment. Finally, to verify the scale-up approach determined from the pilot scale, experiments on a commercial scale were performed. The good correlation between the surface roughness (CQA) and the water content (CMA) identified at the pilot scale was also retained at the commercial scale, indicating that our proposed method should be useful as a scale-up approach for film coating process.

Development and evaluation of a culture-independent method for source determination of fecal wastes in surface and storm waters using reverse transcriptase-PCR detection of FRNA coliphage genogroup gene sequences.

PubMed

Paar, Jack; Doolittle, Mark M; Varma, Manju; Siefring, Shawn; Oshima, Kevin; Haugland, Richard A

2015-05-01

A method, incorporating recently improved reverse transcriptase-PCR primer/probe assays and including controls for detecting interferences in RNA recovery and analysis, was developed for the direct, culture-independent detection of genetic markers from FRNA coliphage genogroups I, II & IV in water samples. Results were obtained from an initial evaluation of the performance of this method in analyses of waste water, ambient surface water and stormwater drain and outfall samples from predominantly urban locations. The evaluation also included a comparison of the occurrence of the FRNA genetic markers with genetic markers from general and human-related bacterial fecal indicators determined by current or pending EPA-validated qPCR methods. Strong associations were observed between the occurrence of the putatively human related FRNA genogroup II marker and the densities of the bacterial markers in the stormwater drain and outfall samples. However fewer samples were positive for FRNA coliphage compared to either the general bacterial fecal indicator or the human-related bacterial fecal indicator markers particularly for ambient water samples. Together, these methods show promise as complementary tools for the identification of contaminated storm water drainage systems as well as the determination of human and non-human sources of contamination. Published by Elsevier B.V.

Progression towards optimization of viscosity of highly concentrated carbonaceous solid-water slurries by incorporating and modifying surface chemistry parameters with and without additives

NASA Astrophysics Data System (ADS)

Mukherjee, Amrita

Carbonaceous solid-water slurries (CSWS) are concentrated suspensions of coal, petcoke bitumen, pitch etc. in water which are used as feedstock for gasifiers. The high solid loading (60-75 wt.%) in the slurry increases CSWS viscosity. For easier handling and pumping of these highly loaded mixtures, low viscosities are desirable. Depending on the nature of the carbonaceous solid, solids loading in the slurry and the particle size distribution, viscosity of a slurry can vary significantly. Ability to accurately predict the viscosity of a slurry will provide a better control over the design of slurry transport system and for viscosity optimization. The existing viscosity prediction models were originally developed for hard-sphere suspensions and therefore do not take into account surface chemistry. As a result, the viscosity predictions using these models for CSWS are not very accurate. Additives are commonly added to decrease viscosity of the CSWS by altering the surface chemistry. Since additives are specific to CSWS, selection of appropriate additives is crucial. The goal of this research was to aid in optimization of CSWS viscosity through improved prediction and selection of appropriate additive. To incorporate effect of surface chemistry in the models predicting suspension viscosity, the effect of the different interfacial interactions caused by different surface chemistries has to be accounted for. Slurries of five carbonaceous solids with varying O/C ratio (to represent different surface chemistry parameters) were used for the study. To determine the interparticle interactions of the carbonaceous solids in water, interfacial energies were calculated on the basis of surface chemistries, characterized by contact angles and zeta potential measurements. The carbonaceous solid particles in the slurries were assumed to be spherical. Polar interaction energy (hydrophobic/hydrophilic interaction energy), which was observed to be 5-6 orders of magnitude higher than the electrostatic interaction energy, and the van der Waals interaction energy, was clearly the dominant interaction energy for such a system. Hydrophobic interactions lead to the formation of aggregation networks of solids in the suspensions, entrapping a part of the bulk water, whereas hydrophilic interactions result in the formation of hydration layers around carbonaceous solids. Both of these phenomena cause a loss of bulk water from the slurry and increase the effective solid volume fraction, resulting in an increase in slurry viscosity. The water in the bulk of the slurry, responsible for the fluidity of the slurry is called free water. The amount of free water was determined using thermogravimetric analysis and was observed to increase with an increase in the O/C ratio of a carbonaceous solid (up to ˜20%). The free water to total water ratio was observed to be constant for the slurry of a particular carbonaceous solid for various loadings of solids (44 wt.% to 67 wt.%). The increase in the effective solid volume fractions of slurries was determined using viscosity measurements. A relationship between the effective solid volume fraction and the O/C ratio of the carbonaceous solid was developed. This correlation was then incorporated into the existing equation for viscosity prediction (developed based on particle size distribution and solid volume fraction), to account for the surface chemistry of the carbonaceous solid and hence improve the predictive capabilities. This modified equation was validated using three concentrated carbonaceous slurries with different particle size distributions and was observed to significantly improve accuracy of prediction (deviation of predicted results decreased from up to 96% to 25%). The validation was performed with a lignite, bituminous coal and a petcoke-all with low ash yield. Additives modify the surface chemistry of the carbonaceous solids, thereby affecting the interfacial interactions. Through this research, the effects of additives on the interfacial interactions and hence on slurry viscosity were determined. Since the additives used are specific to the surface chemistry of the solids in the slurry, this knowledge aids in the selection of the appropriate additive. The study was conducted using three carbonaceous solids with different O/C ratios and an anionic and a non-ionic additive. The adsorption of the additives on the carbonaceous solids, the change in the zeta potential and hydrophobicity/hydrophilicity of the solids and the change in the free water content of the slurries were determined. The adsorption of the additives increased with an increase in the mineral matter content of the carbonaceous solids. There was also an increase in the zeta potential of the carbonaceous solids in water upon the addition of the anionic additive (up to ˜30%). However, the calculated resultant electrostatic repulsion energy upon the addition of the anionic additive was 5-6 orders of magnitude lower than the polar interaction energy of the carbonaceous solids in water. Contact angle measurements indicated that both additives changed the hydrophobicity/hydrophilicity of the solid surface (by up to 70°). This resulted in the release of bound water into the bulk slurries (up to 6%), resulting in greater fluidity. The increase in free water content of the slurries with additives was confirmed by thermogravimetric analysis (TGA). A correlation predicting the slurry viscosity on the basis of the weight fraction of free water in the slurries with additives was also developed.

Mars surface-based factory: Computer control of a water treatment system to support a space colony on Mars

NASA Technical Reports Server (NTRS)

Brice, R.; Mosley, J.; Willis, D.; Coleman, K.; Martin, C.; Shelby, L.; Kelley, U.; Renfro, E.; Griffith, G.; Warsame, A.

1989-01-01

In a continued effort to design a surface-based factory on Mars for the production of oxygen and water, the Design Group at Prairie View A&M University made a preliminary study of the surface and atmospheric composition on Mars and determined the mass densities of the various gases in the martian atmosphere. Based on the initial studies, the design group determined oxygen and water to be the two products that could be produced economically under the martian conditions. Studies were also made on present production techniques to obtain water and oxygen. Analyses were made to evaluate the current methods of production that were adaptable to the martian conditions. The detailed report was contained in an Interim Report submitted to NASA/USRA in Aug. of 1986. Even though the initial effort was the production of oxygen and water, we found it necessary to produce some diluted gases that can be mixed with oxygen to constitute 'breathable' air. In Phase 2--Task 1A, the Prairie View A&M University team completed the conceptual design of a breathable-air manufacturing system, a means of drilling for underground water, and storage of water for future use. The design objective of the team for the 1987-1988 academic year was the conceptual design of an integrated system for the supply of quality water for biological consumption, farming, and residential and industrial use. The design has also been completed. Phase 2--Task 1C is the present task for the Prairie View Design Team. This is a continuation of the previous task, and the continuation of this effort is the investigation into the extraction of water from beneath the surface and an alternative method of extraction from ice formations on the surface of Mars if accessible. In addition to investigation of water extraction, a system for computer control of extraction and treatment was developed with emphasis on fully automated control with robotic repair and maintenance. It is expected that oxygen- and water-producing plants on Mars will be limited in the amount of human control that will be available to operate large and/or isolated plants. Therefore, it is imperative that computers be integrated into plant operation with the capability to maintain life support systems and analyze and replace defective parts or systems with no human interface.

Water quality indicators obtainable from aircraft and Landsat images and their use in classifying lakes

NASA Technical Reports Server (NTRS)

Scherz, J. P.; Van Domelen, J. F.

1975-01-01

Equations describing the interaction of sunlight and skylight with the surface of a lake, particles in the water to the depth where light is extinguished, and lake bottom are presented, and the use of aircraft and Landsat images to derive water quality indicators on the basis of these interactions is discussed. A very clear, deep lake with a backscatter signal similar to that of distilled water is used as a reference standard. The degree of turbidity of other target lakes is determined by comparing their residual radiance with the clear lake standard and with the residual radiance of a lake whose turbidity has been determined from water samples. The relative and absolute strengths of residual radiance are used to determine the type and concentration of suspended material, respectively. Oil slicks are characterized by an increased specular reflectance component, decreased signal from the underlying water, and added backscatter signal from the oil volume.

Multidrug-Resistant and Extended Spectrum Beta-Lactamase-Producing Escherichia coli in Dutch Surface Water and Wastewater

PubMed Central

Blaak, Hetty; Lynch, Gretta; Italiaander, Ronald; Hamidjaja, Raditijo A.; Schets, Franciska M.; de Roda Husman, Ana Maria

2015-01-01

Objective The goal of the current study was to gain insight into the prevalence and concentrations of antimicrobial resistant (AMR) Escherichia coli in Dutch surface water, and to explore the role of wastewater as AMR contamination source. Methods The prevalence of AMR E. coli was determined in 113 surface water samples obtained from 30 different water bodies, and in 33 wastewater samples obtained at five health care institutions (HCIs), seven municipal wastewater treatment plants (mWWTPs), and an airport WWTP. Overall, 846 surface water and 313 wastewater E. coli isolates were analysed with respect to susceptibility to eight antimicrobials (representing seven different classes): ampicillin, cefotaxime, tetracycline, ciprofloxacin, streptomycin, sulfamethoxazole, trimethoprim, and chloramphenicol. Results Among surface water isolates, 26% were resistant to at least one class of antimicrobials, and 11% were multidrug-resistant (MDR). In wastewater, the proportions of AMR/MDR E. coli were 76%/62% at HCIs, 69%/19% at the airport WWTP, and 37%/27% and 31%/20% in mWWTP influents and effluents, respectively. Median concentrations of MDR E. coli were 2.2×102, 4.0×104, 1.8×107, and 4.1×107 cfu/l in surface water, WWTP effluents, WWTP influents and HCI wastewater, respectively. The different resistance types occurred with similar frequencies among E. coli from surface water and E. coli from municipal wastewater. By contrast, among E. coli from HCI wastewater, resistance to cefotaxime and resistance to ciprofloxacin were significantly overrepresented compared to E. coli from municipal wastewater and surface water. Most cefotaxime-resistant E. coliisolates produced ESBL. In two of the mWWTP, ESBL-producing variants were detected that were identical with respect to phylogenetic group, sequence type, AMR-profile, and ESBL-genotype to variants from HCI wastewater discharged onto the same sewer and sampled on the same day (A1/ST23/CTX-M-1, B23/ST131/CTX-M-15, D2/ST405/CTX-M-15). Conclusion In conclusion, our data show that MDR E. coli are omnipresent in Dutch surface water, and indicate that municipal wastewater significantly contributes to this occurrence. PMID:26030904

National Water Quality Laboratory Profile

USGS Publications Warehouse

Raese, Jon W.

1994-01-01

The National Water Quality Laboratory determines organic and inorganic constituents in samples of surface and ground water, river and lake sediment, aquatic plant and animal material, and precipitation collected throughout the United States and its territories by the U.S. Geological Survey. In water year 1994, the Laboratory produced more than 900,000 analytical results for about 65,000 samples. The Laboratory also coordinates an extensive network of contract laboratories for the determination of radiochemical and stable isotopes and work for the U.S. Department of Defense Environmental Contamination Hydrology Program. Heightened concerns about water quality and about the possible effects of toxic chemicals at trace and ultratrace levels have contributed to an increased demand for impartial, objective, and independent data.

HYDROBIOLOGICAL CHARACTERISTICS OF THE COASTAL LAGOONS AT HUGH TAYLOR BIRCH STATE RECREATION AREA, FORT LAUDERDALE, FLORIDA: A HISTORICAL PERSPECTIVE.

USGS Publications Warehouse

Brock, Robert J.

1987-01-01

The author presents initial results of an ongoing study of Southeast Florida coastal lagoon lakes. Objectives include presenting environmental conditions within and adjacent to the lagoons under a variety of hydrologic conditions and to determine water-quality changes in ground water and surface water and how these changes in water quality affect lagoonal biological communities within the lagoons.