Chemical characteristics of surface systems in the Simpevarp area. Visualisation and statistical evaluation of data from surface water, precipitation, shallow groundwater, and regolith

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-01-15

The Swedish Nuclear Fuel and Waste management Co (SKB) initiated site investigations for a deep repository for spent nuclear fuel at two different sites in Sweden, Forsmark and Oskarshamn, in 2002. This report evaluates the results from chemical investigations of the surface system in the Simpevarp area in Oskarshamn, i.e. both the Laxemar subarea and the Simpevarp subarea, during the period Nov 2002 - Mar 2005. The evaluation includes data from surface waters (lakes, streams and the sea), precipitation, shallow groundwater and regolith (till, soil, peat, sediments and biota) in the area. The main focus of the study is to visualize the vast amount of data collected hitherto in the site investigations, and to give a chemical characterisation of the investigated media at the site. The results will be used to support the site descriptive models, which in turn are used for safety assessment studies and for the environmental impact assessment. The data used consist of water chemical composition in lakes, streams and coastal sites, and in precipitation, predominantly sampled on a monthly basis, and in groundwater from soil tubes and wells. Moreover, regolith data includes information on the chemical composition of till, soil, sediment and vegetation samples from the area. The characterisations include all measured chemical parameters, i.e. major and minor constituents, trace elements, nutrients, isotopes and radio nuclides, as well as field measured parameters. The evaluation of data from each medium has been divided into the following parts: Characterisation of individual sampling sites, and comparisons within and among sampling sites as well as comparisons with local, regional and national reference data. Analysis of time trends and seasonal variation (for surface waters). Exploration of relationships among the various chemical parameters. For all investigated parameters, the report presents selected statistics for each sampling site, as well as for available reference

Chemical characteristics of surface systems in the Simpevarp area. Visualisation and statistical evaluation of data from surface water, precipitation, shallow groundwater, and regolith

International Nuclear Information System (INIS)

Troejbom, Mats; Soederbaeck, Bjoern

2006-01-01

The Swedish Nuclear Fuel and Waste management Co (SKB) initiated site investigations for a deep repository for spent nuclear fuel at two different sites in Sweden, Forsmark and Oskarshamn, in 2002. This report evaluates the results from chemical investigations of the surface system in the Simpevarp area in Oskarshamn, i.e. both the Laxemar subarea and the Simpevarp subarea, during the period Nov 2002 - Mar 2005. The evaluation includes data from surface waters (lakes, streams and the sea), precipitation, shallow groundwater and regolith (till, soil, peat, sediments and biota) in the area. The main focus of the study is to visualize the vast amount of data collected hitherto in the site investigations, and to give a chemical characterisation of the investigated media at the site. The results will be used to support the site descriptive models, which in turn are used for safety assessment studies and for the environmental impact assessment. The data used consist of water chemical composition in lakes, streams and coastal sites, and in precipitation, predominantly sampled on a monthly basis, and in groundwater from soil tubes and wells. Moreover, regolith data includes information on the chemical composition of till, soil, sediment and vegetation samples from the area. The characterisations include all measured chemical parameters, i.e. major and minor constituents, trace elements, nutrients, isotopes and radio nuclides, as well as field measured parameters. The evaluation of data from each medium has been divided into the following parts: Characterisation of individual sampling sites, and comparisons within and among sampling sites as well as comparisons with local, regional and national reference data. Analysis of time trends and seasonal variation (for surface waters). Exploration of relationships among the various chemical parameters. For all investigated parameters, the report presents selected statistics for each sampling site, as well as for available reference

Experimental study on soluble chemical transfer to surface runoff from soil.

Science.gov (United States)

Tong, Juxiu; Yang, Jinzhong; Hu, Bill X; Sun, Huaiwei

2016-10-01

Prevention of chemical transfer from soil to surface runoff, under condition of irrigation and subsurface drainage, would improve surface water quality. In this paper, a series of laboratory experiments were conducted to assess the effects of various soil and hydraulic factors on chemical transfer from soil to surface runoff. The factors include maximum depth of ponding water on soil surface, initial volumetric water content of soil, depth of soil with low porosity, type or texture of soil and condition of drainage. In the experiments, two soils, sand and loam, mixed with different quantities of soluble KCl were filled in the sandboxes and prepared under different initial saturated conditions. Simulated rainfall induced surface runoff are operated in the soils, and various ponding water depths on soil surface are simulated. Flow rates and KCl concentration of surface runoff are measured during the experiments. The following conclusions are made from the study results: (1) KCl concentration in surface runoff water would decrease with the increase of the maximum depth of ponding water on soil surface; (2) KCl concentration in surface runoff water would increase with the increase of initial volumetric water content in the soil; (3) smaller depth of soil with less porosity or deeper depth of soil with larger porosity leads to less KCl transfer to surface runoff; (4) the soil with finer texture, such as loam, could keep more fertilizer in soil, which will result in more KCl concentration in surface runoff; and (5) good subsurface drainage condition will increase the infiltration and drainage rates during rainfall event and will decrease KCl concentration in surface runoff. Therefore, it is necessary to reuse drained fertile water effectively during rainfall, without polluting groundwater. These study results should be considered in agriculture management to reduce soluble chemical transfer from soil to surface runoff for reducing non-point sources pollution.

Chemical quality of surface waters in Devils Lake basin, North Dakota

Science.gov (United States)

Swenson, Herbert; Colby, Bruce R.

1955-01-01

fallen slowly. Hydrologic changes that may have caused Devils Lake to alter from a very large, moderately deep lake of fresh water to a small, shallow body of brackish water are discussed and evaluated on the basis of scanty information. During several years of average precipitation, temperature, and evaporation, Devils Lake and lakes upstream should receive nearly a quarter of an inch of runoff annually from the drainage area of about 3,000 square miles. Approximately 55 square miles of tributary area would be required to maintain each square mile of lake surface. However, runoff, expressed as percentage of the average, differs greatly from year to year. The amount of runoff retained in upstream lakes also Varies greatly. For these two reasons, annual inflow to Devils Lake is extremely variable. Because many waterways in this basin have no surface outlets at normal stages, runoff collects in depressions, is concentrated by evaporation, and forms saline or alkaline lakes. The chemical and physical properties of the lake waters vary chiefly with changes in lake stage and volume of inflow. Scattered records from 1899 to 1923 and more comprehensive data from 1948 to 1952 show a range of salt concentration from 6,130 to 25,000 parts per million (ppm) in the water of Devils Lake. Although concentration has varied, the chemical composition of the dissolved solids has not changed appreciably. Lake waters are more concentrated in the lower part of the basin, downstream from Devils Lake. For periods of record the salt concentration ranged from 14,932 to 62,000 ppm in East Devils Lake and from 19,000 to 106,000 ppm in east Stump Lake. Current and past tonnages of dissolved solids in Devils Lake, East Bay Devils Lake, East Devils Lake, and east and west Stump Lakes were computed from concentrations and from altitude-capacity curves for each lake. Neither the average rate of diversion of water to restore Devils Lake to a higher level nor the quality of the divert

Chemical surface modification of glass beads for the treatment of paper machine process waters

International Nuclear Information System (INIS)

Jradi, Khalil; Daneault, Claude; Chabot, Bruno

2011-01-01

Adsorption of detrimental contaminants on a solid sorbent is proposed to remove these contaminants from process waters to increase water recycling and reduce effluent loads in the papermaking industry. A self-assembly process of attaching (covalent grafting) cationic aminosilane molecules to glass beads was investigated. The existence and the hydrolytic stability of self-assembled monolayers and multilayers were confirmed by X-Ray Photoelectron Spectroscopy and contact angle measurements. Effects of reaction time and curing on aminosilane layer structures are also discussed. The curing step after silanization seems to be crucial in the hydrophobization of the quaternary ammonium silane coated onto glass beads, and curing could affect the final chemical structure of the ammonium groups of grafted organosilane. Results indicated that modified glass beads have a strong hydrophobicity, which is attributed to the hydrophobic property of the longest carbon chain grafted onto the glass surface. Adsorption of a model contaminant (stearic acid) onto chemically modified glass beads was determined using colloidal titration. Hydrophobic interactions could be the main driving force involved between the long carbon chains of stearic acid and the carbon chains of the aminosilane layers on glass bead surfaces. Finally, self-assembly processes applied onto glass beads may have two promising applications for papermaking and self-cleaning systems.

Shake-flask test for determination of biodegradation rates of 14C-labelled chemicals at low concentrations in surface water systems

DEFF Research Database (Denmark)

Ingerslev, F.; Nyholm, Niels

2000-01-01

A simple shake-flask surface water biodegradability die away test with C-14-labeled chemicals added to microgram per liter concentrations (usually 1-100 mu g/L) is described and evaluated. The aim was to provide information on biodegradation behavior and kinetic rates at environmental (low...... regular reinoculation with freshly collected surface water could, however, overcome the problems of false-negative results. (C) 2000 Academic Press....

Surface chemical problems in coal flotation

Science.gov (United States)

Taylor, S. R.; Miller, K. J.; Deurbrouck, A. W.

1981-02-01

As the use of coal increases and more fine material is produced by mining and processing, the need for improved methods of coal beneficiation increases. While flotation techniques can help meet these needs, the technique is beset with many problems. These problems involve surface chemical and interfacial properties of the coal-mineral-water slurry systems used in coal flotation. The problems associated with coal flotation include non-selectivity, inefficient reagent utilization, and excessive variablity of results. These problems can be broadely classified as a lack of predictability. The present knowledge of coal flotation is not sufficient, in terms of surface chemical parameters, to allow prediction of the flotation response of a given coal. In this paper, some of the surface chemical properties of coal and coal minerals that need to be defined will be discussed in terms of the problems noted above and their impact on coal cleaning.

Chemical and toxicologic assessment of organic contaminants in surface water using passive samplers

Science.gov (United States)

Alvarez, D.A.; Cranor, W.L.; Perkins, S.D.; Clark, R.C.; Smith, S.B.

2008-01-01

Passive sampling methodologies were used to conduct a chemical and toxicologic assessment of organic contaminants in the surface waters of three geographically distinct agricultural watersheds. A selection of current-use agrochemicals and persistent organic pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides, were targeted using the polar organic chemical integrative sampler (POCIS) and the semipermeable membrane device passive samplers. In addition to the chemical analysis, the Microtox assay for acute toxicity and the yeast estrogen screen (YES) were conducted as potential assessment tools in combination with the passive samplers. During the spring of 2004, the passive samplers were deployed for 29 to 65 d at Leary Weber Ditch, IN; Morgan Creek, MD; and DR2 Drain, WA. Chemical analysis of the sampler extracts identified the agrochemicals predominantly used in those areas, including atrazine, simazine, acetochlor, and metolachlor. Other chemicals identified included deethylatrazine and deisopropylatrazine, trifluralin, fluoranthene, pyrene, cis- and trans-nonachlor, and pentachloroanisole. Screening using Microtox resulted in no acutely toxic samples. POCIS samples screened by the YES assay failed to elicit a positive estrogenic response. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Chemical application strategies to protect water quality.

Science.gov (United States)

Rice, Pamela J; Horgan, Brian P; Barber, Brian L; Koskinen, William C

2018-07-30

Management of turfgrass on golf courses and athletic fields often involves application of plant protection products to maintain or enhance turfgrass health and performance. However, the transport of fertilizer and pesticides with runoff to adjacent surface waters can enhance algal blooms, promote eutrophication and may have negative impacts on sensitive aquatic organisms and ecosystems. Thus, we evaluated the effectiveness of chemical application setbacks to reduce the off-site transport of chemicals with storm runoff. Experiments with water soluble tracer compounds confirmed an increase in application setback distance resulted in a significant increase in the volume of runoff measured before first off-site chemical detection, as well as a significant reduction in the total percentage of applied chemical transported with the storm runoff. For example, implementation of a 6.1 m application setback reduced the total percentage of an applied water soluble tracer by 43%, from 18.5% of applied to 10.5% of applied. Evaluation of chemographs revealed the efficacy of application setbacks could be observed with storms resulting in lesser (e.g. 100 L) and greater (e.g. > 300 L) quantities of runoff. Application setbacks offer turfgrass managers a mitigation approach that requires no additional resources or time inputs and may serve as an alternative practice when buffers are less appropriate for land management objectives or site conditions. Characterizing potential contamination of surface waters and developing strategies to safeguard water quality will help protect the environment and improve water resource security. This information is useful to grounds superintendents for designing chemical application strategies to maximize environmental stewardship. The data will also be useful to scientists and regulators working with chemical transport and risk models. Copyright © 2018. Published by Elsevier Inc.

Chemical characteristics of surface waters in the Forsmark area. Evaluation of data from lakes, streams and coastal sites

International Nuclear Information System (INIS)

Sonesten, Lars

2005-06-01

This report is an evaluation of the chemical composition of surface water in lakes, streams, and at coastal sampling sites in the Forsmark area. The aim with this study is to characterise the surface water systems in the area, and the further aim with this characterisation is to be used as input material to the safety analyses and environmental impact assessments for the potential deep repository of used nuclear fuels. The data used consist of water chemical composition of lakes, streams and coastal sites from the period March 2002 - April 2004. The sampling has been performed predominantly on a monthly basis. The emphasis of the assessment has been on surface waters (0.5 m), as the water depth at all sampling locations is limited, and thereby the water systems are rarely stratified for prolonged periods. The characterisations have been restricted to the most commonly measured chemical parameters.The assessment has been divided into three parts: Comparisons within and between the lakes, streams, and coastal sites, respectively; Temporal and spatial variation, predominantly within lakes and stream sites; and Relationships between the various chemical parameters. Beside comparisons between the sampling sites within the Forsmark area, comparisons have also been made with regional and national data from the latest Swedish National Survey (2000). The analyses of temporal and spatial variation have been concentrated on the freshwater systems in the Norra Bassaengen catchment area. This catchment area is the most comprehensively investigated, and it also includes the Bolundsfjaerden sub-catchment, which is the area where the continued site investigations will be concentrated. The relationships among the sampling sites, the catchment areas, as well as the chemical parameters investigated, were examined by applying PCA analyses on the lake and stream data. In general, the freshwater systems in the Forsmark area are characterised by small and shallow oligotrophic hardwater

Chemical characteristics of surface waters in the Forsmark area. Evaluation of data from lakes, streams and coastal sites

Energy Technology Data Exchange (ETDEWEB)

Sonesten, Lars [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Environmental Assessment

2005-06-01

This report is an evaluation of the chemical composition of surface water in lakes, streams, and at coastal sampling sites in the Forsmark area. The aim with this study is to characterise the surface water systems in the area, and the further aim with this characterisation is to be used as input material to the safety analyses and environmental impact assessments for the potential deep repository of used nuclear fuels. The data used consist of water chemical composition of lakes, streams and coastal sites from the period March 2002 - April 2004. The sampling has been performed predominantly on a monthly basis. The emphasis of the assessment has been on surface waters (0.5 m), as the water depth at all sampling locations is limited, and thereby the water systems are rarely stratified for prolonged periods. The characterisations have been restricted to the most commonly measured chemical parameters.The assessment has been divided into three parts: Comparisons within and between the lakes, streams, and coastal sites, respectively; Temporal and spatial variation, predominantly within lakes and stream sites; and Relationships between the various chemical parameters. Beside comparisons between the sampling sites within the Forsmark area, comparisons have also been made with regional and national data from the latest Swedish National Survey (2000). The analyses of temporal and spatial variation have been concentrated on the freshwater systems in the Norra Bassaengen catchment area. This catchment area is the most comprehensively investigated, and it also includes the Bolundsfjaerden sub-catchment, which is the area where the continued site investigations will be concentrated. The relationships among the sampling sites, the catchment areas, as well as the chemical parameters investigated, were examined by applying PCA analyses on the lake and stream data. In general, the freshwater systems in the Forsmark area are characterised by small and shallow oligotrophic hardwater

Physico-chemical and mineralogical properties influencing water-stability of aggregates of some Italian surface soils

International Nuclear Information System (INIS)

Mbagwu, J.S.C.; Bazzoffi, P.; Unamba Oparah, I.

1994-06-01

A laboratory study was conducted to determine the relationship between physical, chemical and mineralogical properties of some surface soils (developed in north central Italy) and the stability of their aggregates to water. The index of stability used is the mean-weight diameter of water-stable aggregates (MWD). The ratio of total sand to clay which correlated negatively with MWD (r=-0.638) is the physical property which explained most of the variability in aggregate stability. The chemical properties which correlated best with aggregate stability are FeO (r=0.671), CaO (R=0.635), CaCO 3 (r=0.651) and SiO 2 (r=-0.649). Feldspar, chlorite and calcite are the minerals which influence MWD most, with respective ''r'' values of -0.627, 0.588 and 0.550. The best-fit model developed from soil physical properties explained 59% of the variation in MWD with a standard error of 0.432, that developed from chemical properties explained 97% of the variation in MWD with a standard error of 0.136, whereas the model developed from mineralogical properties explained 78% of the variation in MWD with a standard error of 0.222. Also the closest relationship between measured and model-predicted MWD was obtained with the chemical properties-based model (r=0.985), followed by the mineralogical properties-based model (r=0.884) and then the physical properties-based model (r=0.656). This indicates that the most reliable inference on the stability of these soils in water can be made from a knowledge of the amount and composition of their chemical constituents. (author). 32 refs, 1 fig., 9 tabs

Physico-chemical analyses and corrosion effect of produced water ...

African Journals Online (AJOL)

Physico-chemical characteristics of the composite produced water sample used for the study has a higher concentration compared with DPR standard for discharge of produced formation water into surface environment. It was assumed that the corrosion of the coupons was due to presence of high chemical matters in the ...

Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

Directory of Open Access Journals (Sweden)

Priya Varshney

2016-10-01

Full Text Available In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating and one-step (chemical etching and coating in a single step processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°. Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.

Evaluation of arsenic and other physico-chemical parameters of surface and ground water of Jamshoro, Pakistan

International Nuclear Information System (INIS)

Baig, Jameel Ahmed; Kazi, Tasneem Gul; Arain, Muhammad Balal; Afridi, Hassan Imran; Kandhro, Ghulam Abbas; Sarfraz, Raja Adil; Jamal, Muhammad Khan; Shah, Abdul Qadir

2009-01-01

Arsenic contamination in water has caused severe health problems around the world. The purpose of this study was to evaluate the geological and anthropogenic aspects of As pollution in surface and groundwater resources of Jamshoro Sindh, Pakistan. Hydride generator atomic absorption spectrophotometry (HG-AAS) is employed for the determination of arsenic in water samples, with detection limit of 0.02 μg l -1 . Arsenic concentrations in surface and underground water range from 3.0 to 50.0, and 13 to 106 μg l -1 , respectively. In most of the water samples As levels exceeded the WHO provisional guideline values 10 μg l -1 . The high level of As in under study area may be due to widespread water logging from Indus river irrigation system which causes high saturation of salts in this semi-arid region and lead to enrichment of As in shallow groundwater. Among the physico-chemical parameters, electrical conductivity, Na + , K + , and SO 4 2- were found to be higher in surface and ground water, while elevated levels of Ca 2+ and Cl - were detected only in ground water than WHO permissible limit. The high level of iron was observed in ground water, which is a possible source of As enrichment in the study area. The multivariate technique (cluster analysis) was used for the elucidation of high, medium and low As contaminated areas. It may be concluded that As originate from coal combustion at brick factories and power generation plants, and it was mobilized promotionally by the alkaline nature of the understudy groundwater samples.

chemical and microbiological assessment of surface water samples

African Journals Online (AJOL)

PROF EKWUEME

were investigated in this study: Nine samples from different surface water bodies, two samples from two effluent sources ... Ezeagu, Udi, Nkanu, Oji River and some parts of Awgu and Aninri ..... Study of Stream Output from Small Catchments.

Presence of active pharmaceutical ingredients in the continuum of surface and ground water used in drinking water production.

Science.gov (United States)

Ahkola, Heidi; Tuominen, Sirkku; Karlsson, Sanja; Perkola, Noora; Huttula, Timo; Saraperä, Sami; Artimo, Aki; Korpiharju, Taina; Äystö, Lauri; Fjäder, Päivi; Assmuth, Timo; Rosendahl, Kirsi; Nysten, Taina

2017-12-01

Anthropogenic chemicals in surface water and groundwater cause concern especially when the water is used in drinking water production. Due to their continuous release or spill-over at waste water treatment plants, active pharmaceutical ingredients (APIs) are constantly present in aquatic environment and despite their low concentrations, APIs can still cause effects on the organisms. In the present study, Chemcatcher passive sampling was applied in surface water, surface water intake site, and groundwater observation wells to estimate whether the selected APIs are able to end up in drinking water supply through an artificial groundwater recharge system. The API concentrations measured in conventional wastewater, surface water, and groundwater grab samples were assessed with the results obtained with passive samplers. Out of the 25 APIs studied with passive sampling, four were observed in groundwater and 21 in surface water. This suggests that many anthropogenic APIs released to waste water proceed downstream and can be detectable in groundwater recharge. Chemcatcher passive samplers have previously been used in monitoring several harmful chemicals in surface and wastewaters, but the path of chemicals to groundwater has not been studied. This study provides novel information on the suitability of the Chemcatcher passive samplers for detecting APIs in groundwater wells.

Sampling procedure for lake or stream surface water chemistry

Science.gov (United States)

Robert Musselman

2012-01-01

Surface waters collected in the field for chemical analyses are easily contaminated. This research note presents a step-by-step detailed description of how to avoid sample contamination when field collecting, processing, and transporting surface water samples for laboratory analysis.

Evaluation of arsenic and other physico-chemical parameters of surface and ground water of Jamshoro, Pakistan

Energy Technology Data Exchange (ETDEWEB)

Baig, Jameel Ahmed, E-mail: jab_mughal@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kazi, Tasneem Gul, E-mail: tgkazi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Arain, Muhammad Balal, E-mail: bilal_KU2004@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Afridi, Hassan Imran, E-mail: hassanimranafridi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kandhro, Ghulam Abbas, E-mail: gakandhro@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Sarfraz, Raja Adil, E-mail: rajaadilsarfraz@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Jamal, Muhammad Khan, E-mail: mkhanjamali@yahoo.com [Government Degree College Usta Muhammad, Balochistan 08300 (Pakistan); Shah, Abdul Qadir, E-mail: aqshah07@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)

2009-07-30

Arsenic contamination in water has caused severe health problems around the world. The purpose of this study was to evaluate the geological and anthropogenic aspects of As pollution in surface and groundwater resources of Jamshoro Sindh, Pakistan. Hydride generator atomic absorption spectrophotometry (HG-AAS) is employed for the determination of arsenic in water samples, with detection limit of 0.02 {mu}g l{sup -1}. Arsenic concentrations in surface and underground water range from 3.0 to 50.0, and 13 to 106 {mu}g l{sup -1}, respectively. In most of the water samples As levels exceeded the WHO provisional guideline values 10 {mu}g l{sup -1}. The high level of As in under study area may be due to widespread water logging from Indus river irrigation system which causes high saturation of salts in this semi-arid region and lead to enrichment of As in shallow groundwater. Among the physico-chemical parameters, electrical conductivity, Na{sup +}, K{sup +}, and SO{sub 4}{sup 2-} were found to be higher in surface and ground water, while elevated levels of Ca{sup 2+} and Cl{sup -} were detected only in ground water than WHO permissible limit. The high level of iron was observed in ground water, which is a possible source of As enrichment in the study area. The multivariate technique (cluster analysis) was used for the elucidation of high, medium and low As contaminated areas. It may be concluded that As originate from coal combustion at brick factories and power generation plants, and it was mobilized promotionally by the alkaline nature of the understudy groundwater samples.

Surface Water in Hawaii

Science.gov (United States)

Oki, Delwyn S.

2003-01-01

Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

Particle dry deposition to water surfaces: Processes and consequences

DEFF Research Database (Denmark)

Pryor, S.C.; Barthelmie, R.J.

2000-01-01

flux to coastal waters, atmosphere-surface exchange represents a significant component of the total flux and may be particularly critical during the summertime when both the riverine input and ambient nutrient concentrations are often at a minimum. In this chapter, we present an overview...... of the physical and chemical processes which dictate the quantity (and direction) of atmosphere-surface fluxes of trace chemicals to (and above) water surfaces with particular emphasis on the role of particles. Dry deposition (transfer to the surface in the absence of precipitation) of particles is determined...... efforts to simulate and measure fluxes close to the coastline. These arise in part from the complexity of atmospheric flow in this region where energy and chemical fluxes are highly inhomogeneous in space and time and thermally generated atmospheric circulations are commonplace. (C) 2000 Elsevier Science...

Modelling episodic acidification of surface waters: the state of science.

Science.gov (United States)

Eshleman, K N; Wigington, P J; Davies, T D; Tranter, M

1992-01-01

Field studies of chemical changes in surface waters associated with rainfall and snowmelt events have provided evidence of episodic acidification of lakes and streams in Europe and North America. Modelling these chemical changes is particularly challenging because of the variability associated with hydrological transport and chemical transformation processes in catchments. This paper provides a review of mathematical models that have been applied to the problem of episodic acidification. Several empirical approaches, including regression models, mixing models and time series models, support a strong hydrological interpretation of episodic acidification. Regional application of several models has suggested that acidic episodes (in which the acid neutralizing capacity becomes negative) are relatively common in surface waters in several regions of the US that receive acid deposition. Results from physically based models have suggested a lack of understanding of hydrological flowpaths, hydraulic residence times and biogeochemical reactions, particularly those involving aluminum. The ability to better predict episodic chemical responses of surface waters is thus dependent upon elucidation of these and other physical and chemical processes.

Aerobic biodegradation potential of endocrine disrupting chemicals in surface-water sediment at Rocky Mountains National Park, USA

Science.gov (United States)

Bradley, Paul M.; Battaglin, William A.; Iwanowicz, Luke R.; Clark, Jimmy M.; Journey, Celeste A.

2016-01-01

Endocrine disrupting chemicals (EDC) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDC, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountains National Park (ROMO). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 14C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. ROMO bed sediment microbial communities also effectively degraded the xenoestrogens, bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The current results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged.

Water surface coverage effects on reactivity of plasma oxidized Ti films

International Nuclear Information System (INIS)

Pranevicius, L.; Pranevicius, L.L.; Vilkinis, P.; Baltaragis, S.; Gedvilas, K.

2014-01-01

Highlights: • The reactivity of Ti films immersed in water vapor plasma depends on the surface water coverage. • The adsorbed water monolayers are disintegrated into atomic constituents on the hydrophilic TiO 2 under plasma radiation. • The TiO 2 surface covered by water multilayer loses its ability to split adsorbed water molecules under plasma radiation. - Abstract: The behavior of the adsorbed water on the surface of thin sputter deposited Ti films maintained at room temperature was investigated in dependence on the thickness of the resulting adsorbed water layer, controllably injecting water vapor into plasma. The surface morphology and microstructure were used to characterize the surfaces of plasma treated titanium films. Presented experimental results showed that titanium films immersed in water vapor plasma at pressure of 10–100 Pa promoted the photocatalytic activity of overall water splitting. The surfaces of plasma oxidized titanium covered by an adsorbed hydroxyl-rich island structure water layer and activated by plasma radiation became highly chemically reactive. As water vapor pressure increased up to 300–500 Pa, the formed water multilayer diminished the water oxidation and, consequently, water splitting efficiency decreased. Analysis of the experimental results gave important insights into the role an adsorbed water layer on surface of titanium exposed to water vapor plasma on its chemical activity and plasma activated electrochemical processes, and elucidated the surface reactions that could lead to the split of water molecules

Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources.

Science.gov (United States)

Brack, Werner; Dulio, Valeria; Ågerstrand, Marlene; Allan, Ian; Altenburger, Rolf; Brinkmann, Markus; Bunke, Dirk; Burgess, Robert M; Cousins, Ian; Escher, Beate I; Hernández, Félix J; Hewitt, L Mark; Hilscherová, Klára; Hollender, Juliane; Hollert, Henner; Kase, Robert; Klauer, Bernd; Lindim, Claudia; Herráez, David López; Miège, Cécil; Munthe, John; O'Toole, Simon; Posthuma, Leo; Rüdel, Heinz; Schäfer, Ralf B; Sengl, Manfred; Smedes, Foppe; van de Meent, Dik; van den Brink, Paul J; van Gils, Jos; van Wezel, Annemarie P; Vethaak, A Dick; Vermeirssen, Etienne; von der Ohe, Peter C; Vrana, Branislav

2017-01-15

Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for the protection and sustainable use of European freshwater resources. The practical implementation of the WFD with regard to chemical pollution has faced some challenges. In support of the upcoming WFD review in 2019 the research project SOLUTIONS and the European monitoring network NORMAN has analyzed these challenges, evaluated the state-of-the-art of the science and suggested possible solutions. We give 10 recommendations to improve monitoring and to strengthen comprehensive prioritization, to foster consistent assessment and to support solution-oriented management of surface waters. The integration of effect-based tools, the application of passive sampling for bioaccumulative chemicals and an integrated strategy for prioritization of contaminants, accounting for knowledge gaps, are seen as important approaches to advance monitoring. Including all relevant chemical contaminants in more holistic "chemical status" assessment, using effect-based trigger values to address priority mixtures of chemicals, to better consider historical burdens accumulated in sediments and to use models to fill data gaps are recommended for a consistent assessment of contamination. Solution-oriented management should apply a tiered approach in investigative monitoring to identify toxicity drivers, strengthen consistent legislative frameworks and apply solutions-oriented approaches that explore risk reduction scenarios before and along with risk assessment. Copyright © 2016. Published by Elsevier B.V.

Modification of surface properties of LLDPE by water plasma discharge

International Nuclear Information System (INIS)

Chantara Thevy Ratnam; Hill, D.J.T.; Firas Rasoul; Whittaker, A.K.; Imelda Keen

2007-01-01

Linear low density polyethylene (LLDPE) surface was modified by water plasma treatment. The LLDPE surface was treated at 10 and 20 W discharge power at various exposure times. A laboratory scale Megatherm radio frequency (RF) plasma apparatus that operates at 27 MHz was used to generate the water plasmas. The changes in chemical structure of the LLDPE polymeric chain upon plasma treatment were characterized by FTIR and XPS techniques. The selectivity of trifluoroacetic anhydride (TFAA) toward hydroxyl groups is used to quantify the hydroxyl groups formed on the polymer surface upon plasma treatment. After exposition to the plasma discharge a decline in water contact angle were observed. FTIR and XPS measurements indicate an oxidation of degraded polymeric chains and creation of hydroxyl, carbonyl, ether, ester and carboxyl groups. Chemical derivatization with TFAA of water plasma treated polymer surfaces has shown that under the conditions employed, a very small (less than 5%) of the oxygen introduced by the water plasma treatment was present as hydroxyl group. (Author)

Building surface decontamination for chemical counter-terrorism

Energy Technology Data Exchange (ETDEWEB)

Harrison, S.; Thouin, G.; Kuang, W. [SAIC Canada, Ottawa, ON (Canada); Volchek, K.; Fingas, M.; Li, K. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Division, Environmental Technology Centre, Science and Technology Branch

2006-07-01

A test method to compare and evaluate surface decontamination methods for buildings affected by chemical attacks was developed. Decontamination techniques generally depend on the nature and quantity of the weapon agent, the type of construction material and the location. Cleanup methods can be either physical, chemical or biological. This paper addressed chemical decontamination methods which use reactants to change the molecular structure of the contaminant. Peroxycarboxylic and peroxyacetic acids (PAA) are being used increasingly for both disinfection and environmental protection. In this study, 4 materials were chosen to represent common building materials. Samples were spiked with 10 mg of pesticides such as malathion and diazinon. Decontamination agents included the commercial decontamination agent CASCAD prepared in liquid form, a chemical preparation of PAA, and reagent grade peroxypropionic acid (PPA). The newly developed surface decontamination procedure can evaluate and compare the effectiveness of different chemical decontamination agents. The procedures were used on porous ceiling tile and carpet as well as on non-porous floor tile and painted steel surfaces. Rinse water was collected and analyzed in order to determine if decontamination was a result of chemical destruction or mechanical removal. The extraction efficiencies were found to be acceptable for all materials, with the exception of the highly porous ceiling tile. The extraction of diazinon from all surfaces was less efficient than the extraction of malathion. Results suggest that the performance of decontamination agents can be improved by repeated application of the decontamination agent, along with greater volumes and a combination of chemical and mechanical actions. It was also suggested that breakdown methods and wastewater treatment procedures should be developed because hazardous byproducts were detected in many samples. 18 refs., 1 tab., 17 figs.

Chemical Gel for Surface Decontamination

International Nuclear Information System (INIS)

Jung, Chong Hun; Moon, J. K.; Won, H. J.; Lee, K. W.; Kim, C. K.

2010-01-01

Many chemical decontamination processes operate by immersing components in aggressive chemical solutions. In these applications chemical decontamination technique produce large amounts of radioactive liquid waste. Therefore it is necessary to develop processes using chemical gels instead of chemical solutions, to avoid the well-known disadvantages of chemical decontamination techniques while retaining their high efficiency. Chemical gels decontamination process consists of applying the gel by spraying it onto the surface of large area components (floors, walls, etc) to be decontaminated. The gel adheres to any vertical or complex surface due to their thixotropic properties and operates by dissolving the radioactive deposit, along with a thin layer of the gel support, so that the radioactivity trapped at the surface can be removed. Important aspects of the gels are that small quantities can be used and they show thixitropic properties : liquid during spraying, and solid when stationary, allowing for strong adherence to surfaces. This work investigates the decontamination behaviors of organic-based chemical gel for SS 304 metallic surfaces contaminated with radioactive materials

Chemical bonding of water to metal surfaces studied with core-level spectroscopies

DEFF Research Database (Denmark)

Schiros, T.; Andersson, Klas Jerker; Pettersson, L.G.M.

2010-01-01

The nature of the contact layer of water on surfaces is of relevance for many practical fields, including corrosion, electrochemistry, environmental science and heterogeneous catalysis. Here we focus on the geometric and electronic structure of the water contact layer on transition metal surfaces......-specific information on the partial local density of states, local atomic structure, geometrical parameters and molecular orientation, allowing general principles for water-metal interaction to be derived....

Occurrence of Surface Water Contaminations: An Overview

Science.gov (United States)

Shahabudin, M. M.; Musa, S.

2018-04-01

Water is a part of our life and needed by all organisms. As time goes by, the needs by human increased transforming water quality into bad conditions. Surface water contaminated in various ways which is pointed sources and non-pointed sources. Pointed sources means the source are distinguished from the source such from drains or factory but the non-pointed always occurred in mixed of elements of pollutants. This paper is reviewing the occurrence of the contaminations with effects that occurred around us. Pollutant factors from natural or anthropology factors such nutrients, pathogens, and chemical elements contributed to contaminations. Most of the effects from contaminated surface water contributed to the public health effects also to the environments.

Models of Fate and Transport of Pollutants in Surface Waters

Science.gov (United States)

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.…

Physico-chemical state of mercury, cadmium, and zinc in surface waters of arid zone of the USSR

International Nuclear Information System (INIS)

Kulmatov, R.A.; Rakhmatov, U.; Kist, A.A.; Savenko, V.S.

1983-01-01

Experimental study was made on physico-chemical state of high-toxic heavy metals (Zn, Cd, and Hg) in waters of the Aral Sea and the Syr Darya and the Amu Darya rivers, representing the basic resrevoirs of surface waters of the Middle Asia. The complex of high-sensitive and selective radioanalytical techniques was developed for solution of the problem. The complex uncludes ultrafiltration, centrifugation, electrodialysis, sorption on sorbents of different nature, as well as neutron activation analysis. It was established that the major part of Hg, Cd and Zn can migrate in surface waters of the Middle Asia in the form of real and colloidal solutions. Zn and Cd are characterized by the prevalence of cationic really dissolved forms and Hg-anionic neutral and colloidal forms. The presence of the major mass of the given elements in the form of real and the finest colloids which are rather stable forms and can be transfered to long distances points to the promising character of applying hydrochemical methods of prospecting in arid zone of the USSR, because dispersion aureoles must be sufficiently wide. Possibility of formation of large aureoles of natural water contamination in the regions of mining and metallurgical enterprises must be considered as well

Part 2: Surface water quality

International Nuclear Information System (INIS)

1997-01-01

In 1996 the surface water quality measurements were performed, according to the Agreement, at 8 profiles on the Hungarian territory and at 15 profiles on the Slovak territory. Basic physical and chemical parameters (as water temperature, pH values, conductivity, suspended solids, cations and anions (nitrates, ammonium ion, nitrites, total nitrogen, phosphates, total phosphorus, oxygen and organic carbon regime parameters), metals (iron, manganese and heavy metals), biological and microbiological parameters (coliform bacteria, chlorophyll-a, saprobity index and other biological parameters) and quality of sediment were measured

Nanofiltration in Transforming Surface Water into Healthy Water: Comparison with Reverse Osmosis

Directory of Open Access Journals (Sweden)

L. D. Naidu

2015-01-01

Full Text Available The natural surface water, especially available through rivers, is the main source of healthy water for the living beings throughout the world from ancient days as it consists of all essential minerals. With the advent of industrialization, gradually even the most prominent rivers have been polluted in all parts of the world. Although there are lots of technologies, nanofiltration (NF has been chosen to transform river water into healthy water due to its unique advantages of retaining optimum TDS (with essential minerals required for human body, consuming of lower energy, and no usage of any chemicals. The prominent parameters of surface water and macro/microminerals of treated water have been analyzed. It is shown that NF is better in producing healthy water with high flux by consuming low energy.

Aerobic biodegradation potential of endocrine-disrupting chemicals in surface-water sediment at Rocky Mountain National Park, USA.

Science.gov (United States)

Bradley, Paul M; Battaglin, William A; Iwanowicz, Luke R; Clark, Jimmy M; Journey, Celeste A

2016-05-01

Endocrine-disrupting chemicals (EDCs) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDCs, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountain National Park (Colorado, USA). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 (14) C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. Bed sediment microbial communities in Rocky Mountain National Park also effectively degraded the xenoestrogens bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The present study's results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.

Physico-chemical characterization of surface waters of the west coast of Algeria: Bay of Mostaganem and Cheliff estuary

Directory of Open Access Journals (Sweden)

Fatima Kies

2014-12-01

Full Text Available A follow-up in 2013 of the indicators of pollution (temperature, hydrogen potential, salinity, dissolved oxygen, ammonium, nitrites, nitrates, orthophosphates, ortho silicates, biological oxygen demand, chemical oxygen demand, suspended solids in surface water was performed, in order to estimate the physicochemical quality of the west coast of Algeria. The results obtained revealed the existence of a water contamination by domestic and industrial waste water conveyed to the north by the Cheliff River for discharge into the Bay of Mostaganem, marked by significant space-time variations. In January (24 mg / l, the values of nitrates recorded west of the mouth of Cheliff exceed norms. Ammonium records strong concentrations in January (1.2 mg NH4+/ l and in February (0.8 mg /l. Nitrites such lagging of high contents in January (NO2- 0.99 mg / l and February (NO2- 0.59 mg /l, respectively. The ortho phosphates post a maximum concentration in January (6.6mg PO43-/ l. In addition, the organic matter rate measured in surface water is maximum during periods of flooding especially in January (7.51 mg / l and lowest in the exceptionally dry season in August (2.19 mg / l.

Trace organic chemicals contamination in ground water recharge.

Science.gov (United States)

Díaz-Cruz, M Silvia; Barceló, Damià

2008-06-01

Population growth and unpredictable climate changes will pose high demands on water resources in the future. Even at present, surface water is certainly not enough to cope with the water requirement for agricultural, industrial, recreational and drinking purposes. In this context, the usage of ground water has become essential, therefore, their quality and quantity has to be carefully managed. Regarding quantity, artificial recharge can guarantee a sustainable level of ground water, whilst the strict quality control of the waters intended for recharge will minimize contamination of both the ground water and aquifer area. However, all water resources in the planet are threatened by multiple sources of contamination coming from the extended use of chemicals worldwide. In this respect, the environmental occurrence of organic micropollutants such as pesticides, pharmaceuticals, industrial chemicals and their metabolites has experienced fast growing interest. In this paper an overview of the priority and emerging organic micropollutants in the different source waters used for artificial aquifer recharge purposes and in the recovered water is presented. Besides, some considerations regarding fate and removal of such compounds are also addressed.

Specifics of adsorption and chemical processes on the surface of gamma-irradiated vanadium dioxide

International Nuclear Information System (INIS)

Kaurkovskaya, V.N.; Dzyubenko, L.S.; Doroshenko, V.N.; Chujko, A.A.; Shakhov, A.P.

2006-01-01

Effect of γ-irradiation on electrophysical properties and processes of thermal desorption of water from the surface of vanadium oxides V 2 O 3 -VO 2-δ -VO 2+δ -V 2 O 5 was investigated by derivatography and electric conductivity. Content of adsorbed water at the surface and phase composition of the surface was demonstrated to change under the action of low radiation doses. Surface electric conductivity of the irradiated samples VO 2-δ in the process of chemical reactions of adsorbed following irradiation benzoic acid and ethanol was established to be much above than in irradiated-free ones. It is presumed that metal-semiconductor phase transition at the surface of VO 2-δ during chemical reaction is intensified by irradiation [ru

Variability in chemistry of surface and soil waters of an ...

African Journals Online (AJOL)

Water chemistry is important for the maintenance of wetland structure and function. Interpreting ecological patterns in a wetland system therefore requires an in-depth understanding of the water chemistry of that system. We investigated the spatial distribution of chemical solutes both in soil pore water and surface water, ...

High volume hydraulic fracturing operations: potential impacts on surface water and human health.

Science.gov (United States)

Mrdjen, Igor; Lee, Jiyoung

2016-08-01

High volume, hydraulic fracturing (HVHF) processes, used to extract natural gas and oil from underground shale deposits, pose many potential hazards to the environment and human health. HVHF can negatively affect the environment by contaminating soil, water, and air matrices with potential pollutants. Due to the relatively novel nature of the process, hazards to surface waters and human health are not well known. The purpose of this article is to link the impacts of HVHF operations on surface water integrity, with human health consequences. Surface water contamination risks include: increased structural failure rates of unconventional wells, issues with wastewater treatment, and accidental discharge of contaminated fluids. Human health risks associated with exposure to surface water contaminated with HVHF chemicals include increased cancer risk and turbidity of water, leading to increased pathogen survival time. Future research should focus on modeling contamination spread throughout the environment, and minimizing occupational exposure to harmful chemicals.

Water-chemical regime of a fast reactor ower complex

International Nuclear Information System (INIS)

Musikhin, R.N.; Piskunov, E.M.; Samarkin, A.A.; Yurchenko, D.S.

1983-01-01

Some peculiarities of water-chemical regime of a power compleX in Shevchenko are considered. The complex comprises a desalination unit, a gas-masout heating-and-power plant and the BN-350 reactor. The compleX is used for the production of electric and thermal energy and fresh water. The power complex peculiarity is the utilization of disalinated seawater in a technological cycle along with highly mineralized seawater with a total salt content of 13.5 g/l (for cooling) in heat exchanges. A regime of ammoniacal correction of feed water was used as a basic water-chemical regime in the initial period of the BN-350 steam generator operation. Deposits composed mainly of iron oxide slime were observed on steam generator surfaces during the operation under these conditions. A conclusion is made that the regime with chelating agent providing steam generator safe operation without chemical cleaning is the most expedient one

UV sensitivity of planktonic net community production in ocean surface waters

OpenAIRE

Regaudie de Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

2014-01-01

The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we tes...

The pollution of water by nitrates of chemical fertilizers

International Nuclear Information System (INIS)

Halwani, Jalal

1998-01-01

The following article is a literature review that summarizes results from field studies devoted to chemical analysis of water in Lebanon. Agricultural practices and the use of fertilizers may affect surface waters, ground water and drinking water. Much attention has been given to their environmental consequences, especially those related to water pollution by Nitrates and human health. The Nitrate content should not exceed in drinking water more than 50 mg/l for adults and 25 mg/l for children and pregnant women. Studies suggest incorporation of quick remedial measures to combat pollution in marine environments

Towards the review of the European Union Water Framework management of chemical contamination in European surface water resources

NARCIS (Netherlands)

Brack, Werner; Dulio, Valeria; Ågerstrand, Marlene; Allan, Ian; Altenburger, Rolf; Brinkmann, Markus; Bunke, Dirk; Burgess, Robert M.; Cousins, Ian; Escher, Beate I.; Hernández, Félix J.; Hewitt, L.M.; Hilscherová, Klára; Hollender, Juliane; Hollert, Henner; Kase, Robert; Klauer, Bernd; Lindim, Claudia; Herráez, David López; Miège, Cécil; Munthe, John; O'Toole, Simon; Posthuma, Leo; Rüdel, Heinz; Schäfer, Ralf B.; Sengl, Manfred; Smedes, Foppe; Meent, van de Dik; Brink, van den Paul J.; Gils, van Jos; Wezel, van Annemarie P.; Vethaak, A.D.; Vermeirssen, Etienne; Ohe, von der Peter C.; Vrana, Branislav

2017-01-01

Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for

Reproductive toxicity assessment of surface water of the Tai section of the Yangtze River, China by in vitro bioassays coupled with chemical analysis

International Nuclear Information System (INIS)

Wang Xiaoyi; Wu Jiang; Hao Yingqun; Zhu Bingqing; Shi Wei; Hu Guanjiu; Han Xiaodong; Giesy, John P.; Yu Hongxia

2011-01-01

Reproductive toxicity of organic extracts of the surface water from the Tai section of the Yangtze River was assessed by in vitro cytotoxity assays and selected persistent organic pollutants including PCBs, OCPs and PAHs were quantified by instrumental analysis. Eleven of the US EPA priority PAHs were detected. Individual PAHs were found to range from 0.7 to 20 ng/L. Concentrations of BaP did not exceed the national drinking water source quality standard of China. However, a 286-fold concentrated organic extract induced significant reproductive toxicity in adult male rats. The morphology of cells, MTT assay and LDH release assay were all affected by exposure to the organic extracts of water. The results of the reproductive toxicity indicated that PAHs posed the greatest risk of the chemicals studied. The compounds present in the water could be bioconcentrated and result in adverse effects. - Highlights: → Only 11 PAHs of US EPA priority PAHs were detected in surface water the Yangtze River. → Level of BaP didn't exceed national drinking water source quality standard of China. → 286-fold concentrated organic extracts induced great reproductive toxicity in rats. → PAHs posed the greatest risk of the chemicals studied. → The compounds in the water could be bioconcentrated and result in adverse effects. - In vitro bioassay responses observed in Yangtze River source water extracts showed great reproductive toxicity, and PAHs were responsible.

Properties of water surface discharge at different pulse repetition rates

International Nuclear Information System (INIS)

Ruma,; Yoshihara, K.; Hosseini, S. H. R.; Sakugawa, T.; Akiyama, H.; Akiyama, M.; Lukeš, P.

2014-01-01

The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H 2 O 2 ) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H 2 O 2 and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

Decontamination of chemical agents from drinking water infrastructure: a literature review and summary.

Science.gov (United States)

Szabo, Jeff; Minamyer, Scott

2014-11-01

This report summarizes the current state of knowledge on the persistence of chemical contamination on drinking water infrastructure (such as pipes) along with information on decontamination should persistence occur. Decontamination options for drinking water infrastructure have been explored for some chemical contaminants, but important data gaps remain. In general, data on chemical persistence on drinking water infrastructure is available for inorganics such as arsenic and mercury, as well as select organics such as petroleum products, pesticides and rodenticides. Data specific to chemical warfare agents and pharmaceuticals was not found and data on toxins is scant. Future research suggestions focus on expanding the available chemical persistence data to other common drinking water infrastructure materials. Decontaminating agents that successfully removed persistent contamination from one infrastructure material should be used in further studies. Methods for sampling or extracting chemical agents from water infrastructure surfaces are needed. Published by Elsevier Ltd.

Characteristics of pulse corona discharge over water surface

Science.gov (United States)

Fujii, Tomio; Arao, Yasushi; Rea, Massimo

2008-12-01

Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though the surface of water was waved by corona wind. The positive streamer corona showed more ozone production than the negative one both in the DC and in the pulse corona.

Characteristics of pulse corona discharge over water surface

International Nuclear Information System (INIS)

Fujii, Tomio; Arao, Yasushi; Rea, Massimo

2008-01-01

Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO 2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though the surface of water was waved by corona wind. The positive streamer corona showed more ozone production than the negative one both in the DC and in the pulse corona.

Method of manipulating the chemical properties of water to improve the effectiveness of a desired chemical process

Science.gov (United States)

Hawthorne, Steven B.; Miller, David J.; Yang, Yu; Lagadec, Arnaud Jean-Marie

1999-01-01

The method of the present invention is adapted to manipulate the chemical properties of water in order to improve the effectiveness of a desired chemical process. The method involves heating the water in the vessel to subcritical temperatures between 100.degree. to 374.degree. C. while maintaining sufficient pressure to the water to maintain the water in the liquid state. Various physiochemical properties of the water can be manipulated including polarity, solute solubility, surface tension, viscosity, and the disassociation constant. The method of the present invention has various uses including extracting organics from solids and semisolids such as soil, selectively extracting desired organics from nonaqueous liquids, selectively separating organics using sorbent phases, enhancing reactions by controlling the disassociation constant of water, cleaning waste water, and removing organics from water using activated carbon or other suitable sorbents.

Influences of chemical aging on the surface morphology and crystallization behavior of basaltic glass fibers

DEFF Research Database (Denmark)

Lund, Majbritt Deichgræber; Yue, Yuanzheng

2008-01-01

The impact of aging in high humidity and water on the surface morphology and crystallization behavior of basaltic glass fibers has been studied using scanning electron microscopy, transmission electron microscopy, calorimetry and X-ray diffraction. The results show that interaction between...... the fibers and the surrounding media (high humidity or water at 70 C) leads to chemical changes strongly affecting the surface morphology. The crystallization peak temperature of the basaltic glass fibers are increased without changing the onset temperature, this may be caused by a chemical depletion...

Mitigation options for chemicals of emerging concern in surface waters operationalising solutions-focused risk assessment

NARCIS (Netherlands)

Van Wezel, Annemarie P.; Ter Laak, Thomas L.; Fischer, Astrid; Bäuerlein, Patrick S.; Munthe, John; Posthuma, Leo

2017-01-01

The water system provides many services to society; industries, municipalities and agriculture all withdraw, use and return water and demand a water quality fit for the intended purposes. Both global production of chemicals and global water withdrawal grow faster than human population. This implies

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

Science.gov (United States)

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.

Adsorption of water, sulfates and chloride on arsenopyrite surface

Science.gov (United States)

Silva, Juliana C. M.; dos Santos, Egon C.; de Oliveira, Aline; Heine, Thomas; De Abreu, Heitor A.; Duarte, Hélio A.

2018-03-01

Arsenopyrite is one of the sulfide minerals responsible for acid rock drainage (ARD) and is one of the most hazardous in regions affected by mining activities. This phenomenon involves complex reaction mechanism. Although it is intensely investigated, there is a lack of consensus concerning the reaction mechanisms and more information is still necessary. In this work, the adsorption of water, hydrochloric acid, and sulfuric acid on arsenopyrite (001) surface was investigated by means of Density Functional calculations and the results compared to other sulfides aiming to understand the mineral/water interface. The interaction of the chemical species with the (001) FeAsS surface is the first step to understand the intricate oxidation mechanism of arsenopyrite. Molecular water adsorption on (001) FeAsS is more favored than the adsorption of sulfate favoring the dissolution of sulfates and enhancing its oxidation. The estimated adsorption energies of water, sulfates and chloride on other sulfide minerals are compared with the estimated values for arsenopyrite and the chemical reactivity differences discussed in detail.

Simulating Mobility of Chemical Contaminants from Unconventional Gas Development for Protection of Water Resources

Science.gov (United States)

Kanno, C.; Edlin, D.; Borrillo-Hutter, T.; McCray, J. E.

2014-12-01

Potential contamination of ground water and surface water supplies from chemical contaminants in hydraulic fracturing fluids or in natural gas is of high public concern. However, quantitative assessments have rarely been conducted at specific energy-producing locations so that the true risk of contamination can be evaluated. The most likely pathways for contamination are surface spills and faulty well bores that leak production fluids directly into an aquifer. This study conducts fate and transport simulations of the most mobile chemical contaminants, based on reactivity to subsurface soils, degradation potential, and source concentration, to better understand which chemicals are most likely to contaminate water resources, and to provide information to planners who wish to be prepared for accidental releases. The simulations are intended to be most relevant to the Niobrara shale formation.

Physically and chemically stable ionic liquid-infused textured surfaces showing excellent dynamic omniphobicity

Energy Technology Data Exchange (ETDEWEB)

Miranda, Daniel F.; Urata, Chihiro; Masheder, Benjamin; Dunderdale, Gary J.; Hozumi, Atsushi, E-mail: a.hozumi@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98, Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya, Aichi 463-8560 (Japan); Yagihashi, Makoto [Nagoya Municipal Industrial Research Institute, Rokuban, Atsuta-ku, Nagoya 456-0058 (Japan)

2014-05-01

A fluorinated and hydrophobic ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, effectively served as an advantageous lubricating liquid for the preparation of physically and chemically stable omniphobic surfaces based on slippery liquid-infused porous surfaces. Here, we used particulate microstructures as supports, prepared by the chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent surface modification with (3-aminopropyl)triethoxysilane. Confirmed by SEM and contact angle measurements, the resulting IL-infused microtextured surfaces are smooth and not only water but also various low surface tension liquids can easily slide off at low substrate tilt angles of <5°, even after exposure to high temperature, vacuum, and UV irradiation.

Physically and chemically stable ionic liquid-infused textured surfaces showing excellent dynamic omniphobicity

Directory of Open Access Journals (Sweden)

Daniel F. Miranda

2014-05-01

Full Text Available A fluorinated and hydrophobic ionic liquid (IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl imide, effectively served as an advantageous lubricating liquid for the preparation of physically and chemically stable omniphobic surfaces based on slippery liquid-infused porous surfaces. Here, we used particulate microstructures as supports, prepared by the chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent surface modification with (3-aminopropyltriethoxysilane. Confirmed by SEM and contact angle measurements, the resulting IL-infused microtextured surfaces are smooth and not only water but also various low surface tension liquids can easily slide off at low substrate tilt angles of <5°, even after exposure to high temperature, vacuum, and UV irradiation.

Simultaneous tuning of chemical composition and topography of copolymer surfaces: micelles as building blocks.

Science.gov (United States)

Zhao, Ning; Zhang, Xiaoyan; Zhang, Xiaoli; Xu, Jian

2007-05-14

A simple method is described for controlling the surface chemical composition and topography of the diblock copolymer poly(styrene)-b-poly(dimethylsiloxane)(PS-b-PDMS) by casting the copolymer solutions from solvents with different selectivities. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively, and the wetting behavior was studied by water contact angle (CA) and sliding angle (SA) and by CA hysteresis. Chemical composition and morphology of the surface depend on solvent properties, humidity of the air, solution concentration, and block lengths. If the copolymer is cast from a common solvent, the resultant surface is hydrophobic, with a flat morphology, and dominated by PDMS on the air side. From a PDMS-selective solvent, the surface topography depends on the morphology of the micelles. Starlike micelles give rise to a featureless surface nearly completely covered by PDMS, while crew-cut-like micelles lead to a rough surface with a hierarchical structure that consists partly of PDMS. From a PS-selective solvent, however, surface segregation of PDMS was restricted, and the surface morphology can be controlled by vapor-induced phase separation. On the basis of the tunable surface roughness and PDMS concentration on the air side, water repellency of the copolymer surface could be tailored from hydrophobic to superhydrophobic. In addition, reversible switching behavior between hydrophobic and superhydrophobic can be achieved by exposing the surface to solvents with different selectivities.

Chemical analysis of water in hydrogeology

International Nuclear Information System (INIS)

Flakova, R.; Zenisova, Z.; Seman, M.

2010-01-01

The aim of the monograph is to give complete information on the chemical analysis of water hydrogeology not only for the students program of Geology study (Bachelor degree study), Engineering Geology and Hydrogeology (Master's degree study) and Engineering Geology (doctoral level study), but also for students from other colleges and universities schools in Slovakia, as well as in the Czech Republic, dealing with the chemical composition of water and its quality, from different perspectives. The benefit would be for professionals with hydrogeological, water and environmental practices, who can find there all the necessary information about proper water sampling, the units used in the chemical analysis of water, expressing the proper chemical composition of water in its various parameters through classification of chemical composition of the water up to the basic features of physical chemistry at thermodynamic calculations and hydrogeochemical modelling.

Quantification of chemical transport processes from the soil to surface runoff.

Science.gov (United States)

Tian, Kun; Huang, Chi-Hua; Wang, Guang-Qian; Fu, Xu-Dong; Parker, Gary

2013-01-01

There is a good conceptual understanding of the processes that govern chemical transport from the soil to surface runoff, but few studies have actually quantified these processes separately. Thus, we designed a laboratory flow cell and experimental procedures to quantify the chemical transport from soil to runoff water in the following individual processes: (i) convection with a vertical hydraulic gradient, (ii) convection via surface flow or the Bernoulli effect, (iii) diffusion, and (iv) soil loss. We applied different vertical hydraulic gradients by setting the flow cell to generate different seepage or drainage conditions. Our data confirmed the general form of the convection-diffusion equation. However, we now have additional quantitative data that describe the contribution of each individual chemical loading process in different surface runoff and soil hydrological conditions. The results of this study will be useful for enhancing our understanding of different geochemical processes in the surface soil mixing zone. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Cell-based Metabolomics for Assessing Chemical Exposure and Toxicity of Environmental Surface Waters

Science.gov (United States)

Waste water treatment plants (WWTPs), concentrated animal feeding operations (CAFOs), mining activities, and agricultural operations release contaminants that negatively affect surface water quality. Traditional methods using live animals/fish to monitor/assess contaminant exposu...

Contaminants of emerging concern in surface waters in Barbados, West Indies.

Science.gov (United States)

Edwards, Quincy A; Kulikov, Sergei M; Garner-O'Neale, Leah D; Metcalfe, Chris D; Sultana, Tamanna

2017-11-14

Contaminants of emerging concern (CECs), including pharmaceuticals, artificial sweeteners, steroid hormones, and current-use pesticides have been detected in surface waters around the world, but to date, there have been no reports in the peer-reviewed literature on the levels of these classes of contaminants in freshwater resources in the Caribbean region. In the present study, multi-residue solid phase extraction (SPE) and liquid chromatography with tandem mass spectroscopy (LC-MS/MS) were used to analyze grab samples of surface waters collected from five different watersheds in Barbados, West Indies. The artificial sweeteners (AS), acesulfame, cyclamate, saccharin, and sucralose were widely detected in the watersheds, indicating contamination from domestic wastewater, and the concentrations of these chemical tracers in water were correlated with the concentrations of the non-prescription pharmaceutical, ibuprofen (R 2 values of 0.4-0.6). Surprisingly, the concentrations of another chemical tracer of domestic wastewater, caffeine were not correlated with ibuprofen or AS concentrations. Several other prescription pharmaceuticals and the steroid hormones, estrone and androstenedione, were detected in selected watersheds at low ng/L concentrations. The fungicide, chlorothalonil was widely detected in surface waters at low (contamination of water resources by pharmaceuticals.

Surface chemical reactions probed with scanning force microscopy

NARCIS (Netherlands)

Werts, M.P L; van der Vegte, E.W.; Hadziioannou, G

1997-01-01

In this letter we report the study of surface chemical reactions with scanning force microscopy (SFM) with chemical specificity. Using chemically modified SFM probes, we can determine the local surface reaction conversion during a chemical surface modification. The adhesion forces between a

Macroelements in the surface microlayer of water of urban ponds

Directory of Open Access Journals (Sweden)

Antonowicz Józef Piotr

2016-03-01

Full Text Available Analyses were conducted concerning the accumulation of four metals representing the group of macroelements, i.e. sodium, potassium, calcium and magnesium in two ponds located in the city of Słupsk. Water samples for chemical analyses were collected from the surface microlayer using a Garrett net. At the same time subsurface water samples were collected. Concentrations of metals were determined using a mass spectrometer. Generally, amounts of sodium, potassium, calcium and magnesium were similar in surface microlayer and subsurface water. Only in the case of potassium and calcium was low enrichment observed in the surface microlayer in one pond, while the greatest extent for magnesium enrichment was observed in the spring period.

Studies Concerning Water-Surface Deposits in Recovery Boilers

Energy Technology Data Exchange (ETDEWEB)

Strandberg, O; Arvesen, J; Dahl, L

1971-11-15

The Feed-water Committee of the Stiftelsen Svensk Cellulosaforskning (Foundation for Swedish Cellulose Research) has initiated research and investigations which aim to increase knowledge about water-surface deposits in boiler tubes, and the resulting risks of gas-surface corrosion in chemical recovery boilers (sulphate pulp industry). The Committee has arranged with AB Atomenergi, Studsvik, for investigations into the water-surface deposits on tubes from six Scandinavian boilers. These investigations have included direct measurements of the thermal conductivity of the deposits, and determinations of their quantity, thickness and structure have been carried out. Previous investigations have shown that gas-surface corrosion can occur at tube temperatures above 330 deg C. The measured values for the thermal conductivity of the deposits indicate that even with small quantities of deposit (c. 1 g/dm2 ) and a moderate boiler pressure (40 atm), certain types of deposit can give rise to the above-mentioned surface temperature, at which the risk of gas-surface corrosion becomes appreciable. For higher boiler pressures the risk is great even with a minimal layer of deposit. The critical deposit thickness can be as low as 0.1 mm

A Facile All-Solution-Processed Surface with High Water Contact Angle and High Water Adhesive Force.

Science.gov (United States)

Chen, Mei; Hu, Wei; Liang, Xiao; Zou, Cheng; Li, Fasheng; Zhang, Lanying; Chen, Feiwu; Yang, Huai

2017-07-12

A series of sticky superhydrophobicity surfaces with high water contact angle and high water adhesive force is facilely prepared via an all-solution-processed method based on polymerization-induced phase separation between liquid crystals (LCs) and epoxy resin, which produces layers of epoxy microspheres (EMSs) with nanofolds on the surface of a substrate. The morphologies and size distributions of EMSs are confirmed by scanning electron microscopy. Results reveal that the obtained EMS coated-surface exhibits high apparent contact angle of 152.0° and high water adhesive force up to 117.6 μN. By varying the composition of the sample or preparing conditions, the sizes of the produced EMSs can be artificially regulated and, thus, control the wetting properties and water adhesive behaviors. Also, the sticky superhydrophobic surface exhibits excellent chemical stability, as well as long-term durability. Water droplet transportation experiments further prove that the as-made surface can be effectively used as a mechanical hand for water transportation applications. Based on this, it is believed that the simple method proposed in this paper will pave a new way for producing a sticky superhydrophobic surface and obtain a wide range of use.

Coastal surface water suitability analysis for irrigation in Bangladesh

Science.gov (United States)

Mahtab, Mohammad Hossain; Zahid, Anwar

2018-03-01

Water with adequate quality and quantity is very important for irrigation to ensure the crop yields. Salinity is common problem in the coastal waters in Bangladesh. The intensity of salinity in the coastal zone in Bangladesh is not same. It fluctuates over the year. Sodium is another hazard which may hamper permeability and ultimately affects the fertility. It can reduce the crop yields. Although surface water is available in the coastal zone of Bangladesh, but its quality for irrigation needs to be monitored over the year. This paper will investigate the overall quality of coastal surface waters. Thirty-three water samples from different rivers were collected both in wet period (October-December) and in dry period (February-April). Different physical and chemical parameters are considered for investigation of the adequacy of water with respect to international irrigation water quality standards and Bangladesh standards. A comparison between the dry and wet period coastal surface water quality in Bangladesh will also be drawn here. The analysis shows that coastal surface water in Bangladesh is overall suitable for irrigation during wet period, while it needs treatment (which will increase the irrigation cost) for using for irrigation during dry period. Adaptation to this situation can improve the scenario. An integrated plan should be taken to increase the water storing capacity in the coastal area to harvest water during wet period.

SURFACE WATER POLLUTION WITH HEAVY METALS IN THE LOWER CATCHMENT OF JIU RIVER BASIN, ACCORDING TO THE WATER FRAMEWORK DIRECTIVE (2000/60/EC

Directory of Open Access Journals (Sweden)

ADINA SANDA ŞERBAN

2011-03-01

Full Text Available Surface water pollution with heavy metals in the lower catchment of Jiu river basin, according to the Water Framework Directive (2000/60/EC. The Water Framework Directive establishes a single transparent, effective and coherent water policy by defining a strategy to combat pollution by requiring specific action programs.Chemical pollution of surface water presents a threat to the aquatic environment with acute and chronic toxicity to aquatic organisms, accumulation in the ecosystem and losses of habitats and biodiversity, as well as a threat to human health (art.1 from Directive 2008/105/EC regarding the environmental quality standards for water policy.The purpose of this study is to evaluate the chemical status for surface water bodies in the lower catchment of Jiu river basin. The assessment was made taking into account the water impact of four heavy metals: cadmium (Cd, nickel (Ni, mercury (Hg and lead (Pb.

Insight into Chemistry on Cloud/Aerosol Water Surfaces.

Science.gov (United States)

Zhong, Jie; Kumar, Manoj; Francisco, Joseph S; Zeng, Xiao Cheng

2018-05-15

Cloud/aerosol water surfaces exert significant influence over atmospheric chemical processes. Atmospheric processes at the water surface are observed to follow mechanisms that are quite different from those in the gas phase. This Account summarizes our recent findings of new reaction pathways on the water surface. We have studied these surface reactions using Born-Oppenheimer molecular dynamics simulations. These studies provide useful information on the reaction time scale, the underlying mechanism of surface reactions, and the dynamic behavior of the product formed on the aqueous surface. According to these studies, the aerosol water surfaces confine the atmospheric species into a specific orientation depending on the hydrophilicity of atmospheric species or the hydrogen-bonding interactions between atmospheric species and interfacial water. As a result, atmospheric species are activated toward a particular reaction on the aerosol water surface. For example, the simplest Criegee intermediate (CH 2 OO) exhibits high reactivity toward the interfacial water and hydrogen sulfide, with the reaction times being a few picoseconds, 2-3 orders of magnitude faster than that in the gas phase. The presence of interfacial water molecules induces proton-transfer-based stepwise pathways for these reactions, which are not possible in the gas phase. The strong hydrophobicity of methyl substituents in larger Criegee intermediates (>C1), such as CH 3 CHOO and (CH 3 ) 2 COO, blocks the formation of the necessary prereaction complexes for the Criegee-water reaction to occur at the water droplet surface, which lowers their proton-transfer ability and hampers the reaction. The aerosol water surface provides a solvent medium for acids (e.g., HNO 3 and HCOOH) to participate in reactions via mechanisms that are different from those in the gas and bulk aqueous phases. For example, the anti-CH 3 CHOO-HNO 3 reaction in the gas phase follows a direct reaction between anti-CH 3 CHOO and HNO 3

CHEMICAL WATER QUALITY INDICATORS IN BASIN FOREST PARCZEW

Directory of Open Access Journals (Sweden)

Antoni Grzywna

2014-10-01

Full Text Available This paper presents the characteristics of the chemistry of surface and ground water in the bottom of the river valley reclaimed Ochoza. Drained grassland accounts for 20% of the total catchment area and are located on organic soils in the valley Tyśmienica classified to the Natura 2000 sites. Analysis of physico-chemical properties of water are to assess the effects of anthropogenic transformation and identify factors that influence water quality in the study area. Water samples were collected in the years 2011–2012 in several points. The walls were characterized by surface water stagnant in the trenches, in July, blueberry plantation. Characterized by the highest quality of surface water runoff river with the test object. Occurring here throughout the growing season water flow reed growing on the bed and temporary impoundment of water contribute to the self-cleaning effect of water. Conducted at different times of the growing season (winter, spring, summer, autumn of water chemistry analysis allows to assess the impact of vegetation on the process of self-purification of water. Based on the survey it was found that the river is reduced by 26% BOD 5, COD by 37%, 12% phosphate and potassium by 13%. Concurrently, an increase in the content of nitrogen compounds – ammonia at 27% and 15% nitrate. The increase in the content of nitrogen compounds is particularly evident in the bottom of the object, which is probably associated with the deep trench causing excessive drying of the soil. The highest values of pollutants were recorded mostly in the spring probably due to the outflow of water from the drans.

Fabrication of Superhydrophobic Surfaces with Controllable Electrical Conductivity and Water Adhesion.

Science.gov (United States)

Ye, Lijun; Guan, Jipeng; Li, Zhixiang; Zhao, Jingxin; Ye, Cuicui; You, Jichun; Li, Yongjin

2017-02-14

A facile and versatile strategy for fabricating superhydrophobic surfaces with controllable electrical conductivity and water adhesion is reported. "Vine-on-fence"-structured and cerebral cortex-like superhydrophobic surfaces are constructed by filtering a suspension of multiwalled carbon nanotubes (MWCNTs), using polyoxymethylene nonwovens as the filter paper. The nonwovens with micro- and nanoporous two-tier structures act as the skeleton, introducing a microscale structure. The MWCNTs act as nanoscale structures, creating hierarchical surface roughness. The surface topography and the electrical conductivity of the superhydrophobic surfaces are controlled by varying the MWCNT loading. The vine-on-fence-structured surfaces exhibit "sticky" superhydrophobicity with high water adhesion. The cerebral cortex-like surfaces exhibit self-cleaning properties with low water adhesion. The as-prepared superhydrophobic surfaces are chemically resistant to acidic and alkaline environments of pH 2-12. They therefore have potential in applications such as droplet-based microreactors and thin-film microextraction. These findings aid our understanding of the role that surface topography plays in the design and fabrication of superhydrophobic surfaces with different water-adhesion properties.

Drivers of contaminant levels in surface water of China during 2000-2030: Relative importance for illustrative home and personal care product chemicals.

Science.gov (United States)

Zhu, Ying; Price, Oliver R; Kilgallon, John; Qi, Yi; Tao, Shu; Jones, Kevin C; Sweetman, Andrew J

2018-03-21

Water pollution are among the most critical problems in China and emerging contaminants in surface water have attracted rising attentions in recent years. There is great interest in China's future environmental quality as the national government has committed to a major action plan to improve surface water quality. This study presents methodologies to rank the importance of socioeconomic and environmental drivers to the chemical concentration in surface water during 2000-2030. A case study is conducted on triclosan, a home and personal care product (HPCP) ingredient. Different economic and discharge flow scenarios are considered. Urbanization and wastewater treatment connection rates in rural and urban areas are collected or projected for 2000-2030 for counties across China. The estimated usage increases from ca. 86 to 340 t. However, emissions decreases from 76 to 52 t during 2000-2030 under a modelled Organisation for Economic Co-operation (OECD) economic scenario because of the urbanization, migration and development of wastewater treatment plants/facilities (WWTPs). The estimated national median concentration of triclosan ranges 1.5-8.2 ng/L during 2000-2030 for different scenarios. It peaks in 2009 under the OECD and three of the Intergovernmental Panel on Climate Change (IPCC), A2, B1 and B2 economic scenarios, but in 2025 under A1 economic scenario. Population distribution and surface water discharge flow rates are ranked as the top two drivers to triclosan levels in surface water over the 30 years. The development of urban WWTPs was the most important driver during 2000-2010 and the development of rural works is projected to be the most important in 2011-2030. Projections suggest discharges of ingredients in HPCPs - controlled by economic growth - should be balanced by the major expenditure programme on wastewater treatment in China. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using Iron-Manganese Co-Oxide Filter Film to Remove Ammonium from Surface Water.

Science.gov (United States)

Zhang, Ruifeng; Huang, Tinglin; Wen, Gang; Chen, Yongpan; Cao, Xin; Zhang, Beibei

2017-07-19

An iron-manganese co-oxide filter film (MeO x ) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeO x was used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeO x was greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6-8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeO x included both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeO x was formed by abiotic ways and the main elements on the surface of MeO x were distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeO x as both ammonia molecules and ammonium ions and the active species of O₂ were possibly • O and O₂ - .

Surface Modification of α-Fe Metal Particles by Chemical Surface Coating

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

The structure of α-Fe metal magnetic recording particles coated with silane coupling agents have been studied by TEM, FT-IR, EXAFS, Mossbauer. The results show that a close, uniform, firm and ultra thin layer, which is beneficial to the magnetic and chemical stability, has been formed by the cross-linked chemical bond Si-O-Si. And the organic molecule has chemically bonded to the particle surface, which has greatly affected the surface Fe atom electronic structure. Furthermore, the covalent bond between metal particle surface and organic molecule has obvious effect on the near edge structure of the surface Fe atoms.

Chemical composition of water extracts from shungite and shungite water

International Nuclear Information System (INIS)

Charykova, M.V.; Bornyakova, I.I.; Polekhovskij, Yu.S.; Charykov, N.A.; Kustova, E.V.; Arapov, O.V.

2006-01-01

Chemical analysis of water extracts from shungite-3 of Zagozhino deposit (Karelia) and natural water contacting with shungite rocks are done. Chemical composition and bactericide properties of shungite water are studied [ru

Inorganic chemical quality of European tap-water: 2. Geographical distribution

International Nuclear Information System (INIS)

Flem, B.; Reimann, C.; Birke, M.; Banks, D.; Filzmoser, P.; Frengstad, B.

2015-01-01

Highlights: • European scale comparison of tap water. • 579 tap water samples have been analyses for more than 60 parameters. • Chemical geographical distribution. • Water treatment processes. • Importance of geology on tap water quality. - Abstract: 579 tap water samples were collected at the European scale and analysed at a single laboratory for more than 60 parameters. This dataset is analysed here in terms of the spatial and national distribution of the analysed inorganic chemical parameters. The distribution of most parameters is controlled by various artificial and natural factors (land use, distribution network, water source and treatment, geographical location and geology). The distribution of nitrate can be interpreted in terms of land use and climate. Water treatment affects the distribution of phosphorus in tap water; especially the policy of adding phosphate to potable water in the UK to suppress plumbosolvency. The distribution of alkalinity, Ca, Mg, Sr and Li appears to reflect both water source (low in surface waters) and the geological contrast between base-poor crystalline rock terrains and carbonate rich sedimentary rock. The Scandinavian nations’ tap water shows the highest concentrations of most of the rare earth elements, probably reflecting their geological availability and mobility in low pH raw water sources. The distribution of fluoride, uranium and arsenic also appear to exhibit geological and source (groundwater versus surface water) controls. Hungary returns several high As results, which may reflect As-rich reducing groundwaters of the Pannonian basin. Much Estonian tap water reflects a very specific hydrochemical environment, namely Palaeozoic near-coastal aquifers, which yield deep, reducing or saline groundwater (possibly influenced by marine intrusion), enriched in Ba, B, Br − , Cl − , Eu, F − , I, Li, K, Mn and Na

Radionuclides as natural tracers of the interaction between groundwater and surface water in the River Andarax, Spain.

Science.gov (United States)

Navarro-Martinez, Francisco; Salas Garcia, Alejandro; Sánchez-Martos, Francisco; Baeza Espasa, Antonio; Molina Sánchez, Luis; Rodríguez Perulero, Antonio

2017-12-01

The identification of specific aquifers that supply water to river systems is fundamental to understanding the dynamics of the rivers' hydrochemistry, particularly in arid and semiarid environments where river flow may be discontinuous. There are multiple methods to identify the source of river water. In this study of the River Andarax, in the Southeast of Spain, an analysis of natural tracers (physico-chemical parameters, uranium, radium and radon) in surface water and groundwater indicates that chemical parameters and uranium clearly identify the areas where there is groundwater-surface water interaction. The concentration of uranium found in the river defines two areas: the headwaters with U concentrations of 2 μg L -1 and the lower reaches, with U of 6 μg L -1 . Furthermore, variation in the 234 U/ 238 U isotopic ratio allowed us to detect the influence that groundwater from the carbonate aquifer has on surface water in the headwaters of the river, where the saline content is lower and the water has a calcium bicarbonate facies. The concentration of 226 Ra and 222 Rn are low in the surface waters: aquifer on the surface waters. The results of this study indicate the utility in the use of physico-chemical and radiological data conjointly as tracers of groundwater-surface water interaction in semiarid areas where the lithology of aquifers is diverse (carbonate and detritic) and where evaporitic rocks are present. Copyright © 2017 Elsevier Ltd. All rights reserved.

Review: Impacts of permafrost degradation on inorganic chemistry of surface fresh water

Science.gov (United States)

Colombo, Nicola; Salerno, Franco; Gruber, Stephan; Freppaz, Michele; Williams, Mark; Fratianni, Simona; Giardino, Marco

2018-03-01

Recent studies have shown that climate change is impacting the inorganic chemical characteristics of surface fresh water in permafrost areas and affecting aquatic ecosystems. Concentrations of major ions (e.g., Ca2 +, Mg2 +, SO42 -, NO3-) can increase following permafrost degradation with associated deepening of flow pathways and increased contributions of deep groundwater. In addition, thickening of the active layer and melting of near-surface ground ice can influence inorganic chemical fluxes from permafrost into surface water. Permafrost degradation has also the capability to modify trace element (e.g., Ni, Mn, Al, Hg, Pb) contents in surface water. Although several local and regional modifications of inorganic chemistry of surface fresh water have been attributed to permafrost degradation, a comprehensive review of the observed changes is lacking. The goal of this paper is to distil insight gained across differing permafrost settings through the identification of common patterns in previous studies, at global scale. In this review we focus on three typical permafrost configurations (pervasive permafrost degradation, thermokarst, and thawing rock glaciers) as examples and distinguish impacts on (i) major ions and (ii) trace elements. Consequences of warming climate have caused spatially-distributed progressive increases of major ion and trace element delivery to surface fresh water in both polar and mountain areas following pervasive permafrost degradation. Moreover, localised releases of major ions and trace elements to surface water due to the liberation of soluble materials sequestered in permafrost and ground ice have been found in ice-rich terrains both at high latitude (thermokarst features) and high elevation (rock glaciers). Further release of solutes and related transport to surface fresh water can be expected under warming climatic conditions. However, complex interactions among several factors able to influence the timing and magnitude of the impacts

The interplay between surface-water and hydrogen bonding in a water adlayer on Pt(111) and Ag(111)

Energy Technology Data Exchange (ETDEWEB)

Delle Site, Luigi [Max-Planck-Institut fuer Polymerforschung, Ackermannweg 10, D-55128 Mainz (Germany); Ghiringhelli, Luca M [Max-Planck-Institut fuer Polymerforschung, Ackermannweg 10, D-55128 Mainz (Germany); Andreussi, Oliviero [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56100 Pisa (Italy); Donadio, Davide [Computational Science, Department of Chemistry and Applied Biosciences, ETH Zurich, USI-Campus, via Giuseppe Buffi 13, CH-6900 Lugano (Switzerland); Parrinello, Michele [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56100 Pisa (Italy)

2007-06-20

The structure of a water adlayer on a Pt(111) surface is investigated by means of extensive first-principles calculations. Allowing for proton disorder, the ground state energy for the {radical}3 x {radical}3R30{sup o} structure can be found. This results from an interplay between water/metal chemical bonding and the hydrogen bonding of the water network. This picture is supported by substituting Pt(111) with Ag(111): the almost inert surface allows for the reconstruction of the hydrogen network. (fast track communication)

The interplay between surface-water and hydrogen bonding in a water adlayer on Pt(111) and Ag(111)

International Nuclear Information System (INIS)

Delle Site, Luigi; Ghiringhelli, Luca M; Andreussi, Oliviero; Donadio, Davide; Parrinello, Michele

2007-01-01

The structure of a water adlayer on a Pt(111) surface is investigated by means of extensive first-principles calculations. Allowing for proton disorder, the ground state energy for the √3 x √3R30 o structure can be found. This results from an interplay between water/metal chemical bonding and the hydrogen bonding of the water network. This picture is supported by substituting Pt(111) with Ag(111): the almost inert surface allows for the reconstruction of the hydrogen network. (fast track communication)

Modeling Groundwater-Surface Water Interaction and Contaminant Transport of Chlorinated Solvent Contaminated Site

Science.gov (United States)

Yimer Ebrahim, Girma; Jonoski, Andreja; van Griensven, Ann; Dujardin, Juliette; Baetelaan, Okke; Bronders, Jan

2010-05-01

Chlorinated-solvent form one of the largest groups of environmental chemicals. Their use and misuse in industry have lead to a large entry of these chemicals into the environment, resulting in widespread dissemination and oftentimes environmental contamination. Chlorinated solvent contamination of groundwater resources has been widely reported. For instance, there has been much interest in the assessment of these contaminant levels and their evolutions with time in the groundwater body below the Vilvoorde-Machelen industrial area (Belgium). The long industrial history of the area has lead to complex patterns of pollution from multiple sources and the site has been polluted to the extent that individual plumes are not definable any more. Understanding of groundwater/surface water interaction is a critical component for determining the fate of contaminant both in streams and ground water due to the fact that groundwater and surface water are in continuous dynamic interaction in the hydrologic cycle. The interaction has practical consequences in the quantity and quality of water in either system in the sense that depletion and/or contamination of one of the system will eventually affect the other one. The transition zone between a stream and its adjacent aquifer referred to as the hyporheic zone plays a critical role in governing contaminant exchange and transformation during water exchange between the two water bodies. The hyporheic zone of Zenne River ( the main receptor ) is further complicated due to the fact that the river banks are artificially trained with sheet piles along its reach extending some 12 m below the surface. This study demonstrates the use of MODFLOW, a widely used modular three-dimensional block-centred finite difference, saturated flow model for simulating the flow and direction of movement of groundwater through aquifer and stream-aquifer interaction and the use of transport model RT3D, a three-dimensional multi-species reactive transport model

Surface-Water Data, Georgia, Water Year 1999

Science.gov (United States)

Alhadeff, S. Jack; Landers, Mark N.; McCallum, Brian E.

1999-01-01

Water resources data for the 1999 water year for Georgia consists of records of stage, discharge, and water quality of streams; and the stage and contents of lakes and reservoirs published in one volume in a digital format on a CD-ROM. This volume contains discharge records of 121 gaging stations; stage for 13 gaging stations; stage and contents for 18 lakes and reservoirs; continuous water quality records for 10 stations; and the annual peak stage and annual peak discharge for 75 crest-stage partial-record stations. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Georgia. Records of discharge and stage of streams, and contents or stage of lakes and reservoirs were first published in a series of U.S. Geological water-supply papers entitled, 'Surface-Water Supply of the United States.' Through September 30, 1960, these water-supply papers were in an annual series and then in a 5-year series for 1961-65 and 1966-70. Records of chemical quality, water temperature, and suspended sediment were published from 1941 to 1970 in an annual series of water-supply papers entitled, 'Quality of Surface Waters of the United States.' Records of ground-water levels were published from 1935 to 1974 in a series of water-supply papers entitled, 'Ground-Water Levels in the United States.' Water-supply papers may be consulted in the libraries of the principal cities in the United States or may be purchased from the U.S. Geological Survey, Branch of Information Services, Federal Center, Box 25286, Denver, CO 80225. For water years 1961 through 1970, streamflow data were released by the U.S. Geological Survey in annual reports on a State-boundary basis prior to the two 5-year series water-supply papers, which cover this period. The data contained in the water-supply papers are considered the official record. Water-quality records for water years 1964 through 1970 were similarly released

A monitoring of chemical contaminants in waters used for field irrigation and livestock watering in the Veneto region (Italy), using bioassays as a screening tool.

Science.gov (United States)

De Liguoro, Marco; Bona, Mirco Dalla; Gallina, Guglielmo; Capolongo, Francesca; Gallocchio, Federica; Binato, Giovanni; Di Leva, Vincenzo

2014-03-01

In this study, 50 livestock watering sources (ground water) and 50 field irrigation sources (surface water) from various industrialised areas of the Veneto region were monitored for chemical contaminants. From each site, four water samples (one in each season) were collected during the period from summer 2009 through to spring 2010. Surface water samples and ground water samples were first screened for toxicity using the growth inhibition test on Pseudokirchneriella subcapitata and the immobilisation test on Daphnia magna, respectively. Then, based on the results of these toxicity tests, 28 ground water samples and 26 surface water samples were submitted to chemical analysis for various contaminants (insecticides/acaricides, fungicides, herbicides, metals and anions) by means of UPLC-MS(n) HPLC-MS(n), AAS and IEC. With the exception of one surface water sample where the total pesticides concentration was greater than 4 μg L(-1), positive samples (51.9 %) showed only traces (nanograms per liter) of pesticides. Metals were generally under the detection limit. High concentrations of chlorines (up to 692 mg L(-1)) were found in some ground water samples while some surface water samples showed an excess of nitrites (up to 336 mg L(-1)). Detected levels of contamination were generally too low to justify the toxicity recorded in bioassays, especially in the case of surface water samples, and analytical results painted quite a reassuring picture, while tests on P. subcapitata showed a strong growth inhibition activity. It was concluded that, from an ecotoxicological point of view, surface waters used for field irrigation in the Veneto region cannot be considered safe.

Water droplet evaporation from sticky superhydrophobic surfaces

Science.gov (United States)

Lee, Moonchan; Kim, Wuseok; Lee, Sanghee; Baek, Seunghyeon; Yong, Kijung; Jeon, Sangmin

2017-07-01

The evaporation dynamics of water from sticky superhydrophobic surfaces was investigated using a quartz crystal microresonator and an optical microscope. Anodic aluminum oxide (AAO) layers with different pore sizes were directly fabricated onto quartz crystal substrates and hydrophobized via chemical modification. The resulting AAO layers exhibited hydrophobic or superhydrophobic characteristics with strong adhesion to water due to the presence of sealed air pockets inside the nanopores. After placing a water droplet on the AAO membranes, variations in the resonance frequency and Q-factor were measured throughout the evaporation process, which were related to changes in mass and viscous damping, respectively. It was found that droplet evaporation from a sticky superhydrophobic surface followed a constant contact radius (CCR) mode in the early stage of evaporation and a combination of CCR and constant contact angle modes without a Cassie-Wenzel transition in the final stage. Furthermore, AAO membranes with larger pore sizes exhibited longer evaporation times, which were attributed to evaporative cooling at the droplet interface.

Studies of the viscoelastic properties of water confined between surfaces of specified chemical nature.

Energy Technology Data Exchange (ETDEWEB)

Houston, Jack E.; Grest, Gary Stephen; Moore, Nathan W.; Feibelman, Peter J.

2010-09-01

This report summarizes the work completed under the Laboratory Directed Research and Development (LDRD) project 10-0973 of the same title. Understanding the molecular origin of the no-slip boundary condition remains vitally important for understanding molecular transport in biological, environmental and energy-related processes, with broad technological implications. Moreover, the viscoelastic properties of fluids in nanoconfinement or near surfaces are not well-understood. We have critically reviewed progress in this area, evaluated key experimental and theoretical methods, and made unique and important discoveries addressing these and related scientific questions. Thematically, the discoveries include insight into the orientation of water molecules on metal surfaces, the premelting of ice, the nucleation of water and alcohol vapors between surface asperities and the lubricity of these molecules when confined inside nanopores, the influence of water nucleation on adhesion to salts and silicates, and the growth and superplasticity of NaCl nanowires.

Chemical grafting of the superhydrophobic surface on copper with hierarchical microstructure and its formation mechanism

Science.gov (United States)

Cai, Junyan; Wang, Shuhui; Zhang, Junhong; Liu, Yang; Hang, Tao; Ling, Huiqin; Li, Ming

2018-04-01

In this paper, a superhydrophobic surface with hierarchical structure was fabricated by chemical deposition of Cu micro-cones array, followed by chemical grafting of poly(methyl methacrylate) (PMMA). Water contact measurements give contact angle of 131.0° on these surfaces after PMMA grafting of 2 min and 165.2° after 6 min. The superhydrophobicity results from two factors: (1) the hierarchical structure due to Cu micro-cones array and the second level structure caused by intergranular corrosion during grafting of PMMA (confirmed by the scanning electron microscopy) and (2) the chemical modification of a low surface energy PMMA layer (confirmed by Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy). In the chemical grafting process, the spontaneous reduction of nitrobenzene diazonium (NBD) tetrafluoroborate not only causes the corrosion of the Cu surface that leads to a hierarchical structure, but also initiates the polymerization of methyl methacrylate (MMA) monomers and thus the low free energy surface. Such a robust approach to fabricate the hierarchical structured surface with superhydrophobicity is expected to have practical application in anti-corrosion industry.

Occurrence of estrogenic activities in second-grade surface water and ground water in the Yangtze River Delta, China

International Nuclear Information System (INIS)

Shi, Wei; Hu, Guanjiu; Chen, Sulan; Wei, Si; Cai, Xi; Chen, Bo; Feng, Jianfang; Hu, Xinxin; Wang, Xinru; Yu, Hongxia

2013-01-01

Second-grade surface water and ground water are considered as the commonly used cleanest water in the Yangtze River Delta, which supplies centralized drinking water and contains rare species. However, some synthetic chemicals with estrogenic disrupting activities are detectable. Estrogenic activities in the second-grade surface water and ground water were surveyed by a green monkey kidney fibroblast (CV-1) cell line based ER reporter gene assay. Qualitative and quantitative analysis were further conducted to identify the responsible compounds. Estrogen receptor (ER) agonist activities were present in 7 out of 16 surface water and all the ground water samples. Huaihe River and Yangtze River posed the highest toxicity potential. The highest equivalent (2.2 ng E 2 /L) is higher than the predicted no-effect-concentration (PNEC). Bisphenol A (BPA) contributes to greater than 50% of the total derived equivalents in surface water, and the risk potential in this region deserves more attention and further research. -- Highlights: •Estrogenic activities were present in second-grade surface water and ground water. •Most of the detected equivalents were higher than the predicted no-effect-concentration of E 2 . •ER-EQ 20–80 ranges showed that samples in Huaihe River and Yangtze River posed the highest toxicity. •Bisphenol A contributes to most of the instrumentally derived equivalents in surface water. -- Estrogenic activities were observed in second-grade surface water and ground water in Yangtze River Delta, and BPA was the responsible contaminant

Cell-based metabolomics for assessing chemical exposure and toxicity of environmental surface waters (presentation)

Science.gov (United States)

Introduction: Waste water treatment plants (WWTPs), concentrated animal feeding operations (CAFOs), mining activities, and agricultural operations release contaminants that negatively affect surface water quality. Traditional methods using live animals (e.g. fish) to monitor/as...

Surface water management at a mixed waste remediation site

International Nuclear Information System (INIS)

Schlotzhauer, D.S.; Warbritton, K.R.

1991-01-01

The Weldon Spring Remedial Action Project (WSSRAP) deals with chemical and radiological contaminants. MK-Ferguson Company is managing the project under contract with the US Department of Energy. Remedial activities include demolishing buildings, constructing material storage and staging areas, excavating and consolidating waste materials, and treating and disposing of the materials in a land disposal facility. Due to the excavation and construction required during remediation, a well-planned surface water management system is essential. Planning involves characterization of source areas and surface water transport mechanisms and identification of applicable regulations. System components include: erosion control sediment control, flow attenuation, and management of contaminated water. Combinations of these components may be utilized during actual construction and remediation to obtain optimum control. Monitoring is performed during implementation in order to assess the effectiveness of control measures. This management scheme provides for comprehensive management of surface water at this site by providing control and/or treatment to appropriate standards. Although some treatment methodologies for contaminated water are specific to site contaminants, this comprehensive program provides a management approach which is applicable to many remedial projects in order to minimize contaminant release and meet Clean Water Act requirements

Molecular Dynamics Simulations of Water Nanodroplets on Silica Surfaces

DEFF Research Database (Denmark)

Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard L.

2009-01-01

and DNA microarrays technologies.4,5,6,7,8 Although extensive experimental, theoretical and computational work has been devoted to study the nature of the interaction between silica and water,2,9-16 at the molecular level a complete understanding of silica-water systems has not been reached. Contact angle...... computations of water droplets on silica surfaces offers a useful fundamental and quantitative measurement in order to study chemical and physical properties of water-silica systems.3,16,17,18 For hydrophobic systems the static and dynamic properties of the fluid-solid interface are influenced by the presence...

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

Energy Technology Data Exchange (ETDEWEB)

Majewski, Peter, E-mail: peter.majewski@unisa.edu.au [School of Advanced Manufacturing and Mechanical Engineering, Mawson Institute, University of South Australia, Adelaide (Australia); Keegan, Alexandra [Microbiology Research, Australian Water Quality Centre, South Australian Water Corporation, Adelaide (Australia)

2012-01-15

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/g{sub silica}. 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 10{sup 2} and 10{sup 4} cfu/mL.

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

International Nuclear Information System (INIS)

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/g silica . 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 10 2 and 10 4 cfu/mL.

Surface Water & Surface Drainage

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

Robust superhydrophobic surface by nature-inspired polyphenol chemistry for effective oil-water separation

Science.gov (United States)

Bu, Yiming; Huang, Jingjing; Zhang, Shiyu; Wang, Yinghua; Gu, Shaojin; Cao, Genyang; Yang, Hongjun; Ye, Dezhan; Zhou, Yingshan; Xu, Weilin

2018-05-01

With the ever-increasing oil spillages, oil-water separation has attracted widespread concern in recent years. In this work, a nature-inspired polyphenol method has been developed to fabricate the durable superhydrophobic surfaces for the oil-water separation. Inspiring from the adhesion of polyphenol and reducing capacity of free catechol/pyrogallol groups in polyphenol, firstly, the simple immersion of commercial materials (melamine sponge, PET, and nonwoven cotton fabrics) in tannic acid (TA) solution allows to form a multifunctional coating on the surface of sponge or fabrics, which was used as reducing reagent to generate Ag nanoparticles (NPs). Then, decoration of 1H, 1H, 2H, 2H-perfluorodecanethiol (PFDT) molecules produced superhydrophobic surfaces. The surface topological structure, chemical composition, and superhydrophobic property of the as-prepared surface are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), and water contact angle (WCA) measurements. The WCAs of as-prepared sponge and fabrics were higher than 150°. The stability, absorption capacity, and recyclability of as-prepared sponge and fabrics were investigated. The as-prepared sponge demonstrates high oil/water selectivity and high absorption capacity (66-150 g/g) for a broad variety of oils and organic solvents, and was chemically resistant, robust against abrasion, and long-term durability in harsh environments. Most important of all, it can continuously separate various kinds of oils or organic pollutants from the surface of water. This study presents a facile strategy to fabricate superhydrophobic materials for continuous oil-water separation, displaying great potential in large-scale practical application.

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

Science.gov (United States)

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.

Flow Alteration and Chemical Reduction: Air Stripping to Lessen Subsurface Discharges of Mercury to Surface Water

Science.gov (United States)

Brooks, S. C.; Bogle, M.; Liang, L.; Miller, C. L.; Peterson, M.; Southworth, G. R.; Spalding, B. P.

2009-12-01

Mercury concentrations in groundwater, surface water, and biota near an industrial facility in Oak Ridge, Tennessee remain high some 50 years after the original major releases from the facility to the environment. Since the mid-1980s, various remedial and abatement actions have been implemented at the facility, including re-routing water flows, armoring contaminated stream banks, relining or cleanout of facility storm drains, and activated charcoal treatment of groundwater and sump discharges. These actions were taken to reduce inorganic mercury inputs from the facility to the stream; a strategy that assumes limiting the inorganic mercury precursor will reduce Hg methylation and its subsequent bioaccumulation. To date, such actions have reduced mercury loading from the site by approximately 90% from levels typical of the mid 1980's, but waterborne mercury at the facility boundary remains roughly 100 times the typical local background concentration and methylmercury accumulation in aquatic biota exceed standards for safe consumption by humans and wildlife. In 2008 and 2009, a series of investigations was initiated to explore innovative approaches to further control mercury concentrations in stream water. Efforts in this study focused on decreasing waterborne inorganic mercury inputs from two sources. The first, a highly localized source, is the discharge point of the enclosed stormdrain network whereas the second is a more diffuse short reach of stream where metallic Hg in streambed sediments generates a continued input of dissolved Hg to the overlying water. Moving a clean water flow management discharge point to a position downstream of the contaminated reach reduced mercury loading from the streambed source by 75% - 100%, likely by minimizing resuspension of Hg-rich fine particulates and changing characteristic hyporheic flow path length and residence time. Mercury in the stormdrain discharge exists as highly reactive dissolved Hg(II) due to residual chlorine in

Determination of Groundwater and Surface Water Qualities at Si Racha, Chon Buri

International Nuclear Information System (INIS)

Wangsawang, Jarinee; Naenorn, Warinlada; Khuntong, Soontree; Wongsorntam, Krirk; Udomsomporn, Suchin

2011-06-01

Full text: Groundwater (13 wells) and surface water (7 ponds) at Si Racha, Chon Buri province were collected for measurement of water qualities and radionuclides. The water qualities included physical and chemical analysis such as pH, EC, TS, TDS, TSS, TKN, total phosphate, BOD, COD, total hardness and FOG based on standard methods for examination of water and wastewater. Heavy metals (Cd, Cu, Cr, Fe, Mn, Ni and Zn) were analyzed by ICP-AES while total coliform was determined by Multiple Tube Methods. Moreover, radionuclides were analyzed by gamma spectrometer and gross beta and gross alpha were obtained from low background gas proportional counter. Values of most parameters in groundwater were below water qualities standards but all parameters in surface water samples were exceeded water qualities standards. It was found that all radionuclides in water samples were originated from natural uranium and thorium series. The data obtained enabled evaluation of pollutants in groundwater and surface water

Liquid interfacial water and brines in the upper surface of Mars

Science.gov (United States)

Moehlmann, Diedrich

2013-04-01

Liquid interfacial water and brines in the upper surface of Mars Diedrich T.F. Möhlmann DLR Institut für Planetenforschung, Rutherfordstr. 2, D - 12489 Berlin, Germany dirk.moehlmann@dlr.de Interfacial water films and numerous brines are known to remain liquid at temperatures far below 0° C. The physical processes behind are described in some detail. Deliquescence, i.e. the liquefaction of hygroscopic salts at the threshold of a specific "Deliquescence Relative Humidity", is shown to be that process, which on present Mars supports the formation of stable interfacial water and bulk liquids in form of temporary brines on and in a salty upper surface of present Mars in a diurnally temporary and repetitive process. Temperature and relative humidity are the governing conditions for deliquescence (and the counterpart "efflorescence") to evolve. The current thermo-dynamical conditions on Mars support these processes to evolve on present Mars. The deliquescence-driven presence of liquid brines in the soil of the upper surface of Mars can expected to be followed by physical and chemical processes like "surface cementation", down-slope flows, and physical and chemical weathering processes. A remarkable and possibly also biologically relevant evolution towards internally interfacial water bearing structures of dendritic capillaries is related to their freezing - thawing driven formation. The internal walls of these network-pores or -tubes can be covered by films of interfacial water, providing that way possibly habitable crack-systems in soil and rock. These evolutionary processes of networks, driven by their tip-growth, can expected to be ongoing also at present.

Chemical surface tuning electrocatalysis of redox-active nanoparticles

DEFF Research Database (Denmark)

Zhu, Nan; Ulstrup, Jens; Chi, Qijin

This work focuses on electron transfer (ET) and electrocatalysis of inorganic hybrid Prussian blue nanoparticles (PBNPs, 6 nm) immobilized on different chemical surfaces. Through surface self-assembly chemistry, we have enabled to tune chemical properties of the electrode surface. Stable immobili...

Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

Energy Technology Data Exchange (ETDEWEB)

Angermann, Heike, E-mail: angermann@helmholtz-berlin.de

2014-09-01

Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D{sub it}(E), and density D{sub it,min} of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly

Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

International Nuclear Information System (INIS)

Angermann, Heike

2014-01-01

Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D it (E), and density D it,min of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly based on

Development of chemical cleaning formulation for service water system of FBTR

International Nuclear Information System (INIS)

Velmurugan, S.; Narasimhan, S.V.; Das, P.C.; Mathur, P.K.

1995-01-01

Service water system of Fast Breeder Test Reactor (FBTR) was found to be corroded and at few locations, the corrosion product oxides were choking the smaller diameter pipelines. An attempt was made to develop a chemical cleaning formulation to chemically remove the oxides using a surface conditioner and chelating agents. Of the several complexants tested, hydroxyethylethylene diamine tetraacetic acid (HEDTA) was found to be better than other complexants from the point of view of oxide dissolution efficiency, solubility etc. A two stage chemical cleaning process involving conditioning of the oxide layer with 0.1% tannic acid followed by exposure of the conditioned oxide layer with a formulation containing 1% HEDTA + 0.5% Sodium Gluconate +0.2% hexamine was recommended to remove the corrosion product oxide present in the service water system. (author). 4 refs., 2 tabs

Sulphur dioxide removal by turbulent transfer over grass, snow, and water surfaces

Energy Technology Data Exchange (ETDEWEB)

Whelpdale, D M; Shaw, R W

1974-01-01

Vertical gradients of sulphur dioxide concentration have been measured over grass, snow, and water surfaces in order to assess the importance of these surfaces as SO/sub 2/ sinks. Concentrations were usually found to be lower near the surface indicating that removal occurs there. Vertical concentration gradients, normalized with repect to the concentration at 8 m, were generally greatest over water and least over snow, independent of meteorological conditions, suggesting that a water surface is the strongest SO/sub 2/ sink, with grass next, and snow weakest. The turbulent transfer of SO/sub 2/ to the interface is discussed in relation to stability of the lower atmosphere and physical and chemical properties of the surfaces. Using a bulk aerodynamic transfer approach similar to that for water vapour, values of SO/sub 2/ flux averaged over periods of from one to several hours were found to be of the order of 1 microgram/M/sup 2//S to the water and grass surfaces, and an order of magnitude smaller to the snow surface. Deposition velocities were found to be of the order of 1 cm/s.

Relationships between precipitation and surface water chemistry in three Carolina bays

International Nuclear Information System (INIS)

Monegue, R.L.; Jagoe, C.H.

1995-01-01

Carolina Bays are shallow freshwater wetlands, the only naturally occurring lentic systems on the southeastern coastal plain. Bays are breeding sites for many amphibian species, but data on precipitation/surface water relationships and long-term chemical trends are lacking. Such data are essential to interpret major fluctuations in amphibian populations. Surface water and bulk precipitation were sampled bi-weekly for over two years at three bays along a 25 km transect on the Savannah River Site in South Carolina. Precipitation chemistry was similar at all sites; average pH was 4.56, and the major ions were H + (30.8 % of total), and SO 4 (50.3% of total). H + was positively correlated with SO 4 , suggesting the importance of anthropogenic acids to precipitation chemistry. All three bays, Rainbow Bay (RB), Thunder Bay (TB), and Ellenton Bay (EB), contained soft (specific conductivity 5--90 microS/cm), acidic water (pH 4.0--5.9) with DOM from 4--40 mg/L. The major cation for RB, TB, and EB, respectively, was: Mg (30.8 % of total); Na (27% of total); and Ca (34.2% of total). DOM was the major anion for all bays, and SO 4 represented 13 to 28 % of total anions. H + was not correlated to DOM or SO, in RB; H + was positively correlated to DOM and SO 4 in TB, and negatively correlated to DOM and SO 4 in EB. Different biogeochemical processes probably control pH and other chemical variables in each bay. While surface water H + was not directly correlated with precipitation H + , NO 3 , or SO 4 , precipitation and shallow groundwater are dominant water sources for these bays. Atmospheric inputs of anthropogenic acids and other chemicals are important factors influencing bay chemistry

Modeling diffuse sources of surface water contamination with plant protection products

Science.gov (United States)

Wendland, Sandra; Bock, Michael; Böhner, Jürgen; Lembrich, David

2015-04-01

Entries of chemical pollutants in surface waters are a serious environmental problem. Among water pollutants plant protection products (ppp) from farming practice are of major concern not only for water suppliers and environmental agencies, but also for farmers and industrial manufacturers. Lost chemicals no longer fulfill their original purpose on the field, but lead to severe damage of the environment and surface waters. Besides point-source inputs of chemical pollutants, the diffuse-source inputs from agricultural procedures play an important and not yet sufficiently studied role concerning water quality. The two most important factors for diffuse inputs are erosion and runoff. The latter usually occurs before erosion begins, and is thus often not visible in hindsight. Only if it has come to erosion, it is obvious to expect runoff in foresight at this area, too. In addition to numerous erosion models, there are also few applications to model runoff processes available. However, these conventional models utilize approximations of catchment parameters based on long-term average values or theoretically calculated concentration peaks which can only provide indications to relative amounts. Our study aims to develop and validate a simplified spatially-explicit dynamic model with high spatiotemporal resolution that enables to measure current and forecast runoff potential not only at catchment scale but field-differentiated. This method allows very precise estimations of runoff risks and supports risk reduction measures to be targeted before fields are treated. By focusing on water pathways occurring on arable land, targeted risk reduction measures like buffer strips at certain points and adapted ppp use can be taken early and pollution of rivers and other surface waters through transported pesticides, fertilizers and their products could be nearly avoided or largely minimized. Using a SAGA-based physical-parametric modeling approach, major factors influencing runoff

The degradation behaviour of nine diverse contaminants in urban surface water and wastewater prior to water treatment.

Science.gov (United States)

Cormier, Guillaume; Barbeau, Benoit; Arp, Hans Peter H; Sauvé, Sébastien

2015-12-01

An increasing diversity of emerging contaminants are entering urban surface water and wastewater, posing unknown risks for the environment. One of the main contemporary challenges in ensuring water quality is to design efficient strategies for minimizing such risks. As a first step in such strategies, it is important to establish the fate and degradation behavior of contaminants prior to any engineered secondary water treatment. Such information is relevant for assessing treatment solutions by simple storage, or to assess the impacts of contaminant spreading in the absence of water treatment, such as during times of flooding or in areas of poor infrastructure. Therefore in this study we examined the degradation behavior of a broad array of water contaminants in actual urban surface water and wastewater, in the presence and absence of naturally occurring bacteria and at two temperatures. The chemicals included caffeine, sulfamethoxazole, carbamazepine, atrazine, 17β-estradiol, ethinylestradiol, diclofenac, desethylatrazine and norethindrone. Little information on the degradation behavior of these pollutants in actual influent wastewater exist, nor in general in water for desethylatrazine (a transformation product of atrazine) and the synthetic hormone norethindrone. Investigations were done in aerobic conditions, in the absence of sunlight. The results suggest that all chemicals except estradiol are stable in urban surface water, and in waste water neither abiotic nor biological degradation in the absence of sunlight contribute significantly to the disappearance of desethylatrazine, atrazine, carbamazepine and diclofenac. Biological degradation in wastewater was effective at transforming norethindrone, 17β-estradiol, ethinylestradiol, caffeine and sulfamethoxazole, with measured degradation rate constants k and half-lives ranging respectively from 0.0082-0.52 d(-1) and 1.3-85 days. The obtained degradation data generally followed a pseudo-first-order-kinetic model

Surface-water surveillance

Energy Technology Data Exchange (ETDEWEB)

Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

1995-06-01

This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995).

Surface-water surveillance

International Nuclear Information System (INIS)

Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

1995-01-01

This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995)

Novel Americium Treatment Process for Surface Water and Dust Suppression Water

International Nuclear Information System (INIS)

Tiepel, E.W.; Pigeon, P.; Nesta, S.; Anderson, J.

2006-01-01

The Rocky Flats Environmental Technology Site (RFETS), a former nuclear weapons production plant, has been remediated under CERCLA and decommissioned to become a National Wildlife Refuge. The site conducted this cleanup effort under the Rocky Flats Cleanup Agreement (RFCA) that established limits for the discharge of surface and process waters from the site. At the end of 2004, while a number of process buildings were undergoing decommissioning, routine monitoring of a discharge pond (Pond A-4) containing approximately 28 million gallons of water was discovered to have been contaminated with a trace amount of Americium-241 (Am-241). While the amount of Am-241 in the pond waters was very low (0.5 - 0.7 pCi/l), it was above the established Colorado stream standard of 0.15 pCi/l for release to off site drainage waters. The rapid successful treatment of these waters to the regulatory limit was important to the site for two reasons. The first was that the pond was approaching its hold-up limit. Without rapid treatment and release of the Pond A-4 water, typical spring run-off would require water management actions to other drainages onsite or a mass shuttling of water for disposal. The second reason was that this type of contaminated water had not been treated to the stringent stream standard at Rocky Flats before. Technical challenges in treatment could translate to impacts on water and secondary waste management, and ultimately, cost impacts. All of the technical challenges and specific site criteria led to the conclusion that a different approach to the treatment of this problem was necessary and a crash treatability program to identify applicable treatment techniques was undertaken. The goal of this program was to develop treatment options that could be implemented very quickly and would result in the generation of no high volume secondary waste that would be costly to dispose. A novel chemical treatment system was developed and implemented at the RFETS to treat Am

Mechanical and chemical decontamination of surfaces

International Nuclear Information System (INIS)

Kienhoefer, M.

1982-01-01

Decontamination does not mean more than a special technique of cleaning surfaces by methods well known in the industry. The main difference consists in the facts that more than just the visible dirt is to be removed and that radioactive contamination cannot be seen. Especially, intensive mechanical and chemical carry-off methods are applied to attack the surfaces. In order to minimize damages caused to the surfaces, the decontamination method is to adapt to the material and the required degree of decontamination. The various methods, their advantages and disadvantages are described, and the best known chemical solutions are shown. (orig./RW)

UV sensitivity of planktonic net community production in ocean surface waters

Science.gov (United States)

Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

2014-05-01

The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

Surface freezing of water

OpenAIRE

P?rez-D?az, J. L.; ?lvarez-Valenzuela, M. A.; Rodr?guez-Celis, F.

2016-01-01

Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered?exclusively?by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on ...

Hydrogeology and chemical quality of water and soil at Carroll Island, Aberdeen Proving Ground, Maryland

Science.gov (United States)

Tenbus, F.J.; Phillips, S.W.

1996-01-01

Carroll Island was used for open-air testing of chemical warfare agents from the late 1940's until 1971. Testing and disposal activities weresuspected of causing environmental contamination at 16 sites on the island. The hydrogeology and chemical quality of ground water, surface water, and soil at these sites were investigated with borehole logs, environmental samples, water-level measurements, and hydrologic tests. A surficial aquifer, upper confining unit, and upper confined aquifer were defined. Ground water in the surficial aquifer generally flows from the east-central part of the island toward the surface-water bodies, butgradient reversals caused by evapotranspiration can occur during dry seasons. In the confined aquifer, hydraulic gradients are low, and hydraulic head is affected by tidal loading and by seasonal pumpage from the west. Inorganic chemistry in the aquifers is affected by brackish-water intrusion from gradient reversals and by dissolution ofcarboniferous shell material in the confining unit.The concentrations of most inorganic constituents probably resulted from natural processes, but some concentrations exceeded Federal water-quality regulations and criteria. Organic compounds were detected in water and soil samples at maximum concentrations of 138 micrograms per liter (thiodiglycol in surface water) and 12 micrograms per gram (octadecanoic acid in soil).Concentrations of organic compounds in ground water exceeded Federal drinking-water regulations at two sites. The organic compounds that weredetected in environmental samples were variously attributed to natural processes, laboratory or field- sampling contamination, fallout from industrial air pollution, and historical military activities.

Assessment of Surface Water Quality in the Malaysian Coastal Waters by Using Multivariate Analyses

International Nuclear Information System (INIS)

Yap, C.K.; Chee, M.W.; Shamarina, S.; Edward, F.B.; Chew, W.; Tan, S.G.

2011-01-01

Coastal water samples were collected from 20 sampling sites in the southern part of Peninsular Malaysia. Seven physico-chemical parameters were measured directly in-situ while water samples were collected and analysed for 6 dissolved trace metal concentrations. The surface water (0-20 cm) physico-chemical parameters including temperature, salinity, dissolved oxygen (DO), pH, total dissolved solids (TDS), specific conductance (SpC) and turbidity while the dissolved trace metals were Cd, Cu, Fe, Ni, Pb and Zn. The ranges for the physico-chemical parameters were 28.07-35.6 degree Celsius for temperature, 0.18-32.42 ppt for salinity, 2.20-12.03 mg/ L for DO, 5.50-8.53 for pH, 0.24-31.65 mg/ L for TDS, 368-49452 μS/ cm for SpC and 0-262 NTU for turbidity while the dissolved metals (mg/ L) were 0.013-0.147 for Cd, 0.024-0.143 for Cu, 0.266-2.873 for Fe, 0.027-0.651 for Ni, 0.018-0.377 for Pb and 0.032-0.099 for Zn. Based on multivariate analysis (including correlation, cluster and principal component analyses), the polluted sites were found at Kg. Pasir Puteh and Tg. Kupang while Ni and Pb were identified as two major dissolved metals of high variation in the coastal waters. Therefore, water quality monitoring and control of release of untreated anthropogenic wastes into rivers and coastal waters are strongly needed. (author)

Microcystin-LR in surface water of Ponjavica river

Directory of Open Access Journals (Sweden)

Natić Dejan

2012-01-01

Full Text Available Background/Aim. Cyanobacterial toxins befall a group of various compounds according to chemical structure and health effects on people and animals. The most significant in this large group of compounds are microcystins. Their presence in water used for human consumption causes serious health problems, liver beeing the target organ. Microcystins are spread all over the world. Waterblooms of cyanobacterias and their cyanotoxins are also common in the majority of surface waters in Serbia. The aim of this study was to propose HPLC method for determination of mikrocystin-LR, to validate the method and to use it for determination of microcystin-LR in the surface water of the river Ponjavica. The Ponjavica is very eutrophic water and has ideal conditions for the cyanobacterial growth. Methods. Sample of water form the Ponjavica river were collected during the summer 2008. Coupled columns (HLB, Sep-Pak, were used for sample preparation and HPLC/PDA method was used for quantification of microcystin- LR. Results. Parameters of validation show that the proposed method is simple, fast, sensitive (0.1 mg/L and selective with the yield of 89%-92%. The measuring uncertainty of

Assessment of Hyporheic Zone, Flood-Plain, Soil-Gas, Soil, and Surface-Water Contamination at the McCoys Creek Chemical Training Area, Fort Gordon, Georgia, 2009-2010

Science.gov (United States)

Guimaraes, Wladmir B.; Falls, W. Fred; Caldwell, Andral W.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

2011-01-01

The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the hyporheic zone, flood plain, soil gas, soil, and surface water for contaminants at the McCoys Creek Chemical Training Area (MCTA) at Fort Gordon, from October 2009 to September 2010. The assessment included the detection of organic contaminants in the hyporheic zone, flood plain, soil gas, and surface water. In addition, the organic contaminant assessment included the analysis of organic compounds classified as explosives and chemical agents in selected areas. Inorganic contaminants were assessed in soil and surface-water samples. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Ten passive samplers were deployed in the hyporheic zone and flood plain, and total petroleum hydrocarbons (TPH) and octane were detected above the method detection level in every sampler. Other organic compounds detected above the method detection level in the hyporheic zone and flood-plain samplers were trichloroethylene, and cis- and trans- 1, 2-dichloroethylene. One trip blank detected TPH below the method detection level but above the nondetection level. The concentrations of TPH in the samplers were many times greater than the concentrations detected in the blank; therefore, all other TPH concentrations detected are considered to represent environmental conditions. Seventy-one soil-gas samplers were deployed in a grid pattern across the MCTA. Three trip blanks and three method blanks were used and not deployed, and TPH was detected above the method detection level in two trip blanks and one method blank. Detection of TPH was observed at all 71 samplers, but because TPH was detected in the trip and method blanks, TPH was

Supersonic molecular beam experiments on surface chemical reactions.

Science.gov (United States)

Okada, Michio

2014-10-01

The interaction of a molecule and a surface is important in various fields, and in particular in complex systems like biomaterials and their related chemistry. However, the detailed understanding of the elementary steps in the surface chemistry, for example, stereodynamics, is still insufficient even for simple model systems. In this Personal Account, I review our recent studies of chemical reactions on single-crystalline Cu and Si surfaces induced by hyperthermal oxygen molecular beams and by oriented molecular beams, respectively. Studies of oxide formation on Cu induced by hyperthermal molecular beams demonstrate a significant role of the translational energy of the incident molecules. The use of hyperthermal molecular beams enables us to open up new chemical reaction paths specific for the hyperthermal energy region, and to develop new methods for the fabrication of thin films. On the other hand, oriented molecular beams also demonstrate the possibility of understanding surface chemical reactions in detail by varying the orientation of the incident molecules. The steric effects found on Si surfaces hint at new ways of material fabrication on Si surfaces. Controlling the initial conditions of incoming molecules is a powerful tool for finely monitoring the elementary step of the surface chemical reactions and creating new materials on surfaces. Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface water assessment on the influence of space distribution on ...

African Journals Online (AJOL)

In this work, the influence of space distribution on physico-chemical parameters of refinery effluent discharge has been studied, using treated effluent water discharged from the Port Harcourt Refinery Company (PHRC) into the Ekerekana Creek in Okrika as reference. Samples were collected at surface level from the ...

Study and interpretation of the chemical characteristics of natural water

Science.gov (United States)

Hem, John David

1985-01-01

The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater.

Anthropogenic influence on surface water quality of the Nhue and Day sub-river systems in Vietnam.

Science.gov (United States)

Hanh, Pham Thi Minh; Sthiannopkao, Suthipong; Kim, Kyoung-Woong; Ba, Dang The; Hung, Nguyen Quang

2010-06-01

In order to investigate the temporal and spatial variations of 14 physical and chemical surface water parameters in the Nhue and Day sub-river systems of Vietnam, surface water samples were taken from 43 sampling sites during the dry and rainy seasons in 2007. The results were statistically examined by Mann-Whitney U-test and hierarchical cluster analysis. The results show that water quality of the Day River was significantly improved during the rainy season while this was not the case of the Nhue River. However, the river water did not meet the Vietnamese surface water quality standards for dissolved oxygen (DO), biological oxygen demand (BOD(5)), chemical oxygen demand (COD), nutrients, total coliform, and fecal coliform. This implies that the health of local communities using untreated river water for drinking purposes as well as irrigation of vegetables may be at risk. Forty-three sampling sites were grouped into four main clusters on the basis of water quality characteristics with particular reference to geographic location and land use and revealed the contamination levels from anthropogenic sources.

Endocrine active chemicals, pharmaceuticals, and other chemicals of concern in surface water, wastewater-treatment plant effluent, and bed sediment, and biological characteristics in selected streams, Minnesota-design, methods, and data, 2009

Science.gov (United States)

Lee, Kathy E.; Langer, Susan K.; Barber, Larry B.; Writer, Jeff H.; Ferrey, Mark L.; Schoenfuss, Heiko L.; Furlong, Edward T.; Foreman, William T.; Gray, James L.; ReVello, Rhiannon C.; Martinovic, Dalma; Woodruff, Olivia R.; Keefe, Steffanie H.; Brown, Greg K.; Taylor, Howard E.; Ferrer, Imma; Thurman, E. Michael

2011-01-01

This report presents the study design, environmental data, and quality-assurance data for an integrated chemical and biological study of selected streams or lakes that receive wastewater-treatment plant effluent in Minnesota. This study was a cooperative effort of the U.S. Geological Survey, the Minnesota Pollution Control Agency, St. Cloud State University, the University of St. Thomas, and the University of Colorado. The objective of the study was to identify distribution patterns of endocrine active chemicals, pharmaceuticals, and other organic and inorganic chemicals of concern indicative of wastewater effluent, and to identify biological characteristics of estrogenicity and fish responses in the same streams. The U.S. Geological Survey collected and analyzed water, bed-sediment, and quality-assurance samples, and measured or recorded streamflow once at each sampling location from September through November 2009. Sampling locations included surface water and wastewater-treatment plant effluent. Twenty-five wastewater-treatment plants were selected to include continuous flow and periodic release facilities with differing processing steps (activated sludge or trickling filters) and plant design flows ranging from 0.002 to 10.9 cubic meters per second (0.04 to 251 million gallons per day) throughout Minnesota in varying land-use settings. Water samples were collected from the treated effluent of the 25 wastewater-treatment plants and at one point upstream from and one point downstream from wastewater-treatment plant effluent discharges. Bed-sediment samples also were collected at each of the stream or lake locations. Water samples were analyzed for major ions, nutrients, trace elements, pharmaceuticals, phytoestrogens and pharmaceuticals, alkylphenols and other neutral organic chemicals, carboxylic acids, and steroidal hormones. A subset (25 samples) of the bed-sediment samples were analyzed for carbon, wastewater-indicator chemicals, and steroidal hormones; the

Effects of blending of desalinated and conventionally treated surface water on iron corrosion and its release from corroding surfaces and pre-existing scales.

Science.gov (United States)

Liu, Haizhou; Schonberger, Kenneth D; Peng, Ching-Yu; Ferguson, John F; Desormeaux, Erik; Meyerhofer, Paul; Luckenbach, Heidi; Korshin, Gregory V

2013-07-01

This study examined effects of blending desalinated water with conventionally treated surface water on iron corrosion and release from corroding metal surfaces and pre-existing scales exposed to waters having varying fractions of desalinated water, alkalinities, pH values and orthophosphate levels. The presence of desalinated water resulted in markedly decreased 0.45 μm-filtered soluble iron concentrations. However, higher fractions of desalinated water in the blends were also associated with more fragile corroding surfaces, lower retention of iron oxidation products and release of larger iron particles in the bulk water. SEM, XRD and XANES data showed that in surface water, a dense layer of amorphous ferrihydrite phase predominated in the corrosion products. More crystalline surface phases developed in the presence of desalinated water. These solid phases transformed from goethite to lepidocrocite with increased fraction of desalinated water. These effects are likely to result from a combination of chemical parameters, notably variations of the concentrations of natural organic matter, calcium, chloride and sulfate when desalinated and conventionally treated waters are blended. Copyright © 2013 Elsevier Ltd. All rights reserved.

Antibiotic Algae by Chemical Surface Engineering.

Science.gov (United States)

Kerschgens, Isabel P; Gademann, Karl

2018-03-02

Chemical cell-surface engineering is a tool for modifying and altering cellular functions. Herein, we report the introduction of an antibiotic phenotype to the green alga Chlamydomonas reinhardtii by chemically modifying its cell surface. Flow cytometry and confocal microscopy studies demonstrated that a hybrid of the antibiotic vancomycin and a 4-hydroxyproline oligomer binds reversibly to the cell wall without affecting the viability or motility of the cells. The modified cells were used to inhibit bacterial growth of Gram-positive Bacillus subtilis cultures. Delivery of the antibiotic from the microalgae to the bacterial cells was verified by microscopy. Our studies provide compelling evidence that 1) chemical surface engineering constitutes a useful tool for the introduction of new, previously unknown functionality, and 2) living microalgae can serve as new platforms for drug delivery. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Observation of dynamic water microadsorption on Au surface

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiaokang, E-mail: xiaokang.huang@tqs.com; Gupta, Gaurav; Gao, Weixiang; Tran, Van; Nguyen, Bang; McCormick, Eric; Cui, Yongjie; Yang, Yinbao; Hall, Craig; Isom, Harold [TriQuint Semiconductor, Inc., 500 W Renner Road, Richardson, Texas 75080 (United States)

2014-05-15

Experimental and theoretical research on water wettability, adsorption, and condensation on solid surfaces has been ongoing for many decades because of the availability of new materials, new detection and measurement techniques, novel applications, and different scales of dimensions. Au is a metal of special interest because it is chemically inert, has a high surface energy, is highly conductive, and has a relatively high melting point. It has wide applications in semiconductor integrated circuitry, microelectromechanical systems, microfluidics, biochips, jewelry, coinage, and even dental restoration. Therefore, its surface condition, wettability, wear resistance, lubrication, and friction attract a lot of attention from both scientists and engineers. In this paper, the authors experimentally investigated Au{sub 2}O{sub 3} growth, wettability, roughness, and adsorption utilizing atomic force microscopy, scanning electron microscopy, reflectance spectrometry, and contact angle measurement. Samples were made using a GaAs substrate. Utilizing a super-hydrophilic Au surface and the proper surface conditions of the surrounding GaAs, dynamic microadsorption of water on the Au surface was observed in a clean room environment. The Au surface area can be as small as 12 μm{sup 2}. The adsorbed water was collected by the GaAs groove structure and then redistributed around the structure. A model was developed to qualitatively describe the dynamic microadsorption process. The effective adsorption rate was estimated by modeling and experimental data. Devices for moisture collection and a liquid channel can be made by properly arranging the wettabilities or contact angles of different materials. These novel devices will be very useful in microfluid applications or biochips.

Surface freezing of water.

Science.gov (United States)

Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

2016-01-01

Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

Groundwater and surface-water interactions and impacts of human activities in the Hailiutu catchment, northwest China

Science.gov (United States)

Yang, Zhi; Zhou, Yangxiao; Wenninger, Jochen; Uhlenbrook, Stefan; Wang, Xusheng; Wan, Li

2017-08-01

The interactions between groundwater and surface water have been significantly affected by human activities in the semi-arid Hailiutu catchment, northwest China. Several methods were used to investigate the spatial and temporal interactions between groundwater and surface water. Isotopic and chemical analyses of water samples determined that groundwater discharges to the Hailiutu River, and mass balance equations were employed to estimate groundwater seepage rates along the river using chemical profiles. The hydrograph separation method was used to estimate temporal variations of groundwater discharges to the river. A numerical groundwater model was constructed to simulate groundwater discharges along the river and to analyze effects of water use in the catchment. The simulated seepage rates along the river compare reasonably well with the seepage estimates derived from a chemical profile in 2012. The impacts of human activities (river-water diversion and groundwater abstraction) on the river discharge were analyzed by calculating the differences between the simulated natural groundwater discharge and the measured river discharge. Water use associated with the Hailiutu River increased from 1986 to 1991, reached its highest level from 1992 to 2000, and decreased from 2001 onwards. The reduction of river discharge might have negative impacts on the riparian ecosystem and the water availability for downstream users. The interactions between groundwater and surface water as well as the consequences of human activities should be taken into account when implementing sustainable water resources management in the Hailiutu catchment.

Cell behaviour on chemically microstructured surfaces

International Nuclear Information System (INIS)

Magnani, Agnese; Priamo, Alfredo; Pasqui, Daniela; Barbucci, Rolando

2003-01-01

Micropatterned surfaces with different chemical topographies were synthesised in order to investigate the influence of surface chemistry and topography on cell behaviour. The microstructured materials were synthesised by photoimmobilising natural Hyaluronan (Hyal) and its sulphated derivative (HyalS), both adequately functionalised with a photorective moiety, on glass substrates. Four different grating patterns (10, 25, 50 and 100 μm) were used to pattern the hyaluronan. The micropatterned samples were analysed by Secondary Ions Mass Spectrometry, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy to investigate the chemistry and the topography of the surfaces. The spectroscopic and microscopic analysis of the microstructured surfaces revealed that the photoimmobilisation process was successful, demonstrating that the photomask patterns were well reproduced on the sample surface. The influence of chemical topographies on the cell behaviour was then analysed. Human and 3T3 fibroblasts, bovine aortic and human (HGTFN line) endothelial cells were used and their behaviour on the micropatterned surfaces was analysed in terms of adhesion, proliferation, locomotion and orientation. Both chemical and topographical controls were found to be important for cell guidance. By decreasing the stripe dimensions, a more fusiform shape of cell was observed. At the same time, the cell locomotion and orientation parallel to the structure increased. However, differences in cell behaviour were detected according to both cell type and micropattern dimensions

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

Energy Technology Data Exchange (ETDEWEB)

Harris, Aubrey E. [West Virginia Univ., Morgantown, WV (United States); National Energy Technology Lab. (NETL), Morgantown, WV (United States); U.S. Bureau of Reclamation, Albuquerque, NM (United States); Hopkinson, Leslie [West Virginia Univ., Morgantown, WV (United States); Soeder, Daniel [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

2016-12-02

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 used 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.

Tritium in surface water of the Yenisei river Basin

International Nuclear Information System (INIS)

Bondareva, L.G.; Bolsunovsky, A.Ya.

2005-01-01

The paper reports an investigation of the tritium content in the surface waters of the Yenisei River basin near the Mining-and-Chemical Combine (MCC). In 2001-2003 the maximum tritium concentration in the Yenisei River did not exceed 4±1 Bq/L. It has been found that there are surface waters containing enhanced tritium, up to 168 Bq/L, as compared with the background values for the Yenisei River. There are two possible sources of tritium input. First, the last operating reactor of the MCC, which still uses the Yenisei water as coolant. Second, tritium may come from the deep aquifers at the Severny testing site. For the first time tritium has been found in two aquatic plant species of the Yenisei River with maximal tritium concentration 304 Bq/Kg wet weight. Concentration factors of tritium for aquatic plants are much higher than 1

Superhydrophobic surfaces fabricated by femtosecond laser with tunable water adhesion: from lotus leaf to rose petal.

Science.gov (United States)

Long, Jiangyou; Fan, Peixun; Gong, Dingwei; Jiang, Dafa; Zhang, Hongjun; Li, Lin; Zhong, Minlin

2015-05-13

Superhydrophobic surfaces with tunable water adhesion have attracted much interest in fundamental research and practical applications. In this paper, we used a simple method to fabricate superhydrophobic surfaces with tunable water adhesion. Periodic microstructures with different topographies were fabricated on copper surface via femtosecond (fs) laser irradiation. The topography of these microstructures can be controlled by simply changing the scanning speed of the laser beam. After surface chemical modification, these as-prepared surfaces showed superhydrophobicity combined with different adhesion to water. Surfaces with deep microstructures showed self-cleaning properties with extremely low water adhesion, and the water adhesion increased when the surface microstructures became flat. The changes in surface water adhesion are attributed to the transition from Cassie state to Wenzel state. We also demonstrated that these superhydrophobic surfaces with different adhesion can be used for transferring small water droplets without any loss. We demonstrate that our approach provides a novel but simple way to tune the surface adhesion of superhydrophobic metallic surfaces for good potential applications in related areas.

Molecular Structure and Dynamics in Thin Water Films at the Silica and Graphite Surfaces

Energy Technology Data Exchange (ETDEWEB)

Argyris, Dr. Dimitrios [University of Oklahoma; Tummala, Dr. Naga Rajesh [University of Oklahoma; StrioloDr., A [Vanderbilt University; Cole, David R [ORNL

2008-01-01

The structure and dynamic properties of interfacial water at the graphite and silica solid surfaces were investigated using molecular dynamics simulations. The effect of surface properties on the characteristics of interfacial water was quantified by computing density profiles, radial distribution functions, surface density distributions, orientation order parameters, and residence and reorientation correlation functions. In brief, our results show that the surface roughness, chemical heterogeneity, and surface heterogeneous charge distribution affect the structural and dynamic properties of the interfacial water molecules, as well as their rate of exchange with bulk water. Most importantly, our results indicate the formation of two distinct water layers at the SiO2 surface covered by a large density of hydroxyl groups. Further analysis of the data suggests a highly confined first layer where the water molecules assume preferential hydrogen-down orientation and a second layer whose behavior and characteristics are highly dependent on those of the first layer through a well-organized hydrogen bond network. The results suggest that water-water interactions, in particular hydrogen bonds, may be largely responsible for macroscopic interfacial properties such as adsorption and contact angle.

Molecular Dynamics Simulation and Analysis of Interfacial Water at Selected Sulfide Mineral Surfaces under Anaerobic Conditions

Energy Technology Data Exchange (ETDEWEB)

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

2014-04-10

In this paper, we report on a molecular dynamics simulation (MDS) study of the behavior of interfacial water at selected sulfide mineral surfaces under anaerobic conditions. The study revealed the interfacial water structure and wetting characteristics of the pyrite (100) surface, galena (100) surface, chalcopyrite (012) surface, sphalerite (110) surface, and molybdenite surfaces (i.e., the face, armchair-edge, and zigzag-edge surfaces), including simulated contact angles, relative number density profiles, water dipole orientations, hydrogen-bonding, and residence times. For force fields of the metal and sulfur atoms in selected sulfide minerals used in the MDS, we used the universal force field (UFF) and another set of force fields optimized by quantum chemical calculations for interactions with interfacial water molecules at selected sulfide mineral surfaces. Simulation results for the structural and dynamic properties of interfacial water molecules indicate the natural hydrophobic character for the selected sulfide mineral surfaces under anaerobic conditions as well as the relatively weak hydrophobicity for the sphalerite (110) surface and two molybdenite edge surfaces. Part of the financial support for this study was provided by the U.S. Department of Energy (DOE) under Basic Science Grant No. DE-FG-03-93ER14315. The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences (BES), of the DOE, funded work performed by Liem X. Dang. Battelle operates Pacific Northwest National Laboratory for DOE. The calculations were carried out using computer resources provided by BES. The authors are grateful to Professor Tsun-Mei Chang for valuable discussions.

Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces.

Science.gov (United States)

Jogikalmath, G; Stuart, J K; Pungor, A; Hlady, V

1999-08-01

Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface more uniform. The subsequent hydrolysis of the terminal epoxide groups resulted in a larger surface heterogeneity which was modeled by two populations of the terminal hydroxyl groups, each with its own distribution of adhesion forces and force variance. The activation of the hydroxyls with carbonyldiimmidazole (CDI) healed the surface and lowered its adhesion, however, the force variance remained rather large. Finally, the grafting of the α,ω-diamino poly(ethyleneoxide) chains to the CDI-activated glass largely eliminated adhesion except at a few discrete regions. The adhesion on the PEO grafted layer followed the Poisson distribution of the pull-off forces. With the exception of the glass surface, a correlation between the water contact angles and the mean pull-off forces measured with the Si(3)N(4) tip surfaces was found for all modified glass surfaces.

Chemical treatment of the intra-canal dentin surface: a new approach to modify dentin hydrophobicity

Directory of Open Access Journals (Sweden)

Cesar GAITAN-FONSECA

2013-01-01

Full Text Available Objective This study evaluated the hydrophobicity of dentin surfaces that were modified through chemical silanization with octadecyltrichlorosilane (OTS. Material and Methods An in vitro experimental study was performed using 40 human permanent incisors that were divided into the following two groups: non-silanized and silanized. The specimens were pretreated and chemically modified with OTS. After the chemical modification, the dentin hydrophobicity was examined using a water contact angle measurement (WCA. The effectiveness of the modification of hydrophobicity was verified by the fluid permeability test (FPT. Results and Conclusions Statistically significant differences were found in the values of WCA and FPT between the two groups. After silanization, the hydrophobic intraradicular dentin surface exhibited in vitro properties that limit fluid penetration into the sealed root canal. This chemical treatment is a new approach for improving the sealing of the root canal system.

Nature and analysis of chemical species: pollution effects on surface waters and groundwater

International Nuclear Information System (INIS)

Young, R.H.F.

1975-01-01

A literature review of 103 items covers: nutrients in surface waters; runoff and waste discharges primarily from energy-intensive activities; groundwater pollution causes, effects, controls and monitoring; land and subsurface wastewater disposal; radionuclides; biological effects; thermal effluents; and biological and mathematical models for rivers

Chemicalization in water treatment in peat production areas

International Nuclear Information System (INIS)

Madekivi, O.; Marja-Aho, J.; Selin, P.; Jokinen, S.

1995-01-01

Chemicalization of runoff waters of peat production has been studied since 1989, first in laboratory and since 1990 in practice. The methods have been developed as cooperation between Vapo Oy and Kemira Chemicals Oy. In chemicalization the dissolved substances are coagulated and they settle after that into sedimentation basins. Good purification results require rapid and effective mixing, so the formed particles are combined to larger particles, and they form settleable flock. The coagulation efficiency depends on the properties of the water to be purified, such as alkalinity and pH, the quality and the quantity of humic substances, and the quality and the quantity of the flocking chemicals. Chemicalization is at present the most effective, but also the most expensive method for purification of drying waters of peat production areas. The chemicalized water is on the basis of most quality factors cleaner than water running off a virgin bog. The most visible change is the clarification of the water which is due to the coagulation of the colouring humic substances and iron. The colorimetric value is decreased by over 70 %, the best results being over 90 %. The colorimetric value of the purified water (30-100 mg Pt/l) is below the values of the runoff water of a virgin bog (100-200 mg Pt/l). The chemicalization process and the results of the researches are presented in the article. (3 refs., 6 figs., 2 tabs.)

Theoretical Study of Sodium-Water Surface Reaction Mechanism

Science.gov (United States)

Kikuchi, Shin; Kurihara, Akikazu; Ohshima, Hiroyuki; Hashimoto, Kenro

Computational study of the sodium-water reaction at the gas (water) - liquid (sodium) interface has been carried out using the ab initio (first-principle) method. A possible reaction channel has been identified for the stepwise OH bond dissociations of a single water molecule. The energetics including the binding energy of a water molecule on the sodium surface, the activation energies of the bond cleavages, and the reaction energies, have been evaluated, and the rate constants of the first and second OH bond-breakings have been compared. It was found that the estimated rate constant of the former was much larger than the latter. The results are the basis for constructing the chemical reaction model used in a multi-dimensional sodium-water reaction code, SERAPHIM, being developed by Japan Atomic Energy Agency (JAEA) toward the safety assessment of the steam generator (SG) in a sodium-cooled fast reactor (SFR).

Theoretical study of sodium-water surface reaction mechanism

International Nuclear Information System (INIS)

Kikuchi, Shin; Kurihara, Akikazu; Ohshima, Hiroyuki; Hashimoto, Kenro

2012-01-01

Computational study of the sodium-water reaction at the gas (water) - liquid (sodium) interface has been carried out using the ab initio (first-principle) method. A possible reaction channel has been identified for the stepwise OH bond dissociations of a single water molecule. The energetics including the binding energy of a water molecule on the sodium surface, the activation energies of the bond cleavages, and the reaction energies, have been evaluated, and the rate constants of the first and second OH bond-breakings have been compared. It was found that the estimated rate constant of the former was much larger than the latter. The results are the basis for constructing the chemical reaction model used in a multi-dimensional sodium-water reaction code, SERAPHIM, being developed by Japan Atomic Energy Agency (JAEA) toward the safety assessment of the steam generator (SG) in a sodium-cooled fast reactor (SFR). (author)

Chemical speciation of 239240Pu and 137Cs in Lake Michigan waters

International Nuclear Information System (INIS)

Alberts, J.J.; Wahlgren, M.A.; Jehn, P.J.; Nelson, D.M.; Orlandini, K.A.

1974-01-01

Studies of the submicron size distribution and charge characteristics of naturally occurring levels of 239 Pu, 240 Pu, and 137 Cs were conducted to help define the physico-chemical state of these fallout derived nuclides in Lake Michigan waters and in precipitation samples taken in the Argonne Laboratory area. Procedures are described for sample collection, size distribution determination, analysis of ion exchange resins, and plutonium determination by evaporation. Results indicated that the radioisotopes exist in several different fractions within the water column and that the total charge of these fractions is different from what would be predicted by simple solution chemistry. The distribution of the isotopes in snow appears to be different from that in the water column, indicating that considerable chemical or physical transformations must take place after the atomospheric input has reached the lake surface

Calcium carbonate nucleation in an alkaline lake surface water, Pyramid Lake, Nevada, USA

Science.gov (United States)

Reddy, Michael M.; Hoch, Anthony

2012-01-01

Calcium concentration and calcite supersaturation (Ω) needed for calcium carbonate nucleation and crystal growth in Pyramid Lake (PL) surface water were determined during August of 1997, 2000, and 2001. PL surface water has Ω values of 10-16. Notwithstanding high Ω, calcium carbonate growth did not occur on aragonite single crystals suspended PL surface water for several months. However, calcium solution addition to PL surface-water samples caused reproducible calcium carbonate mineral nucleation and crystal growth. Mean PL surface-water calcium concentration at nucleation was 2.33 mM (n = 10), a value about nine times higher than the ambient PL surface-water calcium concentration (0.26 mM); mean Ω at nucleation (109 with a standard deviation of 8) is about eight times the PL surface-water Ω. Calcium concentration and Ω regulated the calcium carbonate formation in PL nucleation experiments and surface water. Unfiltered samples nucleated at lower Ω than filtered samples. Calcium concentration and Ω at nucleation for experiments in the presence of added particles were within one standard deviation of the mean for all samples. Calcium carbonate formation rates followed a simple rate expression of the form, rate (mM/min) = A (Ω) + B. The best fit rate equation "Rate (Δ mM/Δ min) = -0.0026 Ω + 0.0175 (r = 0.904, n = 10)" was statistically significant at greater than the 0.01 confidence level and gives, after rearrangement, Ω at zero rate of 6.7. Nucleation in PL surface water and morphology of calcium carbonate particles formed in PL nucleation experiments and in PL surface-water samples suggest crystal growth inhibition by multiple substances present in PL surface water mediates PL calcium carbonate formation, but there is insufficient information to determine the chemical nature of all inhibitors.

Surface qualities after chemical-mechanical polishing on thin films

International Nuclear Information System (INIS)

Fu, Wei-En; Lin, Tzeng-Yow; Chen, Meng-Ke; Chen, Chao-Chang A.

2009-01-01

Demands for substrate and film surface planarizations significantly increase as the feature sizes of Integrated Circuit (IC) components continue to shrink. Chemical Mechanical Polishing (CMP), incorporating chemical and mechanical interactions to planarize chemically modified surface layers, has been one of the major manufacturing processes to provide global and local surface planarizations in IC fabrications. Not only is the material removal rate a concern, the qualities of the CMP produced surface are critical as well, such as surface finish, defects and surface stresses. This paper is to examine the CMP produced surface roughness on tungsten or W thin films based on the CMP process conditions. The W thin films with thickness below 1000 nm on silicon wafer were chemical-mechanical polished at different down pressures and platen speeds to produce different surface roughness. The surface roughness measurements were performed by an atomic force microscope (DI D3100). Results show that the quality of surface finish (R a value) is determined by the combined effects of down pressures and platen speeds. An optimal polishing condition is, then, possible for selecting the down pressures and platen speeds.

A regional assessment of chemicals of concern in surface waters of four Midwestern United States national parks

Science.gov (United States)

Elliott, Sarah M.; VanderMeulen, David

2017-01-01

Anthropogenic chemicals and their potential for adverse biological effects raise concern for aquatic ecosystem health in protected areas. During 2013–15, surface waters of four Midwestern United States national parks were sampled and analyzed for wastewater indicators, pharmaceuticals, personal care products, and pesticides. More chemicals and higher concentrations were detected at the two parks with greater urban influences (Mississippi National River and Recreation Area and Indiana Dunes National Lakeshore) than at the two more remote parks (Apostle Islands National Lakeshore and Isle Royale National Park). Atrazine (10–15 ng/L) and N,N-diethyl-meta-toluamide (16–120 ng/L) were the only chemicals detected in inland lakes of a remote island national park (Isle Royale National Park). Bisphenol A and organophosphate flame retardants were commonly detected at the other sampled parks. Gabapentin and simazine had the highest observed concentrations (> 1000 ng/L) in three and two samples, respectively. At the two parks with urban influences, metolachlor and simazine concentrations were similar to those reported for other major urban rivers in the United States. Environmental concentrations of detected chemicals were often orders of magnitude less than standards or reference values with three exceptions: (1) hydrochlorothiazide exceeded a human health-based screening value in seven samples, (2) estrone exceeded a predicted critical environmental concentration for fish pharmacological effects in one sample, and (3) simazine was approaching the 4000 ng/L Maximum Contaminant Level in one sample even though this concentration is not expected to reflect peak pesticide use. Although few environmental concentrations were approaching or exceeded standards or reference values, concentrations were often in ranges reported to elicit effects in aquatic biota. Data from this study will assist in establishing a baseline for chemicals of concern in Midwestern national parks and

Accessible surface area from NMR chemical shifts

Energy Technology Data Exchange (ETDEWEB)

Hafsa, Noor E.; Arndt, David; Wishart, David S., E-mail: david.wishart@ualberta.ca [University of Alberta, Department of Computing Science (Canada)

2015-07-15

Accessible surface area (ASA) is the surface area of an atom, amino acid or biomolecule that is exposed to solvent. The calculation of a molecule’s ASA requires three-dimensional coordinate data and the use of a “rolling ball” algorithm to both define and calculate the ASA. For polymers such as proteins, the ASA for individual amino acids is closely related to the hydrophobicity of the amino acid as well as its local secondary and tertiary structure. For proteins, ASA is a structural descriptor that can often be as informative as secondary structure. Consequently there has been considerable effort over the past two decades to try to predict ASA from protein sequence data and to use ASA information (derived from chemical modification studies) as a structure constraint. Recently it has become evident that protein chemical shifts are also sensitive to ASA. Given the potential utility of ASA estimates as structural constraints for NMR we decided to explore this relationship further. Using machine learning techniques (specifically a boosted tree regression model) we developed an algorithm called “ShiftASA” that combines chemical-shift and sequence derived features to accurately estimate per-residue fractional ASA values of water-soluble proteins. This method showed a correlation coefficient between predicted and experimental values of 0.79 when evaluated on a set of 65 independent test proteins, which was an 8.2 % improvement over the next best performing (sequence-only) method. On a separate test set of 92 proteins, ShiftASA reported a mean correlation coefficient of 0.82, which was 12.3 % better than the next best performing method. ShiftASA is available as a web server ( http://shiftasa.wishartlab.com http://shiftasa.wishartlab.com ) for submitting input queries for fractional ASA calculation.

Sustaining dry surfaces under water

DEFF Research Database (Denmark)

Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.

2015-01-01

Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional...... mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have...... not been investigated, and are critically important to maintain surfaces dry under water.In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical...

Chemical and electrical passivation of Si(1 1 1) surfaces

International Nuclear Information System (INIS)

Tian Fangyuan; Yang Dan; Opila, Robert L.; Teplyakov, Andrew V.

2012-01-01

This paper compares the physical and chemical properties of hydrogen-passivated Si(1 1 1) single crystalline surfaces prepared by two main chemical preparation procedures. The modified RCA cleaning is commonly used to prepare atomically flat stable surfaces that are easily identifiable spectroscopically and are the standard for chemical functionalization of silicon. On the other hand electronic properties of these surfaces are sometimes difficult to control. A much simpler silicon surface preparation procedure includes HF dipping for a short period of time. This procedure yields an atomically rough surface, whose chemical identity is not well-defined. However, the surfaces prepared by this approach often exhibit exceptionally attractive electronic properties as determined by long charge carrier lifetimes. This work utilizes infrared spectroscopy and X-ray photoelectron spectroscopy to investigate chemical modification of the surfaces prepared by these two different procedures with PCl 5 (leading to surface chlorination) and with short- and long-alkyl-chain alkenes (1-decene and 1-octodecene, respectively) and follows the electronic properties of the starting surfaces produced by measuring charge-carrier lifetimes.

Chemical and electrical passivation of Si(1 1 1) surfaces

Science.gov (United States)

Tian, Fangyuan; Yang, Dan; Opila, Robert L.; Teplyakov, Andrew V.

2012-01-01

This paper compares the physical and chemical properties of hydrogen-passivated Si(1 1 1) single crystalline surfaces prepared by two main chemical preparation procedures. The modified RCA cleaning is commonly used to prepare atomically flat stable surfaces that are easily identifiable spectroscopically and are the standard for chemical functionalization of silicon. On the other hand electronic properties of these surfaces are sometimes difficult to control. A much simpler silicon surface preparation procedure includes HF dipping for a short period of time. This procedure yields an atomically rough surface, whose chemical identity is not well-defined. However, the surfaces prepared by this approach often exhibit exceptionally attractive electronic properties as determined by long charge carrier lifetimes. This work utilizes infrared spectroscopy and X-ray photoelectron spectroscopy to investigate chemical modification of the surfaces prepared by these two different procedures with PCl5 (leading to surface chlorination) and with short- and long-alkyl-chain alkenes (1-decene and 1-octodecene, respectively) and follows the electronic properties of the starting surfaces produced by measuring charge-carrier lifetimes.

Surface-water resources of Polecat Creek basin, Oklahoma

Science.gov (United States)

Laine, L.L.

1956-01-01

A compilation of basic data on surface waters in Polecat Creek basin is presented on a monthly basis for Heyburn Reservoir and for Polecat Creek at Heyburn, Okla. Chemical analyses are shown for five sites in the basin. Correlation of runoff records with those for nearby basins indicates that the average annual runoff of the basin above gaging station at Heyburn is 325 acre-feet per square mile. Estimated duration curves of daily flow indicate that under natural conditions there would be no flow in Polecat Creek at Heyburn (drainage area, 129 square miles) about 16 percent of the time on an average, and that the flow would be less than 3 cubic feet per second half of the time. As there is no significant base flow in the basin, comparable low flows during dry-weather periods may be expected in other parts of the basin. During drought periods Heyburn Reservoir does not sustain a dependable low-water flow in Polecat Creek. Except for possible re-use of the small sewage effluent from city of Sapulpa, dependable supplies for additional water needs on the main stem will require development of supplemental storage. There has been no regular program for collection of chemical quality data in the basin, but miscellaneous analyses indicate a water of suitable quality for municipal and agricultural uses in Heyburn Reservoir and Polecat Creek near Heyburn. One recent chemical analysis indicates the possibility of a salt pollution problem in the Creek near Sapulpa. (available as photostat copy only)

Effectiveness of a chemical herder in association with in-situ burning of oil spills in ice-infested water

DEFF Research Database (Denmark)

van Gelderen, Laurens; Fritt-Rasmussen, Janne; Jomaas, Grunde

2017-01-01

The average herded slick thickness, surface distribution and burning efficiency of a light crude oil were studied in ice-infested water to determine the effectiveness of a chemical herder in facilitating the in-situ burning of oil. Experiments were performed in a small scale (1.0m2) and an interm......The average herded slick thickness, surface distribution and burning efficiency of a light crude oil were studied in ice-infested water to determine the effectiveness of a chemical herder in facilitating the in-situ burning of oil. Experiments were performed in a small scale (1.0m2...

Superhydrophobic Cu{sub 2}S@Cu{sub 2}O film on copper surface fabricated by a facile chemical bath deposition method and its application in oil-water separation

Energy Technology Data Exchange (ETDEWEB)

Pi, Pihui, E-mail: phpi@scut.edu.cn; Hou, Kun; Zhou, Cailong; Li, Guidong; Wen, Xiufang; Xu, Shouping; Cheng, Jiang; Wang, Shuangfeng

2017-02-28

Highlights: • A superhydrophobic film with macro/nano structure was fabricated on copper surface. • The as-prepared film shows outstanding water repellency and long-term storage stability. • The same method was used to fabricate superhydrophobic/superoleophilic copper mesh. • The obtained mesh could realize separation of various oily sewages with separation efficiency above 94%. - Abstract: Cu{sub 2}S and Cu{sub 2}O composite (Cu{sub 2}S@Cu{sub 2}O) film with micro/nano binary structure was created on copper surface using the mixing solution of sodium thiosulphate and copper sulfate by a facile chemical bath deposition method. After modification with low-cost polydimethylsioxane (PDMS), the superhydrophobic Cu{sub 2}S@Cu{sub 2}O film was obtained. The as-prepared film shows outstanding water repellency with a water contact angle larger than 150° and long-term storage stability. The geometric morphology and chemical composition of the film were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), respectively. Moreover, the same method was used to fabricate superhydrophobic/superoleophilic copper mesh, and it could realize separation of various oily sewages with separation efficiency above 94%. This strategy has potential to fabricate the practical superhydrophobic Cu{sub 2}S@Cu{sub 2}O film on copper surface on a large scale due to its simplicity and low cost.

Modeling the thermostability of surface functionalisation by oxygen, hydroxyl, and water on nanodiamonds.

Science.gov (United States)

Lai, Lin; Barnard, Amanda S

2011-06-01

Understanding nanodiamond functionalisation is of great importance for biological and medical applications. Here we examine the stabilities of oxygen, hydroxyl, and water functionalisation of the nanodiamonds using the self-consistent charge density functional tight-binding simulations. We find that the oxygen and hydroxyl termination are thermodynamically favourable and form strong C–O covalent bonds on the nanodiamond surface in an O2 and H2 gas reservoir, which confirms previous experiments. Yet, the thermodynamic stabilities of oxygen and hydroxyl functionalisation decrease dramatically in a water vapour reservoir. In contrast, H2O molecules are found to be physically adsorbed on the nanodiamond surface, and forced chemical adsorption results in decomposition of H2O. Moreover, the functionalisation efficiency is found to be facet dependent. The oxygen functionalisation prefers the {100} facets as opposed to alternative facets in an O2 and H2 gas reservoir. The hydroxyl functionalisation favors the {111} surfaces in an O2 and H2 reservoir and the {100} facets in a water vapour reservoir, respectively. This facet selectivity is found to be largely dependent upon the environmental temperature, chemical reservoir, and morphology of the nanodiamonds.

Dissolved organic matter in sea spray: a transfer study from marine surface water to aerosols

Science.gov (United States)

Schmitt-Kopplin, P.; Liger-Belair, G.; Koch, B. P.; Flerus, R.; Kattner, G.; Harir, M.; Kanawati, B.; Lucio, M.; Tziotis, D.; Hertkorn, N.; Gebefügi, I.

2012-04-01

Atmospheric aerosols impose direct and indirect effects on the climate system, for example, by absorption of radiation in relation to cloud droplets size, on chemical and organic composition and cloud dynamics. The first step in the formation of Organic primary aerosols, i.e. the transfer of dissolved organic matter from the marine surface into the atmosphere, was studied. We present a molecular level description of this phenomenon using the high resolution analytical tools of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and nuclear magnetic resonance spectroscopy (NMR). Our experiments confirm the chemoselective transfer of natural organic molecules, especially of aliphatic compounds from the surface water into the atmosphere via bubble bursting processes. Transfer from marine surface water to the atmosphere involves a chemical gradient governed by the physicochemical properties of the involved molecules when comparing elemental compositions and differentiating CHO, CHNO, CHOS and CHNOS bearing compounds. Typical chemical fingerprints of compounds enriched in the aerosol phase were CHO and CHOS molecular series, smaller molecules of higher aliphaticity and lower oxygen content, and typical surfactants. A non-targeted metabolomics analysis demonstrated that many of these molecules corresponded to homologous series of oxo-, hydroxy-, methoxy-, branched fatty acids and mono-, di- and tricarboxylic acids as well as monoterpenes and sugars. These surface active biomolecules were preferentially transferred from surface water into the atmosphere via bubble bursting processes to form a significant fraction of primary organic aerosols. This way of sea spray production leaves a selective biological signature of the surface water in the corresponding aerosol that may be transported into higher altitudes up to the lower atmosphere, thus contributing to the formation of secondary organic aerosol on a global scale or transported laterally with

Chemical and Physical Interactions of Martian Surface Material

Science.gov (United States)

Bishop, J. L.

1999-09-01

A model of alteration and maturation of the Martian surface material is described involving both chemical and physical interactions. Physical processes involve distribution and mixing of the fine-grained soil particles across the surface and into the atmosphere. Chemical processes include reaction of sulfate, salt and oxidizing components of the soil particles; these agents in the soils deposited on rocks will chew through the rock minerals forming coatings and will bind surface soils together to form duricrust deposits. Formation of crystalline iron oxide/oxyhydroxide minerals through hydrothermal processes and of poorly crystalline and amorphous phases through palagonitic processes both contribute to formation of the soil particles. Chemical and physical alteration of these soil minerals and phases contribute to producing the chemical, magnetic and spectroscopic character of the Martian soil as observed by Mars Pathfinder and Mars Global Surveyor. Minerals such as maghemite/magnetite and jarosite/alunite have been observed in terrestrial volcanic soils near steam vents and may be important components of the Martian surface material. The spectroscopic properties of several terrestrial volcanic soils containing these minerals have been analyzed and evaluated in terms of the spectroscopic character of the surface material on Mars.

Numerical study of chemical reactions in a surface microdischarge tube with mist flow based on experiment

International Nuclear Information System (INIS)

Shibata, T; Nishiyama, H

2014-01-01

Recently, a water treatment method of spraying solution into a discharge region has been developed and shows high energy efficiency. In this study, a simulation model of a water treatment method using a surface microdischarge (SMD) tube with mist flow is proposed for further understanding the detailed chemical reactions. Our model has three phases (plasma, gas and liquid) and three simulation steps. The carrier gas is humid air including 2% or 3% water vapour. The chemical species diffusion characteristics in the SMD tube and the concentrations in a droplet are clarified in a wide pH interval. The simulation results show that the chemical species generated on the SMD tube inner wall are diffused to the central axis and dissolved into fine droplets. Especially, OH radicals dissolve into droplets a few mm away from the SMD tube wall because of acidification of the droplets. Furthermore, the hydrogen peroxide density, which is the most important indicator of a radical reaction in water, is influenced by the initial solution pH. This pH dependence results from ozone self-decomposition in water. (paper)

Numerical study of chemical reactions in a surface microdischarge tube with mist flow based on experiment

Science.gov (United States)

Shibata, T.; Nishiyama, H.

2014-03-01

Recently, a water treatment method of spraying solution into a discharge region has been developed and shows high energy efficiency. In this study, a simulation model of a water treatment method using a surface microdischarge (SMD) tube with mist flow is proposed for further understanding the detailed chemical reactions. Our model has three phases (plasma, gas and liquid) and three simulation steps. The carrier gas is humid air including 2% or 3% water vapour. The chemical species diffusion characteristics in the SMD tube and the concentrations in a droplet are clarified in a wide pH interval. The simulation results show that the chemical species generated on the SMD tube inner wall are diffused to the central axis and dissolved into fine droplets. Especially, OH radicals dissolve into droplets a few mm away from the SMD tube wall because of acidification of the droplets. Furthermore, the hydrogen peroxide density, which is the most important indicator of a radical reaction in water, is influenced by the initial solution pH. This pH dependence results from ozone self-decomposition in water.

Spring and surface water quality of the Cyprus ophiolites

Directory of Open Access Journals (Sweden)

C. Neal

2002-01-01

Full Text Available A survey of surface, spring and borehole waters associated with the ophiolite rocks of Cyprus shows five broad water types (1 Mg-HCO3, (2 Na-SO4-Cl-HCO3, (3 Na-Ca-Cl-SO4-OH-CO3, (4 Na-Cl-SO4 and (5 Ca-SO4. The waters represent a progression in chemical reactivity from surface waters that evolve within a groundwater setting due to hydrolysis of the basic/ultrabasic rock as modified by CO2-weathering. An increase in salinity is also observed which is due to mixing with a saline end-member (modified sea-water and dissolution of gypsum/anhydrite. In some cases, the waters have pH values greater than 11. Such high values are associated with low temperature serpentinisation reactions. The system is a net sink for CO2. This feature is related not only to the hydrolysis of the primary minerals in the rock, but also to CaCO3 or Ca-Mg-CO3 solubility controls. Under hyperalkaline conditions, virtually all the carbon dioxide is lost from the water due to the sufficiently high calcium levels and carbonate buffering is then insignificant. Calcium sulphate solubility controls may also be operative when calcium and sulphate concentrations are particularly high. Keywords: Cyprus, Troodos, ophiolite, serpentinisation, spring, stream, water quality, bromide, iodine, boron, trace elements, hyperalkaline.

Reduced chemical warfare agent sorption in polyurethane-painted surfaces via plasma-enhanced chemical vapor deposition of perfluoroalkanes.

Science.gov (United States)

Gordon, Wesley O; Peterson, Gregory W; Durke, Erin M

2015-04-01

Perfluoralkalation via plasma chemical vapor deposition has been used to improve hydrophobicity of surfaces. We have investigated this technique to improve the resistance of commercial polyurethane coatings to chemicals, such as chemical warfare agents. The reported results indicate the surface treatment minimizes the spread of agent droplets and the sorption of agent into the coating. The improvement in resistance is likely due to reduction of the coating's surface free energy via fluorine incorporation, but may also have contributing effects from surface morphology changes. The data indicates that plasma-based surface modifications may have utility in improving chemical resistance of commercial coatings.

Biological methods used to assess surface water quality

Directory of Open Access Journals (Sweden)

Szczerbiñska Natalia

2015-12-01

Full Text Available In accordance with the guidelines of the Water Framework Directive 2000/60 (WFD, both ecological and chemical statuses determine the assessment of surface waters. The profile of ecological status is based on the analysis of various biological components, and physicochemical and hydromorphological indicators complement this assessment. The aim of this article is to present the biological methods used in the assessment of water status with a special focus on bioassay, as well as to provide a review of methods of monitoring water status. Biological test methods include both biomonitoring and bioanalytics. Water biomonitoring is used to assess and forecast the status of water. These studies aim to collect data on water pollution and forecast its impact. Biomonitoring uses organisms which are characterized by particular vulnerability to contaminants. Bioindicator organisms are algae, fungi, bacteria, larval invertebrates, cyanobacteria, macroinvertebrates, and fish. Bioanalytics is based on the receptors of contaminants that can be biologically active substances. In bioanalytics, biosensors such as viruses, bacteria, antibodies, enzymes, and biotests are used to assess degrees of pollution.

A surface chemical model of the bentonite-water interface and its implications for modelling the near field chemistry in a repository for spent fuel

International Nuclear Information System (INIS)

Wieland, E.; Wanner, H.; Albinsson, Y.; Wersin, P.; Karnland, O.

1994-07-01

Understanding the surface chemical properties of montmorillonite in near-neutral and alkaline media is essential for establishing a chemical model of the bentonite/water interaction applicable for repository conditions. A pretreated and well-characterised Wyoming MX-80 bentonite has been used for investigating the acid/base characteristics of Na-montmorillonite. The CEC of Na-montmorillonite was determined to 108 meq/100 g for pretreated bentonite and to 85 meq/100 g for the bulk material. The BET surface area was (31.53±0.16)m 2 /g. Potentiometric titrations of montmorillonite suspensions at ionic strengths I=0.005 M, 0.05 M and 0.5 M were conducted as batch-type experiments. Deprotonation of surface OH groups possibly exposed at the edge surface causes an overall negative charge on the surface of montmorillonite in the alkaline pH range. In this pH range, the protolysis degree of OH groups increases with increasing pH and ionic strength. The proton density on the surface of montmorillonite increases with decreasing pH in the acidic pH range (pH + at the structural-charge sites. The experimental results are interpreted in terms of a two-site model with structural-charge surface sites (X layer sites) and variable-charge surface sites (edge OH groups) as the reactive surface functionalities. The total population of the surface sites are estimated to TOT-OH=2.84*10 -5 mol/g, TOT-X=2.22*10 -5 mol/g. The intrinsic acidity constants for the OH groups are determined to pK int al = (5.4±0.1) and pK int a2 =(6-7±0.1), respectively, using th configuration of the diffuse double layer model (DDLM). 43 refs, 18 figs, 11 tabs

Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

Directory of Open Access Journals (Sweden)

Youngmin Choi

2016-12-01

Full Text Available Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°. Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material.

Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

Science.gov (United States)

Choi, Youngmin; Choo, Hyunwook; Yun, Tae Sup; Lee, Changho; Lee, Woojin

2016-01-01

Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO) ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°). Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material. PMID:28774098

Solar radiation influence on the decomposition process of diclofenac in surface waters

International Nuclear Information System (INIS)

Bartels, Peter; Tuempling, Wolf von

2007-01-01

Diclofenac can be detected in surface water of many rivers with human impacts worldwide. The observed decrease of the diclofenac concentration in waters and the formation of its photochemical transformation products under the impact of natural irradiation during one to 16 days are explained in this article. In semi-natural laboratory tests and in a field experiment it could be shown, that sunlight stimulates the decomposition of diclofenac in surface waters. During one day intensive solar radiation in middle European summer diclofenac decomposes in the surface layer of the water (0 to 5 cm) up to 83%, determined in laboratory exposition experiments. After two weeks in a field experiment, the diclofenac was not detectable anymore in the water surface layer (limit of quantification: 5 ng/L). At a water depth of 50 cm, within two weeks 96% of the initial concentration was degraded, while in 100 cm depth 2/3 of the initial diclofenac concentration remained. With the decomposition, stable and meta-stable photolysis products were formed and observed by UV detection. Beyond that the chemical structure of these products were determined. Three transformation products, that were not described in the literature so far, were identified and quantified with GC-MS

Relevance of leaf surface contamination for assessing chemical composition of bromeliads in a restinga forest

Energy Technology Data Exchange (ETDEWEB)

Elias, C; Fernandes, E A.N.; Franca, E J; Bacchi, M A; Tagliaferro, F S [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Piracicaba, SP (Brazil)

2008-11-15

Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in nonwashed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues. (author)

Relevance of leaf surface contamination for assessing chemical composition of bromeliads in a restinga forest

International Nuclear Information System (INIS)

Elias, C.; Fernandes, E.A.N.; Franca, E.J.; Bacchi, M.A.; Tagliaferro, F.S.

2008-01-01

Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in nonwashed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues. (author)

Groundwater-surface water interaction

International Nuclear Information System (INIS)

White, P.A.; Clausen, B.; Hunt, B.; Cameron, S.; Weir, J.J.

2001-01-01

This chapter discusses natural and modified interactions between groundwater and surface water. Theory on recharge to groundwater from rivers is introduced, and the relative importance of groundwater recharge from rivers is illustrated with an example from the Ngaruroro River, Hawke's Bay. Some of the techniques used to identify and measure recharge to groundwater from gravel-bed rivers will be outlined, with examples from the Ngaruroro River, where the recharge reach is relatively well defined, and from the Rakaia River, where it is poorly defined. Groundwater recharged from rivers can have characteristic chemical and isotopic signatures, as shown by Waimakariri River water in the Christchurch-West Melton groundwater system. The incorporation of groundwater-river interaction in a regional groundwater flow model is outlined for the Waimea Plains, and relationships between river scour and groundwater recharge are examined for the Waimakariri River. Springs are the result of natural discharge from groundwater systems and are important water sources. The interactions between groundwater systems, springs, and river flow for the Avon River in New Zealand will be outlined. The theory of depletion of stream flow by groundwater pumpage will be introduced with a case study from Canterbury, and salt-water intrusion into groundwater systems with examples from Nelson and Christchurch. The theory of artificial recharge to groundwater systems is introduced with a case study from Hawke's Bay. Wetlands are important to flora, and the relationship of the wetland environment to groundwater hydrology will be discussed, with an example from the South Taupo wetland. (author). 56 refs., 25 figs., 3 tabs

Estimation of surface water quality in a Yazoo River tributary using the duration curve and recurrence interval approach

Science.gov (United States)

Ying Ouyang; Prem B. Parajuli; Daniel A. Marion

2013-01-01

Pollution of surface water with harmful chemicals and eutrophication of rivers and lakes with excess nutrients are serious environmental concerns. This study estimated surface water quality in a stream within the Yazoo River Basin (YRB), Mississippi, USA, using the duration curve and recurrence interval analysis techniques. Data from the US Geological Survey (USGS)...

Precise Chemical Analyses of Planetary Surfaces

Science.gov (United States)

Kring, David; Schweitzer, Jeffrey; Meyer, Charles; Trombka, Jacob; Freund, Friedemann; Economou, Thanasis; Yen, Albert; Kim, Soon Sam; Treiman, Allan H.; Blake, David;

Oil Contact Angles in a Water-Decane-Silicon Dioxide System: Effects of Surface Charge.

Science.gov (United States)

Xu, Shijing; Wang, Jingyao; Wu, Jiazhong; Liu, Qingjie; Sun, Chengzhen; Bai, Bofeng

2018-04-19

Oil wettability in the water-oil-rock systems is very sensitive to the evolution of surface charges on the rock surfaces induced by the adsorption of ions and other chemical agents in water flooding. Through a set of large-scale molecular dynamics simulations, we reveal the effects of surface charge on the oil contact angles in an ideal water-decane-silicon dioxide system. The results show that the contact angles of oil nano-droplets have a great dependence on the surface charges. As the surface charge density exceeds a critical value of 0.992 e/nm 2 , the contact angle reaches up to 78.8° and the water-wet state is very apparent. The variation of contact angles can be confirmed from the number density distributions of oil molecules. With increasing the surface charge density, the adsorption of oil molecules weakens and the contact areas between nano-droplets and silicon dioxide surface are reduced. In addition, the number density distributions, RDF distributions, and molecular orientations indicate that the oil molecules are adsorbed on the silicon dioxide surface layer-by-layer with an orientation parallel to the surface. However, the layered structure of oil molecules near the silicon dioxide surface becomes more and more obscure at higher surface charge densities.

Responsiveness summary for the engineering evaluation/cost analysis for the proposed management of contaminated water impounded at the Weldon Spring Chemical Plant Area

International Nuclear Information System (INIS)

Maxey, M.L.; MacDonell, M.M.; Peterson, J.M.

1991-01-01

The US Department of Energy (DOE) issued the Engineering Evaluation/Cost Analysis for the Proposed Management of Contaminated Water Impounded at the Weldon Spring Chemical Plant Area in July 1990. The engineering evaluation/cost analysis (EE/CA) examines various alternatives for the proposed action to manage contaminated surface water impounded at the chemical plant area. The primary objective is to minimize potential migration of contaminants from surface impoundments to the local environment. The EE/CA addresses water currently impounded in four waste raffinate pits and two small ponds and water that will be impounded in the future as a result of upcoming response actions. Radioactive and chemical contaminants are migrating from the currently impounded water to underlying on-site groundwater via seepage and to off-site surface water via runoff. The treatment process and facilities that will be provided for management of currently impounded water can subsequently be used to manage other contaminated water in the future. Based on the evaluation of various alternatives in the EE/CA, DOE determined that the best approach for managing surface water impounded at the chemical plant area would be to remove contaminants from the water and release the treatment water to the Missouri River via a natural drainage channel. To establish requirements for releasing this treated water, DOE applied for a modification to its existing discharge permit from the Missouri Department of Natural Resources (DNR) under the National Pollutant Discharge Elimination System (NPDES) program. The EE/CA provided a major source of technical input to the application for modifying the permit. This responsiveness summary has been prepared to address the major issues identified in oral and written comments on the proposed action. 1 tab

Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources

Science.gov (United States)

Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protectingit from chemical contamination is a major societal goal in the European Union. The Water Framework Directive(WFD) and its daughter directives are the major body of ...

Water on a Hydrophobic surface

Science.gov (United States)

Scruggs, Ryan; Zhu, Mengjue; Poynor, Adele

2012-02-01

Hydrophobicity, meaning literally fear of water, is exhibited on the surfaces of non-stick cooking pans and water resistant clothing, on the leaves of the lotus plan, or even during the protein folding process in our bodies. Hydrophobicity is directly measured by determining a contact angle between water and an objects surface. Associated with a hydrophobic surface is the depletion layer, a low density region approximately 0.2 nm thick. We study this region by comparing data found in lab using surface plasmon resonance techniques to theoretical calculations. Experiments use gold slides coated in ODT and Mercapto solutions to model both hydrophobic and hydrophilic surfaces respectively.

Physico-chemical forms and migration in continental waters of radium from uranium mining and milling

International Nuclear Information System (INIS)

Benes, P.

1982-01-01

Recent advances in knowledge of the physico-chemical forms and migration of radium in continental waters are reviewed and recommendations for future research in this field are given. Computations of solution equilibria based on the reported and newly determined stability constants and solubilities of radium compounds show that a significant percentage of dissolved radium can exist in some waste and natural waters as an RaSO 4 ion pair, besides a significant percentage of Ra 2+ ions. The formation of a solid phase consisting mainly of sparingly soluble radium compounds can be excluded in waste and natural waters. Model experiments revealed that radium can be bound in complexes with some as yet unidentified ligands, probably of organic nature. Direct determinations of the physico-chemical forms of radium in surface and groundwaters were mostly confined to the analysis of the ratio of dissolved to particulate forms of radium. Ratios from 0.01 to 100 were found, depending on the type of water examined. Recently a newly suggested method of selective dissolution was applied to characterize the nature of particulate forms of radium in surface waters. Migration of radium is reviewed, covering the release of radium from its source, its transport in ground and surface waters and its deposition in various sinks. Factors influencing radium release from the sources into the hydrosphere are discussed. The following processes affecting radium migration are discussed: adsorption of dissolved radium on suspended solids and bottom sediments, coprecipitation of radium with solids formed in waste waters or in natural waters, sedimentation of particulate forms of radium in reservoirs and streams, resuspension of bottom sediments and dissolution of radium from suspended solids or bottom sediments

Contamination of ground water, surface water, and soil, and evaluation of selected ground-water pumping alternatives in the Canal Creek area of Aberdeen Proving Ground, Maryland

Science.gov (United States)

Lorah, Michelle M.; Clark, Jeffrey S.

1996-01-01

Chemical manufacturing, munitions filling, and other military-support activities have resulted in the contamination of ground water, surface water, and soil in the Canal Creek area of Aberdeen Proving Ground, Maryland. Chlorinated volatile organic compounds, including 1,1,2,2-tetrachloroethane and trichloroethylene, are widespread ground-water contaminants in two aquifers that are composed of unconsolidated sand and gravel. Distribution and fate of chlorinated organic compounds in the ground water has been affected by the movement and dissolution of solvents in their dense immiscible phase and by microbial degradation under anaerobic conditions. Detection of volatile organic contaminants in adjacent surface water indicates that shallow contaminated ground water discharges to surface water. Semivolatile organic compounds, especially polycyclic aromatic hydrocarbons, are the most prevalent organic contaminants in soils. Various trace elements, such as arsenic, cadmium, lead, and zinc, were found in elevated concentrations in ground water, surface water, and soil. Simulations with a ground-water-flow model and particle tracker postprocessor show that, without remedial pumpage, the contaminants will eventually migrate to Canal Creek and Gunpowder River. Simulations indicate that remedial pumpage of 2.0 million gallons per day from existing wells is needed to capture all particles originating in the contaminant plumes. Simulated pumpage from offsite wells screened in a lower confined aquifer does not affect the flow of contaminated ground water in the Canal Creek area.

Molecular Dynamics Simulations of Water Droplets On Hydrophilic Silica Surfaces

DEFF Research Database (Denmark)

Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard L.

2009-01-01

and DNA microarrays technologies.Although extensive experimental, theoretical and computational work has been devoted to study the nature of the interaction between silica and water, at the molecular level a complete understanding of silica-water systems has not been reached. Contact angle computations...... dynamics (MD) simulations of a hydrophilic air-water-silica system using the MD package FASTTUBE. We employ quantum chemistry calculation to obtain air-silica interaction parameters for the simulations. Our simulations are based in the following force fields: i) The silica-silica interaction is based...... of water droplets on silica surfaces offers a useful fundamental and quantitative measurement in order to study chemical and physical properties of water-silica systems. For hydrophobic systems the static and dynamic properties of the fluid-solid interface are influenced by the presence of air. Hence...

A laboratory investigation of mixing dynamics between biofuels and surface waters

Science.gov (United States)

Wang, Xiaoxiang; Cotel, Aline

2017-11-01

Recently, production and usage of ethanol-blend fuels or biofuels have increased dramatically along with increasing risk of spilling into surface waters. Lack of understanding of the environmental impacts and absence of standard clean-up procedures make it crucial to study the mixing behavior between biofuels and water. Biofuels are represented by a solution of ethanol and glycol. A Plexiglas tank in conjunction with a wave generator is used to simulate the mixing of surface waters and biofuels under different natural conditions. In our previous experiments, two distinct mixing regimes were observed. One regime was driven by turbulence and the other by interfacial instabilities. However, under more realistic situations, without wind driven waves, only the first mixing regime was found. After one minute of rapid turbulent mixing, biofuels and water were fully mixed and no interface was formed. During the mixing process, chemical reactions happened simultaneously and influenced mixing dynamics. Current experiments are investigating the effect of waves on the mixing dynamics. Support from NSF CBET 1335878.

Evaluation of chemical sensors for in situ ground-water monitoring at the Hanford Site

Energy Technology Data Exchange (ETDEWEB)

Murphy, E.M.; Hostetler, D.D.

1989-03-01

This report documents a preliminary review and evaluation of instrument systems and sensors that may be used to detect ground-water contaminants in situ at the Hanford Site. Three topics are covered in this report: (1) identification of a group of priority contaminants at Hanford that could be monitored in situ, (2) a review of current instrument systems and sensors for environmental monitoring, and (3) an evaluation of instrument systems that could be used to monitor Hanford contaminants. Thirteen priority contaminants were identified in Hanford ground water, including carbon tetrachloride and six related chlorinated hydrocarbons, cyanide, methyl ethyl ketone, chromium (VI), fluoride, nitrate, and uranium. Based on transduction principles, chemical sensors were divided into four classes, ten specific types of instrument systems were considered: fluorescence spectroscopy, surface-enhanced Raman spectroscopy (SERS), spark excitation-fiber optic spectrochemical emission sensor (FOSES), chemical optrodes, stripping voltammetry, catalytic surface-modified ion electrode immunoassay sensors, resistance/capacitance, quartz piezobalance and surface acoustic wave devices. Because the flow of heat is difficult to control, there are currently no environmental chemical sensors based on thermal transduction. The ability of these ten instrument systems to detect the thirteen priority contaminants at the Hanford Site at the required sensitivity was evaluated. In addition, all ten instrument systems were qualitatively evaluated for general selectivity, response time, reliability, and field operability. 45 refs., 23 figs., 7 tabs.

Evaluation of chemical sensors for in situ ground-water monitoring at the Hanford Site

International Nuclear Information System (INIS)

Murphy, E.M.; Hostetler, D.D.

1989-03-01

This report documents a preliminary review and evaluation of instrument systems and sensors that may be used to detect ground-water contaminants in situ at the Hanford Site. Three topics are covered in this report: (1) identification of a group of priority contaminants at Hanford that could be monitored in situ, (2) a review of current instrument systems and sensors for environmental monitoring, and (3) an evaluation of instrument systems that could be used to monitor Hanford contaminants. Thirteen priority contaminants were identified in Hanford ground water, including carbon tetrachloride and six related chlorinated hydrocarbons, cyanide, methyl ethyl ketone, chromium (VI), fluoride, nitrate, and uranium. Based on transduction principles, chemical sensors were divided into four classes, ten specific types of instrument systems were considered: fluorescence spectroscopy, surface-enhanced Raman spectroscopy (SERS), spark excitation-fiber optic spectrochemical emission sensor (FOSES), chemical optrodes, stripping voltammetry, catalytic surface-modified ion electrode immunoassay sensors, resistance/capacitance, quartz piezobalance and surface acoustic wave devices. Because the flow of heat is difficult to control, there are currently no environmental chemical sensors based on thermal transduction. The ability of these ten instrument systems to detect the thirteen priority contaminants at the Hanford Site at the required sensitivity was evaluated. In addition, all ten instrument systems were qualitatively evaluated for general selectivity, response time, reliability, and field operability. 45 refs., 23 figs., 7 tabs

Chemical Controls of Ozone Dry Deposition to the Sea Surface Microlayer

Science.gov (United States)

Carpenter, L.; Chance, R.; Tinel, L.; Saint, A.; Sherwen, T.; Loades, D.; Evans, M. J.; Boxhall, P.; Hamilton, J.; Stolle, C.; Wurl, O.; Ribas-Ribas, M.; Pereira, R.

2017-12-01

Oceanic dry deposition of atmospheric ozone (O3) is both the largest and most uncertain O3 depositional sink, and is widely acknowledged to be controlled largely by chemical reactions in the sea surface microlayer (SML) involving iodide (I-) and dissolved organic material (DOM). These reactions not only determine how quickly O3 can be removed from the atmosphere, but also result in emissions of trace gases including volatile organic compounds and may constitute a source of secondary organic aerosols to the marine atmosphere. Iodide concentrations at the sea surface vary by approximately an order of magnitude spatially, leading to more than fivefold variation in ozone deposition velocities (and volatile iodine fluxes). Sea-surface temperature is a reasonable predictor of [I-], however two recent parameterisations for surface I- differ by a factor of two at low latitudes. The nature and reactivity of marine DOM to O3 is almost completely unknown, although studies have suggested approximately equivalent chemical control of I- and DOM on ozone deposition. Here we present substantial new measurements of oceanic I- in both bulk seawater and the overlying SML, and show improved estimates of the global sea surface iodide distribution. We also present analyses of water-soluble DOM isolated from the SML and bulk seawater, and corresponding laboratory studies of ozone uptake to bulk and SML seawater, with the aim of characterizing the reactivity of O3 towards marine DOM.

Investigation of surface and underground waters about the Blayais nuclear site - 2010

International Nuclear Information System (INIS)

Migeon, A.; Bernollin, A.; Dunand, E.; Barbey, P.; Boilley, D.; Josset, M.

2011-01-01

This investigation aims at proposing a first assessment of the impact of releases on surface and underground waters around the Blayais nuclear power station, i.e. the assessment of the (mainly radiological) quality of waters. The report identifies the various pollution sources: old sources (like atmospheric nuclear tests, nuclear accidents), incidents in the Blayais station, and potential sources for the present contamination. Different radionuclides are searched like tritium, carbon 14, gamma radioactivity (from different elements), some beta emitters, radon as well as some chemicals related to the station activity (hydrazine, boric acid, EDTA, lithium, morpholine). Sampling sites are presented (estuary, canals, reservoirs). Radiological and chemical analysis are reported and commented. Significant presence of Tritium and Nickel-63 are noticed

Towards the review of the European Union Water Framework Directive: Recommendations for more efficient assessment and management of chemical contamination in European surface water resources

NARCIS (Netherlands)

Brack, W.; Dulio, V.; Agerstrand, M.; Allan, I.; Altenburger, R.; Brinkmann, M.; Bunke, D.; Burgess, R.M.; Cousins, I.; Escher, B.I.; Hernandez, F.J.; Hewitt, L.M.; Hilscherova, K.; Hollender, J.; Hollert, H.; Kase, R.; Klauer, B.; Lindim, C.; Herraez, D.L.; Miege, C.; Munthe, J.; O'Toole, S.; Posthuma, L.; Rudel, H.; Schafer, R.B.; Sengl, M.; Smedes, F.; van de Meent, D.; van den Brink, P.J.; van Gils, J.; van Wezel, A.P.; Vethaak, A.D.; Vermeirssen, E.; von der Ohe, P.C.; Vrana, B.

2017-01-01

Water is a vital resource for natural ecosystems and human life, and assuring a high quality of water and protecting it from chemical contamination is a major societal goal in the European Union. The Water Framework Directive (WFD) and its daughter directives are the major body of legislation for

Membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

Science.gov (United States)

Rivero, M J; Parsons, S A; Jeffrey, P; Pidou, M; Jefferson, B

2006-01-01

Urban water recycling is now becoming an important issue where water resources are becoming scarce. This paper looks at reusing grey water; the preference is treatment processes based on biological systems to remove the dissolved organic content. Here, an alternative process, photocatalysis is discussed as it is an attractive technology that could be well-suited for treating the recalcitrant organic compounds found in grey water. The photocatalytic process oxidises organic reactants at a catalyst surface in the presence of ultraviolet light. Given enough exposure time, organic compounds will be oxidized into CO2 and water. The best contact is achieved in a slurry reactor but a second step to separate and recover the catalyst is need. This paper discusses a new membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.

Influence of surface mining on ground water (effects and possibilities of prevention)

Energy Technology Data Exchange (ETDEWEB)

Libicki, J

1977-01-01

This article analyzes the negative impact of surface mining on ground water. The effects of water depression on water supply for households and industry, and for vegetation and agriculture are evaluated. The negative impact of lowering the ground water level under various water conditions are analyzed: (1) vegetation is supplied with water only by rainfall, (2) vegetation is supplied with water in some seasons by rainfall and in some by ground water, and (3) vegetation uses ground water only. The impact of deteriorating water supply on forests is discussed. Problems connected with storage of waste materials in abandoned surface mines are also discussed. The influence of black coal ash and waste material from coal preparation plants on ground water is analyzed: penetration of some elements and chemical compounds to the ground water and its pollution. Some preventive measures are proposed: injection of grout in the bottom and walls of storage areas to reduce their permeability (organic resins can also be used but they are more expensive). The distance between injection boreholes should be 15 to 20 m. Covering the bottom of the storage area with plastic sheets can also be applied.

Structure of adsorbed monolayers. The surface chemical bond

International Nuclear Information System (INIS)

Somorjai, G.A.; Bent, B.E.

1984-06-01

This paper attempts to provide a summary of what has been learned about the structure of adsorbed monolayers and about the surface chemical bond from molecular surface science. While the surface chemical bond is less well understood than bonding of molecules in the gas phase or in the solid state, our knowledge of its properties is rapidly accumulating. The information obtained also has great impact on many surface science based technologies, including heterogeneous catalysis and electronic devices. It is hoped that much of the information obtained from studies at solid-gas interfaces can be correlated with molecular behavior at solid-liquid interfaces. 31 references, 42 figures, 1 table

A method for screening for the risk of chronic effects of surface water pollution.

Science.gov (United States)

Soldán, Přemysl; Badurová, Jana

2013-01-01

The article describes a method for screening for the risk of chronic surface water pollution which was developed at the T. G. Masaryk Water Research Institute. The approach, which is based on exotoxicological analyses, can be classed as a rapid method of assessment. The degree of risk of chronic effects surface water pollution is determined from an evaluation of two major parameters-toxicity and genotoxicity. As the method utilizes relative simple procedures for sample collection, pretreatment of the sample, chemical analyses, bioassays and results assessment, this approach is suitable for widespread practical use. Extensive utilization of this approach for assessing river basins in the Czech Republic has proved its suitability for a more sophisticated detection of the biological impact of surface water pollution. This is documented in the article where the method is used in a study of the Bílina River, and in the overview of the results of the risk assessment of chronic effects of surface water pollution in selected sections of three international river basins in the Czech Republic.

The groundwater contribution to surface water contamination in a region with intensive agricultural land use (Noord-Brabant, The Netherlands)

International Nuclear Information System (INIS)

Rozemeijer, J.C.; Broers, H.P.

2007-01-01

Traditionally, monitoring of soil, groundwater and surface water quality is coordinated by different authorities in the Netherlands. Nowadays, the European Water Framework Directive (EU, 2000) stimulates an integrated approach of the complete soil-groundwater-surface water system. Based on water quality data from several test catchments, we propose a conceptual model stating that stream water quality at different discharges is the result of different mixing ratios of groundwater from different depths. This concept is used for a regional study of the groundwater contribution to surface water contamination in the Dutch province of Noord-Brabant, using the large amount of available data from the regional monitoring networks. The results show that groundwater is a dominant source of surface water contamination. The poor chemical condition of upper and shallow groundwater leads to exceedance of the quality standards in receiving surface waters, especially during quick flow periods. - Water quality monitoring data show the importance of the groundwater contribution to surface water pollution

Nanoscale Structural/Chemical Characterization of Manganese Oxide Surface Layers and Nanoparticles, and the Associated Implications for Drinking Water

Science.gov (United States)

Michel Eduardo Vargas Vallejo

Water treatment facilities commonly reduce soluble contaminants, such as soluble manganese (Mn2+), in water by oxidation and subsequent filtration. Previous studies have shown that conventional porous filter system removes Mn2+ from drinking water by developing Mn-oxides (MnO x(s)) bearing coating layers on the surface of filter media. Multiple models have been developed to explain this Mn2+ removal process and the formation mechanism of MnOx(s) coatings. Both, experimental and theoretical studies to date have been largely focused on the micrometer to millimeter scale range; whereas, coating layers are composed of nanoscale particles and films. Hence, understanding the nanoscale particle and film formation mechanisms is essential to comprehend the complexity of soluble contaminant removal processes. The primary objective of this study was to understand the initial MnOx(s) coating formation mechanisms and evaluate the influence of filter media characteristics on these processes. We pursued this objective by characterizing at the micro and nanoscale MnO x(s) coatings developed on different filter media by bench-scale column tests with simulating inorganic aqueous chemistry of a typical coagulation fresh water treatment plant, where free chlorine is present across filter bed. Analytical SEM and TEM, powder and synchrotron-based XRD, XPS, and ICPMS were used for characterization of coatings, filter media and water solution elemental chemistry. A secondary objective was to model how surface coating formation occurred and its correlation with experimentally observed physical characteristics. This modeling exercise indicates that surface roughness and morphology of filtering media are the major contributing factors in surface coating formation process. Contrary to previous models that assumed a uniform distribution and growth of surface coating, the experimental results showed that greater amounts of coating were developed in rougher areas. At the very early stage of

A surface chemical model of the bentonite-water interface and its implications for modelling the near field chemistry in a repository for spent fuel

Energy Technology Data Exchange (ETDEWEB)

Wieland, E; Wanner, H [MBT Umwelttechnik AG, Zuerich, (Switzerland); Albinsson, Y [Chalmers Univ. of Technology, Gothenburg (Sweden); Wersin, P [MBT Tecnologia Ambiental, Cerdanyola (Spain); Karnland, O [Clay Technology AB, Lund (Sweden)

1994-07-01

Understanding the surface chemical properties of montmorillonite in near-neutral and alkaline media is essential for establishing a chemical model of the bentonite/water interaction applicable for repository conditions. A pretreated and well-characterised Wyoming MX-80 bentonite has been used for investigating the acid/base characteristics of Na-montmorillonite. The CEC of Na-montmorillonite was determined to 108 meq/100 g for pretreated bentonite and to 85 meq/100 g for the bulk material. The BET surface area was (31.53{+-}0.16)m{sup 2}/g. Potentiometric titrations of montmorillonite suspensions at ionic strengths I=0.005 M, 0.05 M and 0.5 M were conducted as batch-type experiments. Deprotonation of surface OH groups possibly exposed at the edge surface causes an overall negative charge on the surface of montmorillonite in the alkaline pH range. In this pH range, the protolysis degree of OH groups increases with increasing pH and ionic strength. The proton density on the surface of montmorillonite increases with decreasing pH in the acidic pH range (pH<7.5). In this pH range, two simultaneously occurring surface reactions account for the observed proton density on montmorillonite: Protonation of edge OH groups and ion exchange of the major cations for H{sup +} at the structural-charge sites. The experimental results are interpreted in terms of a two-site model with structural-charge surface sites (X layer sites) and variable-charge surface sites (edge OH groups) as the reactive surface functionalities. The total population of the surface sites are estimated to TOT-OH=2.84*10{sup -5} mol/g, TOT-X=2.22*10{sup -5} mol/g. The intrinsic acidity constants for the OH groups are determined to pK{sup int}{sub al}= (5.4{+-}0.1) and pK{sup int}{sub a2}=(6-7{+-}0.1), respectively, using th configuration of the diffuse double layer model (DDLM). 43 refs, 18 figs, 11 tabs.

Sacrificial amphiphiles: Eco-friendly chemical herders as oil spill mitigation chemicals.

Science.gov (United States)

Gupta, Deeksha; Sarker, Bivas; Thadikaran, Keith; John, Vijay; Maldarelli, Charles; John, George

2015-06-01

Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as "chemical herder" is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the air-sea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, and hence remain in the marine ecosystem for years. We architect an eco-friendly, sacrificial, and effective green herder derived from the plant-based small-molecule phytol, which is abundant in the marine environment, as an alternative to the current chemical herders. Phytol consists of a regularly branched chain of isoprene units that form the hydrophobe of the amphiphile; the chain is esterified to cationic groups to form the polar group. The ester linkage is proximal to an allyl bond in phytol, which facilitates the hydrolysis of the amphiphile after adsorption to the sea surface into the phytol hydrophobic tail, which along with the unhydrolyzed herder, remains on the surface to maintain herding action, and the cationic group, which dissolves into the water column. Eventual degradation of the phytol tail and dilution of the cation make these sacrificial amphiphiles eco-friendly. The herding behavior of phytol-based amphiphiles is evaluated as a function of time, temperature, and water salinity to examine their versatility under different conditions, ranging from ice-cold water to hot water. The green chemical herder retracted oil slicks by up to ~500, 700, and 2500% at 5°, 20°, and 35°C, respectively, during the first 10 min of the experiment, which is on a par with the current best chemical herders in practice.

Effect of magnetic treatment of water on chemical properties of water ...

African Journals Online (AJOL)

This study assessed effect of magnetic treatment of water on chemical properties of water, sodium adsorption ratio, electrical conductivity (EC) of the water and the lifespan of the magnetic effect on water. Magnetic flux densities used for treating the water were 124, 319, 443 and 719 gauss. All the cations (Calcium, Sodium, ...

Shift in the microbial community composition of surface water and sediment along an urban river.

Science.gov (United States)

Wang, Lan; Zhang, Jing; Li, Huilin; Yang, Hong; Peng, Chao; Peng, Zhengsong; Lu, Lu

2018-06-15

Urban rivers represent a unique ecosystem in which pollution occurs regularly, leading to significantly altered of chemical and biological characteristics of the surface water and sediments. However, the impact of urbanization on the diversity and structure of the river microbial community has not been well documented. As a major tributary of the Yangtze River, the Jialing River flows through many cities. Here, a comprehensive analysis of the spatial microbial distribution in the surface water and sediments in the Nanchong section of Jialing River and its two urban branches was conducted using 16S rRNA gene-based Illumina MiSeq sequencing. The results revealed distinct differences in surface water bacterial composition along the river with a differential distribution of Proteobacteria, Cyanobacteria, Actinobacteria, Bacteroidetes and Acidobacteria (P urban water. PICRUSt metabolic inference analysis revealed a growing number of genes associated with xenobiotic metabolism and nitrogen metabolism in the urban water, indicating that urban discharges might act as the dominant selective force to alter the microbial communities. Redundancy analysis suggested that the microbial community structure was influenced by several environmental factors. TP (P urban river. These results highlight that river microbial communities exhibit spatial variation in urban areas due to the joint influence of chemical variables associated with sewage discharging and construction of hydropower stations. Copyright © 2018 Elsevier B.V. All rights reserved.

Service water chemical cleaning at River Bend gets results

International Nuclear Information System (INIS)

Brice, T.O.; Glover, W.A.

1994-01-01

The largest known Service Water System (SWS) chemical cleaning ever performed at a nuclear plant was successfully completed at, River Bend Station. Corrosion product buildup was observed during system inspections in the first operating cycle and the first refueling outage in 1987. Under deposit corrosion was followed with microbiologically influenced corrosion (MIC) occurring as a later stage under deposits. The heavy corrosion caused blockage of heat exchanger tubes, fouling of valve seats, and general flow blockage throughout the system. Various options were evaluated for restoring the SWS back to an acceptable long term operating condition. The large scale chemical cleaning performed arrested the corrosion by removing the deposits down to the bare metal surfaces and leaving behind a protective passivation layer. After the cleaning, the open recirculating SWS was converted to a closed system. The implementation of a molybdate/nitrate water treatment program with a copper corrosion inhibitor maintained at a high pH (8.5--10.5) has significantly reduced corrosion rates in the closed system. This should extend the life of the SWS piping for the remaining life of the plant. Several field tests were conducted to qualify the process and demonstrate its ability to achieve acceptable cleaning results prior to being used on a larger scale. In the summer of 1992, temporary and permanent modifications were installed to divide the SWS into two separate cleaning loops for the system wide cleaning. The SWS chemical was successfully performed and completed on schedule during the fourth refueling outage. Post cleaning inspections at various locations throughout the Service Water System showed the process to be very effective at complete deposit removal

Chemical-to-Electricity Carbon: Water Device.

Science.gov (United States)

He, Sisi; Zhang, Yueyu; Qiu, Longbin; Zhang, Longsheng; Xie, Yun; Pan, Jian; Chen, Peining; Wang, Bingjie; Xu, Xiaojie; Hu, Yajie; Dinh, Cao Thang; De Luna, Phil; Banis, Mohammad Norouzi; Wang, Zhiqiang; Sham, Tsun-Kong; Gong, Xingao; Zhang, Bo; Peng, Huisheng; Sargent, Edward H

2018-03-26

The ability to release, as electrical energy, potential energy stored at the water:carbon interface is attractive, since water is abundant and available. However, many previous reports of such energy converters rely on either flowing water or specially designed ionic aqueous solutions. These requirements restrict practical application, particularly in environments with quiescent water. Here, a carbon-based chemical-to-electricity device that transfers the chemical energy to electrical form when coming into contact with quiescent deionized water is reported. The device is built using carbon nanotube yarns, oxygen content of which is modulated using oxygen plasma-treatment. When immersed in water, the device discharges electricity with a power density that exceeds 700 mW m -2 , one order of magnitude higher than the best previously published result. X-ray absorption and density functional theory studies support a mechanism of operation that relies on the polarization of sp 2 hybridized carbon atoms. The devices are incorporated into a flexible fabric for powering personal electronic devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical denaturation of globular proteins at the air/water interface: an x-ray and neutron reflectometry study

International Nuclear Information System (INIS)

Perriman, A.W.; Henderson, M.J.; White, J.W.

2003-01-01

Full text: X-ray and neutron reflectometry has been used to probe the equilibrium surface structure of hen egg white lysozyme (lysozyme) and bovine β -lactoglobulin (β -lactoglobulin) under denaturing conditions at the air-water interface. This was achieved by performing experiments on 10 mg mL -1 protein solutions containing increasing concentrations of the chemical denaturant guanidinium hydrochloride (G.HCl). For solutions containing no G.HCl, the surface structure of the proteins was represented by a two-layer model with total thicknesses of 48 Angstroms and 38 Angstroms for lysozyme and β -lactoglobulin, respectively. The total volume of a single protein molecule and the associated water molecules was evaluated to be approximately 45 (0.3) nm 3 for lysozyme, and 60 (0.3) nm 3 for β-lactoglobulin. The thickness dimensions and the total volumes compared favourably with the crystal dimensions of 45 x 30 x 30 Angstroms (40.5 nm 3 ),1 and 36 x 36 x 36 Angstroms (47 nm 3 ) 2 for lysozyme and β -lactoglobulin, respectively. This comparison suggests that when no denaturant was present, the structures of lysozyme and β -lactoglobulin were near to their native conformations at the air-water interface. The response to the presence of the chemical denaturant was different for each protein. The surface layer of β-lactoglobulin expanded at very low concentrations (0.2 mol dm -3 ) of G.HCl. In contrast, the lysozyme layer contracted. At higher concentrations, unfolding of both the proteins led to the formation of a third diffuse layer. In general, lysozyme appeared to be less responsive to the chemical denaturant, which is most likely a result of the higher disulfide content of lysozyme. A protocol allowing quantitative thermodynamic analysis of the contribution from the air-water interface to the chemical denaturation of a protein was developed

Pharmaceuticals and personal care products (PPCPs) in surface and treated waters of Louisiana, USA and Ontario, Canada.

Science.gov (United States)

Boyd, Glen R; Reemtsma, Helge; Grimm, Deborah A; Mitra, Siddhartha

2003-07-20

A newly developed analytical method was used to measure concentrations of nine pharmaceuticals and personal care products (PPCPs) in samples from two surface water bodies, a sewage treatment plant effluent and various stages of a drinking water treatment plant in Louisiana, USA, and from one surface water body, a drinking water treatment plant and a pilot plant in Ontario, Canada. The analytical method provides for simultaneous extraction and quantification of the following broad range of PPCPs and endocrine-disrupting chemicals: naproxen; ibuprofen; estrone; 17beta-estradiol; bisphenol A; clorophene; triclosan; fluoxetine; and clofibric acid. Naproxen was detected in Louisiana sewage treatment plant effluent at 81-106 ng/l and Louisiana and Ontario surface waters at 22-107 ng/l. Triclosan was detected in Louisiana sewage treatment plant effluent at 10-21 ng/l. Of the three surface waters sampled, clofibric acid was detected in Detroit River water at 103 ng/l, but not in Mississippi River or Lake Pontchartrain waters. None of the other target analytes were detected above their method detection limits. Based on results at various stages of treatment, conventional drinking-water treatment processes (coagulation, flocculation and sedimentation) plus continuous addition of powdered activated carbon at a dosage of 2 mg/l did not remove naproxen from Mississippi River waters. However, chlorination, ozonation and dual media filtration processes reduced the concentration of naproxen below detection in Mississippi River and Detroit River waters and reduced clofibric acid in Detroit River waters. Results of this study demonstrate that existing water treatment technologies can effectively remove certain PPCPs. In addition, our study demonstrates the importance of obtaining data on removal mechanisms and byproducts associated with PPCPs and other endocrine-disrupting chemicals in drinking water and sewage treatment processes.

Escherichia coli in the surface waters and in oysters of two cultivations of Guaratuba Bay - Paraná - Brazil

Directory of Open Access Journals (Sweden)

Helenita Catharina Dalla-Lana Forcelini

2013-04-01

Full Text Available The present work aimed to evaluate the contamination of Escherichia coli in the surface waters and oysters from two cultivations of Guaratuba Bay and to analyze the correlation patterns among the concentrations of E. coli in the waters and in the oysters with the local physical-chemical parameters. Samples were collected in the spring of 2007 and summer, autumn and winter of 2008 from two points of the bay (internal point and external point. From each cultivation and sampling period, 18 oysters were collected. The samples of surface water were collected for the measurement of physical-chemical parameters (pH, salinity, temperature, dissolved oxygen, seston, particulate organic matter and quantification of E. coli. The surface water analyzed in the summer presented the largest most probable number of E. coli, (1,659.22 MPN.100 ml-1 and 958,55 MPN.100 ml-1 at external and internal points, respectively. The oysters from the internal point presented more E. coli, except in the winter sampling. The largest contamination was observed in the spring, at the internal point (979,78 MPN.g-1. The Principal Components Analysis showed direct correlation among the amount of E. coli in the oysters and in the surface water.

Evaluation Of The Hydraulic Connection Between The Surface Water And The Groundwater Along El-Salam Canal, North Eastern Coast, Egypt

International Nuclear Information System (INIS)

Ismail, Y.L.; Ismail, N.A.; Abdel Mogheeth, S.M.; Salem, W.M.

2012-01-01

In the present study, the interconnection between the surface water of El-Salam Canal and the shallow groundwater in the adjacent aquifer has been discussed using both the environmental isotopes and the chemical analyses of the different water bodies along the canal trajectory from Faraskour in the west to Balousa in the east. The isotopic techniques were applied to investigate this relationship and to estimate the possible contribution from various sources such as groundwater, sea water and/or irrigation water, and finally to determine the extent of mixing between El-Salam Canal and the adjacent aquifers. Since the groundwater in the area is saline (more than 10000 ppm) while the mixed canal water is mainly fresh (less than 1000 ppm), the interconnection between the canal water and surrounding shallow groundwater leads to one of the following two hydrologic processes; seepage from the canal water to the shallow groundwater which means fresh water losses or leakage from the groundwater into the surface water which means water quality deterioration The present study aims to detect the hydraulic interconnection between the two water bodies by using environmental isotope techniques as well as detailed chemical analysis. For this purpose, 31 water samples from both surface water and groundwater were collected and analyzed for 18 O and 2 H contents as well as 44 representative water samples were collected and analyzed for the chemical components (anions and cations) as a major ions and minor constituents. The distribution of the analyzed samples on the 18 O vs. D diagram indicated that the samples could be classified into three genetic groups representing different sources of water. The first group reflects a contribution from evaporated rain water prior to infiltration to the groundwater, the second group represents a mixing trend between both of El-Farma drain water and El-Manzala lake water with the groundwater which have enriched isotopic values as well as high

Controls on Surface Water Chemistry in the Upper Merced River Basin, Yosemite National Park, California

Science.gov (United States)

Clow, David W.; Alisa Mast, M.; Campbell, Donald H.

1996-05-01

Surface water draining granitic bedrock in Yosemite National Park exhibits considerable variability in chemical composition, despite the relative homogeneity of bedrock chemistry. Other geological factors, including the jointing and distribution of glacial till, appear to exert strong controls on water composition. Chemical data from three surface water surveys in the upper Merced River basin conducted in August 1981, June 1988 and August 1991 were analysed and compared with mapped geological, hydrological and topographic features to identify the solute sources and processes that control water chemistry within the basin during baseflow. Water at most of the sampling sites was dilute, with alkalinities ranging from 26 to 77 equiv. l-1. Alkalinity was much higher in two subcatchments, however, ranging from 51 to 302 equiv. l-1. Base cations and silica were also significantly higher in these two catchments than in the rest of the watershed. Concentrations of weathering products in surface water were correlated to the fraction of each subcatchment underlain by surficial material, which is mostly glacial till. Silicate mineral weathering is the dominant control on concentrations of alkalinity, silica and base cations, and ratios of these constituents in surface water reflect the composition of local bedrock. Chloride concentrations in surface water samples varied widely, ranging from <1 to 96 equiv. l-1. The annual volume-weighted mean chloride concentration in the Merced River at the Happy Isles gauge from 1968 to 1990 was 26 equiv. l-1, which was five times higher than in atmospheric deposition (4-5 equiv. l-1), suggesting that a source of chloride exists within the watershed. Saline groundwater springs, whose locations are probably controlled by vertical jointing in the bedrock, are the most likely source of the chloride. Sulphate concentrations varied much less than most other solutes, ranging from 3 to 14 equiv. l-1. Concentrations of sulphate in quarterly samples

Physico-chemical characteristics of surface and groundwater in ...

African Journals Online (AJOL)

musa kizito ojochenemi

drinking water recommended by the World Health Organisation except for iron which had elevated ... Key words: Obajana, water resources, physico - chemical, cation, anion and pollution. ..... Exposition (AUGA EXPO'83) Acapulco, Mexico.

Hydrochemical characteristics of mine waters from abandoned mining sites in Serbia and their impact on surface water quality.

Science.gov (United States)

Atanacković, Nebojša; Dragišić, Veselin; Stojković, Jana; Papić, Petar; Zivanović, Vladimir

2013-11-01

Upon completion of exploration and extraction of mineral resources, many mining sites have been abandoned without previously putting environmental protection measures in place. As a consequence, mine waters originating from such sites are discharged freely into surface water. Regional scale analyses were conducted to determine the hydrochemical characteristics of mine waters from abandoned sites featuring metal (Cu, Pb-Zn, Au, Fe, Sb, Mo, Bi, Hg) deposits, non-metallic minerals (coal, Mg, F, B) and uranium. The study included 80 mine water samples from 59 abandoned mining sites. Their cation composition was dominated by Ca2+, while the most common anions were found to be SO4(2-) and HCO3-. Strong correlations were established between the pH level and metal (Fe, Mn, Zn, Cu) concentrations in the mine waters. Hierarchical cluster analysis was applied to parameters generally indicative of pollution, such as pH, TDS, SO4(2-), Fe total, and As total. Following this approach, mine water samples were grouped into three main clusters and six subclusters, depending on their potential environmental impact. Principal component analysis was used to group together variables that share the same variance. The extracted principal components indicated that sulfide oxidation and weathering of silicate and carbonate rocks were the primary processes, while pH buffering, adsorption and ion exchange were secondary drivers of the chemical composition of the analyzed mine waters. Surface waters, which received the mine waters, were examined. Analysis showed increases of sulfate and metal concentrations and general degradation of surface water quality.

The chemical physics of surfaces

CERN Document Server

Morrison, Stanley Roy

1990-01-01

Even more importantly, some authors who have contributed substantially to an area may have been overlooked. For this I apologize. I have, however, not attempted to trace techniques or observa­ tions historically, so there is no implication (unless specified) that the authors referred to were or were not the originators of a given method or observation. I would like to acknowledge discussions with co-workers at SFU for input relative to their specialties, to acknowledge the help of students who have pointed out errors and difficulties in the earlier presentation, and to acknowledge the infinite patience of my wife Phyllis while I spent my sabbatical and more in libraries and punching computers. S. Roy Morrison 0 1 Contents Notation XV 1. Introduction 1 1. 1. Surface States and Surface Sites . 1 1. 1. 1. The Chemical versus Electronic Representation of the Surface. 1 1. 1. 2. The Surface State on the Band Diagram 4 1. 1. 3. The Fermi Energy in the Surface State Model. 6 1. 1. 4. Need for Both Surface...

Chemical effluents in surface waters from nuclear power plants. Quarterly progress report

International Nuclear Information System (INIS)

Harrison, F.L.

1978-01-01

The objectives of this research project are threefold: to obtain data on the behavior of potentially toxic substances introduced into surface waters from nuclear power plants; to determine the magnitude of the impact of these substances on representative and economically important aquatic species; and to develop models with which to predict the partitioning of these substances among the abiotic aquatic compartments. To fulfill these objectives in our investigation of copper, we are determining copper partitioning in marine and freshwater systems, evaluating the toxicity of copper to representative aquatic organisms, and developing a mathematical model to predict copper partitioning

Quality of surface water and ground water in the proposed artificial-recharge project area, Rillito Creek basin, Tucson, Arizona, 1994

Science.gov (United States)

Tadayon, Saeid

1995-01-01

Controlled artificial recharge of surface runoff is being considered as a water-management technique to address the problem of ground-water overdraft. The planned use of recharge facilities in urban areas has caused concern about the quality of urban runoff to be recharged and the potential for ground-water contamination. The proposed recharge facility in Rillito Creek will utilize runoff entering a 1-mile reach of the Rillito Creek between Craycroft Road and Swan Road for infiltration and recharge purposes within the channel and excavated overbank areas. Physical and chemical data were collected from two surface-water and two ground-water sites in the study area in 1994. Analyses of surface-water samples were done to determine the occurrence and concentration of potential contaminants and to determine changes in quality since samples were collected during 1987-93. Analyses of ground-water samples were done to determine the variability of ground-water quality at the monitoring wells throughout the year and to determine changes in quality since samples were collected in 1989 and 1993. Surface-water samples were collected from Tanque Verde Creek at Sabino Canyon Road (streamflow-gaging station Tanque Verde Creek at Tucson, 09484500) and from Alamo Wash at Fort Lowell Road in September and May 1994, respectively. Ground-water samples were collected from monitoring wells (D- 13-14)26cbb2 and (D-13-14)26dcb2 in January, May, July, and October 1994. In surface water, calcium was the dominant cation, and bicarbonate was the dominant anion. In ground water, calcium and sodium were the dominant cations and bicarbonate was the dominant anion. Surface water in the area is soft, and ground water is moderately hard to hard. In surface water and ground water, nitrogen was found predominantly as nitrate. Concentrations of manganese in ground-water samples ranged from 60 to 230 micrograms per liter and exceeded the U.S. Environmental Protection Agency secondary maximum contaminant

Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

Energy Technology Data Exchange (ETDEWEB)

Moraczewski, Krzysztof, E-mail: kmm@ukw.edu.pl [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Rytlewski, Piotr [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland); Malinowski, Rafał [Institute for Engineering of Polymer Materials and Dyes, ul. M. Skłodowskiej–Curie 55, 87-100 Toruń (Poland); Żenkiewicz, Marian [Department of Materials Engineering, Kazimierz Wielki University, Department of Materials Engineering, ul. Chodkiewicza 30, 85-064 Bydgoszcz (Poland)

2015-08-15

Highlights: • We modified polylactide surface layer with chemical, plasma or laser methods. • We tested selected properties and surface structure of modified samples. • We stated that the plasma treatment appears to be the most beneficial. - Abstract: The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm{sup 2} was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

Radiocaesium and plutonium in Atlantic surface waters from 73oN to 72oS

International Nuclear Information System (INIS)

Holm, E.; Roos, P.; Persson, R.B.R.; Livingston, H.D.

1991-01-01

During the recent Swedish Antartic research Expedition (SWEDARP 89/89) samples of surface sea water were collected on board the Stena Arctica between Gothenburgh, Sweden and the Antarctic Peninsula. Radio chemical separation was performed for radiocaesium on 200 1 samples and for plutonium on samples between 200 and 1500 1. The results are compared with those of the GEOSECS expedition in the North and South Atlantic in 1972-73 and the Polish expedition in 1977-78. They show that radiocaesium has behaved rather conservatively and that the decrease in surface water concentrations during 16 years is due to physical decay. On the other hand levels of 239+240 Pu have decreased by a factor of 4-5 giving a half life of 7-8 years in open Atlantic surface waters. (Author)

Physical and chemical quality, biodiversity, and thermodynamic prediction of adhesion of bacterial isolates from a water purification system: a case study

Directory of Open Access Journals (Sweden)

Roberta Barbosa Teodoro Alves

2017-06-01

Full Text Available ABSTRACT The objective of this study was to evaluate the quality of water purification system and identify the bacteria this system, predict bacterial adherence according to the hydrophobicity of these microorganisms and of the polypropylene distribution loop for purified water. The assessment of drinking water that supplies the purification system allowed good-quality physical, chemical, and microbiological specifications. The physicochemical specifications of the distributed purified water were approved, but the heterotrophic bacteria count was higher than allowed (>2 log CFU mL-1.The sanitation of the storage tank with chlorine decreased the number of bacteria adhered to the surface (4.34 cycles log. By sequencing of the 16SrDNA genes, six species of bacteria were identified. The contact angle was determined and polypropylene surface and all bacteria were considered to be hydrophilic, and adhesion was thermodynamically unfavorable. This case study showed the importance of monitoring the water quality in the purified water systems and the importance of sanitization with chemical agents. The count of heterotrophic bacteria on the polypropylene surface was consistent with the predicted thermodynamics results because the number of adhered cells reached approximate values of 5 log CFU cm-2.

Atomic Resolution Imaging and Quantification of Chemical Functionality of Surfaces

Energy Technology Data Exchange (ETDEWEB)

Schwarz, Udo D. [Yale Univ., New Haven, CT (United States). Dept. of Mechanical Engineering and Materials Science; Altman, Eric I. [Yale Univ., New Haven, CT (United States). Dept. of Chemical and Environmental Engineering

2014-12-10

The work carried out from 2006-2014 under DoE support was targeted at developing new approaches to the atomic-scale characterization of surfaces that include species-selective imaging and an ability to quantify chemical surface interactions with site-specific accuracy. The newly established methods were subsequently applied to gain insight into the local chemical interactions that govern the catalytic properties of model catalysts of interest to DoE. The foundation of our work was the development of three-dimensional atomic force microscopy (3DAFM), a new measurement mode that allows the mapping of the complete surface force and energy fields with picometer resolution in space (x, y, and z) and piconewton/millielectron volts in force/energy. From this experimental platform, we further expanded by adding the simultaneous recording of tunneling current (3D-AFM/STM) using chemically well-defined tips. Through comparison with simulations, we were able to achieve precise quantification and assignment of local chemical interactions to exact positions within the lattice. During the course of the project, the novel techniques were applied to surface-oxidized copper, titanium dioxide, and silicon oxide. On these materials, defect-induced changes to the chemical surface reactivity and electronic charge density were characterized with site-specific accuracy.

Radiation-chemical degradation of chloroform in water solutions

International Nuclear Information System (INIS)

Ahmadov, S.A; Gurbanov, M.A; Iskenderova, Z.I; Abdullaev, E.T; Ibadov, N.A.

2006-01-01

Full text: Chloroform is the major chlorine-containing compound forming at chlorination of drinking water. As our basic water resources of Kur and Araz rivers are mostly polluted along the territory of the neighbor republics their chlorination for the purpose of biological purification can result in forming of chloroform. Unfortunately, there are only poor data about containing of chloroform in drinking water in the Republic, however the particular problem is to develop new methods of drinking water purification from chloroform, taking into account the high toxicity of this compounds. Appropriate works indicate that radiation-chemical processing can mostly reduce the concentration of chloroform in drinking water. The purification degree can achieve 95-98%. This work studies the tendency of chloroform decomposition at its radiolysis processes in percentage. Taking into account the dissolvability of chloroform in water solutions it can be said that examined water solutions are homogeneous. Following advancements are studied: b Determination of radiation-chemical yield of chloroform decomposition at its various initial concentrations;Impact of adsorbed dose on pH of solutions;Formation of by-products.It is set that radiation-chemical output of chloroform decomposition is equal to 3.10-3-125 mol 100ev.

Chemical composition of water hyacinth (Eichhronia Crassipes) a comparison indication of heavy metal pollution in egyptian water bodies. Vol. 4

Energy Technology Data Exchange (ETDEWEB)

Abdel-sabour, M F [Soil pollution unit, Soil and water Department. Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt); Abdel-Haleem, A S [Hot Lab. Center, Atomic Energy Authority, Cairo (Egypt); Zohny, E [Physics Department, Faculty of Science, Cairo University, Beni-Sweif Branch, Cairo (Egypt)

1996-03-01

Water hyacinth is tested as an indicator for pollution in egyptian fresh surface waters. Chemical composition of water hyacinth as affected area of collection (water bodies) was studied and the suitability of this plant as a biological indicator for water pollution is discussed. Water hyacinth samples were collected three times per year for two years (1991-1993). Sample sites include one location in the river nile (at Helwan area), one site in Ismaillia canal, (at Mostrod industrial area), and one site in Abo-Zabal drain (at Abo-Zabal city). The concentration of 19 major major and trace elements in plant samples were determined by prompt gamma-ray neutron activation analysis. Results indicated that plant parts as well as location have a significant effect on elements content. Water hyacinth roots showed high affinity for accumulation of trace elements. 5 tabs.

Chemical composition of water hyacinth (Eichhronia Crassipes) a comparison indication of heavy metal pollution in egyptian water bodies. Vol. 4

International Nuclear Information System (INIS)

Abdel-sabour, M.F.; Abdel-Haleem, A.S.; Zohny, E.

1996-01-01

Water hyacinth is tested as an indicator for pollution in egyptian fresh surface waters. Chemical composition of water hyacinth as affected area of collection (water bodies) was studied and the suitability of this plant as a biological indicator for water pollution is discussed. Water hyacinth samples were collected three times per year for two years (1991-1993). Sample sites include one location in the river nile (at Helwan area), one site in Ismaillia canal, (at Mostrod industrial area), and one site in Abo-Zabal drain (at Abo-Zabal city). The concentration of 19 major major and trace elements in plant samples were determined by prompt gamma-ray neutron activation analysis. Results indicated that plant parts as well as location have a significant effect on elements content. Water hyacinth roots showed high affinity for accumulation of trace elements. 5 tabs

Structure and optical properties of water covered Cu(110) surfaces

International Nuclear Information System (INIS)

Baghbanpourasl, A.

2014-01-01

In this thesis structural and optical properties of the water covered Cu(110) surface is studied using density functional theory within independent particle approximation. Several stable adsorption structures are studied such as water clusters (monomer, dimer, trimer, tetramer and pentamer), different hexagonal monolayers, partially dissociated water monolayers and three different types of chains among them a chain that consists of pentagon rings. For a copper surface in contact with water vapor, the energetically stable H 2 O/OH adsorbed structures are compared thermodynamically using adsorption free energy (change of free energy due to adsorption). Several phase diagrams with respect to temperature and pressure are calculated. It is found that among the large number of energetically stable structures (i.e. structures with positive adsorption energy ) only limited number of them are thermodynamically stable. These thermodynamically stable structures are the class of almost energetically degenerate hexagonal overlayers, one type of partially dissociated water structure that contains Bjerrum defect in the hydrogen bond network and pentagon chain. Since hydrogen atoms are light weight their vibrational effects can be considerable. Zero point vibration decreases the adsorption energy up to 0.1 eV and free energy of adsorbed molecules arising from vibrational degree of freedom can go up to -0.2 eV per adsorbed molecule at 500 Kelvin. However zero point energy and vibrational free energy of adsorbed molecules do not alter relative stability of the adsorbed structures. To account for the long range van der Waals interactions, a semi-empirical scheme is applied. Reflectance Anisotropy Spectroscopy (RAS) is a fast and non destructive optical method that can be used to prob the surface in different conditions such as vacuum and electro-chemical environment. Elasto-optic coeficients of bulk are calculated from first principles and the change of the RA spectrum of the bare Cu

Chemical diffusion on solid surfaces. Final report

International Nuclear Information System (INIS)

Hudson, J.B.

1980-12-01

The techniques of surface science have been applied to the problem of the measurement of the surface diffusion rate of an adsorbed species over the surface of a chemically dissimilar material. Studies were carried out for hydrogen and nitrogen adatoms on a Ni(100) surface and for silver adatoms on a sapphire surface. Positive results were obtained only for the case of nitrogen on Ni(100). In this system the diffusivity is characterized by the expression D = D 0 exp (/sup -ΔH//RT), with D 0 = 0.25 cm 2 /sec and ΔH = 28kcal/mol

Evaluation of genotoxic effects of surface waters using a battery of bioassays indicating different mode of action.

Science.gov (United States)

Han, Yingnan; Li, Na; Oda, Yoshimitsu; Ma, Mei; Rao, Kaifeng; Wang, Zijian; Jin, Wei; Hong, Gang; Li, Zhiguo; Luo, Yi

2016-11-01

With the burgeoning contamination of surface waters threatening human health, the genotoxic effects of surface waters have received much attention. Because mutagenic and carcinogenic compounds in water cause tumors by different mechanisms, a battery of bioassays that each indicate a different mode of action (MOA) is required to evaluate the genotoxic effects of contaminants in water samples. In this study, 15 water samples from two source water reservoirs and surrounding rivers in Shijiazhuang city of China were evaluated for genotoxic effects. Target chemical analyses of 14 genotoxic pollutants were performed according to the Environmental quality standards for surface water of China. Then, the in vitro cytokinesis-block micronucleus (CBMN) assay, based on a high-content screening technique, was used to detect the effect of chromosome damage. The SOS/umu test using strain TA1535/pSK1002 was used to detect effects on SOS repair of gene expression. Additionally, two other strains, NM2009 and NM3009, which are highly sensitive to aromatic amines and nitroarenes, respectively, were used in the SOS/umu test to avoid false negative results. In the water samples, only two of the genotoxic chemicals listed in the water standards were detected in a few samples, with concentrations that were below water quality standards. However, positive results for the CBMN assay were observed in two river samples, and positive results for the induction of umuC gene expression in TA1535/pSK1002 were observed in seven river samples. Moreover, positive results were observed for NM2009 with S9 and NM3009 without S9 in some samples that had negative results using the strain TA1535/pSK1002. Based on the results with NM2009 and NM3009, some unknown or undetected aromatic amines and nitroarenes were likely in the source water reservoirs and the surrounding rivers. Furthermore, these compounds were most likely the causative pollutants for the genotoxic effect of these water samples. Therefore

Screening for contaminants of emerging concern in Northern Colorado Plateau Network waters: 2015 surface-water data

Science.gov (United States)

Weissinger, R; Battaglin, William A.; Bradley, Paul M.

2016-01-01

In 2015, as part of an on-going screening program for contaminants of emerging concern (CECs) in conjunction with the Environmental Protection Agency (EPA) Region 8, surface waters at 18 locations in or near seven national park units within the Northern Colorado Plateau Network (NCPN) were sampled for pesticides and pesticide degradation products, pharmaceuticals and personal care products, hormones, organic-wastewater-indictor chemicals, and nutrients. Most sites were sampled in spring (May or June) and fall (September).

EFFECT OF TROUT PRODUCTION IN CONCRETE PONDS WITH A CASCADING FLOW OF WATER ON PHYSICAL AND CHEMICAL PROPERTY OF WATER

Directory of Open Access Journals (Sweden)

Marcin Sidoruk

2014-10-01

Full Text Available Fish rearing causes changes in water quality due to the use of feed, mineral and organic fertilizers, pharmaceuticals and disinfectants. Rational fishery management aims to maintain or restore the quality of water in natural ecosystems. Cultures produce a certain amount of waste and pollutants released into the environment with waters departing from ponds, but their harmfulness depends on the conditions and type of farming. Studies on the assessment of the effects of rearing trout on physical and chemical properties of surface water were carried out in 2010-2012. Were chosen trout farm located in the Pomeranian province about 36 miles southeast of Słupsk. Water samples for physical and chemical analysis were collected every two months (a total of 12 sets samples collected and labeled them: temperature [°C], dissolved oxygen [mg · dm-3], oxygen saturation [%] electrolytic conductivity [S · cm-1], pH, redox potential [mV] and BOD5 and CODCr. The study showed that the water used to supply breeding facilities meet the requirements to be met which are inland water salmonid habitat. Only periodically for BOD5 standards have been slightly exceeded. After passing through the joints deterioration of water quality did not cause a change in the quality of the class, if only temporarily BOD5 ratio were lower in its quality from the first to the third class.

Water-assisted growth of graphene on carbon nanotubes by the chemical vapor deposition method.

Science.gov (United States)

Feng, Jian-Min; Dai, Ye-Jing

2013-05-21

Combining carbon nanotubes (CNTs) with graphene has been proved to be a feasible method for improving the performance of graphene for some practical applications. This paper reports a water-assisted route to grow graphene on CNTs from ferrocene and thiophene dissolved in ethanol by the chemical vapor deposition method in an argon flow. A double injection technique was used to separately inject ethanol solution and water for the preparation of graphene/CNTs. First, CNTs were prepared from ethanol solution and water. The injection of ethanol solution was suspended and water alone was injected into the reactor to etch the CNTs. Thereafter, ethanol solution was injected along with water, which is the key factor in obtaining graphene/CNTs. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and Raman scattering analyses confirmed that the products were the hybrid materials of graphene/CNTs. X-ray photo-electron spectroscopy analysis showed the presence of oxygen rich functional groups on the surface of the graphene/CNTs. Given the activity of the graphene/CNT surface, CdS quantum dots adhered onto it uniformly through simple mechanical mixing.

Mechanisms and energetics of surface reactions at the copper-water interface. A critical literature review with implications for the debate on corrosion of copper in anoxic water

Energy Technology Data Exchange (ETDEWEB)

Johansson, Adam Johannes; Brinck, Tore [Applied Physical Chemistry, KTH Royal Inst. of Technology, Stockholm (Sweden)

2012-06-15

In order to make a critical analysis of the discussion of corrosion of copper in pure anoxic water it is necessary to understand the chemical reactivity at the copper-water interface. Even though the most fundamental issue, i.e. the nature and existence of a hypothetical product that is thermodynamically stable, is still under debate, it is clear that if anoxic corrosion really exists, it must be initiated through oxidative surface reactions at the copper-water interface. This report presents a survey of the peer reviewed literature on the reactivity of copper surfaces in water. Reactions discussed involve molecular adsorption of water, dissociation of the OH-bonds in adsorbed water molecules and hydroxyl groups, the disproportionation/synproportionation equilibrium between hydroxyl groups/hydroxide ions, water molecules and atomic oxygen, the surface diffusion of adsorbed species, and the formation of hydrogen gas (molecular hydrogen). Experimental, as well as theoretical (quantum chemical) studies are reviewed. It is concluded that a limited amount of hydrogen gas (H{sub 2}) should be formed as the result of dissociative water adsorption at certain copper surfaces. Quantitative estimates of the amounts of H2 that could form at the copper-water interface are made. Assuming that the water-cleavage/hydrogen-formation reaction proceeds on an ideal [110] or [100] surface until a hydroxyl monolayer (ML) is reached, the amount of H{sub 2} formed is {approx} 2.4 ng cm{sup -2} copper surface. Based on the literature cited, this is most likely possible, thermodynamically as well as kinetically. Although not proven, it is not unlikely that the reaction can proceed until an oxide ML is formed, which would give 4.8 ng cm{sup -2}. If the formation of an oxide ML is thermodynamically feasible the surface will probably react further, since Cu{sub 2}O(s) is known to activate and cleave the water molecule when it adsorbs at the Cu{sub 2}O(s) surface. Assuming the formation of a

Controllability of Surface Water Networks

Science.gov (United States)

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.

Residence time, chemical and isotopic analysis of nitrate in the groundwater and surface water of a small agricultural watershed in the Coastal Plain, Bucks Branch, Sussex County, Delaware

Science.gov (United States)

Clune, John W.; Denver, Judith M.

2012-01-01

Nitrate is a common contaminant in groundwater and surface water throughout the Nation, and water-resource managers need more detailed small-scale watershed research to guide conservation efforts aimed at improving water quality. Concentrations of nitrate in Bucks Branch are among the highest in the state of Delaware and a scientific investigation was performed to provide water-quality information to assist with the management of agriculture and water resources. A combination of major-ion chemistry, nitrogen isotopic composition and age-dating techniques was used to estimate the residence time and provide a chemical and isotopic analysis of nitrate in the groundwater in the surficial aquifer of the Bucks Branch watershed in Sussex County, Delaware. The land use was more than 90 percent agricultural and most nitrogen inputs were from manure and fertilizer. The apparent median age of sampled groundwater is 18 years and the estimated residence time of groundwater contributing to the streamflow for the entire Bucks Branch watershed at the outlet is approximately 19 years. Concentrations of nitrate exceeded the U.S. Environmental Protection Agency drinking-water standard of 10 milligrams per liter (as nitrogen) in 60 percent of groundwater samples and 42 percent of surface-water samples. The overall geochemistry in the Bucks Branch watershed indicates that agriculture is the predominant source of nitrate contamination and the observed patterns in major-ion chemistry are similar to those observed in other studies on the Mid-Atlantic Coastal Plain. The pattern of enrichment in nitrogen and oxygen isotopes (δ15N and δ18O) of nitrate in groundwater and surface water indicates there is some loss of nitrate through denitrification, but this process is not sufficient to remove all of the nitrate from groundwater discharging to streams, and concentrations of nitrate in streams remain elevated.

CLEAN CHEMICAL SYNTHESIS IN WATER

Science.gov (United States)

Newer green chemistry approach to accomplish chemical synthesis in water is summarized. Recent global developments pertaining to C-C bond forming reactions using metallic reagents and direct use of the renewable materials such as carbohydrates without derivatization are described...

Groundwater–Surface Water Exchange

DEFF Research Database (Denmark)

Karan, Sachin

The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

Facile fabrication of superhydrophobic surfaces from austenitic stainless steel (AISI 304) by chemical etching

Science.gov (United States)

Kim, Jae-Hun; Mirzaei, Ali; Kim, Hyoun Woo; Kim, Sang Sub

2018-05-01

Stainless steels are among the most common engineering materials and are used extensively in humid areas. Therefore, it is important that these materials must be robust to humidity and corrosion. This paper reports the fabrication of superhydrophobic surfaces from austenitic stainless steel (type AISI 304) using a facile two-step chemical etching method. In the first step, the stainless steel plates were etched in a HF solution, followed by a fluorination process, where they showed a water contact angle (WCA) of 166° and a sliding angle of 5° under the optimal conditions. To further enhance the superhydrophobicity, in the second step, they were dipped in a 0.1 wt.% NaCl solution at 100 °C, where the WCA was increased to 168° and the sliding angle was decreased to ∼2°. The long-term durability of the fabricated superhydrophobic samples for 1 month storage in air and water was investigated. The potential applicability of the fabricated samples was demonstrated by the excellent superhydrophobicity after 1 month. In addition, the self-cleaning properties of the fabricated superhydrophobic surface were also demonstrated. This paper outlines a facile, low-cost and scalable chemical etching method that can be adopted easily for large-scale purposes.

TURBIDITY REMOVAL FROM SURFACE WATER USING ...

African Journals Online (AJOL)

User

2016-06-01

Jun 1, 2016 ... Plant-based coagulants are potential alternatives to chemical coagulants used in drinking water treatment. ... Conventional water treatment systems involve the use of synthetic ..... Thesis, Royal Institute of Technology (KTH),.

An novel identification method of the environmental risk sources for surface water pollution accidents in chemical industrial parks.

Science.gov (United States)

Peng, Jianfeng; Song, Yonghui; Yuan, Peng; Xiao, Shuhu; Han, Lu

2013-07-01

The chemical industry is a major source of various pollution accidents. Improving the management level of risk sources for pollution accidents has become an urgent demand for most industrialized countries. In pollution accidents, the released chemicals harm the receptors to some extent depending on their sensitivity or susceptibility. Therefore, identifying the potential risk sources from such a large number of chemical enterprises has become pressingly urgent. Based on the simulation of the whole accident process, a novel and expandable identification method for risk sources causing water pollution accidents is presented. The newly developed approach, by analyzing and stimulating the whole process of a pollution accident between sources and receptors, can be applied to identify risk sources, especially on the nationwide scale. Three major types of losses, such as social, economic and ecological losses, were normalized, analyzed and used for overall consequence modeling. A specific case study area, located in a chemical industry park (CIP) along the Yangtze River in Jiangsu Province, China, was selected to test the potential of the identification method. The results showed that there were four risk sources for pollution accidents in this CIP. Aniline leakage in the HS Chemical Plant would lead to the most serious impact on the surrounding water environment. This potential accident would severely damage the ecosystem up to 3.8 km downstream of Yangtze River, and lead to pollution over a distance stretching to 73.7 km downstream. The proposed method is easily extended to the nationwide identification of potential risk sources.

Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern

Science.gov (United States)

Kassotis, Christopher D.; Alvarez, David A.; Taylor, Julia A.; vom Saal, Frederick S.; Nagel, Susan C.; Tillitt, Donald E.

2015-01-01

Surface water contamination by chemical pollutants increasingly threatens water quality around the world. Among the many contaminants found in surface water, there is growing concern regarding endocrine disrupting chemicals, based on their ability to interfere with some aspect of hormone action in exposed organisms, including humans. This study assessed water quality at several sites across Missouri (near wastewater treatment plants and airborne release sites of bisphenol A) based on hormone receptor activation potencies and chemical concentrationspresent in the surface water. We hypothesized that bisphenol A and ethinylestradiol would be greater in water near permitted airborne release sites and wastewater treatment plant inputs, respectively, and that these two compounds would be responsible for the majority of activities in receptor-based assays conducted with water collected near these sites. Concentrations of bisphenol A and ethinylestradiol were compared to observed receptor activities using authentic standards to assess contribution to total activities, and quantitation of a comprehensive set of wastewater compounds was performed to better characterize each site. Bisphenol A concentrations were found to be elevated in surface water near permitted airborne release sites, raising questions that airborne releases of BPA may influence nearby surface water contamination and may represent a previously underestimated source to the environment and potential for human exposure. Estrogen and androgen receptor activities of surface water samples were predictive of wastewater input, although the lower sensitivity of the ethinylestradiol ELISA relative to the very high sensitivity of the bioassay approaches did not allow a direct comparison. Wastewater-influenced sites also had elevated anti-estrogenic and anti-androgenic equivalence, while sites without wastewater discharges exhibited no antagonist activities.

Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern.

Science.gov (United States)

Kassotis, Christopher D; Alvarez, David A; Taylor, Julia A; vom Saal, Frederick S; Nagel, Susan C; Tillitt, Donald E

2015-08-15

Surface water contamination by chemical pollutants increasingly threatens water quality around the world. Among the many contaminants found in surface water, there is growing concern regarding endocrine disrupting chemicals, based on their ability to interfere with some aspect of hormone action in exposed organisms, including humans. This study assessed water quality at several sites across Missouri (near wastewater treatment plants and airborne release sites of bisphenol A) based on hormone receptor activation potencies and chemical concentrations present in the surface water. We hypothesized that bisphenol A and ethinylestradiol would be greater in water near permitted airborne release sites and wastewater treatment plant inputs, respectively, and that these two compounds would be responsible for the majority of activities in receptor-based assays conducted with water collected near these sites. Concentrations of bisphenol A and ethinylestradiol were compared to observed receptor activities using authentic standards to assess contribution to total activities, and quantitation of a comprehensive set of wastewater compounds was performed to better characterize each site. Bisphenol A concentrations were found to be elevated in surface water near permitted airborne release sites, raising questions that airborne releases of BPA may influence nearby surface water contamination and may represent a previously underestimated source to the environment and potential for human exposure. Estrogen and androgen receptor activities of surface water samples were predictive of wastewater input, although the lower sensitivity of the ethinylestradiol ELISA relative to the very high sensitivity of the bioassay approaches did not allow a direct comparison. Wastewater-influenced sites also had elevated anti-estrogenic and anti-androgenic equivalence, while sites without wastewater discharges exhibited no antagonist activities. Published by Elsevier B.V.

Water response to ganglioside GM1 surface remodelling.

Science.gov (United States)

Brocca, P; Rondelli, V; Mallamace, F; Di Bari, M T; Deriu, A; Lohstroh, W; Del Favero, E; Corti, M; Cantu', L

2017-01-01

Gangliosides are biological glycolipids participating in rafts, structural and functional domains of cell membranes. Their headgroups are able to assume different conformations when packed on the surface of an aggregate, more lying or standing. Switching between different conformations is possible, and is a collective event. Switching can be induced, in model systems, by concentration or temperature increase, then possibly involving ganglioside-water interaction. In the present paper, the effect of GM1 ganglioside headgroup conformation on the water structuring and interactions is addressed. Depolarized Rayleigh Scattering, Raman Scattering, Quasielastic Neutron Scattering and NMR measurements were performed on GM1 ganglioside solutions, focusing on solvent properties. All used techniques agree in evidencing differences in the structure and dynamics of solvent water on different time-and-length scales in the presence of either GM1 headgroup conformations. In general, all results indicate that both the structural properties of solvent water and its interactions with the sugar headgroups of GM1 respond to surface remodelling. The extent of this modification is much higher than expected and, interestingly, ganglioside headgroups seem to turn from cosmotropes to chaotropes upon collective rearrangement from the standing- to the lying-conformation. In a biological perspective, water structure modulation could be one of the physico-chemical elements contributing to the raft strategy, both for rafts formation and persistence and for their functional aspects. In particular, the interaction with approaching bodies could be favoured or inhibited or triggered by complex-sugar-sequence conformational switch. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface water/groundwater relationship in Chaj Doab. Final report for the period November 1985 - December 1989

International Nuclear Information System (INIS)

Hussain, S.D.

1989-01-01

In order to understand the relationship between surface water and groundwater in Chaj Doab area, isotopic and chemical studies were undertaken. Seven sets of water samples from hand pumps, tube wells, rivers and canals were collected during the period November 1985 to October 1988 and all the samples were analysed for environmental isotopes such as 2 H, 3 H, 18 O and the dissolved chemical constituents like Na + , K + , Ca ++ , Mg ++ , Cl - , NO 3 - , SO 4 -- and TIC. Some of the water samples having very low tritium concentrations were analysed for 14 C content. Analysis for 13 C values for two sets of samples was also carried out. 8 refs, 13 figs, 6 tabs

Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

Science.gov (United States)

Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

2011-01-01

Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

Comparison of some effects of modification of a polylactide surface layer by chemical, plasma, and laser methods

Science.gov (United States)

Moraczewski, Krzysztof; Rytlewski, Piotr; Malinowski, Rafał; Żenkiewicz, Marian

2015-08-01

The article presents the results of studies and comparison of selected properties of the modified PLA surface layer. The modification was carried out with three methods. In the chemical method, a 0.25 M solution of sodium hydroxide in water and ethanol was utilized. In the plasma method, a 50 W generator was used, which produced plasma in the air atmosphere under reduced pressure. In the laser method, a pulsed ArF excimer laser with fluency of 60 mJ/cm2 was applied. Polylactide samples were examined by using the following techniques: scanning electron microscopy (SEM), atomic force microscopy (AFM), goniometry and X-ray photoelectron spectroscopy (XPS). Images of surfaces of the modified samples were recorded, contact angles were measured, and surface free energy was calculated. Qualitative and quantitative analyses of chemical composition of the PLA surface layer were performed as well. Based on the survey it was found that the best modification results are obtained using the plasma method.

Surface composition and surface properties of water hyacinth ...

African Journals Online (AJOL)

Surface composition and surface properties of water hyacinth ( Eichhornia ... (2/1, v/v) followed by ethanol, using Fourier Transform Infra-red (FT-IR) spectroscopy, ... polar organic solvents and non-polar n-alkane hydrocarbons is discussed.

Evaluation of chemical surface treatment methods for mitigation of PWSCC

International Nuclear Information System (INIS)

Dame, C.; Marks, C.; Olender, A.; Farias, J.

2015-01-01

As part of its mission to propose innovative and safe technologies to mitigate Primary Water Stress Corrosion Cracking (PWSCC) in Pressurized Water Reactors (PWR), EPRI recently initiated a program to evaluate potential new chemical surface treatments that might delay the occurrence of PWSCC such that no failure of components would be observed during their lifetime. Among the initial screening of more than thirty technologies, seven were selected for a more detailed review. The selected technologies were: nickel and nickel alloy plating, organic inhibitors, chromium-based inhibitors, silicon carbide, titanium-based inhibitors, rare earth metal (REM)-based inhibitors and encapsulation. The conclusions of the review of these technologies were that two of them were worth pursuing, titanium-based and REM-based inhibitors, and that evaluating the radiological consequences of injecting these products in the primary system, as well as assessing their efficacy to mitigate PWSCC, should be prioritized as the next required steps in qualification for implementation. (authors)

Chemical state analysis of oxidation products on steel surface by conversion electron Moessbauer spectrometry

International Nuclear Information System (INIS)

Ujihira, Yusuke; Nomura, Kiyoshi

1978-01-01

The polished NT-70H steel (Fe: 95.97%, C: 0.56%, diameter: 5 cm, thickness: 0.5 cm) was immersed in deionized water or in solutions containing (0.25 -- 0.5) M of chloride, sulfate and nitrate ions. The chemical states of oxidation products of iron on the surface were identified through the analysis of conversion electron Moessbauer spectra (CEMS). CEMS of the steel surface, which had been dipped in deionized water, revealed that γ-FeOOH was formed on the surface. The thickness of γ-FeOOH layer increased with the increase of the duration of dipping. Dissolved oxygen in the solution played an essential role in the oxidation of iron to γ-FeOOH. Oxidation product of iron dipped in the 0.5 M sodium chloride solution was identified as γ-FeOOH. Amorphous paramagnetic iron (III) compound tended to form in the presence of hydrogen peroxide or ammonium ions in the solutions. The increase of alkalinity of the solution up to pH 12 suppressed the oxidation rate and assisted the formation of green rust, which was confirmed by the appearance of the quadrupole splitting peaks of the green rust. In the 0.25 M sodium sulfate solution, oxidation of the steel surface proceeded slowly and the quadrupole splitting peaks of Fe(OH) 2 were seen in the CEMS. The peak intensity of Fe(OH) 2 gradually decreased and that of γ-FeOOH increased by the extension of immersion of steel in the solution. Magnetite (Fe 3 O 4 ) layer was developed beneath the γ-FeOOH layer, when steel was dipped in 0.5 M sodium nitrate solution. However, the peaks of Fe 3 O 4 were not seen on CEMS of steel surface immersed in 0.5 M ammonium nitrate solution. Thus, applying the feasibility of CEMS for the characterization of oxidated compounds of iron on the steel surface formed by the immersion in solutions, the oxidation mechanism of the steel surface was discussed based upon the results of chemical state analyses. (author)

Infiltration of pesticides in surface water into nearby drinking water supply wells

DEFF Research Database (Denmark)

Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

Drinking water wells are often placed near streams because streams often overly permeable sediments and the water table is near the surface in valleys, and so pumping costs are reduced. The lowering of the water table by pumping wells can reverse the natural flow from the groundwater to the stream......, inducing infiltration of surface water to groundwater and consequently to the drinking water well. Many attenuation processes can take place in the riparian zone, mainly due to mixing, biodegradation and sorption. However, if the water travel time from the surface water to the pumping well is too short......, or if the compounds are poorly degradable, contaminants can reach the drinking water well at high concentrations, jeopardizing drinking water quality. Here we developed a reactive transport model to evaluate the risk of contamination of drinking water wells by surface water pollution. The model was validated using...

availability analysis of chemicals for water treatment

African Journals Online (AJOL)

NIJOTECH

In most countries, chemicals are generally recognized as being vital in the production of potable water and will ... industries and water utility ventures are being started in Nigeria ... are being dumped into rivers thereby polluting them the more.

Temperature dependence on sodium-water chemical reaction

International Nuclear Information System (INIS)

Tamura, Kenta; Deguchi, Yoshihiro; Suzuki, Koichi; Takata, Takashi; Yamaguchi, Akira; Kikuchi, Shin; Ohshima, Hiroyuki

2012-01-01

In a sodium-cooled fast reactor (SFR), liquid sodium is used as a heat transfer fluid because of its excellent heat transport capability. On the other hand, it has strong chemical reactivity with water vapor. One of the design basis accidents of the SFR is the water leakage into the liquid sodium flow by a breach of heat transfer tubes. This process ends up damages on the heat transport equipment in the SFR. Therefore, the study on sodium-water chemical reactions is of paramount importance for security reasons. This study aims to clarify the sodium-water reaction mechanisms using laser diagnostics. A quasi one-dimensional flame model is also applied to a sodium-water counter-flow reaction field. Temperature, H 2 , H 2 O, OH, Na and Particulate matter were measured using laser induced fluorescence and CARS in the counter-flow reaction field. The temperature of the reaction field was also modified to reduce the condensation of Na in the reaction zone. (author)

Physico-chemical properties of water in bentonite

International Nuclear Information System (INIS)

Torikai, Yuji; Sato, Seichi; Ohashi, Hiroshi

1994-01-01

As a part of safety analysis on ground layer disposal, in order to estimate nuclides migration behavior from engineering shielding materials, it is required to modelize migration process of nuclides in bentonite and chemical species relating to corrosion, to estimate solubility and to specify application condition of geochemical calculation code. In this study, as a part of elucidation of nuclide migration process, physico-chemical properties of water in bentonite and montmorillonite using steam pressure method were determined. As a result, following items were found: (1) Even if 1/3 of water in bentonite is near free water, it is far from a region dealable with dilute solution in the electrolyte solution theory. And, (2) the water in bentonite has generally small activity in comparison with dilute solution, then has smaller solubility than estimation value of calculation code. (G.K.)

Innovative coatings and surface modification of titanium for sea water condenser applications

International Nuclear Information System (INIS)

George, R.P.; Anandkumar, B.; Vanithakumari, S.C.; Kamachi Mudali, U.

2016-01-01

Effectiveness of cooling water systems in various power plants to maintain highest electrical energy output per tonne of fuel is important as part of good energy management. Cooling water systems of nuclear power plants using seawater for cooling comes under constant attack from the marine and sea water environment. Many metallic components and civil structures in the cooling water systems like bridges, intake wells, intake pipes, pump house wells, water boxes, condenser pipes are subjected to severe fouling and corrosion which limits the service life and availability of power plants. The experience with a coastal water cooled power plant at Kalpakkam (MAPS), India, showed that chlorination and screening control macrofouling to a great extend by controlling protozoans, invertebrates, algae and fungi. However 90% of marine bacteria are resistant to such control measures, and they cause microfouling of condenser pipes leading to poor heat transfer and microbially influenced corrosion (MIC) failures. Titanium is used as condenser for Indian nuclear power plants employing sea water cooling, including the PFBR at Kalpakkam. Though titanium is excellent with respect to corrosion behavior under sea water conditions, its biocompatible nature results in biofouling and MIC during service. Therefore innovative antifouling coatings and surface modification techniques for titanium condenser applications in seawater and marine environments are the need of the hour. Extensive investigations were carried out by different methods including nanostructuring of surfaces for making them antibacterial. The microroughness of titanium was produced by repeated pickling and polishing which by itself reduced microbial adhesion. To utilize photocatalytic activity for antibacterial property, anodization of titanium surfaces followed by heat treatment was adopted and this also has controlled microbial fouling. Electroless plating of nanofilm of copper-nickel alloy decreased biofouling of

The formation of the chemical composition of groundwater in South Prohibiny using the example of "Predgorny" water intake

Directory of Open Access Journals (Sweden)

Mazukhina S. I.

2018-05-01

Full Text Available Researchers from Russia and foreign countries, studying medical and environmental contamination of drinking water, point to the relationship of public health with chemical composition of groundwater and anthropogenic inclusions. The aim of the work is to detect the change in chemical composition of natural waters formed within the Khibiny massif and its closest framing depending on the composition of rocks in the catchment area and on anthropogenic impact by means of physical and chemical modeling and modern precision methods of analysis. To achieve the goal the sampling has been taken at the "Predgorny" water intake (Koashva, the Kirovsk district. The complete hydrochemical analysis has shown the presence in waters of such elements as uranium, molybdenum, silver, barium, which supplemented the database of groundwater chemical composition. For the physical-chemical modeling, there have been made some samples of chemical analyzes of the most common rocks composing the southeastern part of the Khibiny massif as the main catchment area. The analysis of the obtained results has made it possible to separate the rock influence from anthropogenic, natural chemical composition of waters from filtered mined (anthropogenic. It has been shown that already in natural (pure waters the ratios of Ca/P and Ca/Sr can lead to bone diseases. It has been determined that the chemical composition of groundwater from the "Predgorny" water intake is affected by the chemical composition of rocks and surface waters containing oxygen, nitrogen nitrates, chlorine, which affect pH (reducing it, the migration patterns of aluminum, manganese, iron and other elements. In the bones of humans and animals, approximately 70 % falls on hydroxyl apatite Ca5(PO43OH. OH group can be replaced by F, Cl, O. Calcium can be isomorphically replaced by a number of elements: Sr, U, Ba, etc. that lead to diseases of bones and teeth. The research results can be useful in the fields of

Hydrogen generation due to water splitting on Si - terminated 4H-Sic(0001) surfaces

Science.gov (United States)

Li, Qingfang; Li, Qiqi; Yang, Cuihong; Rao, Weifeng

2018-02-01

The chemical reactions of hydrogen gas generation via water splitting on Si-terminated 4H-SiC surfaces with or without C/Si vacancies were studied by using first-principles. We studied the reaction mechanisms of hydrogen generation on the 4H-SiC(0001) surface. Our calculations demonstrate that there are major rearrangements in surface when H2O approaches the SiC(0001) surface. The first H splitting from water can occur with ground-state electronic structures. The second H splitting involves an energy barrier of 0.65 eV. However, the energy barrier for two H atoms desorbing from the Si-face and forming H2 gas is 3.04 eV. In addition, it is found that C and Si vacancies can form easier in SiC(0001)surfaces than in SiC bulk and nanoribbons. The C/Si vacancies introduced can enhance photocatalytic activities. It is easier to split OH on SiC(0001) surface with vacancies compared to the case of clean SiC surface. H2 can form on the 4H-SiC(0001) surface with C and Si vacancies if the energy barriers of 1.02 and 2.28 eV are surmounted, respectively. Therefore, SiC(0001) surface with C vacancy has potential applications in photocatalytic water-splitting.

DRINKING WATER QUALITY IN DISTRIBUTION SYSTEMS OF SURFACE AND GROUND WATERWORKS IN FINLAND

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Jenni Meirami Ikonen

2017-06-01

Full Text Available Physico-chemical and microbiological water quality in the drinking water distribution systems (DWDSs of five waterworks in Finland with different raw water sources and treatment processes was explored. Water quality was monitored during four seasons with on-line equipment and bulk water samples were analysed in laboratory. Seasonal changes in the water quality were more evident in DWDSs of surface waterworks compared to the ground waterworks and artificially recharging ground waterworks (AGR. Between seasons, temperature changed significantly in every system but pH and EC changed only in one AGR system. Seasonal change was seen also in the absorbance values of all systems. The concentration of microbially available phosphorus (MAP, μg PO₄-P/l was the highest in drinking water originating from the waterworks supplying groundwater. Total assimilable organic carbon (AOC, μg AOC-C/l concentrations were significantly different between the DWDSs other than between the two AGR systems. This study reports differences in the water quality between surface and ground waterworks using a wide set of parameters commonly used for monitoring. The results confirm that every distribution system is unique, and the water quality is affected by environmental factors, raw water source, treatment methods and disinfection.

47nm alumina–water nanofluid flow within boundary layer formed on upper horizontal surface of paraboloid of revolution in the presence of quartic autocatalysis chemical reaction

Directory of Open Access Journals (Sweden)

Isaac Lare Animasaun

2016-09-01

Full Text Available In this article, a modified version of buoyancy-induced model is considered to investigate the flow of 47nm alumina–water nanofluid along an upper surface of horizontal paraboloid of revolution in the presence of nonlinear thermal radiation, Lorentz force and quartic autocatalysis kind of homogeneous heterogeneous chemical reaction. The case of unequal diffusion coefficients of reactant A (bulk fluid and B (high concentration of catalyst at the surface in the presence of bioconvection is considered. Governing equation suitable to unravel the thermophoresis which takes place within the boundary layer is presented. Since chemical reactant B is of higher concentration at the surface more than the concept described as cubic autocatalytic, the suitable schemes are herein described as isothermal quartic autocatalytic reaction and first order reaction. The viscosity and thermal conductivity are assumed to vary with volume fraction (ϕ and suitable models for the case 0%⩽ϕ⩽0.8% are adopted. The transformed governing equations are solved numerically using Runge–Kutta fourth order along with shooting technique (RK4SM. Good agreement is obtained between the solutions of RK4SM and MATLAB bvp5c for a limiting case. The influence of some pertinent parameters on velocity, temperature, diffusion of motile microorganism, concentration of bulk fluid and catalyst is illustrated graphically and discussed.

Environmental geochemistry of surface and subsurface water from Dera Ismail Khan Division, Khyber Pakhtunkhwa, Pakistan

International Nuclear Information System (INIS)

Shah, M.T.; Alizai, A.H.; Khan, S.D.

2012-01-01

The Dera Ismail Khan division is situated in the southern most part of the Khyber-Pakhtunkhwa province in Pakistan. Majority of population in this region obtain domestic water from tube wells, dug wells, ponds, stored run off of the Indus and Gomal rivers and perennial streams. This study is aimed to determine the physio-chemical contaminants in the surface and subsurface water which could cause environmental problem. For this purpose, representative water sample were collected from tube wells, dug wells, streams and rivers. These analyses were performed using Hach DR/2000 spectrophotometer and graphite furnace atomic absorption spectrometer. Chemically both surface and subsurface water samples of the area were classified as alkaline fresh water. The comparison of the data with standard limits set by Word Health Organization (WHO) for drinking water suggested that in certain areas of the division, the drinking water samples have high concentrations of Total Dissolved Solids, NO/sub 3//sup 2-/, SO/sub 4//sup 2-/, F-, Cl-, Fe/sup 2+/, Ca/sup 2+/, Mg/sup 2+/, Pb/sup 2+/, Ni/sup 2+/ and Cd/sup 2+/ while pH, EC, HCO/sub 3/-, PO/sub 4//sup 3-/, Na/sup +/, Mn/sup 2+/, K/sup +/, Cr/sup 3+/ and Zn/sup 2+/ were within the permissible limits. These contaminations could be attributed to the geogenic sources which might be responsible for the health related problems in certain areas of the division. (author)

Waste water treatment in surface mines

Energy Technology Data Exchange (ETDEWEB)

Navasardyants, M A; Esipov, V Z; Ryzhkov, Yu A

1981-01-01

This paper evaluates problems associated with waste water from coal surface mines of the Kemerovougol' association in the Kuzbass. Waste water treatment in the Kuzbass is of major importance as the region is supplied with water from only one river, the Tom river. Water influx to Kemerovougol' surface mines in a year amounts to 136 million m/sup 3/. The water is used during technological processes, for fire fighting, and spraying to prevent dusting; the rest, about 82.1 million m/sup 3/, is discharged into surface waters. Of this amount, 25.1 million m/sup 3/ is heavily polluted water, 46.6 million m3 are polluted but within limits, and 10.4 million m/sup 3/ are characterized as relatively clean. Waste water is polluted with: suspended matters, oils and oil products, nitrates, nitrides and chlorides. Suspended matter content sometimes reaches 4,000 and 5,000 mg/l, and oil product content in water amounts to 2.17 mg/l. Water treatment in surface mines is two-staged: sumps and sedimentation tanks are used. Water with suspended matter content of 50 to 100 mg/l in winter and summer, and 200 to 250 mg/l in spring and autumn is reduced in sumps to 25 to 30 mg/l in summer and winter and to 40 to 50 mg/l in autumn and spring. During the first stage water treatment efficiency ranges from 50 to 80%. During the second stage water is collected in sedimentation tanks. It is noted that so-called secondary pollution is one of the causes of the relatively high level of suspended matter in discharged water. Water discharged from sedimentation tanks carries clay and loam particles from the bottom and walls of water tanks and channels.

Characterization of the parameters at the origin of the chemical species hideout process at the fuel rod surface in boiling conditions

International Nuclear Information System (INIS)

Peybernes, J.; March, P.

1999-01-01

Current trends in nuclear power generation (and particularly in pressurized water reactors) are toward plant life extension and extended fuel burnup. A higher heat generation rate can induce local boiling regimes at the fuel rod surface in the hottest channels of the core, which can strongly modify the chemical environment of the cladding and influence the oxidation rate of zirconium alloys. Tests performed in out-of-pile loops under severe chemical and thermal-hydraulic conditions (nucleate boiling, higher lithium contents compared to PWRs) reveal two important phenomena: an increase of the oxidation rate of Zircaloy-4 cladding materials in 'high' lithiated environments; an enrichment of the chemical additives in the primary water (boron, lithium) at the surface of the cladding under nucleate boiling conditions. The latter phenomenon, also called 'hideout effect', is mainly controlled by some thermal hydraulic parameters such as bubble diameters and nucleation site density. These parameters strongly depend on the oxide morphology (roughness, porosity). The lack of reliable data in high temperature water environments has led to the development of a specific instrumentation based on visualization. The fitting of windows on the REGGAE out-of-pile loop provides an optical access to the two-phase flow regime under PWR operating conditions, allowing for the characterization of the parameters at the origin of the chemical species hideout process. These direct observations of the cladding surfaces subjected to nucleate boiling conditions provide information about the development of the boiling mechanisms in relation to the morphology of the oxide layers (porosity, thickness, roughness). (author)

Pharmaceuticals and personal care products (PPCPs) and artificial sweeteners (ASs) in surface and ground waters and their application as indication of wastewater contamination.

Science.gov (United States)

Yang, Yuan-Yuan; Zhao, Jian-Liang; Liu, You-Sheng; Liu, Wang-Rong; Zhang, Qian-Qian; Yao, Li; Hu, Li-Xin; Zhang, Jin-Na; Jiang, Yu-Xia; Ying, Guang-Guo

2018-03-01

We systematically investigated the occurrence and distribution of 93 pharmaceuticals and personal care products (PPCPs) and 5 artificial sweeteners (ASs) in surface water and groundwater of Dongjiang River basin in south China. In surface water, 52 compounds were detected with median concentrations ranging from 0.06ng/L to 504ng/L, while in groundwater, 33 compounds were detected with concentrations up to 4580ng/L for acesulfame. PPCPs and ASs were widely detected in the surface water and groundwater samples, which indicated contamination by domestic wastewater in the surface water and groundwater of Dongjiang River basin. Temporal and spatial variations of the detected chemicals were observed in surface water. Acesulfame, sucralose and cyclamate can be used as wastewater indicators to imply contamination in groundwater caused by domestic wastewater due to their hydrophilicity, anthropogenic sources and ubiquity in groundwater. Moreover, the detection of the readily degradable ASs, cyclamate, was a strong indication of untreated wastewater in groundwater. Sucralose was found to be a suitable wastewater indicator to reflect domestic wastewater contamination in surface water and groundwater qualitatively and quantitatively, and it can be used to evaluate wastewater burden in surface water and groundwater of Dongjiang River basin. The wastewater burden data from this survey implied serious contamination in surface water and groundwater by domestic wastewater at Shima River, a tributary of the Dongjiang River. The findings from this study suggest that the selected labile and conservative chemicals can be used as indication of wastewater contamination for aquatic environments qualitatively and quantitatively. Copyright © 2017 Elsevier B.V. All rights reserved.

Fecal pollution source tracking toolbox for identification, evaluation and characterization of fecal contamination in receiving urban surface waters and groundwater.

Science.gov (United States)

Tran, Ngoc Han; Gin, Karina Yew-Hoong; Ngo, Huu Hao

2015-12-15

The quality of surface waters/groundwater of a geographical region can be affected by anthropogenic activities, land use patterns and fecal pollution sources from humans and animals. Therefore, the development of an efficient fecal pollution source tracking toolbox for identifying the origin of the fecal pollution sources in surface waters/groundwater is especially helpful for improving management efforts and remediation actions of water resources in a more cost-effective and efficient manner. This review summarizes the updated knowledge on the use of fecal pollution source tracking markers for detecting, evaluating and characterizing fecal pollution sources in receiving surface waters and groundwater. The suitability of using chemical markers (i.e. fecal sterols, fluorescent whitening agents, pharmaceuticals and personal care products, and artificial sweeteners) and/or microbial markers (e.g. F+RNA coliphages, enteric viruses, and host-specific anaerobic bacterial 16S rDNA genetic markers) for tracking fecal pollution sources in receiving water bodies is discussed. In addition, this review also provides a comprehensive approach, which is based on the detection ratios (DR), detection frequencies (DF), and fate of potential microbial and chemical markers. DR and DF are considered as the key criteria for selecting appropriate markers for identifying and evaluating the impacts of fecal contamination in surface waters/groundwater. Copyright © 2015 Elsevier B.V. All rights reserved.

Indices of quality surface water bodies in the planning of water resources

Directory of Open Access Journals (Sweden)

Rodríguez-Miranda, Juan Pablo

2016-12-01

Full Text Available This paper considers a review of the literature major and significant methods of quality indices of water applied in surface water bodies, used and proposed for assessing the significance of parameters of water quality in the assessment of surface water currents and they are usually used in making decisions for intervention and strategic prevention measures for those responsible for the conservation and preservation of watersheds where these water bodies belong. An exploratory methodology was applied to realize the conceptualization of each water quality index. As a result, it is observed that there are several important methods for determining the water quality index applied in surface water bodies.

Chemical sensitivity of InP/In0.48Ga0.52P surface quantum dots studied by time-resolved photoluminescence spectroscopy

International Nuclear Information System (INIS)

De Angelis, Roberta; Casalboni, Mauro; De Matteis, Fabio; Hatami, Fariba; Masselink, William T.; Zhang, Hong; Prosposito, Paolo

2015-01-01

InP/InGaP surface quantum dots represent an attractive material for optical chemical sensors since they show a remarkable near infra-red emission at room temperature, whose intensity increases rapidly and reversibly depending on the composition of the environmental atmosphere. We show here their emission properties by time resolved photoluminescence spectroscopy investigation. Photoluminescence transients with and without chemical solvent vapours (methanol, clorophorm, acetone and water) were fitted with a 3-exponential decay law with times of about 0.5 ns, 2 ns and 7 ns. The measurements revealed a weak effect on clorophorm, acetone and water, while the initial decay time of InP surface quantum dots increases (up to 15%) upon methanol vapour exposure, indicating that the organic molecules efficiently saturate QD non-radiative surface states. - Highlights: • InP SQDs emission depends on the presence of solvent vapours in the atmosphere. • TR photoluminescence transients were fitted with a 3-exponential decay law. • The initial decay time increases (up to 15%) upon methanol vapour exposure. • Organic molecules efficiently saturate QD non-radiative surface states.

Preparation and characterization of soy protein films with a durable water resistance-adjustable and antimicrobial surface.

Science.gov (United States)

Li, Shuzhao; Donner, Elizabeth; Xiao, Huining; Thompson, Michael; Zhang, Yachuan; Rempel, Curtis; Liu, Qiang

2016-12-01

A water resistant surface was first obtained by immobilizing hydrophobic copolymers, poly (styrene-co-glycidyl methacrylate) (PSG), with functional groups on soy protein isolate (SPI) films. XPS and AFM results showed that PSG copolymers were immobilized on the film by chemical bonding, and formed a rough surface with some bumps because of the segregation of two different phases on PSG copolymers. Water resistance of the modified films could be adjusted dramatically by further immobilizing different amounts of guanidine-based antimicrobial polymers, poly (hexamethylene guanidine hydrochloride) (PHMG) on the resulting hydrophobic surface. The introduction of hydrophilic PHMG on the resulting surface generated many micropores, which potentially increased the water uptake of the modified films. Furthermore, the modified SPI films showed higher thermostability compared to native SPI film and broad-spectrum antimicrobial activity by contact killing, attributed to the presence of PHMG on the surface. The modified SPI film with a multi-functional surface showed potential for applications in the packaging and medical fields. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

MSINDO quantum chemical modeling study of water molecule adsorption at nano-sized anatase TiO2 surfaces

International Nuclear Information System (INIS)

Wahab, Hilal S.; Bredow, Thomas; Aliwi, Salah M.

2008-01-01

In this work, we studied the adsorption of water molecule onto the (1 0 0), (0 1 0) and (0 0 1) surfaces of nano-sized anatase TiO 2 with semiempirical SCF MO method, MSINDO. The anatase TiO 2 particles are modeled with free clusters (TiO 2 ) n, where n = 20-80. Whereas, the surfaces have been modeled with two saturated clusters, Ti 21 O 58 H 32 and Ti 36 O 90 H 36 . The surface lattice fivefold coordinated titanium atoms (Ti 5C ), which represent the Lewis acid sites, are selected as adsorption centers. We also investigated the effect of TiO 2 cluster size on the computed band gap energy. Results reveal that the electronic properties of a cluster in the lowest excited state differ from that of the ground state. Furthermore, the MSINDO band gap energies of 3.68-3.77 eV for the anatase TiO 2 are in a fair accordance with other literature data. In agreement with other computational and experimental studies, the dissociated form of water molecule adsorption on anatase TiO 2 surfaces is always more stabilized than the molecular form

Forensic collection of trace chemicals from diverse surfaces with strippable coatings.

Science.gov (United States)

Jakubowski, Michael J; Beltis, Kevin J; Drennan, Paul M; Pindzola, Bradford A

2013-11-07

Surface sampling for chemical analysis plays a vital role in environmental monitoring, industrial hygiene, homeland security and forensics. The standard surface sampling tool, a simple cotton gauze pad, is failing to meet the needs of the community as analytical techniques become more sensitive and the variety of analytes increases. In previous work, we demonstrated the efficacy of non-destructive, conformal, spray-on strippable coatings for chemical collection from simple glass surfaces. Here we expand that work by presenting chemical collection at a low spiking level (0.1 g m(-2)) from a diverse array of common surfaces - painted metal, engineering plastics, painted wallboard and concrete - using strippable coatings. The collection efficiency of the strippable coatings is compared to and far exceeds gauze pads. Collection from concrete, a particular challenge for wipes like gauze, averaged 73% over eight chemically diverse compounds for the strippable coatings whereas gauze averaged 10%.

Hydraulic "fracking": are surface water impacts an ecological concern?

Science.gov (United States)

Burton, G Allen; Basu, Niladri; Ellis, Brian R; Kapo, Katherine E; Entrekin, Sally; Nadelhoffer, Knute

2014-08-01

Use of high-volume hydraulic fracturing (HVHF) in unconventional reservoirs to recover previously inaccessible oil and natural gas is rapidly expanding in North America and elsewhere. Although hydraulic fracturing has been practiced for decades, the advent of more technologically advanced horizontal drilling coupled with improved slickwater chemical formulations has allowed extensive natural gas and oil deposits to be recovered from shale formations. Millions of liters of local groundwaters are utilized to generate extensive fracture networks within these low-permeability reservoirs, allowing extraction of the trapped hydrocarbons. Although the technology is relatively standardized, the geographies and related policies and regulations guiding these operations vary markedly. Some ecosystems are more at risk from these operations than others because of either their sensitivities or the manner in which the HVHF operations are conducted. Generally, the closer geographical proximity of the susceptible ecosystem to a drilling site or a location of related industrial processes, the higher the risk of that ecosystem being impacted by the operation. The associated construction of roads, power grids, pipelines, well pads, and water-extraction systems along with increased truck traffic are common to virtually all HVHF operations. These operations may result in increased erosion and sedimentation, increased risk to aquatic ecosystems from chemical spills or runoff, habitat fragmentation, loss of stream riparian zones, altered biogeochemical cycling, and reduction of available surface and hyporheic water volumes because of withdrawal-induced lowering of local groundwater levels. The potential risks to surface waters from HVHF operations are similar in many ways to those resulting from agriculture, silviculture, mining, and urban development. Indeed, groundwater extraction associated with agriculture is perhaps a larger concern in the long term in some regions. Understanding the

Biomimetic hydrophobic surface fabricated by chemical etching method from hierarchically structured magnesium alloy substrate

Energy Technology Data Exchange (ETDEWEB)

Liu, Yan; Yin, Xiaoming; Zhang, Jijia [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Wang, Yaming [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Han, Zhiwu, E-mail: zwhan@jlu.edu.cn [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Ren, Luquan [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China)

2013-09-01

As one of the lightest metal materials, magnesium alloy plays an important role in industry such as automobile, airplane and electronic product. However, magnesium alloy is hindered due to its high chemical activity and easily corroded. Here, inspired by typical plant surfaces such as lotus leaves and petals of red rose with super-hydrophobic character, the new hydrophobic surface is fabricated on magnesium alloy to improve anti-corrosion by two-step methodology. The procedure is that the samples are processed by laser first and then immersed and etched in the aqueous AgNO{sub 3} solution concentrations of 0.1 mol/L, 0.3 mol/L and 0.5 mol/L for different times of 15 s, 40 s and 60 s, respectively, finally modified by DTS (CH{sub 3}(CH{sub 2}){sub 11}Si(OCH{sub 3}){sub 3}). The microstructure, chemical composition, wettability and anti-corrosion are characterized by means of SEM, XPS, water contact angle measurement and electrochemical method. The hydrophobic surfaces with microscale crater-like and nanoscale flower-like binary structure are obtained. The low-energy material is contained in surface after DTS treatment. The contact angles could reach up to 138.4 ± 2°, which hydrophobic property is both related to the micro–nano binary structure and chemical composition. The results of electrochemical measurements show that anti-corrosion property of magnesium alloy is improved. Furthermore, our research is expected to create some ideas from natural enlightenment to improve anti-corrosion property of magnesium alloy while this method can be easily extended to other metal materials.

Chemical speciation of Pu in natural waters

International Nuclear Information System (INIS)

Nelson, D.M.; Larsen, R.P.; Penrose, W.R.

1983-01-01

The behavior of plutonium in natural waters is determined to a major degree by the chemical forms which are present. We have characterized the ambient Pu in a number of surface waters with regard to its oxidation state and association with natural colloidal organic carbon compounds using a combination of field measurements and laboratory experiments. Both of these factors are shown to have a profound effect on the adsorption of Pu to natural sediments, since both complexation with organic matter and oxidation compete with adsorption. The concentration of organic carbon in the water is the key variable influencing both oxidation state and organic binding. The adsorption process conforms to the laws applicable to a reversible equilibrium with values of the distribution coefficient, K/sub D/, measured in laboratory experiments being similar to those observed for ambient Pu. Experiments using natural waters and sediments in which the Pu concentration was varied show the forms present at typical ambient concentrations (10 -17 - 10 -14 M) are the same as those found at concentrations up to 10 -7 M. Moreover, the affinity for sediments did not change with concentration indicating the binding sites for Pu had not become saturated. Thus, the behavior observed for Pu at ultratrace concentrations should remain unchanged throughout this concentration range. The studies in this report all deal with Pu in exchangeable (and hence source independent) forms and should therefore reflect the behavior toward which the plutonium from any source will tend with time. 13 references, 7 figures, 10 tables

Effect of Lakhara chemical power station (LPTS) effluents on the river Indus water quality

International Nuclear Information System (INIS)

Mahar, R.B.; Memon, H.M.; Khushwar, M.Y.

2000-01-01

The variation of the quality of river Indus water with respect to the seasonal changes, discharge of water and dilution with the effluents of Lakhra Thermal Power Station (LTPS), has been monitored. The studies were focussed on the river Indus water quality before and after mixing the effluents of the power station. The samples were collected monthly from the representative locations of the river Indus, and analyzed for the residues (total, filterable, non-filterable, volatile and fixed), pH, temperature (air and water), conductance, chloride, hardness, alkalinity, dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD) /sub 5/- nitrate, phosphate, sulfate, ammonia, ammonium, silicates, magnesium, potassium, calcium and sodium. The results have been compared with the permissible limits of ECC (European Economic Community) standards for drinking and surface water. (author)

Evaluation of water quality and hydrogeochemistry of surface and groundwater, Tiruvallur District, Tamil Nadu, India

Science.gov (United States)

Krishna Kumar, S.; Hari Babu, S.; Eswar Rao, P.; Selvakumar, S.; Thivya, C.; Muralidharan, S.; Jeyabal, G.

2017-09-01

Water quality of Tiruvallur Taluk of Tiruvallur district, Tamil Nadu, India has been analysed to assess its suitability in relation to domestic and agricultural uses. Thirty water samples, including 8 surface water (S), 22 groundwater samples [15 shallow ground waters (SW) and 7 deep ground waters (DW)], were collected to assess the various physico-chemical parameters such as Temperature, pH, Electrical conductivity (EC), Total dissolved solids (TDS), cations (Ca, Mg, Na, K), anions (CO3, HCO3, Cl, SO4, NO3, PO4) and trace elements (Fe, Mn, Zn). Various irrigation water quality diagrams and parameters such as United states salinity laboratory (USSL), Wilcox, sodium absorption ratio (SAR), sodium percentage (Na %), Residual sodium carbonate (RSC), Residual Sodium Bicarbonate (RSBC) and Kelley's ratio revealed that most of the water samples are suitable for irrigation. Langelier Saturation Index (LSI) values suggest that the water is slightly corrosive and non-scale forming in nature. Gibbs plot suggests that the study area is dominated by evaporation and rock-water dominance process. Piper plot indicates the chemical composition of water, chiefly controlled by dissolution and mixing of irrigation return flow.

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

Science.gov (United States)

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.

Influence of surface water accumulations of the Stupnica creek on underground coal mining in the Durdevic coal mine

Energy Technology Data Exchange (ETDEWEB)

Valjarevic, R; Urosevic, V

1986-01-01

Discusses hydrological, geological and mining conditions at the Durdevic underground coal mine. A landslide at a spoil bank dammed the creek flowing above the mine. Two exploratory boreholes (62 m and 68 m) were drilled for hydrological investigations. Water coloring techniques, chemical water analysis, measurement of underground water level and water flow were used to determine whether a sudden inrush of rainfall and accumulated surface water could endanger the mine. Underground water inflow to mine rooms varies from 110-200 m/sup 3//min, depending on the season. Diversion of the creek bed with the accumulated water and accumulation and subsequent drainage of surface water via large diameter concrete pipes were considered as possible ways of improving safety in the mine. Details of these projects are included. 4 refs.

Convergent surface water distributions in U.S. cities

Science.gov (United States)

M.K. Steele; J.B. Heffernan; N. Bettez; J. Cavender-Bares; P.M. Groffman; J.M. Grove; S. Hall; S.E. Hobbie; K. Larson; J.L. Morse; C. Neill; K.C. Nelson; J. O' Neil-Dunne; L. Ogden; D.E. Pataki; C. Polsky; R. Roy Chowdhury

2014-01-01

Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and...

Monitoring of Water and Contaminant Migration at the Groundwater-Surface Water Interface

Science.gov (United States)

2008-08-01

seepage is occurring in a freshwater lake environment and to map the lateral extent of any subsurface contamination at the groundwater –surface water ...and Contaminant Migration at the Groundwater -Surface Water Interface August 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Monitoring of Water and Contaminant Migration at the Groundwater -Surface Water Interface 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Characterization of Drain Surface Water: Environmental Profile, Degradation Level and Geo-statistic Monitoring

International Nuclear Information System (INIS)

Mumtaz, M.W.; Raza, M.A.; Ahmed, Z.; Abbas, M.N.; Hussain, M.

2015-01-01

The physico-chemical characterization of the surface water. Samples was carried out collected from nine sampling points of drain passing by the territory of Hafizabad city, Punjab, Pakistan. The water of drain is used by farmers for irrigation purposes in nearby agricultural fields. Twenty water quality parameters were evaluated in three turns and the results obtained were compared with the National Environmental Quality Standards (NEQS) municipal and industrial effluents prescribed limits. The highly significant difference (p<0.01) was recorded for the content of phenols, carbonyl compounds, cyanides, dissolved oxygen, biological oxygen demand, total soluble salts, total dissolved salts, nitrates and sulphates, whereas, the concentration of magnesium, potassium and oil and grease differed significantly (p<0.05) with respect to the sampling points on average basis. Non-significant difference (p>0.05) was noted for temperature, pH, electrical conductivity, hardness, calcium, sodium, chemical oxygen demand and chloride among water samples from different sampling points. Furthermore, the experimental results of different water quality parameters studied at nine sampling points of the drain were used and interpolated in ArcGIS 9.3 environment system using kriging techniques to obtain calculated values for the remaining locations of the Drain. (author)

Influence of Chemical Surface Modification of Woven Fabrics on Ballistic and Stab Protection of Multilayer Packets

Directory of Open Access Journals (Sweden)

Diana GRINEVIČIŪTĖ

2014-06-01

Full Text Available In order to achieve enhanced protective and wear (flexibility, less bulkiness properties of ballistic and stab protecting panels the investigation of chemical surface modification of woven p-aramid fabrics was performed applying different chemical composition shear thickening fluid (STF which improves friction inside fabric structure. For the chemical treatment silicic acid and acrylic dispersion water solutions were used and influence of their different concentrations on panels’ protective properties were investigated. Results of ballistic tests of multilayer protective panel have revealed that shear thickening effect was negligible when shooting at high energy range (E > 440 J. Determination of stab resistance of p-aramid panels has shown that different chemical composition of STFs had different influence on protective properties of the panels. Application of low concentrations of silicic acid determined higher stab resistance values comparing to higher concentrations of acrylic dispersion water solutions. At this stage of research stab tests results as ballistic ones determined that STF application for multilayer p-aramid fabrics protective panels is more efficient at low strike energy levels. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.3138

Metals content in surface waters of an upwelling system of the northern Humboldt Current (Mejillones Bay, Chile)

Science.gov (United States)

Valdés, Jorge; Román, Domingo; Alvarez, Gabriel; Ortlieb, Luc; Guiñez, Marcos

Physical-chemical parameters (temperature, salinity, dissolved oxygen, nutrients, and chlorophyll concentration) of surface waters were used to evaluate the influence of biological and physical processes over the metal concentrations (Cd, Ni, V, Mo, Mn, and Fe) in different periods of a normal annual cycle (June 2002 and April 2003), in Mejillones Bay (23° S), one of northern Chile's strongest upwelling cells. Two points were sampled every 2 months, but statistical analysis of these parameters did not show any spatial differences in surface water composition (annual average) in this bay. The order of total and dissolved metals by abundance (annual mean) in the Mejillones Bay surface waters during the sampling period was Cd Oxygen Minimum Zone which characterizes the Mejillones bay should have an important influence on surface distribution of trace metals and can explain the high temporal variability observed in most of the metals analyzed in this work. A two-box conceptual model is proposed to suggest possible influences on metals in surface waters of this coastal ecosystem.

Chemical water shutoff profile research status and development trends

Science.gov (United States)

Xu, L. T.

2017-08-01

Excess water production is now a common problem encountered in almost every water flooding mature oilfield. The exploitation of oil field is faced with great challenge because of the decrease of oil field production. For the development of high water cut rare the status quo chemical water shutoff profile control technology is an important solution to solve this problem. Oilfield chemical water shutoff has important application prospects. This paper analyzes the water shutoff profile control and water shutoff profile control agent currently oilfield applications, moreover the use and development of blocking agent profile technology is to improve reservoir recovery and propose solutions. With the constant increase in water cut, profile technology should be simple, efficient, practical and profile control agent of development should be economic, environmental, and long period

Evaluation of surface water treatment and discharge options for the Weldon Spring Site Remedial Action Project

International Nuclear Information System (INIS)

Goyette, M.L.; MacDonell, M.M.

1992-01-01

The US Department of Energy (DOE), under its Environmental Restoration and Waste Management Program, is responsible for conducting response actions at the Weldon Spring site in St. Charles County, Missouri. The site consists of two noncontiguous areas: (1) the chemical plant area, which includes four raffinate pits and two small ponds, and (2) a 3.6-ha (9-acre) quarry located about 6.4 km (4 mi) southwest of the chemical plant area. Both of these areas became chemically and radioactively contaminated as a result of processing and disposal activities that took place from the 1940s through 1960s. The Weldon Spring site, located about 48 km (30 mi) west of St. Louis, is listed on the National Priorities List of the US Environmental Protection Agency. Nitroaromatic explosives were processed by the Army at the chemical plant area during the 1940s, and radioactive materials were processed by DOE's predecessor agency (the Atomic Energy Commission) during the 1950s and 1960s. Overall remediation of the Weldon Spring site is being addressed through the Weldon Spring Site Remedial Action Project, and it consists of several components. One component is the management of radioactively and chemically contaminated surface water impoundments at the chemical plant area -- i.e., the four raffinate pits, Frog Pond, and Ash Pond which was addressed under a separate action and documented in an engineering evaluation/cost analysis report. This report discusses the evaluation of surface water treatment at the Weldon Spring site

Estimation of the amount of surface contamination of a water cooled nuclear reactor by cooling water analysis

Energy Technology Data Exchange (ETDEWEB)

Nagy, G. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary)]. E-mail: nagyg@sunserv.kfki.hu; Somogyi, A. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary); Patek, G. [Paks Nuclear Power Plant, P.O. Box 71, Paks H-7031 (Hungary); Pinter, T. [Paks Nuclear Power Plant, P.O. Box 71, Paks H-7031 (Hungary); Schiller, R. [KFKI Atomic Energy Research Institute, P.O. Box 49, Budapest H-1525 (Hungary)

2007-06-15

Calculations, based upon on-the-spot measurements, were performed to estimate the contamination of NPP primary circuit and spent fuel storage pool solid surfaces via the composition of the cooling water in connection with a non-nuclear incident in the Paks NPP. Thirty partially burnt-up fuel element bundles were damaged during a cleaning process, an incident which resulted in the presence of fission products in the cooling water of the cleaning tank (CT) situated in a separate pool (P1). Since this medium was in contact for an extended period of time with undamaged fuel elements to be used later and also with other structural materials of the spent fuel storage pool (SP), it was imperative to assess the surface contamination of these latter ones with a particular view to the amount of fission material. In want of direct methods, one was restricted to indirect information which rested mainly on the chemical and radiochemical data of the cooling water. It was found that (i) the most important contaminants were uranium, plutonium, cesium and cerium; (ii) after the isolation of P1 and SP and an extended period of filtering the only important contaminants were uranium and plutonium; (iii) the surface contamination of the primary circuit (PC) was much lower than that of either SP or P1; (iv) some 99% of the contamination was removed from the water by the end of the filtering process.

Influence of surface coverage on the chemical desorption process

Energy Technology Data Exchange (ETDEWEB)

Minissale, M.; Dulieu, F., E-mail: francois.dulieu@obspm.fr [LERMA, Université de Cergy Pontoise et Observatoire de Paris, UMR 8112 du CNRS. 5, mail Gay Lussac, 95031 Cergy Pontoise (France)

2014-07-07

In cold astrophysical environments, some molecules are observed in the gas phase whereas they should have been depleted, frozen on dust grains. In order to solve this problem, astrochemists have proposed that a fraction of molecules synthesized on the surface of dust grains could desorb just after their formation. Recently the chemical desorption process has been demonstrated experimentally, but the key parameters at play have not yet been fully understood. In this article, we propose a new procedure to analyze the ratio of di-oxygen and ozone synthesized after O atoms adsorption on oxidized graphite. We demonstrate that the chemical desorption efficiency of the two reaction paths (O+O and O+O{sub 2}) is different by one order of magnitude. We show the importance of the surface coverage: for the O+O reaction, the chemical desorption efficiency is close to 80% at zero coverage and tends to zero at one monolayer coverage. The coverage dependence of O+O chemical desorption is proved by varying the amount of pre-adsorbed N{sub 2} on the substrate from 0 to 1.5 ML. Finally, we discuss the relevance of the different physical parameters that could play a role in the chemical desorption process: binding energy, enthalpy of formation, and energy transfer from the new molecule to the surface or to other adsorbates.

Luminescent, water-soluble silicon quantum dots via micro-plasma surface treatment

International Nuclear Information System (INIS)

Wu, Jeslin J; Siva Santosh Kumar Kondeti, Vighneswara; Bruggeman, Peter J; Kortshagen, Uwe R

2016-01-01

Silicon quantum dots (SiQDs), with their broad absorption, narrow and size-tunable emission, and potential biocompatibility are highly attractive materials in biological imaging applications. The inherent hydrophobicity and instability of hydrogen-terminated SiQDs are obstacles to their widespread implementation. In this work, we successfully produced highly luminescent, hydrophilic SiQDs with long-term stability in water using non-thermal plasma techniques. Hydrogen-terminated SiQDs were produced in a low-pressure plasma and subsequently treated in water using an atmospheric-pressure plasma jet for surface modification. Preliminary assessments of the chemical mechanism(s) involved in the creation of water-soluble SiQDs were performed using Fenton’s reaction and various plasma chemistries, suggesting both OH and O species play a key role in the oxidation of the SiQDs. (letter)

Carcinogenic and mutagenic properties of chemicals in drinking water

Energy Technology Data Exchange (ETDEWEB)

Bull, R J

1985-12-01

Isolated cases of careless handling of industrial and domestic waste has lead to a wide variety of dangerous chemicals being inadvertently introduced into drinking water. However, chemicals with established carcinogenic and mutagenic properties that occur with a high frequency and in multiple locations are limited in number. To date, the chief offenders have been chemicals of relatively low carcinogenic potency. Some of the more common chemicals are formed as by-products of disinfection. The latter process is generally regarded as essential to the production of a ''microbiologically safe'' drinking water. Consequently, any reductions in what may be a relatively small carcinogenic risk must be balanced against a potential for a higher frequency of waterborne infectious disease. The results of recent toxicological investigations will be reviewed to place the potential carcinogenic and mutagenic hazards frequently associated with drinking water into perspective. First, evidence for the carcinogenicity of certain volatile organic compounds such as trichloroethylene, tetrachloroethylene and carbon tetrachloride is considered. Second, the carcinogenic activity that can be ascribed to various by-products of chlorination is reviewed in some detail. Finally, recent evidence that other chemicals derived from the treatment and distribution of drinking water is highlighted as an area requiring move systematic attention. 72 references.

Chemical and microbial characteristics of municipal drinking water supply systems in the Canadian Arctic

DEFF Research Database (Denmark)

Daley, Kiley; Hansen, Lisbeth Truelstrup; Jamieson, Rob C.

2017-01-01

plumbing) could be contributing to Pb, Cu and Fe levels, as the source water in three of the four communities had low alkalinity. The results point to the need for robust disinfection, which may include secondary disinfection or point-of-use disinfection, to prevent microbial risks in drinking water tanks......Drinking water in the vast Arctic Canadian territory of Nunavut is sourced from surface water lakes or rivers and transferred to man-made or natural reservoirs. The raw water is at a minimum treated by chlorination and distributed to customers either by trucks delivering to a water storage tank...... inside buildings or through a piped distribution system. The objective of this study was to characterize the chemical and microbial drinking water quality from source to tap in three hamlets (Coral Harbour, Pond Inlet and Pangnirtung-each has a population of 0.2 mg/L free chlorine). Some buildings...

Polydimethylsiloxane-Based Superhydrophobic Surfaces on Steel Substrate: Fabrication, Reversibly Extreme Wettability and Oil-Water Separation.

Science.gov (United States)

Su, Xiaojing; Li, Hongqiang; Lai, Xuejun; Zhang, Lin; Liang, Tao; Feng, Yuchun; Zeng, Xingrong

2017-01-25

Functional surfaces for reversibly switchable wettability and oil-water separation have attracted much interest with pushing forward an immense influence on fundamental research and industrial application in recent years. This article proposed a facile method to fabricate superhydrophobic surfaces on steel substrates via electroless replacement deposition of copper sulfate (CuSO 4 ) and UV curing of vinyl-terminated polydimethylsiloxane (PDMS). PDMS-based superhydrophobic surfaces exhibited water contact angle (WCA) close to 160° and water sliding angle (WSA) lower than 5°, preserving outstanding chemical stability that maintained superhydrophobicity immersing in different aqueous solutions with pH values from 1 to 13 for 12 h. Interestingly, the superhydrophobic surface could dramatically switch to the superhydrophilic state under UV irradiation and then gradually recover to the highly hydrophobic state with WCA at 140° after dark storage. The underlying mechanism was also investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Additionally, the PDMS-based steel mesh possessed high separation efficiency and excellent reusability in oil-water separation. Our studies provide a simple, fast, and economical fabrication method for wettability-transformable superhydrophobic surfaces and have the potential applications in microfluidics, the biomedical field, and oil spill cleanup.

Physico-Chemical Characterization and Pollution Index ...

African Journals Online (AJOL)

MICHAEL HORSFALL

bodies; groundwater and surface water (Slomwcznska ... may then enter the environment and pollute the surrounding water ... In order to avoid chemical and biological changes that have the ..... disposal of treated leachates to inland surface water .... India. 3(5): 147-153. Kumar, D., and Alappat, B. J. (2003b). A technique.

Underground coal mine subsidence impacts on surface water

International Nuclear Information System (INIS)

Stump, D.E. Jr.

1992-01-01

This paper reports that subsidence from underground coal mining alters surface water discharge and availability. The magnitude and areal extent of these impacts are dependent on many factors, including the amount of subsidence, topography, geology, climate, surface water - ground water interactions, and fractures in the overburden. There alterations may have positive and/or negative impacts. One of the most significant surface water impacts occurred in July 1957 near West Pittston, Pennsylvania. Subsidence in the Knox Mine under the Coxton Yards of the Lehigh Valley Railroad allowed part of the discharge in the Susquehanna River to flow into the mine and create a crater 200 feet in diameter and 300 feet deep. Fourteen railroad gondola cars fell into the hole which was eventually filled with rock, sand, and gravel. Other surface water impacts from subsidence may include the loss of water to the ground water system, the gaining of water from the ground water system, the creation of flooded subsidence troughs, the increasing of impoundment storage capacity, the relocation of water sources (springs), and the alteration of surface drainage patterns

Spatially telescoping measurements for improved characterization of groundwater-surface water interactions

Science.gov (United States)

Kikuchi, Colin; Ferre, Ty P.A.; Welker, Jeffery M.

2012-01-01

The suite of measurement methods available to characterize fluxes between groundwater and surface water is rapidly growing. However, there are few studies that examine approaches to design of field investigations that include multiple methods. We propose that performing field measurements in a spatially telescoping sequence improves measurement flexibility and accounts for nested heterogeneities while still allowing for parsimonious experimental design. We applied this spatially telescoping approach in a study of ground water-surface water (GW-SW) interaction during baseflow conditions along Lucile Creek, located near Wasilla, Alaska. Catchment-scale data, including channel geomorphic indices and hydrogeologic transects, were used to screen areas of potentially significant GW-SW exchange. Specifically, these data indicated increasing groundwater contribution from a deeper regional aquifer along the middle to lower reaches of the stream. This initial assessment was tested using reach-scale estimates of groundwater contribution during baseflow conditions, including differential discharge measurements and the use of chemical tracers analyzed in a three-component mixing model. The reach-scale measurements indicated a large increase in discharge along the middle reaches of the stream accompanied by a shift in chemical composition towards a regional groundwater end member. Finally, point measurements of vertical water fluxes -- obtained using seepage meters as well as temperature-based methods -- were used to evaluate spatial and temporal variability of GW-SW exchange within representative reaches. The spatial variability of upward fluxes, estimated using streambed temperature mapping at the sub-reach scale, was observed to vary in relation to both streambed composition and the magnitude of groundwater contribution from differential discharge measurements. The spatially telescoping approach improved the efficiency of this field investigation. Beginning our assessment

Chemical Reactions at Surfaces. Final Progress Report

Energy Technology Data Exchange (ETDEWEB)

Freud, Hans-Joachim [Max-Planck-Gesellschaft, Berlin (Germany). Fritz-Haber-Inst.

2003-02-21

The Gordon Research Conference (GRC) on Chemical Reactions at Surfaces was held at Holiday Inn, Ventura, California, 2/16-21/03. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

Chemical oxygen demand (cod) attenuation of methyl red in water ...

African Journals Online (AJOL)

Chemical oxygen demand (cod) attenuation of methyl red in water using biocarbons obtained from Nipa palm leaves. ... eco-friendly and locally accessible biocarbon for mitigation of organic contaminants in water. Keywords: Chemical oxygen demand, biocarbon, methyl red, biodegradation, bioremediation, Nipa palm ...

Investigation of the potential influence of production treatment chemicals on produced water toxicity

International Nuclear Information System (INIS)

Stine, E.R.; Gala, W.R.; Henry, L.R.

1993-01-01

Production treatment chemicals represent a diverse collection of chemical classes, added at various points from the wellhead to the final flotation cell, to prevent operational upsets and enhance the separation of oil from water. Information in the literature indicates that while many treatment chemicals are thought to partition into oil and not into the produced water, there are cases where a sufficiently water soluble treatment chemical is added at high enough concentrations to suggest that the treatment chemical may add to the aquatic toxicity of the produced water. A study was conducted to evaluate the potential effect of production treatment chemicals on the toxicity of produced waters using the US EPA Seven-day Mysidopsis bahia Survival, Growth and Fecundity Test. Samples of produced water were collected and tested for toxicity from three platforms under normal operating conditions, followed by repeated sampling and testing after a 72-hour period in which treatment chemical usage was discontinued, to the degree possible. Significant reductions in produced water toxicity were observed for two of the three platforms tested following either cessation of treatment chemical usage, or by comparing the toxicity of samples collected upstream and downstream of the point of treatment chemical addition

Oxide/water interfaces: how the surface chemistry modifies interfacial water properties

International Nuclear Information System (INIS)

Gaigeot, Marie-Pierre; Sprik, Michiel; Sulpizi, Marialore

2012-01-01

The organization of water at the interface with silica and alumina oxides is analysed using density functional theory-based molecular dynamics simulation (DFT-MD). The interfacial hydrogen bonding is investigated in detail and related to the chemistry of the oxide surfaces by computing the surface charge density and acidity. We find that water molecules hydrogen-bonded to the surface have different orientations depending on the strength of the hydrogen bonds and use this observation to explain the features in the surface vibrational spectra measured by sum frequency generation spectroscopy. In particular, ‘ice-like’ and ‘liquid-like’ features in these spectra are interpreted as the result of hydrogen bonds of different strengths between surface silanols/aluminols and water. (paper)

Adhesive and morphological characteristics of surface chemically modified polytetrafluoroethylene films

International Nuclear Information System (INIS)

Hopp, B.; Kresz, N.; Kokavecz, J.; Smausz, T.; Schieferdecker, H.; Doering, A.; Marti, O.; Bor, Z.

2004-01-01

In the present paper, we report an experimental determination of adhesive and topographic characteristics of chemically modified surface of polytetrafluoroethylene (PTFE) films. The surface chemistry was modified by ArF excimer laser irradiation in presence of triethylene-tetramine photoreagent. The applied laser fluence was varied in the range of 0.4-9 mJ/cm 2 , and the number of laser pulses incident on the same area was 1500. To detect the changes in the adhesive features of the treated Teflon samples, we measured receding contact angle for distilled water and adhesion strength, respectively. It was found that the receding contact angle decreased from 96 deg. to 30-37 deg. and the adhesion strength of two-component epoxy glue to the treated sample surface increased from 0.03 to 9 MPa in the applied laser fluence range. Additionally, it was demonstrated that the adhesion of human cells to the modified Teflon samples is far better than to the untreated ones. The contact mode and pulsed force mode atomic force microscopic investigations of the treated samples demonstrated that the measured effective contact area of the irradiated films does not differ significantly from that of the original films, but the derived adhesion force is stronger on the modified samples than on the untreated ones. Hence, the increased adhesion of the treated Teflon films is caused by the higher surface energy

Chemical characteristics of surface systems in the Forsmark area. Visualisation and statistical evaluation of data from shallow groundwater, precipitation, and regolith

International Nuclear Information System (INIS)

Troejbom, Mats; Soederbaeck, Bjoern

2006-02-01

The Swedish Nuclear Fuel and Waste management Co (SKB) initiated site investigations for a deep repository for spent nuclear fuel at two different sites in Sweden, Forsmark and Oskarshamn, in 2002. This report evaluates the results from chemical investigations of the surface system in the Forsmark area during the period November 2002 - March 2005. The evaluation includes data from surface waters (lakes, streams and the sea), precipitation, shallow groundwater and regolith (till, soil, peat, sediments and biota) in the area. Results from surface waters are not presented in this report since these were treated in a recently published report. The main focus of the study is to visualize the vast amount of data collected hitherto in the site investigations, and to give a chemical characterisation of the investigated media at the site. The results will be used to support the site descriptive models, which in turn are used for safety assessment studies and for the environmental impact assessment. The data used consist of water chemical composition in lakes, streams, coastal sites, and in precipitation, predominantly sampled on a monthly basis, and in groundwater from soil tubes and wells, sampled up to four times per year. Moreover, regolith data includes information on the chemical composition of till, soil, sediment and vegetation samples from the area. The characterisations include all measured chemical parameters, i.e. major and minor constituents, trace elements, nutrients, isotopes and radio nuclides, as well as field measured parameters. The evaluation of data from each medium has been divided into the following parts: Characterisation of individual sampling sites, and comparisons within and among sampling sites as well as comparisons with local, regional and national reference data; Analysis of time trends and seasonal variation (for shallow groundwater); Exploration of relationships among the various chemical parameters. For all investigated parameters, the

Water's Interfacial Hydrogen Bonding Structure Reveals the Effective Strength of Surface-Water Interactions.

Science.gov (United States)

Shin, Sucheol; Willard, Adam P

2018-06-05

We combine all-atom molecular dynamics simulations with a mean field model of interfacial hydrogen bonding to analyze the effect of surface-water interactions on the structural and energetic properties of the liquid water interface. We show that the molecular structure of water at a weakly interacting ( i.e., hydrophobic) surface is resistant to change unless the strength of surface-water interactions are above a certain threshold. We find that below this threshold water's interfacial structure is homogeneous and insensitive to the details of the disordered surface, however, above this threshold water's interfacial structure is heterogeneous. Despite this heterogeneity, we demonstrate that the equilibrium distribution of molecular orientations can be used to quantify the energetic component of the surface-water interactions that contribute specifically to modifying the interfacial hydrogen bonding network. We identify this specific energetic component as a new measure of hydrophilicity, which we refer to as the intrinsic hydropathy.

Effect-based trigger values for in vitro and in vivo bioassays performed on surface water extracts supporting the environmental quality standards (EQS) of the European Water Framework Directive.

Science.gov (United States)

Escher, Beate I; Aїt-Aїssa, Selim; Behnisch, Peter A; Brack, Werner; Brion, François; Brouwer, Abraham; Buchinger, Sebastian; Crawford, Sarah E; Du Pasquier, David; Hamers, Timo; Hettwer, Karina; Hilscherová, Klára; Hollert, Henner; Kase, Robert; Kienle, Cornelia; Tindall, Andrew J; Tuerk, Jochen; van der Oost, Ron; Vermeirssen, Etienne; Neale, Peta A

2018-07-01

Effect-based methods including cell-based bioassays, reporter gene assays and whole-organism assays have been applied for decades in water quality monitoring and testing of enriched solid-phase extracts. There is no common EU-wide agreement on what level of bioassay response in water extracts is acceptable. At present, bioassay results are only benchmarked against each other but not against a consented measure of chemical water quality. The EU environmental quality standards (EQS) differentiate between acceptable and unacceptable surface water concentrations for individual chemicals but cannot capture the thousands of chemicals in water and their biological action as mixtures. We developed a method that reads across from existing EQS and includes additional mixture considerations with the goal that the derived effect-based trigger values (EBT) indicate acceptable risk for complex mixtures as they occur in surface water. Advantages and limitations of various approaches to read across from EQS are discussed and distilled to an algorithm that translates EQS into their corresponding bioanalytical equivalent concentrations (BEQ). The proposed EBT derivation method was applied to 48 in vitro bioassays with 32 of them having sufficient information to yield preliminary EBTs. To assess the practicability and robustness of the proposed approach, we compared the tentative EBTs with observed environmental effects. The proposed method only gives guidance on how to derive EBTs but does not propose final EBTs for implementation. The EBTs for some bioassays such as those for estrogenicity are already mature and could be implemented into regulation in the near future, while for others it will still take a few iterations until we can be confident of the power of the proposed EBTs to differentiate good from poor water quality with respect to chemical contamination. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of chemical treatment on surface characteristics of sputter deposited Ti-rich NiTi shape memory alloy thin-films

International Nuclear Information System (INIS)

Sharma, S.K.; Mohan, S.

2014-01-01

Graphical abstract: FTIR spectra recorded for sputter deposited (a) untreated and (b) chemically treated NiTi SMA thin-films. - Highlights: • The effect of chemical treatment on surface properties of NiTi films demonstrated. • Chemically treated films offer strong ability to form protective TiO 2 layer. • TiO 2 layer formation offer great application prospects in biomedical fields. - Abstract: NiTi thin-films were deposited by DC magnetron sputtering from single alloy target (Ni/Ti:45/55 at.%). The rate of deposition and thickness of sputter deposited films were maintained to ∼35 nm min −1 and 4 μm respectively. A set of sputter deposited NiTi films were selected for specific chemical treatment with the solution comprising of de-ionized water, HF and HNO 3 respectively. The influence of chemical treatment on surface characteristics of NiTi films before and after chemical treatment was investigated for their structure, micro-structure and composition using different analytical techniques. Prior to chemical treatment, the composition of NiTi films using energy dispersive X-ray dispersive spectroscopy (EDS), were found to be 51.8 atomic percent of Ti and 48.2 atomic percent of Ni. The structure and morphology of these films were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD investigations, demonstrated the presence of dominant Austenite (1 1 0) phase along with Martensite phase, for untreated NiTi films whereas some additional diffraction peaks viz. (1 0 0), (1 0 1), and (2 0 0) corresponding to Rutile and Anatase phase of Titanium dioxide (TiO 2 ) along with parent Austenite (1 1 0) phase were observed for chemically treated NiTi films. FTIR studies, it can be concluded that chemically treated films have higher tendency to form metal oxide/hydroxide than the untreated NiTi films. XPS investigations, demonstrated the presence of Ni-free surface and formation of a protective metal oxide (TiO 2 ) layer on the surface of

Chromium in surface water and groundwater in the surrounding area of a tannery: relationships with water quality baseline, Elena, Cordoba. Argentina

International Nuclear Information System (INIS)

Matteoda, E.; Blarasin, M.; Damilano, G.; Cabrera, A.; Giuliano Albo, J.

2009-01-01

The basin of the El Barreal stream is a dominantly rural area in which groundwater is used for all activities whereas the stream is used as sink of residues and effluents. The existence of a tannery, which discharge the effluents into a wetland (which is drained by the stream), reveals the need to study the presence of Chromium in surface and groundwater and to compare values derived from pollution with those corresponding to the natural water baseline values. Fifty three samples of surface and groundwater were abstracted and chemical analyses were made, including total Chromium in water and plants. The chemical analysis results were studied by means of conventional and statistical techniques. The local and regional geological characteristics allow us to interpret that Chromium in water is derived from source minerals, being possible to stand out that high values probably are related to nearby serpentinite bodies.The values of total chrome in surface and groundwater are included in the natural quality baseline range calculated for this basin (0,25-5ug/L), exempting those samples with higher values linked to sites with farming activities and to the wetland environment where the Chromium effluent is discharged. In the last place, Chromium was retained in soil and plants whereas the aquifer was affected by a contaminant plume of total dissolved solids because of advective-dispersive transport. In the 2009 monitoring survey, a small increase of Chromium in groundwater was detected in relation to that of 2005, being assumed that partial desorption of Chromium is taking place from the solid phase. (Author) 19 refs.

Surface water/groundwater relationship in Chaj Doab. Final report for the period November 1985 - December 1989

Energy Technology Data Exchange (ETDEWEB)

Hussain, S D [Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan)

1990-12-31

In order to understand the relationship between surface water and groundwater in Chaj Doab area, isotopic and chemical studies were undertaken. Seven sets of water samples from hand pumps, tube wells, rivers and canals were collected during the period November 1985 to October 1988 and all the samples were analysed for environmental isotopes such as {sup 2}H, {sup 3}H, {sup 18}O and the dissolved chemical constituents like Na{sup +}, K{sup +}, Ca{sup ++}, Mg{sup ++}, Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup --} and TIC. Some of the water samples having very low tritium concentrations were analysed for {sup 14}C content. Analysis for {sup 13}C values for two sets of samples was also carried out. 8 refs, 13 figs, 6 tabs.

Chemical Interaction between U(VI) and Eu(III) ions on a Silica Surface

International Nuclear Information System (INIS)

Park, K. K.; Cha, W. S.; Cho, H. R.; Im, H. J.; Jung, E. C.

2010-01-01

Understanding the chemical behavior of actinide in groundwater flow is important for assessing the possibility of its migration with water flow in the radioactive waste disposal site. Precipitation/ dissolution in groundwater and adsorption/desorption onto a geological solid surface would determine its migration. The sorption in a geochemical system was expected to be a reaction on a naturally equilibrated surface. However, the construction of a waste disposal facility could disturb this equilibrium state, induce a new reaction environment and affect a nanoscopic surface reaction of actinide. Uranium is ubiquitous in the natural environment and a representative element in a nuclear fuel cycle and in a high level radioactive waste. In oxic environments, it is typically present as uranyl oxocation (UO 2 2+ ), which is easily adsorbed and thereby removed from a solution in the near neutral pH range. This adsorption would form a new surface condition to give an unexpected adsorption behavior for other actinide ions. Eu(III) frequently is used as a chemical analogue of Am(III) and Cm(III) in migration chemistry. The adsorption phenomena has been interpreted with the help of a SCM(surface complexation model). Some spectroscopic techniques such as EPR (Electron Paramagnetic Resonance), IR (InfraRed), EXAFS (Extended X-ray Absorption Fine Structure) and TRLFS (Time Resolved Laser Fluorescence Spectroscopy) have been used for the identification of a modeled adsorbing species. In the case of fluorescence elements, TRLFS has advantages over other techniques for its high sensitivity being proportional to laser source intensity and good selectivity depending on specific transition and lifetime. This technique can be applied to a species on a solid surface not absorbing light such as silica. U(VI) and Eu(III) have fluorescente properties reflecting their coordination structure. In this study, the interaction between U(VI) and Eu(III) on a silica surface was studied by a

Bacteriological and physico-chemical quality of drinking water ...

African Journals Online (AJOL)

Background: Accesses to safe water is a universal need however, many of the world's population lack access to adequate and safe water. Consumption of water contaminated causes health risk to the public and the situation is serous in rural areas. Objectives: To assess the bacteriological and physico-chemical quality of ...

An ontology design pattern for surface water features

Science.gov (United States)

Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E.; Feng, Chen-Chieh; Usery, E. Lynn; Liebermann, Joshua; Sorokine, Alexandre

2014-01-01

Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities exist due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology for other more context-dependent ontologies. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex or specialized surface water ontologies. A fundamental distinction is made in this ontology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is implemented in OWL, but Description Logic axioms and a detailed explanation is provided in this paper. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. Also provided is a discussion of why there is a need to complement the pattern with other ontologies, especially the previously developed Surface Network pattern. Finally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through an annotated geospatial dataset and sample queries using the classes of the Surface Water pattern.

Water resources data, Iowa, water year 2001, Volume 2. surface water--Missouri River basin, and ground water

Science.gov (United States)

Nalley, G.M.; Gorman, J.G.; Goodrich, R.D.; Miller, V.E.; Turco, M.J.; Linhart, S.M.

2002-01-01

were published in 5- year series. Records of chemical quality, water temperatures, and suspended sediment were published from 1941 to 1970 in an annual series of water-supply papers entitled “Quality of Surface Waters of the United States.” Records of ground-water levels were published from 1935 to 1974 in a series of water-supply papers entitled “Ground-Water Levels in the United States.” Water-supply papers may be consulted in the libraries of the principal cities in the United States, or they may be purchased from Books and Open-File Reports Section, Federal Center, Box 25425, Denver, Colorado 80225. For water years 1961 through 1970, streamflow data were released by the Geological Survey in annual reports on a State-boundary basis. Water-quality records for water years 1964 through 1970 were similarly released either in separate reports or in conjunction with streamflow records. Beginning with the 1971 water year, water data for streamflow, water quality, and ground water is published in official U.S. Geological Survey reports on a State-boundary basis. These official reports carry an identification number consisting of the two-letter State postal abbreviation, the last two digits of the water year, and the volume number. For example, this report is identified as “U.S. Geological Survey Water-Data Report IA-01-1.” These water-data reports are for sale by the National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia 22161.

Rate of Isotope Exchange Reaction Between Tritiated Water in a Gas Phase and Water on the Surface of Piping Materials

International Nuclear Information System (INIS)

Nakashio, Nobuyuki; Yamaguchi, Junya; Kobayashi, Ryusuke; Nishikawa, Masabumi

2001-01-01

The system effect of tritium arises from the interaction of tritium in the gas phase with water on the surface of piping materials. It has been reported that the system effect can be quantified by applying the serial reactor model to the piping system and that adsorption and isotope exchange reactions play the main roles in the trapping of tritium. The isotope exchange reaction that occurs when the chemical form of tritium in the gas phase is in the molecular form, i.e., HT or T 2 , has been named isotope exchange reaction 1, and that which occurs when tritium in the gas phase is in water form, i.e., HTO or T 2 O, has been named isotope exchange reaction 2.The rate of isotope exchange reaction 2 is experimentally quantified, and the rate is observed to be about one-third of the rate of adsorption. The trapping and release behavior of tritium from the piping surface due to isotope exchange reaction 2 is also discussed. It is certified that swamping of water vapor to process gas is effective to release tritium from the surface contaminated with tritium

Physico-chemical treatment of coke plant effluents for control of water pollution in India

Energy Technology Data Exchange (ETDEWEB)

Ghose, M.K. [Indian School of Mines, Dhanbad (India). Center of Mining Environmental

2002-01-01

Coal carbonizing industries in India are important and are growing every year. Large quantities of liquid effluents produced in this industry contain a large amount of suspended solids, high biochemical oxygen demand (BOD), chemical oxygen demand (COD), phenols, ammonia and other toxic substances, which are causing serious surface water pollution in the area. There is a large number of coke plants in the vicinity of Jharia Coal Field (JCF). The working principle of a coke plant and the effluents produced is described. One large coke plant was chosen to evaluate characteristics of the effluent and to suggest a proper treatment method. Present effluent treatment system was found to be inadequate and a large quantity of a very good quality coke breeze is being lost, which is also causing siltation on the riverbed in addition to surface water pollution. Physico-chemical treatment has been considered as a suitable option for the treatment of coke plant effluents. A scheme has been proposed for the treatment, which can be suitably adopted for the recycling, reuse or safe disposal of the treated effluent. Various unit process and unit operations are discussed. The process may be useful on industrial scale for various sites so as to maintain a clean environment.

Evaporation of liquids on chemically patterned surfaces

NARCIS (Netherlands)

Vieyra Salas, J.A.; Darhuber, A.A.

2011-01-01

We studied evaporation rates of volatile liquids deposited onto chemically patterned surfaces by means of experiments and numerical simulations. We quantified the influence of the droplet geometry, in particular circular, triangular, rectangular and square shapes, as well as the influence of contact

Chemical composition of black-watered rivers in the Amazons Region (Brazil)

International Nuclear Information System (INIS)

Horbe, Adriana M.C.; Santos, Ana G. da Silva

2009-01-01

Most investigations addressing Amazonian water chemistry are focused on the Solimoes, Amazonas and Negro rivers. Knowledge of the chemical composition of their smaller tributaries is restricted to some few, punctual data. The smaller rivers, that only present inputs from their catchments, are very important to understand the overall mechanisms controlling the chemistry of larger rivers of the region. With this objective the chemical composition of the principal Solimoes river black-watered tributaries in the western Brazilian Amazon during the low water period were determined. The data reveal the black water chemical composition to be highly variable and strongly influenced by the local geological environment: the Badajos basin being chemically more diluted; the Coari basin presenting higher SiO 2 contents, as well as smaller lakes having higher pH, conductivity, Ca 2+ , Mg 2+ and Sr, yet not as much as those found in the Solimoes river. The chemical composition of these waters is compatible with the low physical erosion and the region's highly leached tropical environment from which most soluble elements were quickly removed. (author)

Formation of the chemical composition of water in channel head in postglacial areas (West Pomerania, Poland)

Science.gov (United States)

Mazurek, Małgorzata; Kruszyk, Robert; Szpikowska, Grażyna

2016-04-01

The channel head is a zone of hydrological changes determining the hydrochemical features of water in the final stage of groundwater flow and the start of the surface cycle. The chemistry of water flowing out of a channel head reflects not only the characteristics of groundwater feeding the zone, but also changes it undergoes in this area during the organisation of channel flow. Groundwater interacts with surface water in the hyporheic zone where water from different environments is mixed and exchanged due to high hydraulic and chemical gradients. The goal of this study was to assess spatial differences in the concentrations of nutrients and compounds produced by chemical weathering in a channel head and to establish the role of the hyporheic zone in the transformation of the chemical composition of groundwater supplying a 1st-order stream. The research area was the channel head Żarnowo, located on the southern slope of the upper Parsęta valley. Three hydrochemical mappings were conducted in the headwater alcove consisting of three parts developed in a glaciofluvial plain and an erosional-accumulative alluvial terrace. Water was sampled in places of groundwater outflow in the footslope zone (9 sites), the hyporheic zone (14 sites), and outflows in the individual alcove parts and the rivulet they formed (5 sites). Water temperature, pH, and electrical conductivity were measured in the field. Concentrations of K, Ca, Mg, Na, Fe, Mn, HCO3, Cl, NO3, PO4, SO4 and SiO2 were determined in the laboratory. The chemical composition of ground- and surface water shows the concentration of geogenic components like K, Ca, Mg, Na, HCO3, and SiO2 to be an effect of chemical weathering and the leaching of its products taking place in a zero-discharge catchment. Those ions display little spatial variability and a stability of concentration in individual measurement periods, while the greatest disproportions in their concentrations among the alcove parts were recorded for Cl, NO3

How to repel hot water from a superhydrophobic surface?

KAUST Repository

Yu, Zhejun

2014-01-01

Superhydrophobic surfaces, with water contact angles greater than 150° and slide angles less than 10°, have attracted a great deal of attention due to their self-cleaning ability and excellent water-repellency. It is commonly accepted that a superhydrophobic surface loses its superhydrophobicity in contact with water hotter than 50 °C. Such a phenomenon was recently demonstrated by Liu et al. [J. Mater. Chem., 2009, 19, 5602], using both natural lotus leaf and artificial leaf-like surfaces. However, our work has shown that superhydrophobic surfaces maintained their superhydrophobicity, even in water at 80 °C, provided that the leaf temperature is greater than that of the water droplet. In this paper, we report on the wettability of water droplets on superhydrophobic thin films, as a function of both their temperatures. The results have shown that both the water contact and slide angles on the surfaces will remain unchanged when the temperature of the water droplet is greater than that of the surface. The water contact angle, or the slide angle, will decrease or increase, however, with droplet temperatures increasingly greater than that of the surfaces. We propose that, in such cases, the loss of superhydrophobicity of the surfaces is caused by evaporation of the hot water molecules and their condensation on the cooler surface. © 2014 the Partner Organisations.

Reaction path analysis of sodium-water reaction phenomena in support of chemical reaction model development

International Nuclear Information System (INIS)

Kikuchi, Shin; Ohshima, Hiroyuki; Hashimoto, Kenro

2011-01-01

Computational study of the sodium-water reaction at the gas (water) - liquid (sodium) interface has been carried out using ab initio (first-principle) method. A possible reaction channel has been identified for the stepwise OH bond dissociations of a single water molecule. The energetics including the binding energy of a water molecule to the sodium surface, the activation energies of the bond cleavages, and the reaction energies, have been evaluated, and the rate constants of the first and second OH bond-breakings have been compared. The results are used as the basis for constructing the chemical reaction model used in a multi-dimensional sodium-water reaction code, SERAPHIM, being developed by JAEA toward the safety assessment of the steam generator (SG) in a sodium-cooled fast reactor (SFR). (author)

Adsorption of surface functionalized silica nanoparticles onto mineral surfaces and decane/water interface

International Nuclear Information System (INIS)

Metin, Cigdem O.; Baran, Jimmie R.; Nguyen, Quoc P.

2012-01-01

The adsorption of silica nanoparticles onto representative mineral surfaces and at the decane/water interface was studied. The effects of particle size (the mean diameters from 5 to 75 nm), concentration and surface type on the adsorption were studied in detail. Silica nanoparticles with four different surfaces [unmodified, surface modified with anionic (sulfonate), cationic (quaternary ammonium (quat)) or nonionic (polyethylene glycol (PEG)) surfactant] were used. The zeta potential of these silica nanoparticles ranges from −79.8 to 15.3 mV. The shape of silica particles examined by a Hitachi-S5500 scanning transmission electron microscope (STEM) is quite spherical. The adsorption of all the nanoparticles (unmodified or surface modified) on quartz and calcite surfaces was found to be insignificant. We used interfacial tension (IFT) measurements to investigate the adsorption of silica nanoparticles at the decane/water interface. Unmodified nanoparticles or surface modified ones with sulfonate or quat do not significantly affect the IFT of the decane/water interface. It also does not appear that the particle size or concentration influences the IFT. However, the presence of PEG as a surface modifying material significantly reduces the IFT. The PEG surface modifier alone in an aqueous solution, without the nanoparticles, yields the same IFT reduction for an equivalent PEG concentration as that used for modifying the surface of nanoparticles. Contact angle measurements of a decane droplet on quartz or calcite plate immersed in water (or aqueous nanoparticle dispersion) showed a slight change in the contact angle in the presence of the studied nanoparticles. The results of contact angle measurements are in good agreement with experiments of adsorption of nanoparticles on mineral surfaces or decane/water interface. This study brings new insights into the understanding and modeling of the adsorption of surface-modified silica nanoparticles onto mineral surfaces and

Radioactivity in surface waters and its effects

International Nuclear Information System (INIS)

Stoeber, I.

1987-01-01

In consequence of the reactor accident in Chernobyl, the State Office for Water and Waste Disposal of North-Rhine Westphalia implemented immediate programmes for monitoring radioactivity in surface waters, including their sediments and organisms. Of the initially-measured radionuclides, only cesium-137, with its long half-life of 30 years, is of interest. Only trace amounts of the almost equally long-lived strontium 90 (half-life 28 years) were present in rainfall. Cs-137 is a non-natural-radionuclide, occurring solely as a by-product of nuclear installations and atomic bomb tests. Following the ban on surface testing of nuclear weapons, the Cs-137 content of surface waters had fallen significantly up to April 1986. The load due to the reactor disaster is of the same order of magnitude as that produced by atomic testing at the end of the nineteen-sixties. The paper surveys radioactive pollution of surface waters in North-Rhine Westphalia and its effects on water use, especially in regard to potable water supplies and the fish population. (orig./HSCH) [de

[Formation mechanism and chemical safety of nonintentional chemical substances present in chlorinated drinking water and wastewater].

Science.gov (United States)

Onodera, Sukeo

2010-09-01

This paper reviews the formation mechanism and chemical safety of nonintentional chemical substances (NICS) present in chlorine-treated water containing organic contaminants. Undesirable compounds, i.e., NICS, may be formed under certain conditions when chlorine reacts with organic matter. The rate and extent of chlorine consumption with organics are strongly dependent on their chemical structures, particularly whether double bonds or sulfur and nitrogen atoms occur in the molecules. Organothiophosphorus pesticides (P=S type) are easily oxidized to their phosphorus compounds (P=O type) in chlorinated water containing HOCl as little as 0.5 mg/l, resulting in an increase in cholinesterase-inhibitory activity. Chlorination of phenols in water also produces a series of highly chlorinated compounds, including chlorophenols, chloroquinones, chlorinated carboxylic acids, and polychlorinated phenoxyphenols (PCPPs). In some of these chloroquinones, 2,6-dichloroalkylsemiquinones exhibit a strong mutagenic response as do positive controls used in the Ames test. 2-phenoxyphenols in these PCPPs are particularly interesting, as they are present in the chlorine-treated phenol solution and they are also precursors (predioxins) of the highly toxic chlorinated dioxins. Polynuclear aromatic hydrocarbons (PAHs) were found to undergo chemical changes due to hypochlorite reactions to give chloro-substituted PAHs, oxygenated (quinones) and hydroxylated (phenols) compounds, but they exhibit a lower mutagenic response. In addition, field work was performed in river water and drinking water to obtain information on chemical distribution and their safety, and the results are compared with those obtained in the model chlorination experiments.

Tissue-based water quality biosensors for detecting chemical warfare agents

Science.gov (United States)

Greenbaum, Elias [Oak Ridge, TN; Sanders, Charlene A [Knoxville, TN

2003-05-27

A water quality sensor for detecting the presence of at least one chemical or biological warfare agent includes: a cell; apparatus for introducing water into the cell and discharging water from the cell adapted for analyzing photosynthetic activity of naturally occurring, free-living, indigenous photosynthetic organisms in water; a fluorometer for measuring photosynthetic activity of naturally occurring, free-living, indigenous photosynthetic organisms drawn into the cell; and an electronics package that analyzes raw data from the fluorometer and emits a signal indicating the presence of at least one chemical or biological warfare agent in the water.

Chemicals of emerging concern in water and bottom sediment in the Great Lakes Basin, 2012: collection methods, analytical methods, quality assurance, and study data

Science.gov (United States)

Lee, Kathy E.; Langer, Susan K.; Menheer, Michael A.; Hansen, Donald S.; Foreman, William T.; Furlong, Edward T.; Jorgenson, Zachary G.; Choy, Steven J.; Moore, Jeremy N.; Banda, JoAnn; Gefell, Daniel J.

2015-01-01

In synoptic surveys of surface-water quality across the United States, a large group of organic chemicals associated with agricultural, household, and industrial waste have been detected. These chemicals are referred to collectively as chemicals of emerging concern (CECs) and include prescription drugs and antibiotics, over-the-counter medications, reproductive hormones, personal-care products, detergent metabolites, and flame retardants.

Radiation-chemical degradation of chloroform in water solutions

International Nuclear Information System (INIS)

Ahmadov, S.A.; Gurbanov, M.A.; Iskenderova, Z.I.; Abdullayev, E.T.; Ibadov, N.A.

2006-01-01

Full text: Chloroform is the major chlorine-containing compound forming at chlorination of drinking water. As our basic water resources of Kur and Araz rivers are mostly polluted along the territory of the neighbour republics their chlorination for the purpose of biological purification can result in forming of chloroform. Unfortunately, there are only poor data about containing of chloroform in drinking water in the Republic, however the particular problem is to develop new methods of drinking water purification from chloroform, taking into account the high toxicity of this compounds. Appropriate works indicate that radiation-chemical processing can mostly reduce the concentration of chloroform in drinking water. The purification degree can achieve 95-98 percent. This work studies the tendency of chloroform decomposition at its radiolysis processes in water solutions. The concentration of chloroform changed in the range of 0,03-1 weight percentage. Taking into account the dissolvability of chloroform in water solutions it can be said that examined water solutions are homogeneous. Following advancements are studied: 1) Determination of radiation-chemical yield of chloroform decomposition at its various initial concentrations; 2) Impact of adsorbed dose on pH of solutions; 3) Formation of by-products. It is set that radiation-chemical output of chloroform decomposition is equal to 3 * 10 - 3 - 125 mol/100 ev. The high yield of chloroform decomposition can be connected with the chain process of oxidation with presence of dissolved oxygen. However, taking into account the fact that at its water radiolysis the yield of active particles of OH, e - aq, H-atoms does not exceed 6-7 particles/100 ev, the observed high yield can be explained only with the chain process with presence of dissolved oxygen

Mineralization sources of surface and subsurface waters at the southeastern edges of dead sea basin in Jordan

International Nuclear Information System (INIS)

AbdEl-Samie, S.G.; EL-Shahat, M.F.; Al-Nawayseh, K.M.

2004-01-01

Surface and ground waters within the shallow-Alluvial and deep- Kurnub aquifers in four areas (Issal, Mazraa, Safi and Haditha) in the southeastern edge of the Dead Sea basin were evaluated according to Salinity changes and water quality degradation. Chemical and isotopic parameters were integrated to follow the chemical evolutionary trend and sources of mineralization in these waters. The isotopic results indicated that the main recharge sources Issal. Mazraa and Safi groundwaters are the flash flood and base flow water from the eastern highland through wadies. In Safi area, the groundwater that mixed with other depleted source could be paleowater seeped from older formation. The depletion in stable isotopic values with low d-parametewr (less than 10%) for Haditha groundwater confirms that the replenishment to the aquifer (Kurnub sandstone) had been formed during the pluvial time. The chemical data showed that the base flow water from the eastern highland is denoted by the least salinity values, whereas drainage water acquired the highest values as aa result of receiving a considerable amount of the remaining water from salt extraction processes. The groundwater in Safi wells has low salt content with respect to the other areas taping the same aquifer. The elevation in Ca and Mg ions reflects the dissolution of Ca-Mg rich minerals that actively reached saturation with respect to calcite and dolomite in all samples except Haditha deep aquifer due to its low ph values. In spite of the meteoric origin of the recharge source, the presence of MgCl 2 and CaCl 2 salts in almost all samples changed the water character to be old or recent marine genesis. This points to the effect of Dead Sea in both surface and ground waters. The obvious depletion in O-18 and isotopes for all ground waters samples with respect to the positive values of Dead Sea sample is good indicative for non mixing trend with Dead Sea water in the Alluvial and Kurnub aquifers

Application of surface plasmons to biological and chemical sensors

International Nuclear Information System (INIS)

Kajikawa, Kotaro

2015-01-01

Surface plasmons (SPs) are a collective normal mode of electrons localized at a metallic surface. It has been used for biological sensors since 1990s. This is because it has the following specific characters: (a) The resonance condition is sensitive to the surrounding dielectric constants (refractive indexes) and (b) Highly enhanced optical-electric-fields are produced adjacent to SPs. A brief introduction is given on the principle of the biological and chemical sensors based on SPs for the readers working in the fields other than SPs, followed by a review on the recent developments of the biological and chemical sensors. (author)

Contrasts between chemical and physical estimates of baseflow help discern multiple sources of water contributing to rivers

Science.gov (United States)

Cartwright, I.; Gilfedder, B.; Hofmann, H.

2013-05-01

This study compares geochemical and physical methods of estimating baseflow in the upper reaches of the Barwon River, southeast Australia. Estimates of baseflow from physical techniques such as local minima and recursive digital filters are higher than those based on chemical mass balance using continuous electrical conductivity (EC). Between 2001 and 2011 the baseflow flux calculated using chemical mass balance is between 1.8 × 103 and 1.5 × 104 ML yr-1 (15 to 25% of the total discharge in any one year) whereas recursive digital filters yield baseflow fluxes of 3.6 × 103 to 3.8 × 104 ML yr-1 (19 to 52% of discharge) and the local minimum method yields baseflow fluxes of 3.2 × 103 to 2.5 × 104 ML yr-1 (13 to 44% of discharge). These differences most probably reflect how the different techniques characterise baseflow. Physical methods probably aggregate much of the water from delayed sources as baseflow. However, as many delayed transient water stores (such as bank return flow or floodplain storage) are likely to be geochemically similar to surface runoff, chemical mass balance calculations aggregate them with the surface runoff component. The mismatch between geochemical and physical estimates is greatest following periods of high discharge in winter, implying that these transient stores of water feed the river for several weeks to months. Consistent with these interpretations, modelling of bank storage indicates that bank return flows provide water to the river for several weeks after flood events. EC vs. discharge variations during individual flow events also imply that an inflow of low EC water stored within the banks or on the floodplain occurs as discharge falls. The joint use of physical and geochemical techniques allows a better understanding of the different components of water that contribute to river flow, which is important for the management and protection of water resources.

Study on the impact of the deposit garbage of Andralanitra on the characteristics of groundwater and surface water using isotopic method

International Nuclear Information System (INIS)

Rakotomalala, C.U.

2014-01-01

Since 1966, Andralanitra has become a place for landfill in Antananarivo. Currently, more dwellings are around this area, the local population uses well water and surface water for their daily water needs and also for their cattle. The goal of the study is to analyze the impact of the landfill on the chemical characteristics of the water using the isotopic method. The chemical results show that the groundwater is characterized by three different chemical types (chlorinated sodium and potassium, chloride-calcium sulfate and magnesium, sodium and potassium carbonate) with high levels of nitrate, both upstream and downstream of the area deposit. For water wells located upstream of the zone, the nitrate would have an anthropogenic origin, mainly because of the presence of latrines and / or barn near water sampling points. For water wells, located directly downstream of the drop zone, there are high levels of nitrate and other major ions. The tritium analyzes indicate the natural origins of the radioisotope ( [fr

Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

OpenAIRE

Kostik, Vesna; Bauer, Biljana; Kavrakovski, Zoran

2014-01-01

The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupl...

Presence and risk assessment of pharmaceuticals in surface water and drinking water

DEFF Research Database (Denmark)

Sanderson, Hans

2011-01-01

Trace amounts of pharmaceuticals have been detected in surface waters in the nano- to microgram per liter range, and in drinking water in the nanogram/L range. The environmental risks of pharmaceuticals in surface waters have been evaluated and generally found to be low if the wastewater is treated...

Anomalous water dynamics at surfaces and interfaces: synergistic effects of confinement and surface interactions

Science.gov (United States)

Biswas, Rajib; Bagchi, Biman

2018-01-01

In nature, water is often found in contact with surfaces that are extended on the scale of molecule size but small on a macroscopic scale. Examples include lipid bilayers and reverse micelles as well as biomolecules like proteins, DNA and zeolites, to name a few. While the presence of surfaces and interfaces interrupts the continuous hydrogen bond network of liquid water, confinement on a mesoscopic scale introduces new features. Even when extended on a molecular scale, natural and biological surfaces often have features (like charge, hydrophobicity) that vary on the scale of the molecular diameter of water. As a result, many new and exotic features, which are not seen in the bulk, appear in the dynamics of water close to the surface. These different behaviors bear the signature of both water-surface interactions and of confinement. In other words, the altered properties are the result of the synergistic effects of surface-water interactions and confinement. Ultrafast spectroscopy, theoretical modeling and computer simulations together form powerful synergistic approaches towards an understanding of the properties of confined water in such systems as nanocavities, reverse micelles (RMs), water inside and outside biomolecules like proteins and DNA, and also between two hydrophobic walls. We shall review the experimental results and place them in the context of theory and simulations. For water confined within RMs, we discuss the possible interference effects propagating from opposite surfaces. Similar interference is found to give rise to an effective attractive force between two hydrophobic surfaces immersed and kept fixed at a separation of d, with the force showing an exponential dependence on this distance. For protein and DNA hydration, we shall examine a multitude of timescales that arise from frustration effects due to the inherent heterogeneity of these surfaces. We pay particular attention to the role of orientational correlations and modification of the

Fabrication of superhydrophobic copper surface on various substrates for roll-off, self-cleaning, and water/oil separation.

Science.gov (United States)

Sasmal, Anup Kumar; Mondal, Chanchal; Sinha, Arun Kumar; Gauri, Samiran Sona; Pal, Jaya; Aditya, Teresa; Ganguly, Mainak; Dey, Satyahari; Pal, Tarasankar

2014-12-24

Superhydrophobic surfaces prevent percolation of water droplets and thus render roll-off, self-cleaning, corrosion protection, etc., which find day-to-day and industrial applications. In this work, we developed a facile, cost-effective, and free-standing method for direct fabrication of copper nanoparticles to engender superhydrophobicity for various flat and irregular surfaces such as glass, transparency sheet (plastic), cotton wool, textile, and silicon substrates. The fabrication of as-prepared superhydrophobic surfaces was accomplished using a simple chemical reduction of copper acetate by hydrazine hydrate at room temperature. The surface morphological studies demonstrate that the as-prepared surfaces are rough and display superhydrophobic character on wetting due to generation of air pockets (The Cassie-Baxter state). Because of the low adhesion of water droplets on the as-prepared surfaces, the surfaces exhibited not only high water contact angle (164 ± 2°, 5 μL droplets) but also superb roll-off and self-cleaning properties. Superhydrophobic copper nanoparticle coated glass surface uniquely withstands water (10 min), mild alkali (5 min in saturated aqueous NaHCO3 of pH ≈ 9), acids (10 s in dilute HNO3, H2SO4 of pH ≈ 5) and thiol (10 s in neat 1-octanethiol) at room temperature (25-35 °C). Again as-prepared surface (cotton wool) was also found to be very effective for water-kerosene separation due to its superhydrophobic and oleophilic character. Additionally, the superhydrophobic copper nanoparticle (deposited on glass surface) was found to exhibit antibacterial activity against both Gram-negative and Gram-positive bacteria.

Improvement of chemical control in the water-steam cycle of thermal power plants

International Nuclear Information System (INIS)

Rajakovic-Ognjanovic, Vladana N.; Zivojinovic, Dragana Z.; Grgur, Branimir N.; Rajakovic, Ljubinka V.

2011-01-01

A more effective chemical control in the water-steam cycle (WSC) of thermal power plants (TPP) is proposed in this paper. Minimization of corrosion effects by the production of ultra pure water and its strict control is the basis of all the investigated processes. The research involved the analysis of water samples in the WSC through key water quality parameters and by the most convenient analytical tools. The necessity for the stricter chemical control is demonstrated through a concrete example of the TPP Nikola Tesla, Serbia. After a thorough analysis of the chemical control system of the WSC, diagnostic and control parameters were chosen for continuous systematic measurements. Sodium and chloride ions were recognized as the ions which indicate the corrosion potential of the water and give insight into the proper production and maintenance of water within the WSC. Chemical transformations of crucial corrosion elements, iron and silica, were considered and related to their quantitative values. - Research highlights: → The more effective chemical control in the water-steam cycle of thermal power plant Nikola Tesla, Serbia. → In chemical control the diagnostic and control parameters were optimized and introduced for the systematic measurements in the water-steam cycle. → Sodium and chloride ions were recognized as ions which indicate corrosion potential of water and give insight to proper function of production and maintenance of water within water-team cycle. → Chemical transformations of crucial corrosion elements, iron and silica are considered and related with their quantitative values.

Method of manipulating the chemical properties of water to improve the effectiveness of a desired process

Science.gov (United States)

Hawthorne, Steven B.; Miller, David J.; Lagadec, Arnaud Jean-Marie; Hammond, Peter James; Clifford, Anthony Alan

2002-01-01

The method of the present invention is adapted to manipulate the chemical properties of water in order to improve the effectiveness of a desired process. The method involves heating the water in the vessel to subcritical temperatures between 100.degree. to 374.degree. C. while maintaining sufficient pressure to the water to maintain the water in the liquid state. Various physiochemical properties of the water can be manipulated including polarity, solute solubility, surface tension, viscosity, and the disassociation constant. The method of the present invention has various uses including extracting organics from solids and semisolids such as soil, selectively extracting desired organics from liquids, selectively separating organics using sorbent phases, enhancing reactions by controlling the disassociation constant of water, cleaning waste water, removing organics from water using activated carbon or other suitable sorbents, and degrading various compounds.

40 CFR 257.3-3 - Surface water.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

DFT simulations of water adsorption and activation on low-index α-Ga2O3 surfaces.

Science.gov (United States)

Zhou, Xin; Hensen, Emiel J M; van Santen, Rutger A; Li, Can

2014-06-02

Density functional theory (DFT) calculations are used to explore water adsorption and activation on different α-Ga2O3 surfaces, namely (001), (100), (110), and (012). The geometries and binding energies of molecular and dissociative adsorption are studied as a function of coverage. The simulations reveal that dissociative water adsorption on all the studied low-index surfaces are thermodynamically favorable. Analysis of surface energies suggests that the most preferentially exposed surface is (012). The contribution of surface relaxation to the respective surface energies is significant. Calculations of electron local density of states indicate that the electron-energy band gaps for the four investigated surfaces appears to be less related to the difference in coordinative unsaturation of the surface atoms, but rather to changes in the ionicity of the surface chemical bonds. The electrochemical computation is used to investigate the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) on α-Ga2O3 surfaces. Our results indicate that the (100) and (110) surfaces, which have low stability, are the most favorable ones for HER and OER, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Understanding the Impact of Intensive Horticulture Land-Use Practices on Surface Water Quality in Central Kenya

Directory of Open Access Journals (Sweden)

Faith K. Muriithi

2015-11-01

Full Text Available Rapid expansion of commercial horticulture production and related activities contribute to declining surface water quality. The study sought to understand the impacts on select rivers in Laikipia and Meru, production hotspots. The specific aims were (1 to identify prevailing surface water quality by examining variations of 14 physico-chemical parameters, and (2 to categorize measured surface water quality parameters into land use types highlighting potential pollutant source processes. Water samples were collected in July and August 2013 along 14 rivers in the study area. The data were analyzed using principal component analysis (PCA and discriminant analysis (DA. Principal components (PCs explained 70% of the observed total variability of water quality, indicating a prevalence of heavy metal traces (cadmium, phosphate, and zinc. These were linked to the rigorous use of phosphate fertilizers and copper-based agrochemicals in intensive farming. DA provided four significant (p < 0.05 discriminant functions, with 89.5% correct assignment enabling the association of land use with observed water quality. Concentrations of dissolved solids, electro-conductivity, and salinity spiked at locations with intensive small-scale and large-scale horticulture. Understanding the impacts of intensive commercial horticulture and land use practices on water quality is critical to formulating ecologically sound watershed management and pollution abatement plans.

Atmospheric Water Harvesting: Role of Surface Wettability and Edge Effect

KAUST Repository

Jin, Yong

2017-06-23

Atmospheric water is emerging as an important potable water source. The present work experimentally and theoretically investigates water condensation and collection on flat surfaces with contrasting contact angles and contact angle hysteresis (CAH) to elucidate their roles on water mass collection efficiency. The experimental results indicate that a hydrophilic surface promotes nucleation and individual droplets growth, and a surface with a low CAH tends to let a smaller droplet to slide down, but the overall water mass collection efficiency is independent of both surface contact angle and CAH. The experimental results agree well with our theoretical calculations. During water condensation, a balance has to be struck between single droplet growth and droplet density on a surface so as to maintain a constant water droplet surface coverage ratio, which renders the role of both surface wettability and hysteresis insignificant to the ultimate water mass collection. Moreover, water droplets on the edges of a surface grow much faster than those on the non-edge areas and thus dominate the contribution to the water mass collection by the entire surface, directly pointing out the very important role of edge effect on water condensation and collection.

Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces

OpenAIRE

Jogikalmath, G.; Stuart, J.K.; Pungor, A.; Hlady, V.

1999-01-01

Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface mo...

Environmentally relevant chemical mixtures of concern in waters of United States tributaries to the Great Lakes

Science.gov (United States)

Elliott, Sarah M.; Brigham, Mark E.; Kiesling, Richard L.; Schoenfuss, Heiko L.; Jorgenson, Zachary G.

2018-01-01

The North American Great Lakes are a vital natural resource that provide fish and wildlife habitat, as well as drinking water and waste assimilation services for millions of people. Tributaries to the Great Lakes receive chemical inputs from various point and nonpoint sources, and thus are expected to have complex mixtures of chemicals. However, our understanding of the co‐occurrence of specific chemicals in complex mixtures is limited. To better understand the occurrence of specific chemical mixtures in the US Great Lakes Basin, surface water from 24 US tributaries to the Laurentian Great Lakes was collected and analyzed for diverse suites of organic chemicals, primarily focused on chemicals of concern (e.g., pharmaceuticals, personal care products, fragrances). A total of 181 samples and 21 chemical classes were assessed for mixture compositions. Basin wide, 1664 mixtures occurred in at least 25% of sites. The most complex mixtures identified comprised 9 chemical classes and occurred in 58% of sampled tributaries. Pharmaceuticals typically occurred in complex mixtures, reflecting pharmaceutical‐use patterns and wastewater facility outfall influences. Fewer mixtures were identified at lake or lake‐influenced sites than at riverine sites. As mixture complexity increased, the probability of a specific mixture occurring more often than by chance greatly increased, highlighting the importance of understanding source contributions to the environment. This empirically based analysis of mixture composition and occurrence may be used to focus future sampling efforts or mixture toxicity assessments. 

Potential Impacts of Spilled Hydraulic Fracturing Fluid Chemicals on Water Resources: Types, volumes, and physical-chemical properties of chemicals

Science.gov (United States)

Hydraulic fracturing (HF) fluid chemicals spilled on-site may impact drinking water resources. While chemicals generally make up <2% of the total injected fluid composition by mass, spills may have undiluted concentrations. HF fluids typically consist of a mixture of base flui...

Public Health Risk Conditioned by Chemical Composition of Ground Water

Science.gov (United States)

Yankovich, E.; Osipova, N.; Yankovich, K.; Matveenko, I.

2016-03-01

The article studies the public health potential risk originated from water consumption and estimated on the basis of the groundwater chemical composition. We have processed the results of chemical groundwater analysis in different aquifers of Tomsk district (Tomsk Oblast, Russia). More than 8400 samples of chemical groundwater analyses were taken during long-term observation period. Human health risk assessment of exposure to contaminants in drinking water was performed in accordance with the risk assessment guidance for public health concerning chemical pollution of the environment (Russian reference number: 2.1.10.1920-04-M, 2004). Identified potential risks were estimated for consuming water of each aquifer. The comparative analysis of water quality of different aquifers was performed on the basis of the risk coefficient of the total non-carcinogenic effects. The non-carcinogenic risk for the health of the Tomsk district population due to groundwater consumption without prior sanitary treatment was admitted acceptable. A rather similar picture is observed for all aquifers, although deeper aquifers show lower hazard coefficients.

A study on the fabrication of superhydrophobic iron surfaces by chemical etching and galvanic replacement methods and their anti-icing properties

Science.gov (United States)

Li, Kunquan; Zeng, Xingrong; Li, Hongqiang; Lai, Xuejun

2015-08-01

Hierarchical structures on iron surfaces were constructed by means of chemical etching by hydrochloric acid (HCl) solution or the galvanic replacement by silver nitrate (AgNO3) solution. The superhydrophobic iron surfaces were successfully prepared by subsequent hydrophobic modification with stearic acid. The superhydrophobic iron surfaces were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and water contact angle (WCA). The effects of reactive concentration and time on the microstructure and the wetting behavior were investigated. In addition, the anti-icing properties of the superhydrophobic iron surfaces were also studied. The FTIR study showed that the stearic acid was chemically bonded onto the iron surface. With the HCl concentration increase from 4 mol/L to 8 mol/L, the iron surface became rougher with a WCA ranging from 127° to 152°. The AgNO3 concentration had little effect on the wetting behavior, but a high AgNO3 concentration caused Ag particle aggregates to transform from flower-like formations into dendritic crystals, owing to the preferential growth direction of the Ag particles. Compared with the etching method, the galvanic replacement method on the iron surface more favorably created roughness required for achieving superhydrophobicity. The superhydrophobic iron surface showed excellent anti-icing properties in comparison with the untreated iron. The icing time of water droplets on the superhydrophobic surface was delayed to 500 s, which was longer than that of 295 s for untreated iron. Meanwhile, the superhydrophobic iron surface maintained superhydrophobicity after 10 icing and de-icing cycles in cold conditions.