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Sample records for adjusting soil ph

  1. Growth and Cadmium Phytoextraction by Swiss Chard, Maize, Rice, Noccaea caerulescens, and Alyssum murale in Ph Adjusted Biosolids Amended Soils.

    PubMed

    Broadhurst, C Leigh; Chaney, Rufus L; Davis, Allen P; Cox, Albert; Kumar, Kuldip; Reeves, Roger D; Green, Carrie E

    2015-01-01

    Past applications of biosolids to soils at some locations added higher Cd levels than presently permitted. Cadmium phytoextraction would alleviate current land use constraints. Unamended farm soil, and biosolids amended farm and mine soils were obtained from a Fulton Co., IL biosolids management facility. Soils contained 0.16, 22.8, 45.3 mg Cd kg(-1) and 43.1, 482, 812 mg Zn kg(-1) respectively with initial pH 6.0, 6.1, 6.4. In greenhouse studies, Swiss chard (Beta vulgaris var. cicla), a Cd-accumulator maize (inbred B37 Zea mays) and a southern France Cd-hyperaccumulator genotype of Noccaea caerulescens were tested for Cd accumulation and phytoextraction. Soil pH was adjusted from ∼5.5-7.0. Additionally 100 rice (Oryza sativa) genotypes and the Ni-hyperaccumulator Alyssum murale were screened for potential phytoextraction use. Chard suffered phytotoxicity at low pH and accumulated up to 90 mg Cd kg(-1) on the biosolids amended mine soil. The maize inbred accumulated up to 45 mg Cd kg(-1) with only mild phytotoxicity symptoms during early growth at pH>6.0. N. caerulescens did not exhibit phytotoxicity symptoms at any pH, and accumulated up to 235 mg Cd kg(-1) in 3 months. Reharvested N. caerulescens accumulated up to 900 mg Cd kg(-1) after 10 months. Neither Alyssum nor 90% of rice genotypes survived acceptably. Both N. caerulescens and B37 maize show promise for Cd phytoextraction in IL and require field evaluation; both plants could be utilized for nearly continuous Cd removal. Other maize inbreds may offer higher Cd phytoextraction at lower pH, and mono-cross hybrids higher shoot biomass yields. Further, maize grown only for biomass Cd maximum removal could be double-cropped.

  2. Biochar's effect on soil nitrous oxide emissions from a maize field with lime adjusted pH treatment

    NASA Astrophysics Data System (ADS)

    Hüppi, Roman; Leifeld, Jens; Felber, Raphael; Neftel, Albrecht; Six, Johan

    2015-04-01

    Biochar is a carbon-rich, porous product from pyrolysis of organic residues. Especially tropical soils have shown positive response in yield to biochar addition. Its high stability in soil makes biochar a potent carbon sequestration option at the same time. A number of laboratory incubations have shown significantly reduced nitrous oxide (N2O) emissions from soil when mixed with biochar. Emission measurements from the field show the same trend but are much more scarce. One of the hypothesized mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH from the application of alkaline biochar. To test the effect of biochar on N2O emissions from a temperate maize system, we set up a field trial with a 20 t/ha biochar treatment, a limestone treatment adjusted to the same pH as with biochar and a control without addition. An automated static chamber greenhouse gas measurement system measured N2O emissions for each replicated (n=3) every 3.6 hours. The field was conventionally fertilised at a rate of 160 kg-N/ha in 3 doses of 40, 80 and 40 kg-N/ha. Cumulative emissions show a significant reduction for N2O in the biochar treatment by about 55 % relative to the control. The limed treatment shows similar emissions than control but with higher variability. This suggests that the N2O reduction effect of biochar is not mainly due to its liming effect. In conclusion, we confirm that biochar is a promising material to reduce N2O emissions from intensively managed agricultural soils.

  3. Growth and cadmium uptake of Swiss chard, Thlaspi caerulescens and corn in pH adjusted biosolids amended soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Before regulations were established, some biosolids applications added higher Cd levels than presently permitted. Cadmium phytoextraction from such soils would alleviate constraints on land use. Unamended farm soil, and biosolids amended farm soil and mine soil were obtained from Fulton County, Il...

  4. MRF with adjustable pH

    NASA Astrophysics Data System (ADS)

    Jacobs, Stephen D.

    2011-10-01

    Deterministic final polishing of high precision optics using sub-aperture processing with magnetorheological finishing (MRF) is an accepted practice throughout the world. A wide variety of materials can be successfully worked with aqueous (pH 10), magnetorheological (MR) fluids, using magnetic carbonyl iron (CI) and either ceria or nanodiamond nonmagnetic abrasives. Polycrystalline materials like zinc sulfide (ZnS) and zinc selenide (ZnSe) are difficult to polish at pH 10 with MRF, due to their grain size and the relatively low stiffness of the MR fluid lap. If microns of material are removed, the grain structure of the material begins to appear. In 2005, Kozhinova et al. (Appl. Opt. 44 4671-4677) demonstrated that lowering pH could improve MRF of ZnS. However, magnetic CI particle corrosion rendered their low pH approach unstable and unsuitable for commercial implementation. In 2009, Shafrir et al. described a sol-gel coating process for manufacturing a zirconia-coated CI particle that protects the magnetic core from aqueous corrosion (Appl. Opt .48 6797-6810). The coating process produces free nanozirconia polishing abrasives during the coating procedure, thereby creating an MR polishing powder that is "self-charged" with the polishing abrasive. By simply adding water, it was possible to polish optical glasses and ceramics with good stability at pH 8 for three weeks. The development of a corrosion resistant, MR polishing powder, opens up the possibility for polishing additional materials, wherein the pH may be adjusted to optimize effectiveness. In this paper we describe the CI coating process, the characterization of the coated powder, and procedures for making stable MR fluids with adjustable pH, giving polishing results for a variety of optical glasses and crystalline ceramics.

  5. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  6. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  7. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  8. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  9. Influence of soil pH on properties of the soil-water interface

    NASA Astrophysics Data System (ADS)

    Diehl, Doerte

    2010-05-01

    Surface characteristics of soils are one of the main factors controlling processes at the soil-water interface like wetting, sorption or dissolution processes and, thereby, have a high impact on natural soil functions like habitat, filter, buffer, storage and transformation functions. Since surface characteristics, like wettability or repellency, are not static soil properties but continuously changing, the relevant processes and mechanisms are in the focus of the presented study. These mechanisms help to gain further insight into the behaviour of soil and its dynamics under changing environmental conditions. The influence of water content, relative air humidity and drying temperature on soil water repellency has been investigated in many studies. In contrast, few studies have systematically investigated the relationship between soil water repellency (SWR) and soil pH. Several studies found alkaline soils to be less prone to SWR compared to acidic soils (e.g., Cerdà, and Doerr 2007; Mataix-Solera et al. 2007). Furthermore, SWR has been successfully reduced in acidic soils by increasing soil pH via liming (e.g., Karnok et al. 1993; Roper 2005). However, SWR has also been reported in calcareous soils in the Netherlands (Dekker and Jungerius 1990), California, USA (Holzhey 1968) and Spain (Mataix-Solera and Doerr 2004). The hypothesis that the pH may control repellency via changes in the variable surface charge of soil material has not yet been tested. Previously it has been shown that it is necessary to eliminate the direct influence of changes in soil moisture content so that the unique relationship between pH and SWR can be isolated (Bayer and Schaumann 2007). A method has been developed which allows adjustment of the pH of soils with low moisture content via the gas phase with minimal change in moisture content. The method was applied to 14 soil samples from Germany, Netherlands, the UK and Australia, using the water drop penetration time (WDPT) as the indicator

  10. Nanomaterials for the cleaning and pH adjustment of vegetable-tanned leather

    NASA Astrophysics Data System (ADS)

    Baglioni, Michele; Bartoletti, Angelica; Bozec, Laurent; Chelazzi, David; Giorgi, Rodorico; Odlyha, Marianne; Pianorsi, Diletta; Poggi, Giovanna; Baglioni, Piero

    2016-02-01

    Leather artifacts in historical collections and archives are often contaminated by physical changes such as soiling, which alter their appearance and readability, and by chemical changes which occur on aging and give rise to excessive proportion of acids that promote hydrolysis of collagen, eventually leading to gelatinization and loss of mechanical properties. However, both cleaning and pH adjustment of vegetable-tanned leather pose a great challenge for conservators, owing to the sensitivity of these materials to the action of solvents, especially water-based formulations and alkaline chemicals. In this study, the cleaning of historical leather samples was optimized by confining an oil-in-water nanostructured fluid in a highly retentive chemical hydrogel, which allows the controlled release of the cleaning fluid on sensitive surfaces. The chemical gel exhibits optimal viscoelasticity, which facilitates its removal after the application without leaving residues on the object. Nanoparticles of calcium hydroxide and lactate, dispersed in 2-propanol, were used to adjust the pH up to the natural value of leather, preventing too high alkalinity which causes swelling of fibers and denaturation of the collagen. The treated samples were characterized using scanning electron microscopy, controlled environment dynamic mechanical analysis, and infrared spectroscopy. The analytical assessment validated the use of tools derived from colloid and materials science for the preservation of collagen-based artifacts.

  11. Mapping Soil pH Buffering Capacity of Selected Fields

    NASA Technical Reports Server (NTRS)

    Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

    2003-01-01

    Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.

  12. Effects of pH adjustment and sodium ions on sour taste intensity of organic acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protonated organic acid species have been shown to be the primary stimuli responsible for sour taste of organic acids. However, we have observed that sour taste may be modulated when the pH of acid solutions is raised using sodium hydroxide. Objectives were to evaluate the effect of pH adjustment on...

  13. Biochar contribution to soil pH buffer capacity

    NASA Astrophysics Data System (ADS)

    Tonutare, Tonu; Krebstein, Kadri; Utso, Maarius; Rodima, Ako; Kolli, Raimo; Shanskiy, Merrit

    2014-05-01

    Biochar as ecologically clean and stable form of carbon has complex of physical and chemical properties which make it a potentially powerful soil amendment (Mutezo, 2013). Therefore during the last decade the biochar application as soil amendment has been a matter for a great number of investigations. For the ecological viewpoint the trend of decreasing of soil organic matter in European agricultural land is a major problem. Society is faced with the task to find possibilities to stabilize or increase soil organic matter content in soil and quality. The availability of different functional groups (e.g. carboxylic, phenolic, acidic, alcoholic, amine, amide) allows soil organic matter to buffer over a wide range of soil pH values (Krull et al. 2004). Therefore the loss of soil organic matter also reduces cation exchange capacity resulting in lower nutrient retention (Kimetu et al. 2008). Biochar can retain elements in soil directly through the negative charge that develops on its surfaces, and this negative charge can buffer acidity in the soil. There are lack of investigations about the effect of biochar to soil pH buffering properties, The aim of our investigation was to investigate the changes in soil pH buffer capacity in a result of addition of carbonizated material to temperate region soils. In the experiment different kind of softwood biochars, activated carbon and different soil types with various organic matter and pH were used. The study soils were Albeluvisols, Leptosols, Cambisols, Regosols and Histosols . In the experiment the series of the soil: biochar mixtures with the biochar content 0 to 100% were used. The times of equiliberation between solid and liquid phase were from 1 to 168 hours. The suspension of soil: biochar mixtures was titrated with HCl solution. The titration curves were established and pH buffer capacities were calculated for the pH interval from 3.0 to 10.0. The results demonstrate the dependence of pH buffer capacity from soil type

  14. Soil pH effect on phosphate induced cadmium precipitation in Arable soil.

    PubMed

    Hong, Chang Oh; Owens, Vance N; Kim, Yong Gyun; Lee, Sang Mong; Park, Hyean Cheal; Kim, Keun Ki; Son, Hong Joo; Suh, Jeong Min; Kim, Pil Joo

    2014-07-01

    The objective of this study was to determine soil pH conditions that allow cadmium (Cd) to precipitate as Cd minerals in phosphate (P) amended soil. Cadmium immobilization could be attributed primarily to Cd adsorption due to increase in pH and negative charge. Soil pH might not affect Cd precipitation as Cd3(PO4)2 by direct reaction of Cd and P in the studied soil, even when soil pH increased up to 9.0. However, Cd might precipitate as CdCO3 with increasing pH up to 9.0 in P untreated soil and up to 8.0 in P treated soil depending on CO2 level.

  15. Crop uptake and extractability of cadmium in soils naturally high in metals at different pH levels

    SciTech Connect

    Singh, B.R.; Almas, A.; Narwal, R.P.; Jeng, A.S.

    1995-12-01

    A greenhouse experiment was conducted for three years to study the effect of different pH levels on metal concentrations in plants and the cadmium (Cd) extractability by DTPA and NH{sub 4}NO{sub 3}. The soils used were an alum shale (clay loam) and a moraine (loam), which were adjusted to pH levels of 5.5, 6.5, 7.0, and 7.5. Wheat (Triticum aestivum), carrot (Daucus carota L.), and lettuce (Lactuca sativa) were grown as test crops. Crop yields were not consistently affected at increasing soil pH levels. The concentration of Cd in plant species decreased with increasing soil pH in both soils and in all three years. Significant concentration differences between soil pH levels were only seen in wheat and carrot crops. Increasing soil pH also decreased the nickel (Ni) and zinc (Zn) concentrations in plants in the first year crop but the copper (Cu) concentration was not consistently affected by soil pH. The effect of pH was more pronounced in the moraine then the alum shale soil. The DTPA-and NH{sub 4}NO{sub 3}-extractable Cd was decreased with the increasing soil pH and the pH effect was more pronounced with NH{sub 4}NO{sub 3} extractable Cd. Both extractants were found equally effective in relation to the Cd concentration in plants in this study. 33 refs., 2 figs., 7 tabs.

  16. Soluble organic carbon and pH of organic amendments affect metal mobility and chemical speciation in mine soils.

    PubMed

    Pérez-Esteban, Javier; Escolástico, Consuelo; Masaguer, Alberto; Vargas, Carmen; Moliner, Ana

    2014-05-01

    We evaluated the effects of pH and soluble organic carbon affected by organic amendments on metal mobility to find out the optimal conditions for their application in the stabilization of metals in mine soils. Soil samples (pH 5.5-6.2) were mixed with 0, 30 and 60 th a(-1) of sheep-horse manure (pH 9.4) and pine bark compost (pH 5.7). A single-step extraction procedure was performed using 0.005 M CaCl2 adjusted to pH 4.0-7.0 and metal speciation in soil solution was simulated using NICA-Donnan model. Sheep-horse manure reduced exchangeable metal concentrations (up to 71% Cu, 75% Zn) due to its high pH and degree of maturity, whereas pine bark increased them (32% Cu, 33% Zn). However, at increasing dose and hence pH, sheep-horse manure increased soluble Cu because of higher soluble organic carbon, whereas soluble Cu and organic carbon increased at increasing dose and correspondingly decreasing pH in pine bark and non-amended treatments. Near the native pH of these soils (at pH 5.8-6.3), with small doses of amendments, there was minimum soluble Cu and organic carbon. Pine bark also increased Zn solubility, whereas sheep-horse manure reduced it as soluble Zn always decreased with increasing pH. Sheep-horse manure also reduced the proportion of free metals in soil solution (from 41% to 4% Cu, from 97% to 94% Zn), which are considered to be more bioavailable than organic species. Sheep-horse manure amendment could be efficiently used for the stabilization of metals with low risk of leaching to groundwater at low doses and at relatively low pH, such as the native pH of mine soils.

  17. CARINA data synthesis project: pH data scale unification and cruise adjustments

    NASA Astrophysics Data System (ADS)

    Velo, A.; Pérez, F. F.; Lin, X.; Key, R. M.; Tanhua, T.; de La Paz, M.; Olsen, A.; van Heuven, S.; Jutterström, S.; Ríos, A. F.

    2010-05-01

    Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruise data sets in the Artic Mediterranean Seas (AMS), Atlantic Ocean and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic Ocean). These data have gone through rigorous quality control (QC) procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values. Systematic biases found in the data have been corrected in the data products, three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; AMS, Atlantic Ocean and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 59 reported pH measured values. All reported pH data have been unified to the Sea-Water Scale (SWS) at 25 °C. Here we present details of the secondary QC of pH in the CARINA database and the scale unification to SWS at 25 °C. The pH scale has been converted for 36 cruises. Procedures of quality control, including crossover analysis between cruises and inversion analysis are described. Adjustments were applied to the pH values for 21 of the cruises in the CARINA dataset. With these adjustments the CARINA database is consistent both internally as well as with the GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s. Based on our analysis we estimate the internal consistency of the CARINA pH data to be 0.005 pH units. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates, for ocean acidification assessment and for model validation.

  18. Soil flushing of cresols contaminated soil: application of nonionic and ionic surfactants under different pH and concentrations.

    PubMed

    Gitipour, Saeid; Narenjkar, Khadijeh; Sanati Farvash, Emad; Asghari, Hossein

    2014-01-01

    In this study, the viability of soil flushing on the removal of cresols (meta-, ortho-, and para-cresols) from contaminated soil has been investigated. High production and distribution of cresols in the environment indicate their potential for a widespread exposure to humans. The presence of these compounds in soil could cause a significant threat to environment, as they are toxic and refractory in nature. Cresols are persistent chemicals which are classified by the United State Environmental Protection Agency (U.S.EPA) as Group C, possible human carcinogens. Soil flushing is one of the soil remediation technologies which could by applied for treatment of hydrocarbon contaminated soil. Flushing of the contaminated soil samples was carried out by using sodium dodecyl sulfate (SDS) and Triton X-100 surfactant solutions at the concentrations of 0.1%, 0.2%, 0.3%, and 0.4% (W/W). Three acidic, neutral, and alkaline environments were utilized by adjusting pH of the washing solutions at 3, 7 and 12 to evaluate the effect of washing environment in removing cresols. The results of this research denote that the highest removal efficiencies of 79.6% and 83.51% were achieved for m-cresol and total o- and p-cresols, respectively, under the alkaline environment of pH12 at 0.4% (W/W) SDS concentration. Regarding performance of Triton X-100, the removal efficiencies of 80.26% and 80.14% for the above cresols were attained under similar conditions. Hence, illustrating the effectiveness of surfactants in soil flushing remediation of cresols contaminated soil.

  19. Variation in pH optima of hydrolytic enzyme activities in tropical rain forest soils.

    PubMed

    Turner, Benjamin L

    2010-10-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.

  20. Variation in pH Optima of Hydrolytic Enzyme Activities in Tropical Rain Forest Soils

    PubMed Central

    Turner, Benjamin L.

    2010-01-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates. PMID:20709838

  1. CARINA data synthesis project: pH data scale unification and cruise adjustments

    NASA Astrophysics Data System (ADS)

    Velo, A.; Pérez, F. F.; Lin, X.; Key, R. M.; Tanhua, T.; de La Paz, M.; van Heuven, S.; Jutterström, S.; Ríos, A. F.

    2009-10-01

    Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from previously non-publicly available cruise data sets in the Artic Mediterranean Seas (AMS), Atlantic and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic). These data have gone through rigorous quality control (QC) procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; AMS, Atlantic and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 59 reported pH measured values. Here we present details of the secondary QC on pH for the CARINA database. Procedures of quality control, including crossover analysis between cruises and inversion analysis of all crossover data are briefly described. Adjustments were applied to the pH values for 21 of the cruises in the CARINA dataset. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s. Based on our analysis we estimate the internal accuracy of the CARINA pH data to be 0.005 pH units. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation.

  2. Application of Acetate Buffer in pH Adjustment of Mash and its Influence on Fuel Ethanol Fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 2M sodium acetate buffer at pH 4.2 was used to adjust pH of liquefied mashes in a simultaneous saccharification and fermentation (SSF) procedure. Although 5 mL of the buffer did not bring the pH values of the mashes (~100 mL) from a sorghum hybrid to 4.2, it kept the system stable (pH from 4.7 to ...

  3. Urea Hydrolysis Rate in Soil Toposequences as Influenced by pH, Carbon, Nitrogen, and Soluble Metals.

    PubMed

    Fisher, Kristin A; Meisinger, John J; James, Bruce R

    2016-01-01

    A simultaneous increase in the use of urea fertilizer and the incidence of harmful algal blooms worldwide has generated interest in potential loss pathways of urea from agricultural areas. The objective of this research was to study the rate of urea hydrolysis in soil profile toposequences sampled from the Coastal Plain (CP) and Piedmont (PM) regions of Maryland to understand native urea hydrolysis rates (UHRs) as well as the controls governing urea hydrolysis both across a landscape and with depth in the soil profile. A pH-adjustment experiment was conducted to explore the relationship between pH and urea hydrolysis because of the importance of pH to both agronomic productivity and microbial communities. Soils were sampled from both A and B horizons along transects containing an agricultural field (AG), a grassed field border (GB), and a perennially vegetated zone adjacent to surface water. On average, the A-horizon UHRs were eight times greater than corresponding B-horizon rates, and within the CP, the riparian zone (RZ) soils hydrolyzed urea faster than the agricultural soils. The pH adjustment of these soils indicated the importance of organic-matter-related factors (C, N, extractable metals) in determining UHR. These results suggest that organic-matter-rich RZ soils may be valuable in mitigating losses of urea from neighboring fields. Additional field-scale urea hydrolysis studies would be valuable to corroborate the mechanisms described herein and to explore the conditions affecting the fate and transport of urea in agroecosystems.

  4. Effects of pH adjustment and sodium ions on sour taste intensity of organic acids.

    PubMed

    Neta, E R D; Johanningsmeier, S D; Drake, M A; McFeeters, R F

    2009-01-01

    Protonated organic acid species have been shown to be the primary stimuli responsible for sour taste of organic acids. However, we have observed that sour taste may be modulated when the pH of acid solutions is raised using sodium hydroxide. Objectives were to evaluate the effect of pH adjustment on sour taste of equimolar protonated organic acid solutions and to investigate the potential roles of organic anions and sodium ions on sour taste perception. Despite equal concentrations of protonated acid species, sour taste intensity decreased significantly with increased pH for acetic, lactic, malic, and citric acids (P < 0.05). Total organic anion concentration did not explain the suppression of sour taste in solutions containing a blend of 3 organic acids with constant concentration of protonated organic acid species and hydrogen ions and variable organic anion concentrations (R(2)= 0.480, P = 0.12). Sour taste suppression in these solutions seemed to be more closely related to sodium ions added in the form of NaOH (R(2)= 0.861, P = 0.007). Addition of 20 mM NaCl to acid solutions resulted in significant suppression of sour taste (P = 0.016). However, sour taste did not decrease with further addition of NaCl up to 80 mM. Presence of sodium ions was clearly shown to decrease sour taste of organic acid solutions. Nonetheless, suppression of sour taste in pH adjusted single acid solutions was greater than what would be expected based on the sodium ion concentration alone, indicating an additional suppression mechanism may be involved.

  5. Sorption of lead in soil as a function of pH: a study case in México.

    PubMed

    Martínez-Villegas, N; Flores-Vélez, L Ma; Domínguez, O

    2004-12-01

    Reactions of lead sorption onto soil are largely affected by properties and composition of soil and its solution. In this study, the lead sorption onto regosol eutric soil from Francisco I. Madero, Zacatecas, Mexico is evaluated at different pH values. Soil samples were suspended in lead solutions of 10, 25, 50, 100, 150, 200, 300, and 400 mg/l (as Pb(NO3)2). The pH was adjusted at 2, 3, 4, and 5.5 with nitric acid for each of the lead solution concentrations. In all the cases the ionic strength was I=0.09 M with calcium nitrate. The solid-liquid-ratios were fixed in 1:100 and 1:200 g/ml. The results show that lead sorption increases when pH increases. Experimental isotherms were adjusted by both Langmuir and Freundlich models. The Langmuir affinity parameter, K, indicates that the lead sorption capacity of Francisco I. Madero soils is largely perceptible to pH changes.

  6. Effect of pH and soil structure on transport of sulfonamide antibiotics in agricultural soils.

    PubMed

    Park, Jong Yol; Huwe, Bernd

    2016-06-01

    We investigated the effect of solution pH and soil structure on transport of sulfonamide antibiotics (sulfamethoxazole, sulfadimethoxine and sulfamethazine) in combination with batch sorption tests and column experiments. Sorption isotherms properly conformed to Freundlich model, and sorption potential of the antibiotics is as follows; sulfadimethoxine > sulfamethoxazole > sulfamethazine. Decreasing pH values led to increased sorption potential of the antibiotics on soil material in pH range of 4.0-8.0. This likely resulted from abundance of neutral and positive-charged sulfonamides species at low pH, which electrostatically bind to sorption sites on soil surface. Due to destruction of macropore channels, lower hydraulic conductivities of mobile zone were estimated in the disturbed soil columns than in the undisturbed soil columns, and eventually led to lower mobility of the antibiotics in disturbed column. The results suggest that knowledge of soil structure and solution condition is required to predict fate and distribution of sulfonamide antibiotics in environmental matrix. PMID:26995452

  7. Effect of pH and soil structure on transport of sulfonamide antibiotics in agricultural soils.

    PubMed

    Park, Jong Yol; Huwe, Bernd

    2016-06-01

    We investigated the effect of solution pH and soil structure on transport of sulfonamide antibiotics (sulfamethoxazole, sulfadimethoxine and sulfamethazine) in combination with batch sorption tests and column experiments. Sorption isotherms properly conformed to Freundlich model, and sorption potential of the antibiotics is as follows; sulfadimethoxine > sulfamethoxazole > sulfamethazine. Decreasing pH values led to increased sorption potential of the antibiotics on soil material in pH range of 4.0-8.0. This likely resulted from abundance of neutral and positive-charged sulfonamides species at low pH, which electrostatically bind to sorption sites on soil surface. Due to destruction of macropore channels, lower hydraulic conductivities of mobile zone were estimated in the disturbed soil columns than in the undisturbed soil columns, and eventually led to lower mobility of the antibiotics in disturbed column. The results suggest that knowledge of soil structure and solution condition is required to predict fate and distribution of sulfonamide antibiotics in environmental matrix.

  8. [Spatiotemporal variation of soil pH in Guangdong Province of China in past 30 years].

    PubMed

    Guo, Zhi-Xing; Wang, Jing; Chai, Min; Chen, Ze-Peng; Zhan, Zhen-Shou; Zheng, Wu-Ping; Wei, Xiu-Guo

    2011-02-01

    Based on the 1980s' soil inventory data and the 2002-2007 soil pH data of Guangdong Province, the spatiotemporal variation of soil pH in the Province in past 30 years was studied. In the study period, the spatial distribution pattern of soil pH in the Province had less change (mainly acidic), except that in Pearl River Delta and parts of Qingyuan and Shaoguan (weak alkaline). The overall variation of soil pH was represented as acidification, with the average pH value changed from 5.70 to 5.44. Among the soil types in the Province, alluvial soil had an increased pH, lateritic red soil, paddy soil, and red soil had a large decrement of pH value, and lime soil was most obvious in the decrease of pH value and its area percentage. The soil acidification was mainly induced by soil characteristics, some natural factors such as acid rain, and human factors such as unreasonable fertilization and urbanization. In addition, industrialization and mining increased the soil pH in some areas.

  9. Evaluation of soil pH and moisture content on in-situ ozonation of pyrene in soils.

    PubMed

    Luster-Teasley, S; Ubaka-Blackmoore, N; Masten, S J

    2009-08-15

    In this study, pyrene spiked soil (300 ppm) was ozonated at pH levels of 2, 6, and 8 and three moisture contents. It was found that soil pH and moisture content impacted the effectiveness of PAH oxidation in unsaturated soils. In air-dried soils, as pH increased, removal increased, such that pyrene removal efficiencies at pH 6 and pH 8 reached 95-97% at a dose of 2.22 mg O(3)/mg pyrene. Ozonation at 16.2+/-0.45 mg O(3)/ppm pyrene in soil resulted in 81-98% removal of pyrene at all pH levels tested. Saturated soils were tested at dry, 5% or 10% moisture conditions. The removal of pyrene was slower in moisturized soils, with the efficiency decreasing as the moisture content increased. Increasing the pH of the soil having a moisture content of 5% resulted in improved pyrene removals. On the contrary, in the soil having a moisture content of 10%, as the pH increased, pyrene removal decreased. Contaminated PAH soils were stored for 6 months to compare the efficiency of PAH removal in freshly contaminated soil and aged soils. PAH adsorption to soil was found to increase with longer exposure times; thus requiring much higher doses of ozone to effectively oxidize pyrene.

  10. Integrating pH, substrate, and plant regrowth effects on soil nitrogen cycling after fire

    NASA Astrophysics Data System (ADS)

    Hanan, E. J.; Schimel, J.; Tague, C.; D'Antonio, C. M.

    2014-12-01

    Mediterranean-type ecosystems are structured by fire. In California chaparral, fires uncouple N production and consumption by enhancing nitrification and reducing plant uptake. NO3- that accumulates after fire is vulnerable to leaching. However, the extent to which fires decouple N fluxes can vary spatially and with timing of fire, and the specific mechanisms controlling N metabolism in recovering chaparral are not well understood. We combined empirical analysis and modeling in two chaparral watersheds to better understand how these systems recover from fire, and to explore their sensitivity to changing climate and fire regimes. To evaluate how pH, charcoal, and NH4+ supply influence N cycling, we measured mineralization and nitrification rates in chaparral soils that burned 1, 4, 20 and 40 years prior to sampling. We then experimentally adjusted pH, charcoal, and NH4+ concentrations for all soils in a factorial design, and incubated them for 8 weeks. Each week, we measured respiration, exchangeable NH4+ and NO3- content, nitrification potential, microbial biomass, and pH. Then to project the effects of altered precipitation patterns and fire timing on nitrogen dynamics and recovery, we used the hydro-biogeochemical model RHESSys. Fires were imposed at the beginning and end of the growing season under various climates. NO3- production was highest in soils collected from the most recently burned sites. Also, NO3- concentrations increased over the course of incubation in soils from all sites, especially at high pH, and with NH4+ addition. Charcoal slightly augmented the effects of elevated pH and NH4+ on NO3- production iduring the early stages of incubation in 1 and 4-year old sites, while it slightly dampened their effects by week 8. However, in 20 and 40-year old sites, charcoal had no effect. Overall, nitrification was most powerfully constrained by NH4+ supply. However, increases in pH that occur after fire may enhance nitrification rates when substrate is

  11. [Inhibitory effect of DMPP on soil nitrification as affected by soil moisture content, pH and organic matter].

    PubMed

    Xue, Yan; Wu, Zhi-Jie; Zhang, Li-Li; Gong, Ping; Dong, Xin-Xin; Nie, Yan-Xia

    2012-10-01

    A laboratory incubation test with meadow brown soil was conducted to study the inhibitory effect of 3,4-dimethylpyrazole phosphate (DMPP) on soil nitrification as affected by soil moisture content (40%, 60% and 80% of the maximum field capacity), pH (4, 7 and 10), and organic matter (retained and removal). With the decrease of soil moisture content, the degradation of DMPP in soil tended to slow down, and the oxidation of soil NH4+ was more inhibited. At pH 10, more DMPP was remained in soil, and had the greatest inhibitory effect; at pH 7 and pH 4, the DMPP was lesser remained, with a smaller inhibitory effect. The removal of organic matter prolonged the remaining time of DMPP in soil, and decreased the apparent soil nitrification rate significantly.

  12. Community structure and soil pH determine chemoautotrophic carbon dioxide fixation in drained paddy soils.

    PubMed

    Long, Xi-En; Yao, Huaiying; Wang, Juan; Huang, Ying; Singh, Brajesh K; Zhu, Yong-Guan

    2015-06-16

    Previous studies suggested that microbial photosynthesis plays a potential role in paddy fields, but little is known about chemoautotrophic carbon fixers in drained paddy soils. We conducted a microcosm study using soil samples from five paddy fields to determine the environmental factors and quantify key functional microbial taxa involved in chemoautotrophic carbon fixation. We used stable isotope probing in combination with phospholipid fatty acid (PLFA) and molecular approaches. The amount of microbial (13)CO2 fixation was determined by quantification of (13)C-enriched fatty acid methyl esters and ranged from 21.28 to 72.48 ng of (13)C (g of dry soil)(-1), and the corresponding ratio (labeled PLFA-C:total PLFA-C) ranged from 0.06 to 0.49%. The amount of incorporationof (13)CO2 into PLFAs significantly increased with soil pH except at pH 7.8. PLFA and high-throughput sequencing results indicated a dominant role of Gram-negative bacteria or proteobacteria in (13)CO2 fixation. Correlation analysis indicated a significant association between microbial community structure and carbon fixation. We provide direct evidence of chemoautotrophic C fixation in soils with statistical evidence of microbial community structure regulation of inorganic carbon fixation in the paddy soil ecosystem.

  13. Effect of iron oxide on nitrification in two agricultural soils with different pH

    NASA Astrophysics Data System (ADS)

    Huang, Xueru; Zhu-Barker, Xia; Horwath, William R.; Faeflen, Sarwee J.; Luo, Hongyan; Xin, Xiaoping; Jiang, Xianjun

    2016-10-01

    Iron (Fe) affects soil nitrogen (N) cycling processes both in anoxic and oxic environments. The role of Fe in soil N transformations including nitrification, mineralization, and immobilization, is influenced by redox activity, which is regulated by soil pH. The effect of Fe minerals, particularly oxides, on soil N transformation processes depends on soil pH, with Fe oxide often stimulating nitrification activity in the soil with low pH. We conducted lab incubations to investigate the effect of Fe oxide on N transformation rates in two subtropical agricultural soils with low pH (pH 5.1) and high pH (pH 7.8). 15N-labeled ammonium and nitrate were used separately to determine N transformation rates combined with Fe oxide (ferrihydrite) addition. Iron oxide stimulated net nitrification in low-pH soil (pH 5.1), while the opposite occurred in high-pH soil (pH 7.8). Compared to the control, Fe oxide decreased microbial immobilization of inorganic N by 50 % in low-pH soil but increased it by 45 % in high-pH soil. A likely explanation for the effects at low pH is that Fe oxide increased NH3-N availability by stimulating N mineralization and inhibiting N immobilization. These results indicate that Fe oxide plays an important role in soil N transformation processes and the magnitude of the effect of Fe oxide is dependent significantly on soil pH.

  14. pH as a Driver for Ammonia-Oxidizing Archaea in Forest Soils.

    PubMed

    Stempfhuber, Barbara; Engel, Marion; Fischer, Doreen; Neskovic-Prit, Ganna; Wubet, Tesfaye; Schöning, Ingo; Gubry-Rangin, Cécile; Kublik, Susanne; Schloter-Hai, Brigitte; Rattei, Thomas; Welzl, Gerhard; Nicol, Graeme W; Schrumpf, Marion; Buscot, Francois; Prosser, James I; Schloter, Michael

    2015-05-01

    In this study, we investigated the impact of soil pH on the diversity and abundance of archaeal ammonia oxidizers in 27 different forest soils across Germany. DNA was extracted from topsoil samples, the amoA gene, encoding ammonia monooxygenase, was amplified; and the amplicons were sequenced using a 454-based pyrosequencing approach. As expected, the ratio of archaeal (AOA) to bacterial (AOB) ammonia oxidizers' amoA genes increased sharply with decreasing soil pH. The diversity of AOA differed significantly between sites with ultra-acidic soil pH (<3.5) and sites with higher pH values. The major OTUs from soil samples with low pH could be detected at each site with a soil pH <3.5 but not at sites with pH >4.5, regardless of geographic position and vegetation. These OTUs could be related to the Nitrosotalea group 1.1 and the Nitrososphaera subcluster 7.2, respectively, and showed significant similarities to OTUs described from other acidic environments. Conversely, none of the major OTUs typical of sites with a soil pH >4.6 could be found in the ultra- and extreme acidic soils. Based on a comparison with the amoA gene sequence data from a previous study performed on agricultural soils, we could clearly show that the development of AOA communities in soils with ultra-acidic pH (<3.5) is mainly triggered by soil pH and is not influenced significantly by the type of land use, the soil type, or the geographic position of the site, which was observed for sites with acido-neutral soil pH.

  15. Cell culturability of Pseudomonas protegens CHA0 depends on soil pH.

    PubMed

    Mascher, Fabio; Hase, Carsten; Bouffaud, Marie-Lara; Défago, Geneviève; Moënne-Loccoz, Yvan

    2014-02-01

    Pseudomonas inoculants may lose colony-forming ability in soil, but soil properties involved are poorly documented. Here, we tested the hypothesis that soil acidity could reduce persistence and cell culturability of Pseudomonas protegens CHA0. At 1 week in vitro, strain CHA0 was found as culturable cells at pH 7, whereas most cells at pH 4 and all cells at pH 3 were noncultured. In 21 natural soils of contrasted pH, cell culturability loss of P. protegens CHA0 took place in all six very acidic soils (pH < 5.0) and in three of five acidic soils (5.0 < pH < 6.5), whereas it was negligible in the neutral and alkaline soils at 2 weeks and 2 months. No correlation was found between total cell counts of P. protegens CHA0 and soil composition data, whereas colony counts of the strain correlated with soil pH. Maintenance of cell culturability in soils coincided with a reduction in inoculant cell size. Some of the noncultured CHA0 cells were nutrient responsive in Kogure's viability test, both in vitro and in soil. Thus, this shows for the first time that the sole intrinsic soil composition factor triggering cell culturability loss in P. protegens CHA0 is soil acidity. PMID:24224494

  16. Cell culturability of Pseudomonas protegens CHA0 depends on soil pH.

    PubMed

    Mascher, Fabio; Hase, Carsten; Bouffaud, Marie-Lara; Défago, Geneviève; Moënne-Loccoz, Yvan

    2014-02-01

    Pseudomonas inoculants may lose colony-forming ability in soil, but soil properties involved are poorly documented. Here, we tested the hypothesis that soil acidity could reduce persistence and cell culturability of Pseudomonas protegens CHA0. At 1 week in vitro, strain CHA0 was found as culturable cells at pH 7, whereas most cells at pH 4 and all cells at pH 3 were noncultured. In 21 natural soils of contrasted pH, cell culturability loss of P. protegens CHA0 took place in all six very acidic soils (pH < 5.0) and in three of five acidic soils (5.0 < pH < 6.5), whereas it was negligible in the neutral and alkaline soils at 2 weeks and 2 months. No correlation was found between total cell counts of P. protegens CHA0 and soil composition data, whereas colony counts of the strain correlated with soil pH. Maintenance of cell culturability in soils coincided with a reduction in inoculant cell size. Some of the noncultured CHA0 cells were nutrient responsive in Kogure's viability test, both in vitro and in soil. Thus, this shows for the first time that the sole intrinsic soil composition factor triggering cell culturability loss in P. protegens CHA0 is soil acidity.

  17. Sorption of toluene by humic acids derived from lake sediment and mountain soil at different pH.

    PubMed

    Chang Chien, S W; Chen, C Y; Chang, J H; Chen, S H; Wang, M C; Mannepalli, Madhava Rao

    2010-05-15

    Contamination of soil and groundwater with BTEX compounds (benzene, toluene, ethylbenzene, and xylene) depends on the sorption behavior of these compounds by soil organic matter (SOM) and humic acids (HAs). In this study sorption of toluene by HAs extracted from lake sediment and mountain soil was investigated. HA suspensions were adjusted to pH 4.00, 6.00, or 8.00 and made to the concentration of 200 mg L(-1). Each HA suspension or solution was subjected to particle size analysis using high performance particle sizer (HPPS). The particle size of HA from lake sediment was around 1000-1200 nm while that from mountain soil was 220-320 nm at suspension pH 4.00. Kinetic studies showed that sorption of toluene by the two HAs followed pseudo-first-order and mainly pseudo-zero-order kinetics. At suspension pH 4.00, the sorption of toluene by the two HAs was best described by Langmuir and Temkin adsorption isotherm models. Further, sorption of toluene by the lake sediment HA was significantly greater than that by mountain soil HA. It was thus suggested that the lake sediment HA with larger particle size may develop beneficially chemical conformation for sorption of toluene and related compounds in soil and associated environments.

  18. Adaptation of Denitrifying Populations to Low Soil pH

    PubMed Central

    Parkin, Timothy B.; Sexstone, Alan J.; Tiedje, James M.

    1985-01-01

    Natural denitrification rates and activities of denitrifying enzymes were measured in an agricultural soil which had a 20-year past history of low pH (pH ca. 4) due to fertilization with acid-generating ammonium salts. The soil adjacent to this site had been limed and had a pH of ca. 6.0. Natural denitrification rates of these areas were of similar magnitude: 158 ng of N g−1 of soil day−1 for the acid soil and 390 ng of N g−1 of soil day−1 at the neutral site. Estimates of in situ denitrifying enzyme activity were higher in the neutral soil, but substantial enzyme activity was also detected in the acid soil. Rates of nitrous oxide reduction were very low, even when NO3− and NO2− were undetectable, and were ca. 400 times lower than the rates of N2O production from NO3−. Denitrification rates measured in slurries of the acid and neutral soil showed distinctly different pH optima (pH 3.9 and pH 6.3) which were near the pH values of the two soils. This suggests that an acid-tolerant denitrifying population had been selected during the 20-year period of low pH. PMID:16346780

  19. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  20. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  1. Urea Hydrolysis Rate in Soil Toposequences as Influenced by pH, Carbon, Nitrogen, and Soluble Metals.

    PubMed

    Fisher, Kristin A; Meisinger, John J; James, Bruce R

    2016-01-01

    A simultaneous increase in the use of urea fertilizer and the incidence of harmful algal blooms worldwide has generated interest in potential loss pathways of urea from agricultural areas. The objective of this research was to study the rate of urea hydrolysis in soil profile toposequences sampled from the Coastal Plain (CP) and Piedmont (PM) regions of Maryland to understand native urea hydrolysis rates (UHRs) as well as the controls governing urea hydrolysis both across a landscape and with depth in the soil profile. A pH-adjustment experiment was conducted to explore the relationship between pH and urea hydrolysis because of the importance of pH to both agronomic productivity and microbial communities. Soils were sampled from both A and B horizons along transects containing an agricultural field (AG), a grassed field border (GB), and a perennially vegetated zone adjacent to surface water. On average, the A-horizon UHRs were eight times greater than corresponding B-horizon rates, and within the CP, the riparian zone (RZ) soils hydrolyzed urea faster than the agricultural soils. The pH adjustment of these soils indicated the importance of organic-matter-related factors (C, N, extractable metals) in determining UHR. These results suggest that organic-matter-rich RZ soils may be valuable in mitigating losses of urea from neighboring fields. Additional field-scale urea hydrolysis studies would be valuable to corroborate the mechanisms described herein and to explore the conditions affecting the fate and transport of urea in agroecosystems. PMID:26828191

  2. Competitive and synergistic effects in pH dependent phosphate adsorption in soils: LCD modeling.

    PubMed

    Weng, Liping; Vega, Flora Alonso; Van Riemsdijk, Willem H

    2011-10-01

    The pH dependency of soluble phosphate in soil was measured for six agricultural soils over a pH range of 3-10. A mechanistic model, the LCD (ligand charge distribution) model, was used to simulate this change, which considers phosphate adsorption to metal (hydr)oxides in soils under the influence of natural organic matter (NOM) and polyvalent cations (Ca(2+), Al(3+), and Fe(3+)). For all soils except one, the description in the normal pH range 5-8 is good. For some soils at more extreme pH values (for low P-loading soils at low pH and for high P-loading soils at high pH), the model over predicts soluble P. The calculation shows that adsorption is the major mechanism controlling phosphate solubility in soils, except at high pH in high P-loading soils where precipitation of calcium phosphate may take place. NOM and polyvalent cations have a very strong effect on the concentration level of P. The pattern of pH dependency of soluble P in soils differs greatly from the pH effects on phosphate adsorption to synthetic metal (hydr)oxides in a monocomponent system. According to the LCD model, the pH dependency in soil is mainly caused by the synergistic effects of Ca(2+) adsorption to oxides. Adsorption of Al(3+) to NOM adsorbed plays an important role only at a pH < 4.5. Presence of NOM coating strongly competes with phosphate for the adsorption and is an important factor to consider in modeling phosphate adsorption in natural samples.

  3. Biochar effects on soil-resident ligninolytic fungi: in vitro growth response and its pH dependence

    NASA Astrophysics Data System (ADS)

    Taskin, Eren; Loffredo, Elisabetta

    2016-04-01

    Ligninolytic fungi play an essential role on soil fertility because of their decomposing activity that allows nutrients inside biomasses to be released back into the soil. Their enzymes are able to degrade lignin which is otherwise recalcitrant to microbial and chemical degradation. Biochar (BC) has been recently proposed as a soil amendment that may contribute to climate change mitigation via carbon sequestration in soil. Pyrolysis conditions, feedstock and several other factors affect BC characteristics which in turn may influence BC impact on soil microorganisms and terrestrial ecosystems. However, limited information is available in the literature about BC's impact on ligninolytic fungi. The objective of this in vitro study was to assess the impact of BC and pH change caused by BC addition on three soil-resident ligninolytic fungi, Pleurotus ostreatus, Trametes versicolor and Bjerkandera adusta. The BC sample used in this study was obtained from 100% red spruce pellets pyrolysed at a temperature of 550 °C, and it was added to PDA medium directly as solid BC at the doses of 2 g L-1 (BC-LD) and 10 g L-1 (BC-HD). pH values were determined and the experiments were conducted either adjusting the pH of the controls either without pH adjustment. The fungi were inoculated separately in Petri dishes filled with the various media and the radial mycelial growth was measured at several sampling times. Results obtained showed a fungal growth response clearly dependent on the species and the BC dose. BC-LD stimulated the growth of P. ostreatus and T. versicolor, whereas it inhibited that of B. adusta. BC-HD stimulated the growth of P. ostreatus and inhibited that of T. versicolor and B. adusta. Similar responses were obtained with or without pH adjustment for P. ostreatus and T. versicolor, whereas a pH dependency was found for B. adusta. The effects of these and other pertinent treatments on fungal enzymes of the fungi are currently under investigation.

  4. Application of acetate buffer in pH adjustment of sorghum mash and its influence on fuel ethanol fermentation.

    PubMed

    Zhao, Renyong; Bean, Scott R; Crozier-Dodson, Beth Ann; Fung, Daniel Y C; Wang, Donghai

    2009-01-01

    A 2 M sodium acetate buffer at pH 4.2 was tried to simplify the step of pH adjustment in a laboratory dry-grind procedure. Ethanol yields or conversion efficiencies of 18 sorghum hybrids improved significantly with 2.0-5.9% (3.9% on average) of relative increases when the method of pH adjustment changed from traditional HCl to the acetate buffer. Ethanol yields obtained using the two methods were highly correlated (R (2) = 0.96, P < 0.0001), indicating that the acetate buffer did not influence resolution of the procedure to differentiate sorghum hybrids varying in fermentation quality. Acetate retarded the growth of Saccharomyces cerevisiae, but did not affect the overall fermentation rate. With 41-47 mM of undissociated acetic acid in mash of a sorghum hybrid at pH 4.7, rates of glucose consumption and ethanol production were inhibited during exponential phase but promoted during stationary phase. The maximum growth rate constants (mu(max)) were 0.42 and 0.32 h(-1) for cells grown in mashes with pH adjusted by HCl and the acetate buffer, respectively. Viable cell counts of yeast in mashes with pH adjusted by the acetate buffer were 36% lower than those in mashes adjusted by HCl during stationary phase. Coupled to a 5.3% relative increase in ethanol, a 43.6% relative decrease in glycerol was observed, when the acetate buffer was substituted for HCl. Acetate helped to transfer glucose to ethanol more efficiently. The strain tested did not use acetic acid as carbon source. It was suggested that decreased levels of ATP under acetate stress stimulate glycolysis to ethanol formation, increasing its yield at the expense of biomass and glycerol production.

  5. Soil pH determines microbial diversity and composition in the park grass experiment.

    PubMed

    Zhalnina, Kateryna; Dias, Raquel; de Quadros, Patricia Dörr; Davis-Richardson, Austin; Camargo, Flavio A O; Clark, Ian M; McGrath, Steve P; Hirsch, Penny R; Triplett, Eric W

    2015-02-01

    The Park Grass experiment (PGE) in the UK has been ongoing since 1856. Its purpose is to study the response of biological communities to the long-term treatments and associated changes in soil parameters, particularly soil pH. In this study, soil samples were collected across pH gradient (pH 3.6-7) and a range of fertilizers (nitrogen as ammonium sulfate, nitrogen as sodium nitrate, phosphorous) to evaluate the effects nutrients have on soil parameters and microbial community structure. Illumina 16S ribosomal RNA (rRNA) amplicon sequencing was used to determine the relative abundances and diversity of bacterial and archaeal taxa. Relationships between treatments, measured soil parameters, and microbial communities were evaluated. Clostridium, Bacteroides, Bradyrhizobium, Mycobacterium, Ruminococcus, Paenibacillus, and Rhodoplanes were the most abundant genera found at the PGE. The main soil parameter that determined microbial composition, diversity, and biomass in the PGE soil was pH. The most probable mechanism of the pH impact on microbial community may include mediation of nutrient availability in the soil. Addition of nitrogen to the PGE plots as ammonium sulfate decreases soil pH through increased nitrification, which causes buildup of soil carbon, and hence increases C/N ratio. Plant species richness and plant productivity did not reveal significant relationships with microbial diversity; however, plant species richness was positively correlated with soil microbial biomass. Plants responded to the nitrogen treatments with an increase in productivity and a decrease in the species richness.

  6. Site-specific management of soil pH and nutrients in blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific management of soil pH and fertilizers is one of the most promising strategies in precision agriculture and is potentially applicable to many horticultural crops, including blueberry. Unlike most fruit crops, blueberry is adapted to low soil pH conditions in the range of 4-5.5 and has ...

  7. Teaching Plant-Soil Relationships with Color Images of Rhizosphere pH.

    ERIC Educational Resources Information Center

    Heckman, J. R.; Strick, J. E.

    1996-01-01

    Presents a laboratory exercise that uses a simple imaging technique to illustrate the profound effects that living roots exert on the pH of the surrounding soil environment. Achieves visually stimulating results that can be used to reinforce lectures on rhizosphere pH, nutrient availability, plant tolerance of soil acidity, microbial activity, and…

  8. pH dominates variation in tropical soil archaeal diversity and community structure.

    PubMed

    Tripathi, Binu M; Kim, Mincheol; Lai-Hoe, Ang; Shukor, Nor A A; Rahim, Raha A; Go, Rusea; Adams, Jonathan M

    2013-11-01

    Little is known of the factors influencing soil archaeal community diversity and composition in the tropics. We sampled soils across a range of forest and nonforest environments in the equatorial tropics of Malaysia, covering a wide range of pH values. DNA was PCR-amplified for the V1-V3 region of the 16S rRNA gene, and 454-pyrosequenced. Soil pH was the best predictor of diversity and community composition of Archaea, being a stronger predictor than land use. Archaeal OTU richness was highest in the most acidic soils. Overall archaeal abundance in tropical soils (determined by qPCR) also decreased at higher pH. This contrasts with the opposite trend previously found in temperate soils. Thaumarcheota group 1.1b was more abundant in alkaline soils, whereas group 1.1c was only detected in acidic soils. These results parallel those found in previous studies in cooler climates, emphasizing niche conservatism among broad archaeal groups. Among the most abundant operational taxonomic units (OTUs), there was clear evidence of niche partitioning by pH. No individual OTU occurred across the entire range of pH values. Overall, the results of this study show that pH plays a major role in structuring tropical soil archaeal communities.

  9. Atmospheric methane consumption by forest soils and extracted bacteria at different pH values

    SciTech Connect

    Amaral, J.A.; Ren, T.; Knowles, R.

    1998-07-01

    The effect of pH on atmospheric methane (CH{sub 4}) consumption was studied with slurries of forest soils and with bacteria extracted from the same soils. Soil samples were collected from a mixed hardwood stand in New Hampshire, from jackpine and aspen stands at the BOREAS (Boreal Ecosystem Atmosphere Study) site near Thompson, northern Manitoba, from sites in southern Quebec, including a beech stand and a meadow, and from a site in Ontario. Consumption of atmospheric CH{sub 4} occurred at depths of >5 cm in both acidic and alkaline soils. In slurries of acidic soils, maximum activity occurred at different pH values. Bacteria extracted from these soils by high-speed blending and density gradient centrifugation showed pH responses different from the pH responses of the slurries. In all cases, these bacteria had a methanotrophy pH optimum of 5.8 and exhibited no activity at pH 6.8 to 7.0, the pH optimum range for known methanotrophs. This difference in pH responses could be useful in modifying media currently used for isolation of these organisms. Methanotrophic activity was induced in previously non-CH{sub 4}-consuming soils by preincubation with 5% (vol/vol) CH{sub 4} or by liquid enrichment with 20% CH{sub 4}. The bacteria showed pH responses typical of known methanotrophs and not typical of preexisting consumers of ambient CH{sub 4}. Furthermore, methanotrophs induced by high CH{sub 4} levels were more readily extracted from soil than preexisting ambient CH{sub 4} consumers were. In the alkaline soils, preexisting activity either was destroyed or resisted extraction by the procedure used. The results support the hypothesis that consumers of ambient CH{sub 4} in soils are physiologically distinct from the known methanotrophs.

  10. Nicotine Absorption from Smokeless Tobacco Modified to Adjust pH

    PubMed Central

    Pickworth, Wallace B.; Rosenberry, Zachary R.; Gold, Wyatt; Koszowski, Bartosz

    2014-01-01

    Introduction Nicotine delivery from smokeless tobacco (ST) products leads to addiction and the use of ST causes pathology that is associated with increased initiation of cigarette smoking. The rapid delivery of nicotine from ST seems to be associated with the pH of the aqueous suspension of the products - high pH is associated with high nicotine absorption. However, early studies compared nicotine absorption from different commercial products that not only differed in pH but in flavoring, nicotine content, and in format-pouches and loose tobacco. Methods The present study compared nicotine absorption from a single unflavored referent ST product (pH 7.7) that was flavored with a low level of wintergreen (2 mg/g) and the pH was amended to either high (8.3) or low (5.4) pH with sodium carbonate or citric acid, respectively. Results In a within-subject clinical study, the higher pH products delivered more nicotine. No significant differences were seen between perceived product strengths and product experience in all conditions. Heart rate increased by 4 to 6 beats per minute after the high pH flavored and the un-amended product but did not change after the low pH flavored product. Conclusions These results indicate that pH is a primary determinant of buccal nicotine absorption. The role of flavoring and other components of ST products in nicotine absorption remain to be determined. PMID:25530912

  11. [Effects of thiourea on pH and availability of metal ions in acid red soil].

    PubMed

    Yang, Bo; Wang, Wen; Zeng, Qing-Ru; Zhou, Xi-Hong

    2014-03-01

    Through the simulation research, the effects of application of thiourea and urea on pH and availability of metal ions in acid red soil were studied, and the results showed that after applying urea, the soil pH increased in the first experimental stage and then reduced gradually to a low level, however, decreased trends of soil pH values were inhibited by the application of thiourea, especially when the concentration of thiourea reached to 5.0 mmol x kg(-1) dry soil, the soil pH was stable at high level, which exceeded to 6.0. It proved that the application of thiourea could inhibit the soil acidification due to urea application. After applying urea with different concentrations of thiourea, the available contents of Zn and Al decreased with the increasing concentration of thiourea, nevertheless, when the concentration of thiourea reached to 5.0 mmol x kg(-1), the available content of Mn was stable at high level which was over 110 mg x kg(-1). In addition, the results showed a highly significant negative correlation between the soil pH and the available content of Cu, Zn and Al, but for Mn, no discipline was found between the soil pH and the availability after applying thiourea. Moreover, the soil pH became higher after applying urea with thiourea compared to add urea only, which led to the decreasing of available content of Al, and it was benefited for the control of the phytotoxic effect of Al. The available content of Mn in the soil not only depended on soil pH but also the content of thiourea due to its redox and complexing reaction with Mn.

  12. Effect of soil pH on as hyperaccumulation capacity in fern species, Pityrogramma calomelanos.

    PubMed

    Anh, B T Kim; Kim, D D; Kuschk, P; Tua, T V; Hue, N T; Minh, N N

    2013-03-01

    Arsenic uptake by hyperaccumulator plant species depends on many different environmental factors. Soil pH is one of the most important factors due to its combined effect on both chemical and biological processes. In greenhouse experiment, the effect of pH (within the pH range 3.6 - 8.9) on As uptake as well as biomass of Pityrogramma calomelanos was evaluated. The plants were grown in mining soil containing 645.6 mg As kg(-1) for 14 weeks. Within this time, the plant biomass growth was 3.78 - 8.64 g d. wt. per plant and the removal amounted 6.3-18.4 mg As per plant. Translocation factor (ratio of As in fronds to roots) of the fern was 3.6 - 9.7, indicating its potential in phytoremediation of As contaminated soil. Influence of pH on As bioavailability was visible as the available As concentration was higher in acidic soil compared to alkaline soil. Furthermore, it was found that As accumulation by Pityrogramma calomelanos was optimum in the soil of pH 3.6. Nevertheless, the results of this study demonstrate that remediation of As-contaminated mining soils, by this fern, can be improved by changing the soil pH from 4.6 to 6.8. PMID:24620585

  13. Solid-phase microextraction with pH adjustment for the determination of aromatic acids and bases in water.

    PubMed

    van Doorn, H; Grabanski, C B; Miller, D J; Hawthorne, S B

    1998-12-31

    Adjusting the pH of water samples before performing solid-phase microextraction (SPME) analysis can be used to selectively extract organic acids (at pH 2) and bases (at pH 12). Sorption behavior of test organics is predictable based on the acid dissociation constant in water. In general, polyacrylate (PA) and Carbowax-divinylbenzene (CW-DVB) show substantially higher fiber/water sorption coefficients (Kd values) than a polydimethylsiloxane (PDMS) coated fiber. Gas chromatography-flame ionization detection (GC-FID) detection limits with the CW-DVB sorbent are approximately 0.5 to 10 ng/ml in a 2-ml water sample for a variety of aromatic amines, phenols, and chlorinated phenols, and are approximately 1 to 50 ng/ml for the same solutes using the PA sorbent. However, the PA fiber is more selective (depending on the water pH) for the acid or base components than the CW-DVB fiber. With proper pH adjustment, the recovery of spiked aromatic amines and phenols from a surface wetlands water ranged from 73 to 118% of the known values, with a precision (R.S.D.) of approximately 5 to 20%. SPME quantitation of phenols in a coal gasification wastewater using a PA fiber also gave excellent agreement with conventional methylene chloride extraction, although continued use of a single fiber with this wastewater led to poorer precision.

  14. Influences of biochar addition on vegetable soil nitrogen balance and pH buffering capacity

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Odindo, AO; Xue, L.; Yang, L.

    2016-08-01

    Leaching is a major path for chemical nitrogen fertilizer loss from in vegetable soil, which would destroy soil pH buffering capacity soil and result in acidification. It has been a common phenomenon in Tai Lake Region, China. However, few study focused on the change soil pH buffering capacity, especially the effect of soil amendment on pH buffering capacity. In this study, a pot experiment was conducted to research the effects of biochar addition to a vegetable soil on nitrogen leaching and pH buffering capacity with pakchoi (B.chinensis L.) growth as the experimental crop. The results showed that biochar could significantly increase the pakchoi nitrogen utilization efficiency, decrease 48%-65% nitrogen loss from leaching under the urea continuous applied condition. Biochar also could effectively maintain the content of soil organic matter and base cations. Therefore, it rose up soil pH buffering capacity by 9.4%-36.8% and significantly slowed down acidification rate. It was suggested that 1%-2% addition ratio was recommended from this study when used as similar soil condition.

  15. Differences in soil micro-eukaryotic communities over soil pH gradients are strongly driven by parasites and saprotrophs.

    PubMed

    Dupont, A Ö C; Griffiths, R I; Bell, T; Bass, D

    2016-06-01

    A recent large-scale assessment of bacterial communities across a range of UK soil types showed that bacterial community structure was strongly determined by soil pH. We analysed a data set of eukaryotic 454 sequencing 18S rDNA from the surveyed samples and showed significant differences in eukaryotic assemblages according to pH class, mostly between low pH and higher pH soils. Soil eukaryote communities (per sample) differed most at the taxonomic rank approximating to order level. Taxonomies assigned with the Protist Ribosomal Reference and the Silva 119 databases were taxonomically inconsistent, mostly due to differing 18S annotations, although general structure and composition according to pH were coherent. A relatively small number of lineages, mostly putative parasitic protists and fungi, drive most differences between pH classes, with weaker contributions from bacterivores and autotrophs. Overall, soil parasites included a large diversity of alveolates, in particular apicomplexans. Phylogenetic analysis of alveolate lineages demonstrates a large diversity of unknown gregarines, novel perkinsids, coccidians, colpodellids and uncharacterized alveolates. Other novel and/or divergent lineages were revealed across the eukaryote tree of life. Our study provides an in-depth taxonomic evaluation of micro-eukaryotic diversity, and reveals novel lineages and insights into their relationships with environmental variables across soil gradients.

  16. Nestedness in Arbuscular Mycorrhizal Fungal Communities along Soil pH Gradients in Early Primary Succession: Acid-Tolerant Fungi Are pH Generalists

    PubMed Central

    Kawahara, Ai; An, Gi-Hong; Miyakawa, Sachie; Sonoda, Jun

    2016-01-01

    Soil acidity is a major constraint on plant productivity. Arbuscular mycorrhizal (AM) fungi support plant colonization in acidic soil, but soil acidity also constrains fungal growth and diversity. Fungi in extreme environments generally evolve towards specialists, suggesting that AM fungi in acidic soil are acidic-soil specialists. In our previous surveys, however, some AM fungi detected in strongly acidic soils could also be detected in a soil with moderate pH, which raised a hypothesis that the fungi in acidic soils are pH generalists. To test the hypothesis, we conducted a pH-manipulation experiment and also analyzed AM fungal distribution along a pH gradient in the field using a synthesized dataset of the previous and recent surveys. Rhizosphere soils of the generalist plant Miscanthus sinensis were collected both from a neutral soil and an acidic soil, and M. sinensis seedlings were grown at three different pH. For the analysis of field communities, rhizosphere soils of M. sinensis were collected from six field sites across Japan, which covered a soil pH range of 3.0–7.4, and subjected to soil trap culture. AM fungal community compositions were determined based on LSU rDNA sequences. In the pH-manipulation experiment the acidification of medium had a significant impact on the compositions of the community from the neutral soil, but the neutralization of the medium had no effect on those of the community from the acidic soil. Furthermore, the communities in lower -pH soils were subsets of (nested in) those in higher-pH soils. In the field communities a significant nestedness pattern was observed along the pH gradient. These observations suggest that the fungi in strongly acidic soils are pH generalists that occur not only in acidic soil but also in wide ranges of soil pH. Nestedness in AM fungal community along pH gradients may have important implications for plant community resilience and early primary succession after disturbance in acidic soils. PMID

  17. Long-term changes in soil pH across major forest ecosystems in China

    NASA Astrophysics Data System (ADS)

    Yang, Yuanhe; Li, Pin; He, Honglin; Zhao, Xia; Datta, Arindam; Ma, Wenhong; Zhang, Ying; Liu, Xuejun; Han, Wenxuan; Wilson, Maxwell C.; Fang, Jingyun

    2015-02-01

    Atmospheric acidic deposition has been a major environmental problem since the industrial revolution. However, our understanding of the effect of acidic deposition on soil pH is inconclusive. Here we examined temporal variations in topsoil pH and their relationships with atmospheric sulfur and nitrogen deposition across China's forests from the 1980s to the 2000s. To accomplish this goal, we conducted artificial neural network simulations using historical soil inventory data from the 1980s and a data set synthesized from literature published after 2000. Our results indicated that significant decreases in soil pH occurred in broadleaved forests, while minor changes were observed in coniferous and mixed coniferous and broadleaved forests. The magnitude of soil pH change was negatively correlated with atmospheric sulfur and nitrogen deposition. This relationship highlights the need for stringent measures that reduce sulfur and nitrogen emissions so as to maintain ecosystem structure and function.

  18. Atmospheric Methane Consumption by Forest Soils and Extracted Bacteria at Different pH Values.

    PubMed

    Amaral; Ren; Knowles

    1998-07-01

    The effect of pH on atmospheric methane (CH4) consumption was studied with slurries of forest soils and with bacteria extracted from the same soils. Soil samples were collected from a mixed hardwood stand in New Hampshire, from jackpine and aspen stands at the BOREAS (Boreal Ecosystem Atmosphere Study) site near Thompson, northern Manitoba, from sites in southern Québec, including a beech stand and a meadow, and from a site in Ontario (cultivated humisol). Consumption of atmospheric CH4 (concentration, approximately 1.8 ppm) occurred at depths of >5 cm in both acidic (pH 4.5 to 5.2) and alkaline (pH 7.2 to 7.8) soils. In slurries of acidic soils, maximum activity occurred at different pH values (pH 4.0 to 6.5). Bacteria extracted from these soils by high-speed blending and density gradient centrifugation showed pH responses different from the pH responses of the slurries. In all cases, these bacteria had a methanotrophy pH optimum of 5.8 and exhibited no activity at pH 6.8 to 7.0, the pH optimum range for known methanotrophs. This difference in pH responses could be useful in modifying media currently used for isolation of these organisms. Methanotrophic activity was induced in previously non-CH4-consuming soils by preincubation with 5% (vol/vol) CH4 (50,000 µl of CH4 per liter) or by liquid enrichment with 20% CH4. The bacteria showed pH responses typical of known methanotrophs and not typical of preexisting consumers of ambient CH4. Furthermore, methanotrophs induced by high CH4 levels were more readily extracted from soil than preexisting ambient CH4 consumers were. In the alkaline soils, preexisting activity either was destroyed or resisted extraction by the procedure used. The results support the hypothesis that consumers of ambient CH4 in soils are physiologically distinct from the known methanotrophs.

  19. Denitrification at pH 4 by a soil-derived Rhodanobacter-dominated community.

    PubMed

    van den Heuvel, R N; van der Biezen, E; Jetten, M S M; Hefting, M M; Kartal, B

    2010-12-01

    Soil denitrification is a major source of nitrous oxide emission that causes ozone depletion and global warming. Low soil pH influences the relative amount of N₂O produced and consumed by denitrification. Furthermore, denitrification is strongly inhibited in pure cultures of denitrifying microorganisms below pH 5. Soils, however, have been shown to denitrify at pH values as low as pH 3. Here we used a continuous bioreactor to investigate the possibility of significant denitrification at low pH under controlled conditions with soil microorganisms and naturally available electron donors. Significant NO₃⁻ and N₂O reduction were observed for 3 months without the addition of any external electron donor. Batch incubations with the enriched biomass showed that low pH as well as low electron donor availability promoted the relative abundance of N₂O as denitrification end-product. Molecular analysis of the enriched biomass revealed that a Rhodanobacter-like bacterium dominated the community in 16S rRNA gene libraries as well as in FISH microscopy during the highest denitrification activity in the reactor. We conclude that denitrification at pH 4 with natural electron donors is possible and that a Rhodanobacter species may be one of the microorganisms involved in acidic denitrification in soils.

  20. Depth Matters: Soil pH and dilution effects in the northern Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the northern Great Plans (NGP), surface sampling depths of 0-15.2 cm or 0-20.3 cm are suggested for testing soil characteristics such as pH. However, acidification is often most pronounced near-surface (e.g., <10 cm). Thus, sampling deeper can potentially dilute (increase) pH measurements and the...

  1. [Short-term changes of pH value and Al activity in acid soils after urea fertilization].

    PubMed

    Zeng, Qingru; Liao, Bohan; Jiang, Zhaohui; Zhou, Xihong; Tang, Can; Zhong, Ning

    2005-02-01

    Acidic soils are widely distributed in South China, and their acidity is the major environmental stress factor limiting the growth of most crops. It is well known that soil Al solubilized at low pH is a main toxic factor for plant growth. Our study with three acidic soils showed that soil pH increased quickly, while soil exchangeable Al decreased sharply with the increasing concentrations of applied urea. The time-course experiment revealed that the increase of soil pH was short-lived, with a subsequently slow drop after reached its maximum. Urea fertilization caused a drastic change of soil pH during 2-4 weeks of the experimental period. There was a negative relationship between soil pH and soil exchangeable Al. Biological toxicity test demonstrated that applying urea to acidic soils could obviously decrease the aluminum toxicity of maize in a short-term period.

  2. PH adjustment of power plant cooling water with flue gas/fly ash

    SciTech Connect

    Brady, Patrick V.; Krumhansl, James L.

    2015-09-22

    A system including a vessel including a heat source and a flue; a turbine; a condenser; a fluid conduit circuit disposed between the vessel, the turbine and the condenser; and a diverter coupled to the flue to direct a portion of an exhaust from the flue to contact with a cooling medium for the condenser water. A method including diverting a portion of exhaust from a flue of a vessel; modifying the pH of a cooling medium for a condenser with the portion of exhaust; and condensing heated fluid from the vessel with the pH modified cooling medium.

  3. Effects of Soil Oxygen Conditions and Soil pH on Remediation of DDT-contaminated Soil by Laccase from White Rot Fungi

    PubMed Central

    Zhao, Yuechun; Yi, Xiaoyun

    2010-01-01

    High residues of DDT in agricultural soils are of concern because they present serious threats to food security and human health. This article focuses on remediation of DDT-contaminated soil using laccase under different soil oxygen and soil pH conditions. The laboratory experiment results showed significant effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase at the end of a 25-d incubation period. This study found the positive correlation between the concentration of oxygen in soil and the degradation of DDT by laccase. The residue of DDTs in soil under the atmosphere of oxygen decreased by 28.1% compared with the atmosphere of nitrogen at the end of the incubation with laccase. A similar pattern was observed in the remediation of DDT-contaminated soil by laccase under different flooding conditions, the higher the concentrations of oxygen in soil, the lower the residues of four DDT components and DDTs in soils. The residue of DDTs in the nonflooding soil declined by 16.7% compared to the flooded soil at the end of the incubation. The residues of DDTs in soils treated with laccase were lower in the pH range 2.5–4.5. PMID:20617049

  4. Effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase from white rot fungi.

    PubMed

    Zhao, Yuechun; Yi, Xiaoyun

    2010-04-01

    High residues of DDT in agricultural soils are of concern because they present serious threats to food security and human health. This article focuses on remediation of DDT-contaminated soil using laccase under different soil oxygen and soil pH conditions. The laboratory experiment results showed significant effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase at the end of a 25-d incubation period. This study found the positive correlation between the concentration of oxygen in soil and the degradation of DDT by laccase. The residue of DDTs in soil under the atmosphere of oxygen decreased by 28.1% compared with the atmosphere of nitrogen at the end of the incubation with laccase. A similar pattern was observed in the remediation of DDT-contaminated soil by laccase under different flooding conditions, the higher the concentrations of oxygen in soil, the lower the residues of four DDT components and DDTs in soils. The residue of DDTs in the nonflooding soil declined by 16.7% compared to the flooded soil at the end of the incubation. The residues of DDTs in soils treated with laccase were lower in the pH range 2.5-4.5. PMID:20617049

  5. Effect of fertilizers on faba bean (V. faba) growth and soil pH

    NASA Astrophysics Data System (ADS)

    Angel, C.

    2013-12-01

    The purpose of this experiment was to see the effect of fertilizers on faba bean (V. faba) growth and soil pH. This experiment is important because of the agriculture here in California and the damage fertilizers are doing to the soil. Three Broad Fava Windsor beans (Vicia faba) were planted per pot, with at least three pots per treatment. There were four treatments: soil with phosphorus (P) fertilizer, soil with nitrogen (N) fertilizer, soil with both N and P fertilizer, and soil without any fertilizers (control). The soil pH was 7.7, and it had 26.6mg/kg Olsen-P, 2.2mg/kg ammonium-N and no nitrate-N (Data from UCD Horwath Lab). All pots were put in a greenhouse with a stable temperature of 80 degrees. I watered them 2-3 times a week. After two months I measured the soil pH using a calibrated pHep HI 98107 pocket-sized pH meter. After letting the plants dry I weighed the shoots and roots separately for dry biomass. From testing pH of the soil of the faba bean plants with and without fertilizer I found that only the nitrogen fertilizer made the soil more acidic than the other ones. The other ones became more basic. Also the N-fertilized plants weighed more than the other ones. This shows how the nitrogen fertilizer had a greater impact on the plants. I think the reason why the nitrogen and the phosphorus fertilizers didn't work as well is because there was an interaction between the fertilizers and the nitrogen one made the soil more acidic because of the way nitrogen is made.

  6. Composition and Flow Behavior of F-Canyon Tank 804 Sludge following Manganese Addition and pH Adjustment

    SciTech Connect

    Poirier, M. R.; Stallings, M. E.; Burket, P.R.; Fink, S. D.

    2005-11-30

    The Site Deactivation and Decommissioning (SDD) Organization is evaluating options to disposition the 800 underground tanks (including removal of the sludge heels from these tanks). To support this effort, SDD requested assistance from Savannah River National Laboratory (SRNL) personnel to examine the composition and flow characteristics of the Tank 804 sludge slurry after diluting it 10:1 with water, adding manganese nitrate to produce a slurry containing 5.5 wt % manganese (40:1 ratio of Mn:Pu), and adding sufficient 8 M caustic to raise the pH to 7, 10, and 14. Researchers prepared slurries containing one part Tank 804 sludge and 10 parts water. The water contained 5.5 wt % manganese (which SDD will add to poison the plutonium in Tank 804) and was pH adjusted to 3, 7, 10, or 14. They hand mixed (i.e., shook) these slurries and allowed them to sit overnight. With the pH 3, 7, and 10 slurries, much of the sludge remained stuck to the container wall. With the pH 14 slurry, most of the sludge appeared to be suspended in the slurry. They collected samples from the top and bottom of each container, which were analyzed for plutonium, manganese, and organic constituents. Following sampling, they placed the remaining material into a viscometer and measured the relationship between applied shear stress and shear rate. The pH 14 slurry was placed in a spiral ''race track'' apparatus and allowed to gravity drain.

  7. Commentary: Attitude Adjustment--Educating PhD Scientist for Business Careers

    ERIC Educational Resources Information Center

    Schuster, Sheldon M.

    2011-01-01

    The PhD graduate from a US research academic institution who has worked 5-7 years to solve a combination of laboratory and computational problems after an in-depth classroom experience is likely superbly trained in at least a subset of the life sciences and the underlying methodology and thought processes required to perform high level research.…

  8. Soil pH management without lime, a strategy to reduce greenhouse gas emissions from cultivated soils

    NASA Astrophysics Data System (ADS)

    Nadeem, Shahid; Bakken, Lars; Reent Köster, Jan; Tore Mørkved, Pål; Simon, Nina; Dörsch, Peter

    2015-04-01

    For decades, agricultural scientists have searched for methods to reduce the climate forcing of food production by increasing carbon sequestration in the soil and reducing the emissions of nitrous oxide (N2O). The outcome of this research is depressingly meagre and the two targets appear incompatible: efforts to increase carbon sequestration appear to enhance the emissions of N2O. Currently there is a need to find alternative management strategies which may effectively reduce both the CO2 and N2O footprints of food production. Soil pH is a master variable in soil productivity and plays an important role in controlling the chemical and biological activity in soil. Recent investigations of the physiology of denitrification have provided compelling evidence that the emission of N2O declines with increasing pH within the range 5-7. Thus, by managing the soil pH at a near neutral level appears to be a feasible way to reduce N2O emissions. Such pH management has been a target in conventional agriculture for a long time, since a near-neutral pH is optimal for a majority of cultivated plants. The traditional way to counteract acidification of agricultural soils is to apply lime, which inevitably leads to emission of CO2. An alternative way to increase the soil pH is the use of mafic rock powders, which have been shown to counteract soil acidification, albeit with a slower reaction than lime. Here we report a newly established field trail in Norway, in which we compare the effects of lime and different mafic mineral and rock powders (olivine, different types of plagioclase) on CO2 and N2O emissions under natural agricultural conditions. Soil pH is measured on a monthly basis from all treatment plots. Greenhouse gas (GHG) emission measurements are carried out on a weekly basis using static chambers and an autonomous robot using fast box technique. Field results from the first winter (fallow) show immediate effect of lime on soil pH, and slower effects of the mafic rocks. The

  9. Effects of soil pH on the Vicia-micronucleus genotoxicity assay.

    PubMed

    Dhyèvre, Adrien; Foltête, Anne Sophie; Aran, Delphine; Muller, Serge; Cotelle, Sylvie

    2014-11-01

    In the field of contaminated sites and soil management, chemical analyses only bring typological data about pollution. As far as bioavailability and effects on organisms are concerned, we need ecotoxicology tools. In this domain, among many existing tests, we chose to study genotoxicity because it is a short-term endpoint with long-term consequences. The aim of this study is to assess the effects of soil pH on the results of the Vicia faba root tip micronucleus test for the two following reasons: (i) to define the pH range within which the test can be performed without modifying the soil to be tested, within the framework of the ISO standard of the test and (ii) to provides information about the effects of the pH on the genotoxic potential of soils. In this context, we modified the pH of a standard soil with HCl or NaOH and we spiked the matrix with copper (2, 4 and 8 mmol kg(-1) dry soil) or with maleic hydrazide, an antigerminative chemical (5, 10 and 20 μmol kg(-1) dry soil). We concluded that the pH had no effect on the mitotic index or micronucleus frequency in the root cells of the negative controls: extreme pH values did not induce micronucleus formation in root cells. Moreover, according to our results, the Vicia-micronucleus test can be performed with pH values ranging between 3.2 and 9.0, but in the ISO 29200 "Soil quality--assessment of genotoxic effects on higher plants--V. faba micronucleus test" we recommended to use a control soil with a pH value ranging between 5 and 8 for a more accurate assessment of chemical genotoxicity. We also found that acid pH could increase the genotoxic potential of pollutants, especially heavy metals. With hydrazide maleic spiked soil, plants were placed in a situation of double stress, i.e. toxicity caused by extreme pH values and toxicity induced by the pollutant.

  10. Optimized coagulation of high alkalinity, low temperature and particle water: pH adjustment and polyelectrolytes as coagulant aids.

    PubMed

    Yu, Jianfeng; Wang, Dongsheng; Yan, Mingquan; Ye, Changqing; Yang, Min; Ge, Xiaopeng

    2007-08-01

    The Yellow River in winter as source water is characterized as high alkalinity, low temperature and low particle concentrations, which have brought many difficulties to water treatment plants. This study fully examines the optimized coagulation process of the Yellow River by conventional and pre-polymerized metal coagulants, pH adjustment and polyelectrolytes as the primary coagulants or coagulant aids. For all the metal coagulants, polyaluminum chlorides are superior to traditional metal coagulants due to their stable polymeric species and low consumption of alkalinity. The removal of natural organic matter by monomeric metal coagulants can be improved through pH adjustment, which is in accordance with the higher concentration of polymeric species formed at corresponding pH value. With the addition of polyelectrolytes as coagulant aids, the coagulation performance is significantly improved. The effective removal of dissolved organic matter is consistent with high charge density, while molecular weight is relatively important for removing particles, which is consistent with polyelectrolytes as primary coagulants. These results suggest that the coagulation mechanisms in the removal of dissolved organic matter and particles are different, which may be exploited for optimized coagulation for the typical source water in practice.

  11. Influence of soil pH in vegetative filter strips for reducing soluble nutrient transport.

    PubMed

    Rahmana, Atikur; Rahmana, Shafiqur; Cihacek, Larry

    2014-08-01

    Low efficacy of vegetative filter strips (VFS) in reducing soluble nutrients has been reported in research articles. Solubility of phosphorus and nitrogen compounds is largely affected by pH of soil. Changing soil pH may result in a decrease in soluble nutrient transportation through VFS. This study was conducted to evaluate the effect of pH levels of VFS soil on soluble nutrient transport reduction from manure-borne runoff. Soil (loamy sand texture; bulk density 1.3 g cm-3) was treated with calcium carbonate to change pH at different pH treatment levels (5.5-6.5, 6.5-7.5, and 7.5-8.5), soil was packed into galvanized metal boxes, and tall fescue grasses were established in the boxes to simulate VFS. Boxes were placed in an open environment, tilted to a 3.0% slope, and 44.0 L manure-amended water was applied through the VFS by a pump at a rate of 1.45 L min-1. Water samples were collected at the inlet and outlet as well as from the leachate. Samples were analysed for ortho-phosphorus, ammonium nitrogen, nitrate nitrogen, and potassium. Highest transport reductions in ortho-phosphorus (42.4%) and potassium (20.5%) were observed at pH range 7.5-8.5. Ammonium nitrogen transport reduction was the highest at pH level of 6.5-7.5 and was 26.1%. Surface transport reduction in nitrate nitrogen was 100%, but leachate had the highest concentration of nitrate nitrogen. Mass transport reduction also suggested that higher pH in the VFS soil are effective in reducing some soluble nutrients transport.

  12. Effect of redox potential and pH on TNT transformation in soil-water slurries

    SciTech Connect

    Price, C.B.; Brannon, J.M.; Hayes, C.A.

    1997-10-01

    The presence of 2,4,6-trinitrotoluene (TNT) and its transformation products in surface soil, the vadose zone, and ground water can present serious environmental problems. This situation is exacerbated because the processes that control the mobility and transformation of TNT are not well understood. The objective of this study was to determine the effects of redox potential (Eh) and pH on the fate and transformation of TNT in soil. An initial investigation of soil components responsible for the observed TNT transformation was also conducted. Laboratory investigations consisted of testing at four separate redox potentials and four pH levels. An 18:1 (water:soil) suspension spiked with 100 {micro}g/g TNT was used. Results indicated that TNT was unstable under all redox and pH conditions, and was least stable under highly reducing conditions at all four pH values. Greater amounts of TNT were incorporated into soil organic matter under anaerobic than under aerobic conditions. Results of the soil component study indicated that the presence of Fe{sup +2} sorbed to clay surfaces may account for the rapid disappearance of TNT at reduced redox potentials. TNT in ground water moving into areas of intense reduction would not persist for long, but would undergo transformation and binding by soil organic matter.

  13. Influence of Microsprinkler Irrigation Amount on Water, Soil, and pH Profiles in a Coastal Saline Soil

    PubMed Central

    Chu, Linlin; Kang, Yaohu; Wan, Shuqin

    2014-01-01

    Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China. PMID:25147843

  14. Influence of microsprinkler irrigation amount on water, soil, and pH profiles in a coastal saline soil.

    PubMed

    Chu, Linlin; Kang, Yaohu; Wan, Shuqin

    2014-01-01

    Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China.

  15. Separation of switchgrass bio-oil by water/organic solvent addition and pH adjustment

    DOE PAGES

    Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira; Ye, X. Philip; Borole, Abhijeet P.; Tsouris, Costas

    2016-01-29

    Applications of bio-oil are limited by its challenging properties including high moisture content, low pH, high viscosity, high oxygen content, and low heating value. Separation of switchgrass bio-oil components by adding water, organic solvents (hexadecane and octane), and sodium hydroxide may help to overcome these issues. Acetic acid and phenolic compounds were extracted in aqueous and organic phases, respectively. Polar chemicals, such as acetic acid, did not partition in the organic solvent phase. Acetic acid in the aqueous phase after extraction is beneficial for a microbial-electrolysis-cell application to produce hydrogen as an energy source for further hydrodeoxygenation of bio-oil. Organicmore » solvents extracted more chemicals from bio-oil in combined than in sequential extraction; however, organic solvents partitioned into the aqueous phase in combined extraction. When sodium hydroxide was added to adjust the pH of aqueous bio-oil, organic-phase precipitation occurred. As the pH was increased, a biphasic aqueous/organic dispersion was formed, and phase separation was optimized at approximately pH 6. The neutralized organic bio-oil had approximately 37% less oxygen and 100% increased heating value than the initial centrifuged bio-oil. In conclusion, the less oxygen content and increased heating value indicated a significant improvement of the bio-oil quality through neutralization.« less

  16. Fluctuations in Ammonia Oxidizing Communities Across Agricultural Soils are Driven by Soil Structure and pH

    PubMed Central

    Pereira e Silva, Michele C.; Poly, Franck; Guillaumaud, Nadine; van Elsas, Jan Dirk; Salles, Joana Falcão

    2012-01-01

    The milieu in soil in which microorganisms dwell is never constant. Conditions such as temperature, water availability, pH and nutrients frequently change, impacting the overall functioning of the soil system. To understand the effects of such factors on soil functioning, proxies (indicators) of soil function are needed that, in a sensitive manner, reveal normal amplitude of variation. Thus, the so-called normal operating range (NOR) of soil can be defined. In this study we determined different components of nitrification by analyzing, in eight agricultural soils, how the community structures and sizes of ammonia oxidizing bacteria and archaea (AOB and AOA, respectively), and their activity, fluctuate over spatial and temporal scales. The results indicated that soil pH and soil type are the main factors that influence the size and structure of the AOA and AOB, as well as their function. The nitrification rates varied between 0.11 ± 0.03 μgN h−1 gdw−1 and 1.68 ± 0.11 μgN h−1 gdw−1, being higher in soils with higher clay content (1.09 ± 0.12 μgN h−1 gdw−1) and lower in soils with lower clay percentages (0.27 ± 0.04 μgN h−1 gdw−1). Nitrifying activity was driven by soil pH, mostly related to its effect on AOA but not on AOB abundance. Regarding the influence of soil parameters, clay content was the main soil factor shaping the structure of both the AOA and AOB communities. Overall, the potential nitrifying activities were higher and more variable over time in the clayey than in the sandy soils. Whereas the structure of AOB fluctuated more (62.7 ± 2.10%) the structure of AOA communities showed lower amplitude of variation (53.65 ± 3.37%). Similar trends were observed for the sizes of these communities. The present work represents a first step toward defining a NOR for soil nitrification. The sensitivity of the process and organisms to impacts from the milieu support their use as proxies in the

  17. Bacterial chitinolytic communities respond to chitin and pH alteration in soil.

    PubMed

    Kielak, Anna M; Cretoiu, Mariana Silvia; Semenov, Alexander V; Sørensen, Søren J; van Elsas, Jan Dirk

    2013-01-01

    Chitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S rRNA and chiA genes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity of chiA gene types in soil is enormous and (i) that different chiA gene types are selected by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one of Actinobacteria in the immediate response to the added chitin (based on 16S rRNA gene abundance and chiA gene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes.

  18. Phylogenetic and functional potential links pH and N2O emissions in pasture soils

    PubMed Central

    Samad, M. d. Sainur; Biswas, Ambarish; Bakken, Lars R.; Clough, Timothy J.; de Klein, Cecile A. M.; Richards, Karl G.; Lanigan, Gary J.; Morales, Sergio E.

    2016-01-01

    Denitrification is mediated by microbial, and physicochemical, processes leading to nitrogen loss via N2O and N2 emissions. Soil pH regulates the reduction of N2O to N2, however, it can also affect microbial community composition and functional potential. Here we simultaneously test the link between pH, community composition, and the N2O emission ratio (N2O/(NO + N2O + N2)) in 13 temperate pasture soils. Physicochemical analysis, gas kinetics, 16S rRNA amplicon sequencing, metagenomic and quantitative PCR (of denitrifier genes: nirS, nirK, nosZI and nosZII) analysis were carried out to characterize each soil. We found strong evidence linking pH to both N2O emission ratio and community changes. Soil pH was negatively associated with N2O emission ratio, while being positively associated with both community diversity and total denitrification gene (nir & nos) abundance. Abundance of nosZII was positively linked to pH, and negatively linked to N2O emissions. Our results confirm that pH imposes a general selective pressure on the entire community and that this results in changes in emission potential. Our data also support the general model that with increased microbial diversity efficiency increases, demonstrated in this study with lowered N2O emission ratio through more efficient conversion of N2O to N2. PMID:27782174

  19. Sorption and pH determine the long-term partitioning of cadmium in natural soils.

    PubMed

    Ardestani, Masoud M; van Gestel, Cornelis A M

    2016-09-01

    The bioavailability of metals in soil is a dynamic process. For a proper extrapolation to the field of laboratory studies on fate and effects, it is important to understand the dynamics of metal bioavailability and the way it is influenced by soil properties. The aim of this study was to assess the parallel (concurrent) effect of pH and aging time on the partitioning of cadmium in natural LUFA 2.2 soil. Cadmium nitrate-spiked pH-amended LUFA 2.2 soils were incubated under laboratory conditions for up to 30 weeks. Measured pHpw was lower after 3 weeks and decreased only slightly toward the end of the test. Cadmium concentrations in the pore water increased with time for all soil pH levels, while they decreased with increasing pH. Freundlich kf values ranged between 4.26 and 934 L kg(-1) (n = 0.79 to 1.36) and were highest at the highest pH tested (pH = 6.5). Multiple linear regression analysis, based on a soil ligand modeling approach, resulted in affinity constants of 2.61 for Ca(2+) (log KCa-SL) and 5.05 for H(+) (log KH-SL) for their binding to the active sites on the soil surface. The results showed that pH and aging time are two important factors which together affect cadmium partitioning and mobility in spiked natural soils. PMID:27287493

  20. Sorption and pH determine the long-term partitioning of cadmium in natural soils.

    PubMed

    Ardestani, Masoud M; van Gestel, Cornelis A M

    2016-09-01

    The bioavailability of metals in soil is a dynamic process. For a proper extrapolation to the field of laboratory studies on fate and effects, it is important to understand the dynamics of metal bioavailability and the way it is influenced by soil properties. The aim of this study was to assess the parallel (concurrent) effect of pH and aging time on the partitioning of cadmium in natural LUFA 2.2 soil. Cadmium nitrate-spiked pH-amended LUFA 2.2 soils were incubated under laboratory conditions for up to 30 weeks. Measured pHpw was lower after 3 weeks and decreased only slightly toward the end of the test. Cadmium concentrations in the pore water increased with time for all soil pH levels, while they decreased with increasing pH. Freundlich kf values ranged between 4.26 and 934 L kg(-1) (n = 0.79 to 1.36) and were highest at the highest pH tested (pH = 6.5). Multiple linear regression analysis, based on a soil ligand modeling approach, resulted in affinity constants of 2.61 for Ca(2+) (log KCa-SL) and 5.05 for H(+) (log KH-SL) for their binding to the active sites on the soil surface. The results showed that pH and aging time are two important factors which together affect cadmium partitioning and mobility in spiked natural soils.

  1. Microbial colonisation of sterilised soils across a pH gradient in a full factorial re-inoculation experiment

    NASA Astrophysics Data System (ADS)

    Barcenas Moreno, Gema; Bååth, Erland; Rousk, Johannes

    2015-04-01

    We compared the influence of community and environmental conditions for the functioning (fungal and bacterial growth and respiration) and trait distribution (bacterial pH-tolerance) of soil microorganisms across a pH gradient. A reciprocal inoculation experiment, including pHs 4.1, 5.2, 6.7, and 8.3, was used. Sterilised soil microcosms with added plant material were inoculated with fresh soil (communities) and monitored for two months. Respiration was dominated by bacteria at high and by fungi at low pHs. The bacterial pH-tolerance of all inoculated communities (initial trait distribution) converged with the pH of the soil (environment). There were also differences between inocula, resulting in suboptimal pH-tolerance when the inoculum pH did not correspond to soil pH; low pH inocula had lower than optimal pH-tolerance in high pH soils and vice versa. Bacterial communities misaligned to their environment had impaired functioning (growth in all soils and respiration in high pH soils). The inoculum effect on bacterial pH tolerance and functioning could be detected within one week and remained for two months. Fungal communities emanating from low pH inocula consistently resulted in higher fungal growth and biomass (all soils) and respiration (low pH soils). This suggested that variation in fungal pH-tolerance did not influence their performance, in contrast with bacteria. It is likely that a larger fungal sample in low pH inocula explained these results. Consequently, respiration was characterised by the alignment of the bacterial trait distribution to the environment for high pH soils, while it was characterised by larger fungal inoculum for low pH soils.

  2. Bioavailability of freshly added and aged naphthalene in soils under gastric pH conditions

    SciTech Connect

    Jin, Z.; Simkins, S.; Xing, B.

    1999-12-01

    The bioavailability of hydrophobic organic chemicals decreases with aging in soil because of sequestration. However, assessments of the risk of exposure to contaminated soils are usually dependent on either chemical concentrations, which are measured using vigorous extraction methods, or models that assume an equilibrium without considering the actual conditions. The objective of this research was to determine the availability and desorption kinetics of freshly added and aged naphthalene from a peat and a mineral soil; naphthalene was desorbed into solutions with pH levels that approximate those found in different gastric regions. Soil and peat samples were spiked with radiolabeled and unlabeled naphthalene at 2 and 20 {micro}g/g and were aged from 0 to 135 d. Desorption kinetics were determined using a simulated stomach solution and a neutral solution that represented the pH of intestinal conditions and most soils. Peat sorbed much more naphthalene than did soil, and it allowed little desorption. Though both acidic and neutral extracting solutions could desorb naphthalene, little apparent effect of aging was observed in peat, whereas desorption from soil declined markedly with aging. In addition, the percentage of naphthalene that desorbed from soil was greater for the higher incubation concentration. The desorption of naphthalene from the peat and soil was higher into the neutral solution than into the gastric solution. These results suggest that aging, exposure conditions, concentration effect, and organic matter content should be taken into account in predictive models and risk assessments.

  3. [Soil pH buffer capacity of tea garden with different planting years].

    PubMed

    Su, You-Jian; Wang, Ye-Jun; Zhang, Yong-Li; Luo, Yi; Sun, Li; Song, Li; Liao, Wan-You

    2014-10-01

    In order to investigate the effects of long-term tea planting on soil pH buffer capacity (pHBC), the variation of pHBC and its influence factors were investigated in tea gardens of 10, 15, 20, 25 and 30 years in Langxi and Qimen of Anhui Province. The results showed that the acid-base titration method was suitable for the determination of soil pHBC of tea gardens. The amount of acid-base added had approximate linear relationship with soil pH value in specific section (pH 4.0-6.0) of acid-base titration curves, so the soil pHBC could be calculated by linear regression equation. Soil pHBC in the tea gardens from the two regions showed a downward trend with increasing the planting years, which decreased at rates of 0.10 and 0.06 mmol · kg(-1) · a(-1) in Langxi and Qimen tea gardens, respectively. Soil pHBC had significant positive correlation with CEC, soil organic matter, base saturation and physical clay content, and significant negative correlation with exchangeable acid and exchange H+. PMID:25796900

  4. [Soil pH buffer capacity of tea garden with different planting years].

    PubMed

    Su, You-Jian; Wang, Ye-Jun; Zhang, Yong-Li; Luo, Yi; Sun, Li; Song, Li; Liao, Wan-You

    2014-10-01

    In order to investigate the effects of long-term tea planting on soil pH buffer capacity (pHBC), the variation of pHBC and its influence factors were investigated in tea gardens of 10, 15, 20, 25 and 30 years in Langxi and Qimen of Anhui Province. The results showed that the acid-base titration method was suitable for the determination of soil pHBC of tea gardens. The amount of acid-base added had approximate linear relationship with soil pH value in specific section (pH 4.0-6.0) of acid-base titration curves, so the soil pHBC could be calculated by linear regression equation. Soil pHBC in the tea gardens from the two regions showed a downward trend with increasing the planting years, which decreased at rates of 0.10 and 0.06 mmol · kg(-1) · a(-1) in Langxi and Qimen tea gardens, respectively. Soil pHBC had significant positive correlation with CEC, soil organic matter, base saturation and physical clay content, and significant negative correlation with exchangeable acid and exchange H+.

  5. Effects of pH and manure on transport of sulfonamide antibiotics in soil.

    PubMed

    Strauss, Claudia; Harter, Thomas; Radke, Michael

    2011-01-01

    Sulfonamide antibiotics are a commonly used group of compounds in animal husbandry. They are excreted with manure, which is collected in a storage lagoon in certain types of confined animal feeding operations. Flood irrigation of forage fields with this liquid manure creates the potential risk of groundwater contamination in areas with shallow groundwater levels. We tested the hypothesis that-in addition to the soil characteristics-manure as cosolute and manure pH are two major parameters influencing sulfonamide transport in soils. Solute displacement experiments in repacked, saturated soil columns were performed with soil (loamy sand) and manure from a dairy farm in California. Breakthrough of nonreactive tracer and sulfadimethoxine, sulfamethazine, and sulfamethoxazole at different solution pH (5, 6.5, 8.5) with and without manure was modeled using Hydrus-1D to infer transport and reaction parameters. Tracer and sulfonamide breakthrough curves were well explained by a model concept based on physical nonequilibrium transport, equilibrium sorption, and first-order dissipation kinetics. Sorption of the antibiotics was low ( K₄ ≤ 0.7 L kg) and only weakly influenced by pH and manure. However, sulfonamide attenuation was significantly affected by both pH and manure. The mass recovery of sulfonamides decreased with decreasing pH, e.g., for sulfamethoxazole from 77 (pH 8.5) to 56% (pH 5). The sulfonamides were highly mobile under the studied conditions, but manure application increased their attenuation substantially. The observed attenuation was most likely caused by a combination of microbial transformation and irreversible sorption to the soil matrix.

  6. Laser-induced breakdown spectroscopy: Extending its application to soil pH measurements

    NASA Astrophysics Data System (ADS)

    Ferreira, Edilene Cristina; Gomes Neto, José A.; Milori, Débora M. B. P.; Ferreira, Ednaldo José; Anzano, Jesús Manuel

    2015-08-01

    Acid-base equilibria are involved in almost all the processes that occur in soil. The bioavailability of nutrients for plants, for instance, depends on the solubilization of mineral nutrients in the soil solution, which is a pH-dependent process. The determination of pH in soil solutions is usually carried out by potentiometry using a glass membrane electrode, after extracting some of the soil components with water or CaCl2 solution. The present work describes a simple method for determining the pH of soil, using laser-induced breakdown spectroscopy (LIBS). Sixty samples presenting different textural composition and pH (previously determined by potentiometry) were employed. The samples were divided into a calibration set with fifty samples and a validation set with ten samples. LIBS spectra were recorded for each pelleted sample using laser pulse energy of 115 mJ. The intensities of thirty-two emission lines for Al, Ca, H, and O were used to fit a partial least squares (PLS) model. The model was validated by prediction of the pH of the validation set samples, which showed good agreement with the reference values. The prediction mean absolute error was 0.3 pH units and the root mean square error of the prediction was 0.4. These results highlight the potential of LIBS for use in other applications beyond elemental composition determinations. For soil analysis, the proposed method offers the possibility of determining pH, in addition to nutrients and contaminants, using a single LIBS measurement.

  7. Effect of Soil Temperature and pH on Resistance of Soybean to Heterodera glycines

    PubMed Central

    Anand, S. C.; Matson, K. W.; Sharma, S. B.

    1995-01-01

    Soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a major pest of soybean, Glycine max L. Merr. Soybean cultivars resistant to SCN are commonly grown in nematode-infested fields. The objective of this study was to examine the stability of SCN resistance in soybean genotypes at different soil temperatures and pH levels. Reactions of five SCN-resistant genotypes, Peking, Plant Introduction (PI) 88788, Custer, Bedford, and Forrest, to SCN races 3, 5, and 14 were studied at 20, 26, and 32 C, and at soil pH's 5.5, 6.5, and 7.5. Soybean cultivar Essex was included as a susceptible check. Temperature, SCN race, soybean genotype, and their interactions significantly affected SCN reproduction. The effect of temperature on reproduction was quadratic with the three races producing significantly greater numbers of cysts at 26 C; however, reproduction on resistant genotypes remained at a low level. Higher numbers of females matured at the soil pH levels of 6.5 and 7.5 than at pH 5.5. Across the ranges of temperature and soil pH studied, resistance to SCN in the soybean genotypes remained stable. PMID:19277315

  8. Interactive Effects of Soil ph, Halosulfuron Rate, and Application Method on Carryover to Turnip Green and Cabbage.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted in 2006 and 2007 to evaluate the tolerance of autumn-planted cabbage and turnip green to halosulfuron applied the previous spring to cantaloupe. Main plots were three levels of soil pH; maintained at a natural pH level, pH raised with Ca(OH)2, and pH lowered with Al2(SO...

  9. Changes in soil pH across England and Wales in response to decreased acid deposition

    NASA Astrophysics Data System (ADS)

    Kirk, G. J. D.; Bellamy, P. H.

    2009-04-01

    In our recent analysis of data from the National Soil Inventory of England and Wales, we found widespread changes in soil pH across both countries between the two samplings of the Inventory. In general, soil pH increased - i.e. soils became less acid - under all land uses. The Inventory was first sampled in 1978-83 on a 5-km grid over the whole area. This yielded about 6,000 sites of which 5,662 could be sampled for soil. Roughly 40% of the sites were re-sampled at intervals from 12 to 25 years after the original sampling - in 1994/96 for agricultural land and in 2002/03 for non-agricultural. Exactly the same sampling and analytical protocols were used in the two samplings. In arable soils, the increase in pH was right across the range, whereas in grassland soils the main increase was at the acid end of the scale (pH < 5.5) with a small increase above pH 7. Some part of the change is likely to have been due to changes in land management. This includes better targeting of agricultural lime on acid soils; changes in nitrogen fertilizer use; deeper ploughing bringing up more calcareous subsoil on soils on calcareous materials; and so forth. However a major driver appears to have been decreased acid deposition to land. The total amounts of nitrogen compounds deposited were relatively unchanged over the survey period, but the amounts of acidifying sulphur compounds decreased by approximately 50%. We constructed a linear regression model to assess the relation between the rate of change in pH (normalised to an annual basis) and the rate of change in acid deposition, as modified by soil properties (pH, clay content, organic matter content), rainfall and past acid deposition. We used data on rainfall and acid deposition over the survey period on the same 5-km grid as the NSI data. We fitted the model separately for each land use category. The results for arable land showed a significant effect of the change in rate of acid deposition, though a significant part of the

  10. pH regulates ammonia-oxidizing bacteria and archaea in paddy soils in Southern China.

    PubMed

    Li, Hu; Weng, Bo-Sen; Huang, Fu-Yi; Su, Jian-Qiang; Yang, Xiao-Ru

    2015-07-01

    Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrogen cycling. However, the effects of environmental factors on the activity, abundance, and diversity of AOA and AOB and the relative contributions of these two groups to nitrification in paddy soils are not well explained. In this study, potential nitrification activity (PNA), abundance, and diversity of amoA genes from 12 paddy soils in Southern China were determined by potential nitrification assay, quantitative PCR, and cloning. The results showed that PNA was highly variable between paddy soils, ranging from 4.05 ± 0.21 to 9.81 ± 1.09 mg NOx-N kg(-1) dry soil day(-1), and no significant correlation with soil parameters was found. The abundance of AOA was predominant over AOB, indicating that AOA may be the major members in aerobic ammonia oxidation in these paddy soils. Community compositions of AOA and AOB were highly variable among samples, but the variations were best explained by pH. AOA sequences were affiliated to the Nitrosopumilus cluster and Nitrososphaera cluster, and AOB were classified into the lineages of Nitrosospira and Nitrosomonas, with Nitrosospira being predominant over Nitrosomonas, accounting for 83.6 % of the AOB community. Moreover, the majority of Nitrosomonas was determined in neutral soils. Canonical correspondence analysis (CCA) analysis further demonstrated that AOA and AOB community structures were significantly affected by pH, soil total organic carbon, total nitrogen, and C/N ratio, suggesting that these factors exert strong effects on the distribution of AOB and AOA in paddy soils in Southern China. In conclusion, our results imply that soil pH was a key explanatory variable for both AOA and AOB community structure and nitrification activity.

  11. Electrokinetic remediation of a Cu-Zn contaminated red soil by controlling the voltage and conditioning catholyte pH.

    PubMed

    Zhou, Dong-Mei; Deng, Chang-Fen; Cang, Long; Alshawabkeh, Akram N

    2005-10-01

    Electrokinetics is an innovative technique for treating heavy metals contaminated soil, especially low pH soils such as the Chinese red soil (Udic Ferrisols). In this paper, a Cu-Zn contaminated red soil is treated by electrokinetics. When the Cu-Zn contaminated red soil was treated without control of catholyte pH during the electrokinetic treatment, the soil pH in the soil sections near cathode after the experiment was high above 6, which resulted in accumulation of large amounts of Cu and Zn in the soil sections with such high pH values. Compared to soil Cu, soil Zn was more efficiently removed from the soil by a controlled electrokinetic method. Application of lactic acid as catholyte pH conditioning solution caused an efficient removal of Cu and Zn from the soil. Increasing the electrolyte strength (salt concentration) of the conditioning solution further increased Cu removal, but did not cause a significant improvement for soil Zn. Soil Cu and Zn fractions after the electrokinetic treatments were analyzed using sequential extraction method, which indicated that Cu and Zn precipitation in the soil section closest to the cathode in the treatments without catholyte pH control limited their removal from the soil column. When the catholyte pH was controlled by lactic acid and CaCl(2), the soil Cu and Zn removal percentage after 554 h running reached 63% and 65%, respectively. Moreover, both the residual soil Cu and Zn concentrations were lower than 100 mg kg(-1), which is adequate and meets the requirement of the Chinese soil environmental quality standards. PMID:16202805

  12. Increasing aridity, temperature and soil pH induce soil C-N-P imbalance in grasslands

    PubMed Central

    Jiao, Feng; Shi, Xin-Rong; Han, Feng-Peng; Yuan, Zhi-You

    2016-01-01

    Due to the different degrees of controls exerted by biological and geochemical processes, climate changes are suggested to uncouple biogeochemical C, N and P cycles, influencing biomass accumulation, decomposition and storage in terrestrial ecosystems. However, the possible extent of such disruption in grassland ecosystems remains unclear, especially in China’s steppes which have undergone rapid climate changes with increasing drought and warming predicted moving forward in these dryland ecosystems. Here, we assess how soil C-N-P stoichiometry is affected by climatic change along a 3500-km temperate climate transect in Inner Mongolia, China. Our results reveal that the soil from more arid and warmer sites are associated with lower soil organic C, total N and P. The ratios of both soil C:P and N:P decrease, but soil C:N increases with increasing aridity and temperature, indicating the predicted decreases in precipitation and warming for most of the temperate grassland region could lead to a soil C-N-P decoupling that may reduce plant growth and production in arid ecosystems. Soil pH, mainly reflecting long-term climate change in our sites, also contributes to the changing soil C-N-P stoichiometry, indicating the collective influences of climate and soil type on the shape of soil C-N-P balance. PMID:26792069

  13. pH affects bacterial community composition in soils across the Huashan Watershed, China.

    PubMed

    Huang, Rui; Zhao, Dayong; Zeng, Jin; Shen, Feng; Cao, Xinyi; Jiang, Cuiling; Huang, Feng; Feng, Jingwei; Yu, Zhongbo; Wu, Qinglong L

    2016-09-01

    To investigate soil bacterial richness and diversity and to determine the correlations between bacterial communities and soil properties, 8 soil samples were collected from the Huashan watershed in Anhui, China. Subsequently, 454 high-throughput pyrosequencing and bioinformatics analyses were performed to examine the soil bacterial community compositions. The operational taxonomic unit richness of the bacterial community ranged from 3664 to 5899, and the diversity indices, including Chao1, Shannon-Wiener, and Faith's phylogenetic diversity ranged from 7751 to 15 204, 7.386 to 8.327, and 415.77 to 679.11, respectively. The 2 most dominant phyla in the soil samples were Actinobacteria and Proteobacteria. The richness and diversity of the bacterial community were positively correlated with soil pH. The Mantel test revealed that the soil pH was the dominant factor influencing the bacterial community. The positive modular structure of co-occurrence patterns at the genus level was discovered by network analysis. The results obtained in this study provide useful information that enhances our understanding of the effects of soil properties on the bacterial communities. PMID:27374919

  14. Influence of pH on wetting kinetics of a pine forest soil

    NASA Astrophysics Data System (ADS)

    Amer, Ahmad; Schaumann, Gabriele; Diehl, Dörte

    2014-05-01

    Water repellent properties of organic matter significantly alter soil water dynamics. Various environmental factors control appearance and breakup of repellency in soil. Beside water content and temperature also pH exerts an influence on soil water repellency although investigations achieved partly ambiguous results; some found increasing repellency with increasing pH (Terashima et al. 2004; Duval et al. 2005), other with decreasing pH (Karnok et al. 1993; Roper 2005) and some found repellency maxima at intermediate pH and an increase with decreasing and with increasing pH (Bayer and Schaumann 2007; Diehl et al. 2010). The breakup of repellency may be observed via the time dependent sessile drop contact angle (TISED). With water contact time, soil-water contact angle decreases until complete wetting is reached. Diehl and Schaumann (2007) calculated the activation energy of the wetting process from the rate of sessile drop wetting obtained at different temperatures and draw conclusions on chemical or physical nature of repellency. The present study aims at the influence of pH on the wetting kinetics of soil. Therefore, TISED of soil was determined as a function of pH and temperature. We used upper soil samples (0 - 10 cm) from a pine forest in the southwest of Germany (Rheinland-Pfalz). Samples were air-dried, sieved < 1.0 mm and pH was modified by NH3 and HCl gas (Diehl et al. 2010) and measured electrometrically in 0.01 M CaCl2 solution. TISED measurements (2007)were conducted at 10, 20 and 30 oC using OCA 15 Contact Angle Meter (Dataphysics, Germany) on three replications for each soil sample. Apparent work of adhesion was calculated, plotted vs. time and mathematically fitted using double exponential function. Rate constants of wetting were used to determine the activation energy by Arrhenius equation. First results indicated that despite comparable initial contact angles, pH alteration strongly changed the wetting rate suggesting maximum wetting resistance at

  15. The effect of pH on the toxicity of zinc oxide nanoparticles to Folsomia candida in amended field soil.

    PubMed

    Waalewijn-Kool, Pauline L; Ortiz, Maria Diez; Lofts, Stephen; van Gestel, Cornelis A M

    2013-10-01

    The effect of soil pH on the toxicity of 30 nm ZnO to Folsomia candida was assessed in Dorset field soils with pHCaCl2 adjusted to 4.31, 5.71, and 6.39. To unravel the contribution of particle size and dissolved Zn, 200 nm ZnO and ZnCl2 were tested. Zinc sorption increased with increasing pH, and Freundlich kf values ranged from 98.9 (L/kg)(1/n) to 333 (L/kg)(1/n) for 30 nm ZnO and from 64.3 (L/kg)(1/n) to 187 (L/kg)(1/n) for ZnCl2. No effect of particle size was found on sorption, and little difference was found in toxicity between 30 nm and 200 nm ZnO. The effect on reproduction decreased with increasing pH for all Zn forms, with 28-d median effective concentrations (EC50s) of 553 mg Zn/kg, 1481 mg Zn/kg, and 3233 mg Zn/kg for 30 nm ZnO and 331 mg Zn/kg, 732 mg Zn/kg, and 1174 mg Zn/kg for ZnCl2 at pH 4.31, 5.71, and 6.39, respectively. The EC50s based on porewater Zn concentrations increased with increasing pH for 30 nm ZnO from 4.77 mg Zn/L to 18.5 mg Zn/L, while for ZnCl2 no consistent pH-related trend in EC50s was found (21.0-63.3 mg Zn/L). Porewater calcium levels were 10 times higher in ZnCl2 -spiked soils than in ZnO-spiked soils. The authors' results suggest that the decreased toxicity of ZnCl2 compared with 30 nm ZnO based on porewater concentrations was because of a protective effect of calcium and not a particle effect.

  16. Persistence of spiromesifen in soil: influence of moisture, light, pH and organic amendment.

    PubMed

    Mate, Ch Jamkhokai; Mukherjee, Irani; Das, Shaon Kumar

    2015-02-01

    Persistence of spiromesifen in soil as affected by varying moisture, light, compost amendment, soil sterilization and pH in aqueous medium were studied. Degradation of spiromesifen in soil followed the first-order reaction kinetics. Effect of different moisture regimes indicated that spiromesifen dissipated faster in submerged soil (t 1/2 14.3-16.7 days) followed by field capacity (t 1/2 18.7-20.0 days), and dry soil (t 1/2 21.9-22.9 days). Dissipation was faster in sterilized submerged (t 1/2 17.7 days) than in sterilized dry (t 1/2 35.8 days). Photo spiromesifen metabolite was not detected under different moisture regimes. After 30 days, enol spiromesifen metabolite was detected under submerged condition and was below detectable limit (<0.001 μg g(-1)) after 90 days. Soil amendment compost (2.5 %) at field capacity enhanced dissipation of the insecticide, and half-life value was 14.3 against 22.4 days without compost amendment. Under different pH condition, residues persisted in water with half-life values 5.7 to 12.5 days. Dissipation in water was faster at pH 9.0 (t 1/2 5.7 days), followed by pH 4.0 (t 1/2 9.7 days) and pH 7.2 (t 1/2 12.5 days). Exposure of spiromesifen to different light conditions indicated that it was more prone to degradation under UV light (t 1/2 3-4 days) than sunlight exposure (t 1/2 5.2-8.1 days). Under sunlight exposure, photo spiromesifen metabolite was detected after 10 and 15 days as compared to 3 and 5 days under UV light exposure. PMID:25616783

  17. Persistence of spiromesifen in soil: influence of moisture, light, pH and organic amendment.

    PubMed

    Mate, Ch Jamkhokai; Mukherjee, Irani; Das, Shaon Kumar

    2015-02-01

    Persistence of spiromesifen in soil as affected by varying moisture, light, compost amendment, soil sterilization and pH in aqueous medium were studied. Degradation of spiromesifen in soil followed the first-order reaction kinetics. Effect of different moisture regimes indicated that spiromesifen dissipated faster in submerged soil (t 1/2 14.3-16.7 days) followed by field capacity (t 1/2 18.7-20.0 days), and dry soil (t 1/2 21.9-22.9 days). Dissipation was faster in sterilized submerged (t 1/2 17.7 days) than in sterilized dry (t 1/2 35.8 days). Photo spiromesifen metabolite was not detected under different moisture regimes. After 30 days, enol spiromesifen metabolite was detected under submerged condition and was below detectable limit (<0.001 μg g(-1)) after 90 days. Soil amendment compost (2.5 %) at field capacity enhanced dissipation of the insecticide, and half-life value was 14.3 against 22.4 days without compost amendment. Under different pH condition, residues persisted in water with half-life values 5.7 to 12.5 days. Dissipation in water was faster at pH 9.0 (t 1/2 5.7 days), followed by pH 4.0 (t 1/2 9.7 days) and pH 7.2 (t 1/2 12.5 days). Exposure of spiromesifen to different light conditions indicated that it was more prone to degradation under UV light (t 1/2 3-4 days) than sunlight exposure (t 1/2 5.2-8.1 days). Under sunlight exposure, photo spiromesifen metabolite was detected after 10 and 15 days as compared to 3 and 5 days under UV light exposure.

  18. [Aluminum dissolution and changes of pH in soil solution during sorption of copper by aggregates of paddy soil].

    PubMed

    Xu, Hai-Bo; Zhao, Dao-Yuan; Qin, Chao; Li, Yu-Jiao; Dong, Chang-Xun

    2014-01-01

    Size fractions of soil aggregates in Lake Tai region were collected by the low-energy ultrasonic dispersion and the freeze-desiccation methods. The dissolution of aluminum and changes of pH in soil solution during sorption of Cu2+ and changes of the dissolution of aluminum at different pH in the solution of Cu2+ by aggregates were studied by the equilibrium sorption method. The results showed that in the process of Cu2+ sorption by aggregates, the aluminum was dissoluted and the pH decreased. The elution amount of aluminum and the decrease of pH changed with the sorption of Cu2+, both increasing with the increase of Cu2+ sorption. Under the same conditions, the dissolution of aluminum and the decrease of pH were in the order of coarse silt fraction > silt fraction > sand fraction > clay fraction, which was negatively correlated with the amount of iron oxide, aluminum and organic matter. It suggested that iron oxide, aluminum and organic matters had inhibitory and buffering effect on the aluminum dissolution and the decrease of pH during the sorption of Cu2+.

  19. Influence of soil-extractable aluminium and pH on the uptake of aluminium from soil into the soybean plant (Glycine max).

    PubMed

    Dong, D; Thornton, I; Ramsey, M H

    1993-09-01

    The effects of soil pH and other soil properties on the uptake of AI by soybean plants have been investigated in a greenhouse experiment. Six soils were compared that were developed over six contrasting bedrock types ranging widely in their AI content and other chemical and physical characteristics, namely Oxford Clay, Chalk, Lower Lias Clay, Devonian Shale, Granite and Lower Greensand. Soil pH varied naturally between soil types and each soil was also amended to give two other pH levels using elemental sulphur and/or calcium carbonate. AI concentrations in various parts of the soybean plants were determined by ICP-AES after acid digestion. The AI solubility in the soils and hence its availability to the plants was estimated using a number of different reagents designed to extract different forms of AI.The AI concentration measured in the soybean leaves was found to be predicted most accurately by the 'available' AI extracted from soils by 0.02 M CaCl2. The relationship appears to the linear, with a correlation coefficient of 0.97 (p <0.01). The AI content of the leaves increases with decreasing soil pH. The relationship is non-linear with a marked increase in leaf AI for soils with pH <4.4. The amounts of 'plant-available' AI in the soils extracted with 0.02 M CaCl2 was much less than that extracted with 0.05 M EDTA, although both increased markedly with decreasing soil pH. The amount of AI measured in the soybean plants was directly related to both the 'available' forms of AI in the soils, and also to the pH of the soils. Soil pH was identified as a major factor that controls the uptake of Al from soil into the soybean plant.

  20. Contrasting pH buffering patterns in neutral-alkaline soils along a 3600 km transect in northern China

    NASA Astrophysics Data System (ADS)

    Luo, W. T.; Nelson, P. N.; Li, M.-H.; Cai, J. P.; Zhang, Y. Y.; Zhang, Y. G.; Yang, S.; Wang, R. Z.; Wang, Z. W.; Wu, Y. N.; Han, X. G.; Jiang, Y.

    2015-12-01

    Soil pH buffering capacity (pHBC) plays a crucial role in predicting acidification rates, yet its large-scale patterns and controls are poorly understood, especially for neutral-alkaline soils. Here, we evaluated the spatial patterns and drivers of pHBC along a 3600 km long transect (1900 km sub-transect with carbonate-containing soils and 1700 km sub-transect with non-carbonate-containing soils) across northern China. Soil pHBC was greater in the carbonate-containing soils than in the non-carbonate-containing soils. Acid addition decreased soil pH in the non-carbonate-containing soils more markedly than in the carbonate-containing soils. Within the carbonate soil sub-transect, soil pHBC was positively correlated with cation exchange capacity (CEC), carbonate content and exchangeable sodium (Na) concentration, but negatively correlated with initial pH and clay content, and not correlated with soil organic carbon (SOC) content. Within the non-carbonate sub-transect, soil pHBC was positively related to initial pH, clay content, CEC and exchangeable Na concentration, but not related to SOC content. Carbonate content was the primary determinant of pHBC in the carbonate-containing soils and CEC was the main determinant of buffering capacity in the non-carbonate-containing soils. Along the transect, soil pHBC was different in regions with different aridity index. Soil pHBC was positively related to aridity index and carbonate content across the carbonate-containing soil sub-transect. Our results indicated that mechanisms controlling pHBC differ among neutral-alkaline soils of northern China, especially between carbonate- and non-carbonate-containing soils. This understanding should be incorporated into the acidification risk assessment and landscape management in a changing world.

  1. Effect of pH and organic acids on nitrogen transformations and metal dissolution in soils

    SciTech Connect

    Fu, Minhong.

    1989-01-01

    The effect of pH (4, 6, and 8) on nitrogen mineralization was evaluated in three Iowa surface soils treated with crop residues (corn (Zea mays L.), soybean (Glycine max (L.) Merr.), and sorghum (Sorghum vulgare Pers.), or alfalfa (Medicago sativa L.)) and incubated in leaching columns under aerobic conditions at 30C for 20 weeks. In general, N mineralization was significantly depressed at soil pH 4, compared with pH 6 or 8. The types of crop residues added influenced the pattern and amount of N mineralization. A study on the effect of 19 trace elements on the nitrate red activity of four Iowa surface soils showed that most trace elements inhibited this enzyme in acid and neutral soils. The trace elements Ag(I), Cd(II), Se(IV), As(V), and W(VI) were the most effective inhibitors, with >75% inhibition. Mn(II) was the least effective inhibitor, with <10% inhibition. Other trace elements included Cu(I), Co(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), Al(III), As(III), Cr(III), Fe(III), V(IV), Mo(VI), and Se(VI). The application of high-performance liquid chromatography (HPLC) showed that, when coupled to a refractive index detector, it is a rapid, sensitive, and accurate method for determining organic acids in soils. Three organic acids, acetic (2-20 mM), propionic (0-3 mM), and n-butyric (0-1.4 mM), were identified with HPLC and confirmed by gas chromatography in crop-residue-treated soils incubated under waterlogged conditions at 25C for 72 h. No organic acids were detected under aerobic conditions. Four mineral acids and 29 organic acids were studied for their effect on N mineralization and metal dissolution in soils incubated under waterlogged conditions at 30C for 10 days.

  2. Research on Time and Spatial Variability of Soil pH in Sanmenxia Planted Tobacco Area

    NASA Astrophysics Data System (ADS)

    Qiao, Hongbo; Rui, Gao; Hui, Zhang; Chen, Yanchun; Su, Yongshi

    Geostatistics combined with GIS spatial technology was applied to analyze the time and spatial variability of pH in topsoil(0-20cm) for planted tobacco region in Sanmenxia district. The results indicated that the pH value range form 6.5 to 8.8 and meet to the need of produce high quality tobacco, but the pH value of partial region is high. The pH value accord with logarithm normal distribution, variance coefficient is 15.2% and 4.5% of 2002 and 2007 year respectively. The semivariogram of pH was best described by the exponential model and spatial heterogeneity of pH were 55.77km and 92.39km. The Kriging interpolated method was applied to calculated the unobserved points and was used to generate the spatial and discrepancy map, analyzed the reason of the pH value increase and the method to improve soil. The research supply important method of the Sanmenxia high quality tobacco produce.

  3. Mycorrhizal fungal communities respond to experimental elevation of soil pH and P availability in temperate hardwood forests.

    PubMed

    Carrino-Kyker, Sarah R; Kluber, Laurel A; Petersen, Sheryl M; Coyle, Kaitlin P; Hewins, Charlotte R; DeForest, Jared L; Smemo, Kurt A; Burke, David J

    2016-03-01

    Many forests are affected by chronic acid deposition, which can lower soil pH and limit the availability of nutrients such as phosphorus (P), but the response of mycorrhizal fungi to changes in soil pH and P availability and how this affects tree acquisition of nutrients is not well understood. Here, we describe an ecosystem-level manipulation in 72 plots, which increased pH and/or P availability across six forests in Ohio, USA. Two years after treatment initiation, mycorrhizal fungi on roots were examined with molecular techniques, including 454-pyrosequencing. Elevating pH significantly increased arbuscular mycorrhizal (AM) fungal colonization and total fungal biomass, and affected community structure of AM and ectomycorrhizal (EcM) fungi, suggesting that raising soil pH altered both mycorrhizal fungal communities and fungal growth. AM fungal taxa were generally negatively correlated with recalcitrant P pools and soil enzyme activity, whereas EcM fungal taxa displayed variable responses, suggesting that these groups respond differently to P availability. Additionally, the production of extracellular phosphatase enzymes in soil decreased under elevated pH, suggesting a shift in functional activity of soil microbes with pH alteration. Thus, our findings suggest that elevating pH increased soil P availability, which may partly underlie the mycorrhizal fungal responses we observed.

  4. Mycorrhizal fungal communities respond to experimental elevation of soil pH and P availability in temperate hardwood forests

    DOE PAGES

    Carrino-Kyker, Sarah R.; Kluber, Laurel A.; Petersen, Sheryl M.; Coyle, Kaitlin P.; Hewins, Charlotte R.; DeForest, Jared L.; Smemo, Kurt A.; Burke, David J.

    2016-02-04

    Many forests are affected by chronic acid deposition, which can lower soil pH and limit the availability of nutrients such as phosphorus (P), but the response of mycorrhizal fungi to changes in soil pH and P availability and how this affects tree acquisition of nutrients is not well understood. Here, we describe an ecosystem-level manipulation in 72 plots, which increased pH and/or P availability across six forests in Ohio, USA. Two years after treatment initiation, mycorrhizal fungi on roots were examined with molecular techniques, including 454-pyrosequencing. Elevating pH significantly increased arbuscular mycorrhizal (AM) fungal colonization and total fungal biomass, andmore » affected community structure of AM and ectomycorrhizal (EcM) fungi, suggesting that raising soil pH altered both mycorrhizal fungal communities and fungal growth. AM fungal taxa were generally negatively correlated with recalcitrant P pools and soil enzyme activity, whereas EcM fungal taxa displayed variable responses, suggesting that these groups respond differently to P availability. Additionally, the production of extracellular phosphatase enzymes in soil decreased under elevated pH, suggesting a shift in functional activity of soil microbes with pH alteration. Furthermore, our findings suggest that elevating pH increased soil P availability, which may partly underlie the mycorrhizal fungal responses we observed.« less

  5. Soil pH effects on the interactions between dissolved zinc, non-nano- and nano-ZnO with soil bacterial communities.

    PubMed

    Read, Daniel S; Matzke, Marianne; Gweon, Hyun S; Newbold, Lindsay K; Heggelund, Laura; Ortiz, Maria Diez; Lahive, Elma; Spurgeon, David; Svendsen, Claus

    2016-03-01

    Zinc oxide nanoparticles (ZnO NPs) are used in an array of products and processes, ranging from personal care products to antifouling paints, textiles, food additives, antibacterial agents and environmental remediation processes. Soils are an environment likely to be exposed to manmade nanoparticles due to the practice of applying sewage sludge as a fertiliser or as an organic soil improver. However, understanding on the interactions between soil properties, nanoparticles and the organisms that live within soil is lacking, especially with regards to soil bacterial communities. We studied the effects of nanoparticulate, non-nanoparticulate and ionic zinc (in the form of zinc chloride) on the composition of bacterial communities in soil with a modified pH range (from pH 4.5 to pH 7.2). We observed strong pH-dependent effects on the interaction between bacterial communities and all forms of zinc, with the largest changes in bacterial community composition occurring in soils with low and medium pH levels (pH 4.8 and 5.9). The high pH soil (pH 7.2) was less susceptible to the effects of zinc exposure. At the highest doses of zinc (2500 mg/kg dw soil), both nano and non-nano particulate zinc applications elicited a similar response in the soil bacterial community, and this differed significantly to the ionic zinc salt treatment. The results highlight the importance of considering soil pH in nanotoxicology studies, although further work is needed to determine the exact mechanisms controlling the toxicity and fate and interactions of nanoparticles with soil microbial communities.

  6. Evaluation of boron isotope ratio as a pH proxy in the deep sea coral Desmophyllum dianthus: Evidence of physiological pH adjustment

    NASA Astrophysics Data System (ADS)

    Anagnostou, E.; Huang, K.-F.; You, C.-F.; Sikes, E. L.; Sherrell, R. M.

    2012-10-01

    The boron isotope ratio (δ11B) of foraminifers and tropical corals has been proposed to record seawater pH. To test the veracity and practicality of this potential paleo-pH proxy in deep sea corals, samples of skeletal material from twelve archived modern Desmophyllum dianthus (D. dianthus) corals from a depth range of 274-1470 m in the Atlantic, Pacific, and Southern Oceans, ambient pH range 7.57-8.05, were analyzed for δ11B. The δ11B values for these corals, spanning a range from 23.56 to 27.88, are found to be related to seawater borate δ11B by the linear regression: δ11Bcoral=(0.76±0.28) δ11Bborate+(14.67±4.19) (1 standard error (SE)). The D. dianthus δ11B values are greater than those measured in tropical corals, and suggest substantial physiological modification of pH in the calcifying space by a value that is an inverse function of seawater pH. This mechanism partially compensates for the range of ocean pH and aragonite saturation at which this species grows, enhancing aragonite precipitation and suggesting an adaptation mechanism to low pH environments in intermediate and deep waters. Consistent with the findings of Trotter et al. (2011) for tropical surface corals, the data suggest an inverse correlation between the magnitude of a biologically driven pH offset recorded in the coral skeleton, and the seawater pH, described by the equation: ΔpH=pH recorded by coral-seawater pH=-(0.75±0.12) pHw+(6.88±0.93) (1 SE). Error analysis based on 95% confidence interval(CI) and the standard deviation of the regression residuals suggests that the uncertainty of seawater pH reconstructed from δ11Bcoral is ±0.07 to 0.12 pH units. This study demonstrates the applicability of δ11B in D. dianthus to record ambient seawater pH and holds promise for reconstructing oceanic pH distribution and history using fossil corals.

  7. Experimental study of the pH influence on the transport mechanisms of phenols in soil.

    PubMed

    Fiore, Silvia; Zanetti, Maria Chiara; Genon, Giuseppe

    2003-01-01

    The study of the transport mechanisms connected to solid-liquid interactions is fundamental in the determination of the extension of the pollution of a site and in the evaluation of the best remediation process to be applied. The sorption of hydrophobic ionizable organic contaminants from the groundwaters is supervised not only by the physico-chemical properties of soil and pollutants, but also by the groundwaters pH, which deeply influences their solubility in the aqueous media, and consequently their transport mechanisms in the aquifer. In this work an experimental study of the sorption of phenol and 2-nitrophenol on two soils, different in particle-size distribution, CEC and organic carbon content, was realized. The sorption potential of the soils was evaluated by means of a physical, mineralogical and chemical characterization. The experimental data coming from some batch tests, performed at pH values equal to 4, 7 and 10 were fitted by means of linear, Freundlich and Langmuir isotherms models. The soil-contaminants interaction mechanisms that influence the isotherms shapes were then analyzed and discussed, and a comparison between the theoretical and experimental values of the partitioning coefficient KD was performed.

  8. Fertilization and pH effects on processes and mechanisms controlling dissolved inorganic phosphorus in soils

    NASA Astrophysics Data System (ADS)

    Devau, Nicolas; Hinsinger, Philippe; Le Cadre, Edith; Colomb, Bruno; Gérard, Frédéric

    2011-05-01

    We used of a set of mechanistic adsorption models (1-pK TPM, ion exchange and Nica-Donnan) within the framework of the component additive (CA) approach in an attempt to determine the effect of repeated massive application of inorganic P fertilizer on the processes and mechanisms controlling the concentration of dissolved inorganic phosphorus (DIP) in soils. We studied the surface layer of a Luvisol with markedly different total concentrations of inorganic P as the result of different P fertilizer history (i.e. massive or no application for 40 years). Soil pH was made to vary from acid to alkaline. Soil solutions were extracted with water and CaCl 2 (0.01 M). The occurrence of montmorillonite led us to determine the binding properties of P and Ca ions for this clay mineral. Satisfactory results were obtained using generic values for model parameters and soil-specific ones, which were either determined directly by measurements or estimated from the literature. We showed that adsorption largely controlled the variations of DIP concentration and that, because of kinetic constrains, only little Ca-phosphates may be precipitated under alkaline conditions, particularly in the P fertilized treatment. The mineral-P pool initially present in both P treatments did not dissolve significantly during the course of the experiments. The adsorption of Ca ions onto soil minerals also promoted adsorption of P ions through electrostatic interactions. The intensity of the mechanism was high under neutral to alkaline conditions. Changes in DIP concentration as a function of these environmental variables can be related to changes in the contribution of the various soil minerals to P adsorption. The extra P adsorbed in the fertilized treatment compared with the control treatment was mainly adsorbed onto illite. This clay mineral was the major P-fixing constituent from neutral to alkaline pH conditions, because the repulsion interactions between deprotonated hydroxyl surface sites and P

  9. Impact of soil pH and organic matter on the chemical bioavailability of vanadium species: The underlying basis for risk assessment.

    PubMed

    Reijonen, Inka; Metzler, Martina; Hartikainen, Helinä

    2016-03-01

    The main objective of this study was to unravel the chemical reactions and processes dictating the potential bioavailability of vanadium (V). In environmental solutions V exists in two stable oxidation states, +IV and +V, of which + V is considered to be more toxic. In this study, the effect of speciation and soil pH on the chemical accessibility of V was investigated with two soils: 1) field soil rather rich in soil organic matter (SOM) and 2) coarse mineral soil low in SOM. Fresh soil samples treated with V(+V) (added as NaVO3) or V(+IV) (added as VOSO4) (pH adjusted to the range 4.0-6.9) were incubated for 3 months at 22 °C. The adsorption tendency of V species was explored by water extraction (Milli-Q water, 1:50 dw/V) and by sequential extraction (0.25 M KCl; 0.1 M KH2/K2HPO4; 0.1 M NaOH; 0.25 M H2SO4, 1:10 dw/V). The potential bioavailability of V was found to be dictated by soil properties. SOM reduced V(+V) to V(+IV) and acted as a sorbent for both species, which lowered the bioaccessibility of V. A high pH, in turn, favored the predominance of the V(+V) species and thus increased the chemical accessibility of V.

  10. [Effects of long-term fertilization on pH buffer system of sandy loam calcareous fluvor-aquic soil].

    PubMed

    Wang, Ji-Dong; Qi, Bing-Jie; Zhang, Yong-Chun; Zhang, Ai-Jun; Ning, Yun-Wang; Xu, Xian-Ju; Zhang, Hui; Ma, Hong-Bo

    2012-04-01

    Soil samples (0-80 cm) were collected from a 30-year fertilization experimental site in Xuzhou, Jiangsu Province of East China to study the variations of the pH, calcium carbonate and active calcium carbonate contents, and pH buffer capacity of sandy loam calcareous fluvor-aquic soil under different fertilization treatments. Thirty-year continuous application of different fertilizers accelerated the acidification of topsoil (0-20 cm), with the soil pH decreased by 0.41-0.70. Under different fertilization, the soil pH buffer capacity (pHBC) varied from 15.82 to 21.96 cmol x kg(-1). As compared with no fertilization, single N fertilization decreased the pHBC significantly, but N fertilization combined with organic fertilization could significantly increase the pHBC. The soil pHBC had significant positive correlations with soil calcium carbonate and active calcium carbonate contents, but less correlation with soil organic matter content and soil cation exchange capacity, suggesting that after a long-term fertilization, the sandy loam calcareous fluvor-aquic soil was still of an elementary calcium carbonate buffer system, and soil organic matter and cation exchange capacity contributed little to the buffer system. The soil calcium carbonate and active calcium carbonate contents were greater in 0-40 cm than in 40-80 cm soil layer. Comparing with soil calcium carbonate, soil active calcium carbonate was more sensitive to reflect the changes of soil physical and chemical properties, suggesting that the calcium carbonate buffer system could be further classified as soil active calcium carbonate buffer system.

  11. [Effects of simulated acid rain on respiration rate of cropland system with different soil pH].

    PubMed

    Zhu, Xue-zhu; Zhang, Gao-chuan; Li, Hui

    2009-10-15

    To evaluate the effects of acid rain on the respiration rate of cropland system, an outdoor pot experiment was conducted with paddy soils of pH 5.48 (S1), pH 6.70 (S1) and pH 8.18 (S3) during the 2005-2007 wheat-growing seasons. The cropland system was exposed to acid rain by spraying the wheat foliage and irrigating the soil with simulated rainwater of T1 (pH 6.0), T2 (pH 6.0, ionic concentration was twice as rainwater T1), and T3 (pH 4.4, ionic concentration was twice as rainwater T1), respectively. The static opaque chamber-gas chromatograph method was used to measure CO2 fluxes from cropland system. The results showed that acid rain affected the respiration rate of cropland system through crop plant, and the cropland system could adapt to acid rain. Acid rainwater significantly increased the average respiration rate in alkaline soil (S3) cropland system, while it had no significant effects on the average respiration rate in neutral soil (S2) and acidic soil (S1) cropland systems. During 2005-2006, after the alkaline soil cropland system was treated with rainwater T3, the average respiration rate was 23.6% and 27.6% higher than that of alkaline soil cropland system treated with rainwater T1 and T2, respectively. During March to April, the respiration rate was enhanced with the increase of rainwater ionic concentration, while it was dropped with the decrease of rainwater pH value in acidic soil cropland system. It was demonstrated that soil pH and crop plant played important roles on the respiration rate of cropland system.

  12. [Effects of simulated acid rain on respiration rate of cropland system with different soil pH].

    PubMed

    Zhu, Xue-zhu; Zhang, Gao-chuan; Li, Hui

    2009-10-15

    To evaluate the effects of acid rain on the respiration rate of cropland system, an outdoor pot experiment was conducted with paddy soils of pH 5.48 (S1), pH 6.70 (S1) and pH 8.18 (S3) during the 2005-2007 wheat-growing seasons. The cropland system was exposed to acid rain by spraying the wheat foliage and irrigating the soil with simulated rainwater of T1 (pH 6.0), T2 (pH 6.0, ionic concentration was twice as rainwater T1), and T3 (pH 4.4, ionic concentration was twice as rainwater T1), respectively. The static opaque chamber-gas chromatograph method was used to measure CO2 fluxes from cropland system. The results showed that acid rain affected the respiration rate of cropland system through crop plant, and the cropland system could adapt to acid rain. Acid rainwater significantly increased the average respiration rate in alkaline soil (S3) cropland system, while it had no significant effects on the average respiration rate in neutral soil (S2) and acidic soil (S1) cropland systems. During 2005-2006, after the alkaline soil cropland system was treated with rainwater T3, the average respiration rate was 23.6% and 27.6% higher than that of alkaline soil cropland system treated with rainwater T1 and T2, respectively. During March to April, the respiration rate was enhanced with the increase of rainwater ionic concentration, while it was dropped with the decrease of rainwater pH value in acidic soil cropland system. It was demonstrated that soil pH and crop plant played important roles on the respiration rate of cropland system. PMID:19968099

  13. An assessment of the association between soil pH and ovine Johne's disease using Australian abattoir surveillance data.

    PubMed

    Cowled, Brendan D; Stevenson, Mark A; Madin, Ben

    2016-04-01

    There has long been discussion in the literature about the role of soil on ovine Johnes disease (OJD). This is especially true of soil pH, however there is very little research to support an association between pH and OJD prevalence. The primary objective of this study was to examine the hypothesis that there is an association between soil pH and OJD. Several additional hypotheses were also assessed. Sheep properties that were surveyed by the Australian National Sheep Health Monitoring Project where classified as OJD reactor positive or otherwise. A variety of explanatory variables such as soil (especially soil pH), environmental and management factors were examined. Spatial regression models were assessed using information theory to examine support for various hypotheses and to examine associations; especially that soil pH is associated with OJD. A total of 1213 properties from 10,578 were classified as OJD positive (11.5%, 95% CI: 10.9-12.1). Within the limitations of the study, only modest support was found for an association between soil pH and the presence or absence of OJD. Instead, OJD prevalence was affected by several factors concurrently, a so called multi-factorial model (hypothesis). In this supported multifactorial hypothesis soil pH was marginally associated with OJD (p=0.04) and had a relatively weak effect (OR 0.91, 95% CI 0.82 to 1.00). OJD was strongly associated with a number of biosecurity and environmental factors such as the time since infection arrived in a region, absence of biosecurity programs (such as regional biosecurity programs or state based programs) and, to a lesser extent, solar irradiation. Soil pH may play a relatively small role in explaining OJD prevalence when evaluated as part of a multifactorial model. Biosecurity and other environmental factors appear to be more strongly associated with the presence of OJD in Australia.

  14. Influence of initial pH on bioleaching of heavy metals from contaminated soil employing indigenous Acidithiobacillus thiooxidans.

    PubMed

    Kumar, R Naresh; Nagendran, R

    2007-01-01

    Bioleaching of heavy metals from contaminated soil was carried out employing indigenous sulfur oxidizing bacterium Acidithiobacillus thiooxidans. Experiments were carried out to assess the influence of initial pH of the system on bioleaching of chromium, zinc, copper, lead and cadmium from metal contaminated soil. pH at the end of four weeks of bioleaching at different initial pH of 3-7 was between 0.9 and 1.3, ORP between 567 and 617mV and sulfate production was in the range of 6090-8418mgl(-1). Chromium, zinc, copper, lead and cadmium solubilization ranged from "59% to 98%" at different initial pH. A. thiooxidans was not affected by the increasing pH of the bioleaching system towards neutral and it was able to utilize elemental sulfur. The results of the present study are encouraging to develop the bioleaching process for decontamination of heavy metal contaminated soil.

  15. Using a toxicokinetics approach to explain the effect of soil pH on cadmium bioavailability to Folsomia candida.

    PubMed

    Ardestani, Masoud M; van Gestel, Cornelis A M

    2013-09-01

    The aim of this study was to improve our understanding of metal bioavailability in soil by linking the biotic ligand approach with toxicokinetics modelling. We determined cadmium bioaccumulation kinetics in Folsomia candida (Collembola) as a function of soil pH. Animals were exposed for 21 days to LUFA 2.2 soil at 5 or 20 μg Cd g(-1) dry soil followed by 21 days elimination in clean soil. Internal cadmium concentrations were modelled using a first-order one-compartment model, relating uptake rate constants (k1) to total soil, water or 0.01 M CaCl2 extractable and porewater concentrations. Based on total soil concentrations, k1 was independent of soil pH while it strongly increased with increasing pH based on porewater concentrations explaining the reduced competition of H(+) ions making cadmium more bioavailable in pore water at high pH. This shows that the principles of biotic ligand modelling are applicable to predict cadmium accumulation kinetics in soil-living invertebrates. PMID:23747820

  16. Effect of acid rain pH on leaching behavior of cement stabilized lead-contaminated soil.

    PubMed

    Du, Yan-Jun; Wei, Ming-Li; Reddy, Krishna R; Liu, Zhao-Peng; Jin, Fei

    2014-04-30

    Cement stabilization is a practical approach to remediate soils contaminated with high levels of lead. However, the potential for leaching of lead out of these stabilized soils under variable acid rain pH conditions is a major environmental concern. This study investigates the effects of acid rain on the leaching characteristics of cement stabilized lead contaminated soil under different pH conditions. Clean kaolin clay and the same soil spiked with 2% lead contamination are stabilized with cement contents of 12 and 18% and then cured for 28 days. The soil samples are then subjected to a series of accelerated leaching tests (or semi-dynamic leaching tests) using a simulated acid rain leachant prepared at pH 2.0, 4.0 or 7.0. The results show that the strongly acidic leachant (pH ∼2.0) significantly altered the leaching behavior of lead as well as calcium present in the soil. However, the differences in the leaching behavior of the soil when the leachant was mildly acidic (pH ∼4.0) and neutral (pH ∼7.0) prove to be minor. In addition, it is observed that the lead contamination and cement content levels can have a considerable impact on the leaching behavior of the soils. Overall, the leachability of lead and calcium is attributed to the stability of the hydration products and their consequent influence on the soil buffering capacity and structure.

  17. Effect of acid rain pH on leaching behavior of cement stabilized lead-contaminated soil.

    PubMed

    Du, Yan-Jun; Wei, Ming-Li; Reddy, Krishna R; Liu, Zhao-Peng; Jin, Fei

    2014-04-30

    Cement stabilization is a practical approach to remediate soils contaminated with high levels of lead. However, the potential for leaching of lead out of these stabilized soils under variable acid rain pH conditions is a major environmental concern. This study investigates the effects of acid rain on the leaching characteristics of cement stabilized lead contaminated soil under different pH conditions. Clean kaolin clay and the same soil spiked with 2% lead contamination are stabilized with cement contents of 12 and 18% and then cured for 28 days. The soil samples are then subjected to a series of accelerated leaching tests (or semi-dynamic leaching tests) using a simulated acid rain leachant prepared at pH 2.0, 4.0 or 7.0. The results show that the strongly acidic leachant (pH ∼2.0) significantly altered the leaching behavior of lead as well as calcium present in the soil. However, the differences in the leaching behavior of the soil when the leachant was mildly acidic (pH ∼4.0) and neutral (pH ∼7.0) prove to be minor. In addition, it is observed that the lead contamination and cement content levels can have a considerable impact on the leaching behavior of the soils. Overall, the leachability of lead and calcium is attributed to the stability of the hydration products and their consequent influence on the soil buffering capacity and structure. PMID:24637445

  18. Using a toxicokinetics approach to explain the effect of soil pH on cadmium bioavailability to Folsomia candida.

    PubMed

    Ardestani, Masoud M; van Gestel, Cornelis A M

    2013-09-01

    The aim of this study was to improve our understanding of metal bioavailability in soil by linking the biotic ligand approach with toxicokinetics modelling. We determined cadmium bioaccumulation kinetics in Folsomia candida (Collembola) as a function of soil pH. Animals were exposed for 21 days to LUFA 2.2 soil at 5 or 20 μg Cd g(-1) dry soil followed by 21 days elimination in clean soil. Internal cadmium concentrations were modelled using a first-order one-compartment model, relating uptake rate constants (k1) to total soil, water or 0.01 M CaCl2 extractable and porewater concentrations. Based on total soil concentrations, k1 was independent of soil pH while it strongly increased with increasing pH based on porewater concentrations explaining the reduced competition of H(+) ions making cadmium more bioavailable in pore water at high pH. This shows that the principles of biotic ligand modelling are applicable to predict cadmium accumulation kinetics in soil-living invertebrates.

  19. Spatial variability of soil carbon, pH, available phosphorous and potassium in organic farm located in Mediterranean Croatia

    NASA Astrophysics Data System (ADS)

    Bogunović, Igor; Pereira, Paulo; Šeput, Miranda

    2016-04-01

    Soil organic carbon (SOC), pH, available phosphorus (P), and potassium (K) are some of the most important factors to soil fertility. These soil parameters are highly variable in space and time, with implications to crop production. The aim of this work is study the spatial variability of SOC, pH, P and K in an organic farm located in river Rasa valley (Croatia). A regular grid (100 x 100 m) was designed and 182 samples were collected on Silty Clay Loam soil. P, K and SOC showed moderate heterogeneity with coefficient of variation (CV) of 21.6%, 32.8% and 51.9%, respectively. Soil pH record low spatial variability with CV of 1.5%. Soil pH, P and SOC did not follow normal distribution. Only after a Box-Cox transformation, data respected the normality requirements. Directional exponential models were the best fitted and used to describe spatial autocorrelation. Soil pH, P and SOC showed strong spatial dependence with nugget to sill ratio with 13.78%, 0.00% and 20.29%, respectively. Only K recorded moderate spatial dependence. Semivariogram ranges indicate that future sampling interval could be 150 - 200 m in order to reduce sampling costs. Fourteen different interpolation models for mapping soil properties were tested. The method with lowest Root Mean Square Error was the most appropriated to map the variable. The results showed that radial basis function models (Spline with Tension and Completely Regularized Spline) for P and K were the best predictors, while Thin Plate Spline and inverse distance weighting models were the least accurate. The best interpolator for pH and SOC was the local polynomial with the power of 1, while the least accurate were Thin Plate Spline. According to soil nutrient maps investigated area record very rich supply with K while P supply was insufficient on largest part of area. Soil pH maps showed mostly neutral reaction while individual parts of alkaline soil indicate the possibility of penetration of seawater and salt accumulation in the

  20. Influence of soil pH on the toxicity of zinc oxide nanoparticles to the terrestrial isopod Porcellionides pruinosus.

    PubMed

    Tourinho, Paula S; van Gestel, Cornelis A M; Lofts, Stephen; Soares, Amadeu M V M; Loureiro, Susana

    2013-12-01

    The effects of soil pH on the toxicity of ZnO nanoparticles (NPs) to the terrestrial isopod Porcellionides pruinosus were evaluated. Isopods were exposed to a natural soil amended with CaCO3 to reach 3 different pH(CaCl2) levels (4.5, 6.2, and 7.3) and to standard LUFA 2.2 soil (pH 5.5) spiked with ZnO NPs (30 nm), non-nano ZnO (200 nm), and ionic Zn as ZnCl₂. Toxicity was expressed based on total Zn concentration in soil, as well as total Zn and free Zn²⁺ ion concentrations in porewater. Compared with ZnO-spiked soils, the ZnCl₂-spiked soils had lower pH and higher porewater Ca²⁺ and Zn levels. Isopod survival did not differ between Zn forms and soils, but survival was higher for isopods exposed to ZnO NPs at pH 4.5. Median effect concentrations (EC50s) for biomass change showed similar trends for all Zn forms in all soils, with higher values at intermediate pH. Median lethal concentration (LC50) and EC50 values based on porewater Zn or free Zn ion concentrations were much lower for ZnO than for ionic zinc. Zn body concentrations increased in a dose-related manner, but no effect of soil pH was found. It is suggested not only that dissolved or free Zn in porewater contributed to uptake and toxicity, but also that oral uptake (i.e., ingestion of soil particles) could be an important additional route of exposure.

  1. Leachability and desorption of PCBs from soil and their dependency on pH and dissolved organic matter.

    PubMed

    Badea, Silviu-Laurentiu; Mustafa, Majid; Lundstedt, Staffan; Tysklind, Mats

    2014-11-15

    pH affects both soil-water partitioning coefficient (Kd) of polychlorinated biphenyls (PCBs) and dissolved organic matter (DOM), thereby influencing PCBs' leachability from contaminated soils. To explore these incompletely understood interactions, the leachability of 11 selected PCBs in a naturally aged soil was investigated in pH static leaching tests spanning a wide pH range (2 to 9). The K(d) was calculated for each of the PCBs, based on their observed concentrations in the soil and leachates obtained from each test. The concentration and composition of DOM in each leachate were also determined, the latter using FTIR spectroscopy. Correlations between the DOM's FTIR spectra and K(d) values were investigated by orthogonal projections to latent structures. The log K(d)-values varied among the PCB congeners and were most variable at low pH, but the values for all studied congeners decreased with increasing pH, by up to 3 log units (for PCB 187). In the pH 5-7 interval, an abrupt decrease in log K(d) values with increases in pH was observed, although the total organic carbon content remained relatively stable. The FTIR data indicate that fulvic and humic acids in DOM partially deprotonate as the pH rises from 5 to 7.

  2. Enhanced-electrokinetic remediation of copper-pyrene co-contaminated soil with different oxidants and pH control.

    PubMed

    Cang, Long; Fan, Guang-Ping; Zhou, Dong-Mei; Wang, Quan-Ying

    2013-02-01

    Electrokinetic (EK) remediation has potential to simultaneously remove heavy metals and organic compounds from soil, but the removal percent of these pollutants is very low in general if no enhancing treatment is applied. This study developed a new enhanced-EK remediation technology to decontaminate a heavy metal-organic compound co-contaminated soil by applying different oxidants and pH control. A red soil was used as a model clayed soil, and was spiked with pyrene and Cu at about 500 mg kg(-1) for both to simulate real situation. Bench-scale EK experiments were performed using four oxidants (H(2)O(2), NaClO, KMnO(4), and Na(2)S(2)O(8)) and controlling electrolyte pH at 3.5 or 10. After the treatments with 1.0 V cm(-1) of voltage gradient for 335 h, soil pH, electrical conductivity, and the concentrations and chemical fractionations of soil pyrene and Cu were analyzed. The results showed that there was significant migration of pyrene and Cu from the soil, and the removal percent of soil pyrene and Cu varied in the range of 30-52% and 8-94%, respectively. Low pH favoured the migration of soil Cu, while KMnO(4) was the best one for the degradation of pyrene among the tested oxidants, although it unfortunately prevented the migration of soil Cu by forming Cu oxide. Application of Na(2)S(2)O(8) and to control the catholyte pH at 3.5 were found to be the best operation conditions for decontaminating the Cu-pyrene co-contaminated soil. PMID:23177009

  3. Soil pH is a Key Determinant of Soil Fungal Community Composition in the Ny-Ålesund Region, Svalbard (High Arctic)

    PubMed Central

    Zhang, Tao; Wang, Neng-Fei; Liu, Hong-Yu; Zhang, Yu-Qin; Yu, Li-Yan

    2016-01-01

    This study assessed the fungal community composition and its relationships with properties of surface soils in the Ny-Ålesund Region (Svalbard, High Arctic). A total of thirteen soil samples were collected and soil fungal community was analyzed by 454 pyrosequencing with fungi-specific primers targeting the rDNA internal transcribed spacer (ITS) region. The following eight soil properties were analyzed: pH, organic carbon (C), organic nitrogen (N), ammonium nitrogen (NH4+-N), silicate silicon (SiO42--Si), nitrite nitrogen (NO2--N), phosphate phosphorus (PO43--P), and nitrate nitrogen (NO3--N). A total of 57,952 reads belonging to 541 operational taxonomic units (OTUs) were found. of these OTUs, 343 belonged to Ascomycota, 100 to Basidiomycota, 31 to Chytridiomycota, 22 to Glomeromycota, 11 to Zygomycota, 10 to Rozellomycota, whereas 24 belonged to unknown fungi. The dominant orders were Helotiales, Verrucariales, Agaricales, Lecanorales, Chaetothyriales, Lecideales, and Capnodiales. The common genera (>eight soil samples) were Tetracladium, Mortierella, Fusarium, Cortinarius, and Atla. Distance-based redundancy analysis (db-rda) and analysis of similarities (ANOSIM) revealed that soil pH (p = 0.001) was the most significant factor in determining the soil fungal community composition. Members of Verrucariales were found to predominate in soils of pH 8–9, whereas Sordariales predominated in soils of pH 7–8 and Coniochaetales predominated in soils of pH 6–7. The results suggest the presence and distribution of diverse soil fungal communities in the High Arctic, which can provide reliable data for studying the ecological responses of soil fungal communities to climate changes in the Arctic. PMID:26955371

  4. Soil pH is a Key Determinant of Soil Fungal Community Composition in the Ny-Ålesund Region, Svalbard (High Arctic).

    PubMed

    Zhang, Tao; Wang, Neng-Fei; Liu, Hong-Yu; Zhang, Yu-Qin; Yu, Li-Yan

    2016-01-01

    This study assessed the fungal community composition and its relationships with properties of surface soils in the Ny-Ålesund Region (Svalbard, High Arctic). A total of thirteen soil samples were collected and soil fungal community was analyzed by 454 pyrosequencing with fungi-specific primers targeting the rDNA internal transcribed spacer (ITS) region. The following eight soil properties were analyzed: pH, organic carbon (C), organic nitrogen (N), ammonium nitrogen (NH4 (+)-N), silicate silicon (SiO4 (2-)-Si), nitrite nitrogen (NO2 (-)-N), phosphate phosphorus (PO4 (3-)-P), and nitrate nitrogen (NO3 (-)-N). A total of 57,952 reads belonging to 541 operational taxonomic units (OTUs) were found. of these OTUs, 343 belonged to Ascomycota, 100 to Basidiomycota, 31 to Chytridiomycota, 22 to Glomeromycota, 11 to Zygomycota, 10 to Rozellomycota, whereas 24 belonged to unknown fungi. The dominant orders were Helotiales, Verrucariales, Agaricales, Lecanorales, Chaetothyriales, Lecideales, and Capnodiales. The common genera (>eight soil samples) were Tetracladium, Mortierella, Fusarium, Cortinarius, and Atla. Distance-based redundancy analysis (db-rda) and analysis of similarities (ANOSIM) revealed that soil pH (p = 0.001) was the most significant factor in determining the soil fungal community composition. Members of Verrucariales were found to predominate in soils of pH 8-9, whereas Sordariales predominated in soils of pH 7-8 and Coniochaetales predominated in soils of pH 6-7. The results suggest the presence and distribution of diverse soil fungal communities in the High Arctic, which can provide reliable data for studying the ecological responses of soil fungal communities to climate changes in the Arctic.

  5. Potential of elemental sulfur fertigation to reduce high soil pH for production of highbush blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blueberry is adapted to acidic soil conditions but is often planted in high pH soils by adding elemental sulfur (S) prior to planting. Two pot experiments were carried out in a glasshouse to determine the potential of applying elemental S by fertigation through a drip irrigation system. In the first...

  6. Inhibitory effect of high soil pH on growth and mineral metabolism of rice and its reversal by zinc.

    PubMed

    Singh, H P; Singh, T N

    2005-10-01

    Increasing soil pH retarded growth, tillers and bio-mass production of rice cultivar Sarjoo-52. Application of 10 to 15 kgZn ha(-1) increased the bio-mass by 33 to 41% at pH 8.5 and 27 to 32% at pH 10.3. Panicle length, rachis branches, total spikelets, filled grains, grain size were all adversely affected to the tune of 19, 23, 40, 74 and 21%, respectively by higher soil alkalinity at pH 10.3. Alkalinity resulted in 19, 31 and 65% spikelet sterility which reduced to 3, 21 and 55% at pH 8.5, 9.5 and 10.3, respectively by Zn applied @ 15 kg ha(-1). Grain yield reduced to 50% at pH 10.3 but Zn in general, raised the yield levels by 1.6 to 2.3, times. The chlorophyll decreased by 36 to 50% whereas carbonic anhydrase activities decreased only by 13% due to increase in soil sodicity and alkalinity. Further, increase in pH caused significant decrease in Zn, Ca, Mg, P and K concentrations but phenomenal rise in Na content Zinc application, apart from increasing tissue Zn content, elevated Ca :Na and K :Na ratio resulting in improved growth and yield of rice under soil sodicity and alkalinity. PMID:16459555

  7. The efficacy of 0.75% bupivacaine with pH adjustment and hyaluronidase for peribulbar blockade: the incidence of prolonged ptosis.

    PubMed

    Mather, C; Smith, J H; Bloom, P A

    1994-01-01

    A prospective, double masked, randomised study was performed to compare the speed of onset of peribulbar anaesthesia using pH adjusted 0.75% bupivacaine, with and without the addition of hyaluronidase. No significant difference in speed of onset occurred due to the addition of hyaluronidase. There were 7 cases of post operative ptosis in the study group, including 1 case of orbital apex syndrome and 2 cases of transient 3rd nerve palsy. This incidence of post operative ptosis using pH adjusted 0.75% bupivacaine was statistically significantly greater than in a matched control group who received a 50:50 mixture of 1% lignocaine and 0.5% bupivacaine with hyaluronidase (p < 0.05). The possible causes of this increased incidence of post operative ptosis are discussed.

  8. The efficacy of 0.75% bupivacaine with pH adjustment and hyaluronidase for peribulbar blockade: the incidence of prolonged ptosis.

    PubMed

    Mather, C; Smith, J H; Bloom, P A

    1994-01-01

    A prospective, double masked, randomised study was performed to compare the speed of onset of peribulbar anaesthesia using pH adjusted 0.75% bupivacaine, with and without the addition of hyaluronidase. No significant difference in speed of onset occurred due to the addition of hyaluronidase. There were 7 cases of post operative ptosis in the study group, including 1 case of orbital apex syndrome and 2 cases of transient 3rd nerve palsy. This incidence of post operative ptosis using pH adjusted 0.75% bupivacaine was statistically significantly greater than in a matched control group who received a 50:50 mixture of 1% lignocaine and 0.5% bupivacaine with hyaluronidase (p < 0.05). The possible causes of this increased incidence of post operative ptosis are discussed. PMID:8019117

  9. Relation of pH and other soil variables to concentrations of Pb, Cu, Zn, Cd, and Se in earthworms

    USGS Publications Warehouse

    Beyer, W.N.; Hensler, G.L.; Moore, J.

    1987-01-01

    Various soil treatments (clay, composted peat, superphosphate, sulfur, calcium carbonate, calcium chloride, zinc chloride, selenous acid) were added to experimental field plots to test the effect of different soil variables on the concentrations of 5 elements in earthworms (Pb, Cu, Zn, Cd, Se). Concentrations of the 5 elements were related to 9 soil variables (soil Pb, soil Cu, soil Zn, pH, organic matter, P, K, Mg, and Ca) with linear multiple regression. Lead concentrations in earthworms were positively correlated with soil Pb and soil organic matter, and negatively correlated with soil pH and soil Mg, with an R2 of 64%. Se concentrations were higher in earthworms from plots amended with Se, and Zn concentrations were higher in earthworms from plots amended with Zn. However, none of the other soil variables had important effects on the concentrations of Cu, Zn, Cd and Se in earthworms. Although some significant statistical relations were demonstrated, the values of r2 of all relations (> 20%) were so low that they had little predictive value.

  10. [Effects of solution pH and simulated acid rain on the behavior of two sulfonylurea herbicides in soil].

    PubMed

    Zhang, Wei; Wang, Jin-Jun

    2007-03-01

    By the methods of batch equilibration and leaching, this paper studied the effects of solution pH and simulated acid rain on the behavior of bensulfuron-methyl and metsulfuron-methyl in soil. The results showed that the adsorption isotherms of these two herbicides fitted Freundlich equation well, and their adsorbed amounts reduced obviously with the increasing pH of water-soil system, which in turn promoted the translocation of the herbicides in soil. The adsorption coefficient (Kf) was positively correlated with soil organic matter and clay contents, while negatively correlated with soil pH. The higher pH of simulated acid rain had a greater contribution on the leaching of the two sulfonylurea herbicides, and their leached amount was increased with increasing acid rain. There was a close relationship between the leaching of the herbicides and the properties of soil. The soils with higher contents of organic matter and clay had a greater retention capability to the herbicides. PMID:17552202

  11. [Effects of solution pH and simulated acid rain on the behavior of two sulfonylurea herbicides in soil].

    PubMed

    Zhang, Wei; Wang, Jin-Jun

    2007-03-01

    By the methods of batch equilibration and leaching, this paper studied the effects of solution pH and simulated acid rain on the behavior of bensulfuron-methyl and metsulfuron-methyl in soil. The results showed that the adsorption isotherms of these two herbicides fitted Freundlich equation well, and their adsorbed amounts reduced obviously with the increasing pH of water-soil system, which in turn promoted the translocation of the herbicides in soil. The adsorption coefficient (Kf) was positively correlated with soil organic matter and clay contents, while negatively correlated with soil pH. The higher pH of simulated acid rain had a greater contribution on the leaching of the two sulfonylurea herbicides, and their leached amount was increased with increasing acid rain. There was a close relationship between the leaching of the herbicides and the properties of soil. The soils with higher contents of organic matter and clay had a greater retention capability to the herbicides.

  12. Influence of Environmental Factors on Antagonism of Fungi by Bacteria in Soil: Clay Minerals and pH

    PubMed Central

    Rosenzweig, William D.; Stotzky, G.

    1979-01-01

    The soil replica plating technique was used to evaluate the influence of clay minerals and pH on antagonistic interactions between fungi and bacteria in soil. In general, the antagonistic activity of bacteria towards filamentous fungi was greater in soil than on agar. The spread of Aspergillus niger through soil was inhibited by Serratia marcescens when the organisms were inoculated into separate sites in soil, and this antagonistic effect was maintained when the soil was amended with 3, 6, 9, or 12% (vol/vol) montmorillonite, whereas the addition of kaolinite at a concentration of 3% reduced the antagonism and at 6, 9, or 12% totally eliminated it. Similar results were obtained with the inhibition of A. niger by Agrobacterium radiobacter and of Penicillium vermiculatum by either S. marcescens or Nocardia paraffinae. When A. niger and S. marcescens were inoculated into the same soil site, A. niger was inhibited in all soils, regardless of clay content, although the extent of inhibition was greater as the concentration of montmorillonite, but not of kaolinite, increased. A. niger was inhibited more when inoculated as spores than as mycelial fragments and when inoculated 96 h after S. marcescens, but a 1% glucose solution reduced the amount of inhibition when the fungus was inoculated 96 h after the bacterium. When the pH of the soil-clay mixtures was altered, the amount of antagonism usually increased as the pH increased. Antagonism appeared to be related to the cation-exchange capacity and the pH of the soil-clay mixtures. Bacillus cereus and another species of Bacillus showed no activity in soil towards A. niger under any of the environmental conditions tested, even though the Bacillus sp. significantly inhibited A. niger and seven other fungi on agar. PMID:16345477

  13. Rate of phosphoantimonylmolybdenum blue complex formation in acidic persulfate digested sample matrix for total dissolved phosphorus determination: importance of post-digestion pH adjustment.

    PubMed

    Huang, Xiao-Lan; Zhang, Jia-Zhong

    2008-10-19

    Acidic persulfate oxidation is one of the most common procedures used to digest dissolved organic phosphorus compounds in water samples for total dissolved phosphorus determination. It has been reported that the rates of phosphoantimonylmolybdenum blue complex formation were significantly reduced in the digested sample matrix. This study revealed that the intermediate products of persulfate oxidation, not the slight change in pH, cause the slowdown of color formation. This effect can be remedied by adjusting digested samples pH to a near neural to decompose the intermediate products. No disturbing effects of chlorine on the phosphoantimonylmolybdenum blue formation in seawater were observed. It is noted that the modification of mixed reagent recipe cannot provide near neutral pH for the decomposition of the intermediate products of persulfate oxidation. This study provides experimental evidence not only to support the recommendation made in APHA standard methods that the pH of the digested sample must be adjusted to within a narrow range of sample, but also to improve the understanding of role of residue from persulfate decomposition on the subsequent phosphoantimonylmolybdenum blue formation.

  14. Iron biofortification of wheat grains through integrated use of organic and chemical fertilizers in pH affected calcareous soil.

    PubMed

    Ramzani, Pia Muhammad Adnan; Khalid, Muhammad; Naveed, Muhammad; Ahmad, Rashid; Shahid, Muhammad

    2016-07-01

    Incidence of iron (Fe) deficiency in human populations is an emerging global challenge. This study was conducted to evaluate the potential of iron sulphate combined with biochar and poultry manure for Fe biofortification of wheat grains in pH affected calcareous soil. In first two incubation studies, rates of sulfur (S) and Fe combined with various organic amendments for lowering pH and Fe availability in calcareous soil were optimized. In pot experiment, best rate of Fe along with biochar (BC) and poultry manure (PM) was evaluated for Fe biofortification of wheat in normal and S treated low pH calcareous soil. Fe applied with BC provided fair increase in root-shoot biomass and photosynthesis up to 79, 53 and 67%, respectively in S treated low pH soil than control. Grain Fe and ferritin concentration was increased up to 1.4 and 1.2 fold, respectively while phytate and polyphenol was decreased 35 and 44%, respectively than control in treatment where Fe was applied with BC and S. In conclusion, combined use of Fe and BC could be an effective approach to improve growth and grain Fe biofortification of wheat in pH affected calcareous soil. PMID:27179316

  15. Iron biofortification of wheat grains through integrated use of organic and chemical fertilizers in pH affected calcareous soil.

    PubMed

    Ramzani, Pia Muhammad Adnan; Khalid, Muhammad; Naveed, Muhammad; Ahmad, Rashid; Shahid, Muhammad

    2016-07-01

    Incidence of iron (Fe) deficiency in human populations is an emerging global challenge. This study was conducted to evaluate the potential of iron sulphate combined with biochar and poultry manure for Fe biofortification of wheat grains in pH affected calcareous soil. In first two incubation studies, rates of sulfur (S) and Fe combined with various organic amendments for lowering pH and Fe availability in calcareous soil were optimized. In pot experiment, best rate of Fe along with biochar (BC) and poultry manure (PM) was evaluated for Fe biofortification of wheat in normal and S treated low pH calcareous soil. Fe applied with BC provided fair increase in root-shoot biomass and photosynthesis up to 79, 53 and 67%, respectively in S treated low pH soil than control. Grain Fe and ferritin concentration was increased up to 1.4 and 1.2 fold, respectively while phytate and polyphenol was decreased 35 and 44%, respectively than control in treatment where Fe was applied with BC and S. In conclusion, combined use of Fe and BC could be an effective approach to improve growth and grain Fe biofortification of wheat in pH affected calcareous soil.

  16. Cr(VI) adsorption/desorption on untreated and mussel shell-treated soil materials: fractionation and effects of pH and chromium concentration

    NASA Astrophysics Data System (ADS)

    Otero, M.; Cutillas-Barreiro, L.; Nóvoa-Muñoz, J. C.; Arias-Estévez, M.; Fernández-Sanjurjo, M. J.; Álvarez-Rodríguez, E.; Núñez-Delgado, A.

    2014-12-01

    We used batch-type experiments to study Cr(VI) adsorption/desorption on granitic material, forest soil, pyritic material, mussel shell, and on forest soil and granitic material amended with 12 t ha-1 shell, considering the effects of varying Cr(VI) concentration and pH. Sequential extractions were carried out to fractionate adsorbed Cr(VI) and to determine the stability of Cr(VI) retention. The pyritic material had the highest Cr(VI) retention capacity, whereas the granitic material showed the lowest retention potential. When high Cr concentrations were added, some saturation of the adsorbent surfaces became apparent, but Cr release remained low. The highest Cr retention was achieved at very acid pH value, with release progressively increasing as a function of increasing pH. The amendment with 12 t ha-1 mussel shell did not cause marked changes in Cr(VI) retention. Adsorption data were satisfactory adjusted to the Freundlich model. Regarding Cr(VI) fractionation, the soluble fraction (weakly bound) was the dominant in mussel shell and in the un-amended and amended granitic material, whereas more stable fractions dominated in the pyritic material (residual fraction) and in the forest soil (oxidizable fraction). In conclusion, the pyritic material presented the highest Cr(VI) retention capacity, while the retention was low and weak on the granitic material; mussel shell was characterized by not marked Cr(VI) retention potential, and it did not cause remarkable increase in Cr(VI) retention when used to amend the granitic material or the forest soil.

  17. The effect of soil pH on N2O/(N2O+N2) product ratio of denitrification depends on soil NO3- concentration

    NASA Astrophysics Data System (ADS)

    Senbayram, Mehmet; Dittert, Klaus; Well, Reinhard; Lewicka-Szczebak, Dominika; Lammel, Joachim; Bakken, Lars

    2015-04-01

    Globally, agricultural soils account for about 60% of the atmospheric N2O emissions and denitrification in soil is the major source of atmospheric N2O, which contributes to global warming and destruction of stratospheric ozone. Denitrification is the microbially mediated process of dissimilatory nitrate reduction that may produce not only N2O but also nitric oxide (NO), and molecular nitrogen (N2). The major controls on denitrification rates are soil NO3, O2, and labile C levels. Typically, when soils become more anoxic, larger proportions of N2O produced in denitrification are further reduced to N2 before leaving the soil. Microbial ecology may possibly find solutions to this major environmental problem of agricultural systems once mechanisms controlling the product ratio of denitrification (N2O/N2O+N2) are better understood. Recent investigations of these gaseous microbial products provided the evidence for a negative effect of soil acidity on the N2O/N2O+N2 product ratio. However, in an earlier study, we showed that, regardless of soil type, higher NO3- concentrations in soil may also retard the reduction of N2O to N2. In this context, the positive effect of higher soil pH on the N2O/(N2O+N2) product ratio in soils with high NO3- content is still poorly understood. Therefore, we set up a number of incubation experiments in order to test short-term and long-term effects of soil pH and NO3- concentration on denitrification rates and the product stoichiometry of denitrification. We measured N2O, NO as well as elemental N2 in soils with pH levels ranging 4.1 to pH 6.9 collected from a long-term liming experiment. In a continuous flow incubation system we evacuated and flushed all vessels with He. Then, fresh He was directed through an inlet in the lid at a flow rate of 15-30 ml min-1. Gas samples were analyzed twice a day for N2O by ECD and for N2 by TCD detectors. Denitrification rates increased significantly with increasing soil pH, however, during the initial

  18. Gravity-driven transport of three engineered nanomaterials in unsaturated soils and their effects on soil pH and nutrient release.

    PubMed

    Conway, Jon R; Keller, Arturo A

    2016-07-01

    The gravity-driven transport of TiO2, CeO2, and Cu(OH)2 engineered nanomaterials (ENMs) and their effects on soil pH and nutrient release were measured in three unsaturated soils. ENM transport was found to be highly limited in natural soils collected from farmland and grasslands, with the majority of particles being retained in the upper 0-3 cm of the soil profile, while greater transport depth was seen in a commercial potting soil. Physical straining appeared to be the primary mechanism of retention in natural soils as ENMs immediately formed micron-scale aggregates, which was exacerbated by coating particles with Suwannee River natural organic matter (NOM) which promote steric hindrance. Small changes in soil pH were observed in natural soils contaminated with ENMs that were largely independent of ENM type and concentration, but differed from controls. These changes may have been due to enhanced release of naturally present pH-altering ions (Mg(2+), H(+)) in the soil via substitution processes. These results suggest ENMs introduced into soil will likely be highly retained near the source zone. PMID:27108211

  19. Gravity-driven transport of three engineered nanomaterials in unsaturated soils and their effects on soil pH and nutrient release.

    PubMed

    Conway, Jon R; Keller, Arturo A

    2016-07-01

    The gravity-driven transport of TiO2, CeO2, and Cu(OH)2 engineered nanomaterials (ENMs) and their effects on soil pH and nutrient release were measured in three unsaturated soils. ENM transport was found to be highly limited in natural soils collected from farmland and grasslands, with the majority of particles being retained in the upper 0-3 cm of the soil profile, while greater transport depth was seen in a commercial potting soil. Physical straining appeared to be the primary mechanism of retention in natural soils as ENMs immediately formed micron-scale aggregates, which was exacerbated by coating particles with Suwannee River natural organic matter (NOM) which promote steric hindrance. Small changes in soil pH were observed in natural soils contaminated with ENMs that were largely independent of ENM type and concentration, but differed from controls. These changes may have been due to enhanced release of naturally present pH-altering ions (Mg(2+), H(+)) in the soil via substitution processes. These results suggest ENMs introduced into soil will likely be highly retained near the source zone.

  20. Soil lime level (pH) and VA-Mycorrhiza effects on growth responses of sweetgum seedlings

    SciTech Connect

    Davis, E.A.; Young, J.L.; Linderman, R.G.

    1983-01-01

    Sequential greenhouse experiments limed a strongly acid surface and subsurface horizons of phosphorus-deficient Jory clay loam with increments of calcium carbonate to attain a range in soil pH from 5.0 to 8.1. In the absence of vesicular-arbuscular mycorrhizae (VAM), neither the organic matter-rich surface nor the organic matter-poor subsurface horizon supported growth of sweetgum seedlings at any pH despite regular nutrient supplements. The effects of pH, VAM, and soil horizon on nutrient accumulation and plant nutrient concentrations were variable. Nitrogen and phosphorus concentrations were generally higher in the VAM than in control seedlings, which suggests that host plant should be matched with VAM species adapted to particular soil and climate conditions to obtain maximum benefit from a mycorrhizal association. 18 references, 2 figures, 3 tables.

  1. Removal of pollutants by enhanced coagulation combined PAC with variable charge soils: flocs' properties and effect of pH.

    PubMed

    Wang, Yu-Jie; Wu, Chun-De; Duan, Yan; Zhang, Zhi-Lin

    2016-09-01

    This study investigated the properties of flocs and effects of the solution pH on removal of representative pollutants by enhanced coagulation with variable charge soils of South China and polyaluminum chloride (PAC). The results demonstrated that the removal efficiency of turbidity was larger and the aggregated flocs had a faster growth rate, bigger size, denser structure and faster settling rate than those generated by PAC alone, when variable charge soil was used in conjunction with PAC. Additionally, initial solutions pH had meaningful effects on removal of pollutants. With the increase in the pH of the solution, the removal efficiencies of turbidity, algae and heavy metal ions significantly increased. Besides, charge neutralization together with physical entrapment of colloids was the dominant mechanism in enhanced coagulation, and variable charge soil displayed a great adsorption effect. PMID:26829123

  2. Dual purpose recovered coagulant from drinking water treatment residuals for adjustment of initial pH and coagulation aid in electrocoagulation process.

    PubMed

    Jung, Kyung-Won; Ahn, Kyu-Hong

    2016-01-01

    The present study is focused on the application of recovered coagulant (RC) by acidification from drinking water treatment residuals for both adjusting the initial pH and aiding coagulant in electrocoagulation. To do this, real cotton textile wastewater was used as a target pollutant, and decolorization and chemical oxygen demand (COD) removal efficiency were monitored. A preliminary test indicated that a stainless steel electrode combined with RC significantly accelerated decolorization and COD removal efficiencies, by about 52% and 56%, respectively, even at an operating time of 5 min. A single electrocoagulation system meanwhile requires at least 40 min to attain the similar removal performances. Subsequently, the interactive effect of three independent variables (applied voltage, initial pH, and reaction time) on the response variables (decolorization and COD removal) was evaluated, and these parameters were statistically optimized using the response surface methodology. Analysis of variance showed a high coefficient of determination values (decolorization, R(2) = 0.9925 and COD removal, R(2) = 0.9973) and satisfactory prediction second-order polynomial quadratic regression models. Average decolorization and COD removal of 89.52% and 94.14%, respectively, were achieved, corresponding to 97.8% and 98.1% of the predicted values under statistically optimized conditions. The results suggest that the RC effectively played a dual role of both adjusting the initial pH and aiding coagulant in the electrocoagulation process.

  3. Soil pH management by calcareous and siliceous minerals: effect on N2O yield in nitrification and denitrification

    NASA Astrophysics Data System (ADS)

    Nadeem, Shahid; Bakken, Lars; Dörsch, Peter

    2016-04-01

    Amelioration of soil pH by liming is necessary and common practice in vast areas of crop production. It is well known that pH is one of the most pervasive factors controlling rates and product stoichiometries in microbially mediated N transformations, including N2O emissions. While liming of acid soils appears to increase N2O reductase activity in denitrification (resulting in less N2O relative to N2), sudden pH raise may boost nitrification and hence N2O emission from ammonia oxidation. Thus, the net effect of liming on N2O emissions is not straightforward, which probably explains why soil pH management has not been embraced as a strategy for mitigating N2O emissions so far. Here we report laboratory incubations in which we determined potential rates and N2O yields in soils from an ongoing field experiment, comparing traditional calcareous limes (calcite, dolomite) with mafic minerals (olivine, different types of plagioclase). The experiment is in its second year, and shows strong pH increase (0.7-1.5, units) in plots with calcareous limes, a weak pH increase (~ 0.2 unit) in the olivine treatment and no measurable pH increase with the plagioclases. Potential nitrification rates correlated positively with effective soil pH as did the N2O yield, measured as N2O accumulation rate over NO2- + NO3- accumulation rate. The N2O yield increased in the order, control < plagioclase < olivine < dolomite < calcite and was significant for calcite and dolomite treated soils. Overall, the N2O yield from nitrification was quite low (0.09 - 0.17%). Potential denitrifications rates showed little response to pH increase (no C source added) but significantly lower N2O product ratios (N2O/(N2O + N2) with increasing pH in the order, calcite < dolomite < olivine < plagioclase < control. Given the overall low N2O yield of nitrification as compared to that of denitrification (10 - 100%), the observed increases in N2O yields of nitrification are unlikely to override a significant reduction

  4. The influence of soil pH and humus content on received by Mehlich 3 method nutrients analysis results

    NASA Astrophysics Data System (ADS)

    Tonutare, Tonu; Krebstein, Kadri; Rodima, Ako; Kõlli, Raimo; Künnapas, Allan; Rebane, Jaanus; Penu, Priit; Vennik, Kersti; Soobik, Liina

    2015-04-01

    Soils provide vital ecosystem functions, playing an important role in our economy and in healthy living environment. However, soils are increasingly degrading in Europe and at the global level. Knowledge about the content of major plant available nutrients, i.e. calcium, magnesium, potassium and phosphorus, plays an important role in the sustainable soil management. Mobility of nutrients depends directly on the environmental conditions, two of the most important factors are the pH and organic matter content. Therefore it is essential to have correct information about the content and behaviour of the above named elements in soil, both from the environmental and agronomical viewpoint. During the last decades several extracting solutions which are suitable for the evaluation of nutrient status of soils have been developed for this purpose. One of them is called Mehlich 3 which is widely used in USA, Canada and some European countries (e.g. Estonia, Czech Republic) because of its suitability to extract several major plant nutrients from the soil simultaneously. There are several different instrumental methods used for the analysis of nutrient elements in the soil extract. Potassium, magnesium and calcium are widely analysed by the AAS (atomic absorption spectroscopic) method or by the ICP (inductively coupled plasma) spectroscopic methods. Molecular spectroscopy and ICP spectroscopy were used for the phosphorus determination. In 2011 a new multielemental instrumental method MP-AES (microwave plasma atomic emission spectroscopy) was added to them. Due to its lower detection limits and multielemental character, compared with AAS, and lower exploitation costs, compared with ICP, the MP-AES has a good potential to achieve a leading position in soil nutrient analysis in the future. The objective of this study was to investigate: (i) the impact of soil pH and humus content and (ii) applicability of MP-AES instrumental method for the determination of soil nutrients extracted

  5. Influence of pH on the toxic effects of zinc, cadmium, and pentachlorophenol on pure cultures of soil microorganisms

    SciTech Connect

    Beelen, P. van; Fleuren-Kemilae, A.K.

    1997-02-01

    In this study the effect of acidification of soil pore water on the uptake and toxicity of cationic and anionic pollutants was measured in an experimental model system. The influence of pH on the toxic effects of zinc, cadmium, and pentachlorophenol was studied in buffered suspensions of pure cultures of soil microorganisms. In this system the speciation of the toxicant, the pH, and the biomass are defined, constant, and thus easier to study than in a system with the solid soil matrix and pore water. The mineralization of [{sup 14}C]acetate to {sup 14}CO{sub 2} was used to measure the toxic effects of pollutants on a fungus (Aspergillus niger CBS 121.49), an actinomycete (Streptomyces lividans 66), two Gram-negative Pseudomonas putida strains (MT-2 and DSM 50026), and a gram-positive strain (Rhodococcus erythropolis A177). Large differences in sensitivity were observed between the species. For pentachlorophenol the highest EC50 was 81 mg/L for Pseudomonas putida at pH 8, whereas the lowest was 0.13 mg/L for Aspergillus niger at pH 6. Aspergillus niger was not sensitive to 1,000 mg Zn/L, whereas Pseudomonas putida at pH 7.8 showed the lowest EC50, 0.14 mg Zn/L. When pH was increased, pentachlorophenol became less toxic and showed less sorption to the biomass, whereas zinc and cadmium became more toxic and showed more sorption to the biomass. The results indicate that higher pore-water concentrations due to acidification of zinc- and cadmium-polluted soils may not be accompanied by increased toxic effects on microorganisms because of the relatively low toxicity of these metals in pore water at low pH.

  6. Sorption, desorption, and speciation of Cd, Ni, and Fe by four calcareous soils as affected by pH.

    PubMed

    Tahervand, Samaneh; Jalali, Mohsen

    2016-06-01

    The sorption, desorption, and speciation of cadmium (Cd), nickel (Ni), and iron (Fe) in four calcareous soils were investigated at the pH range of 2-9. The results indicated that sorption of Fe by four soils was higher than 80 % at pH 2, while in the case of Cd and Ni was less than 30 %. The most common sequence of metal sorption at pH 2-9 for four soils was in the order of Fe ≫ Ni > Cd. Cadmium and Ni sorption as a function of pH showed the predictable trend of increasing metal sorption with increase in equilibrium pH, while the Fe sorption trend was different and characterized by three phases. With regard to the order of Cd, Ni, and Fe sorption on soils, Cd and Ni showed high affinity for organic matter (OM), whereas Fe had high tendency for calcium carbonate (CaCO3). Results of metal desorption using 0.01 M NaCl demonstrated that metal sorption on soils containing high amounts of CaCO3 was less reversible in comparison to soils containing high OM. In general, Cd and Ni desorption curves were characterized by three phases; (1) the greatest desorption at pH 2, (2) the low desorption at pH 3-7, and (3) the least desorption at pH > 7. The MINTEQ speciation solubility program showed that the percentage of free metals declined markedly with increase of pH, while the percentage of carbonate and hydroxyl species increased. Furthermore, MINTEQ predicted that saturation index (SI) of metals increased with increasing pH.

  7. Sorption, desorption, and speciation of Cd, Ni, and Fe by four calcareous soils as affected by pH.

    PubMed

    Tahervand, Samaneh; Jalali, Mohsen

    2016-06-01

    The sorption, desorption, and speciation of cadmium (Cd), nickel (Ni), and iron (Fe) in four calcareous soils were investigated at the pH range of 2-9. The results indicated that sorption of Fe by four soils was higher than 80 % at pH 2, while in the case of Cd and Ni was less than 30 %. The most common sequence of metal sorption at pH 2-9 for four soils was in the order of Fe ≫ Ni > Cd. Cadmium and Ni sorption as a function of pH showed the predictable trend of increasing metal sorption with increase in equilibrium pH, while the Fe sorption trend was different and characterized by three phases. With regard to the order of Cd, Ni, and Fe sorption on soils, Cd and Ni showed high affinity for organic matter (OM), whereas Fe had high tendency for calcium carbonate (CaCO3). Results of metal desorption using 0.01 M NaCl demonstrated that metal sorption on soils containing high amounts of CaCO3 was less reversible in comparison to soils containing high OM. In general, Cd and Ni desorption curves were characterized by three phases; (1) the greatest desorption at pH 2, (2) the low desorption at pH 3-7, and (3) the least desorption at pH > 7. The MINTEQ speciation solubility program showed that the percentage of free metals declined markedly with increase of pH, while the percentage of carbonate and hydroxyl species increased. Furthermore, MINTEQ predicted that saturation index (SI) of metals increased with increasing pH. PMID:27147235

  8. Interrelationships between mycorrhizal symbiosis, soil pH and plant sex modify the performance of Antennaria dioica

    NASA Astrophysics Data System (ADS)

    Varga, Sandra; Kytöviita, Minna-Maarit

    2010-05-01

    AM symbiosis is usually beneficial for plants, but the benefits gained may depend on the soil abiotic factors. In dioecious plants, female and male individuals have different resource demands and allocation patterns. As a consequence of these differences, it is logical to assume that female and male plants differ in their relationship with arbuscular mycorrhizal (AM) fungi, although this has rarely been examined. We used a factorial greenhouse experiment to investigate whether female and male plants in the dioecious model species Antennaria dioica have a different relationship with their AM symbionts under two soil pH levels. In particular, we asked: (1) Do the sexes in A. dioica have sex-specific benefits from AM symbiosis? (2) If so, which sex gains the highest benefit? (3) How does soil pH affect the sex - AM fungal relationship? Our results indicate that the sexes responded similarly to AM symbiosis and pH when mycorrhizal benefit was examined as growth and phosphorus accumulation. However, the sexes differed in response to AM symbiosis in terms of survival, as mortality was increased due to AM symbiosis in female plants whilst the opposite effect was detected in males. The plant-AM fungus relationship was significantly affected by soil pH as lowering the soil pH decreased the benefits gained by the plants from the mycorrhizal fungus. Taken together, our findings indicate that AM symbiosis is beneficial for plants depending on the life history trait considered. In addition, interactions between plants and their AM symbionts are modified by soil factors and the sex of the plant.

  9. DISSOLVED ORGANIC MATTER AND METALS: EFFECTS OF PH ON PARTITIONING NATURAL ORGANIC MATTER IN SOILS AND WATER

    EPA Science Inventory

    Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb, and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was fractionated into three operationally defined fractions: hydrophilic acids (Hyd), fulvic acids (FA), an...

  10. Microalgae harvesting by pH adjusted coagulation-flocculation, recycling of the coagulant and the growth media.

    PubMed

    Das, Probir; Thaher, Mahmoud Ibrahim; Abdul Hakim, Mohammed Abdul Quadir Mohd; Al-Jabri, Hareb Mohammed S J; Alghasal, Ghamza Saed H S

    2016-09-01

    Coagulation-flocculation can be considered as one of the least energy intensive microalgae biomass harvesting processes. However, cost of the coagulant and biomass contamination are two critical issues that need to be considered. In this study, ferric chloride (72-96mg/L) was used to effectively harvest Scenedesmus sp. (530mg/L) - grown in BG-11 media and wastewater. Reducing the culture pH below 6.5, greatly improved the harvesting efficiency. Acidic solution (pH 1.0) was very effective to recover (almost 90%) the associated iron from the harvested biomass. Scenedesmus sp. was able to grow in the supernatant and utilize the residual iron in it. Iron extracted solution, with a supplementation of 9.8mg/L ferric chloride, was able to achieve similar harvesting efficiency. The potential recovery of iron from the harvested biomass and its reuse in the harvesting can improve the biomass quality for subsequent downstream processing while reducing the cost. PMID:27318160

  11. Arsenic release from flooded paddy soils is influenced by speciation, Eh, pH, and iron dissolution.

    PubMed

    Yamaguchi, N; Nakamura, T; Dong, D; Takahashi, Y; Amachi, S; Makino, T

    2011-05-01

    Arsenic (As) is highly mobilized when paddy soil is flooded, causing increased uptake of As by rice. We investigated factors controlling soil-to-solution partitioning of As under anaerobic conditions. Changes in As and iron (Fe) speciation due to flooded incubation of two paddy soils (soils A and B) were investigated by HPLC/ICP-MS and XANES. The flooded incubation resulted in a decrease in Eh, a rise in pH, and an increase in the As(III) fraction in the soil solid phase up to 80% of the total As in the soils. The solution-to-soil ratio of As(III) and As(V) (R(L/S)) increased with pH due to the flooded incubation. The R(L/S) for As(III) was higher than that for As(V), indicating that As(III) was more readily released from soil to solution than was As(V). Despite the small differences in As concentrations between the two soils, the amount of As dissolved by anaerobic incubation was lower in soil A. With the development of anaerobic conditions, Fe(II) remained in the soil solid phase as the secondary mineral siderite, and a smaller amount of Fe was dissolved from soil A than from soil B. The dissolution of Fe minerals rather than redox reaction of As(V) to As(III) explained the different dissolution amounts of As in the two paddy soils. Anaerobic incubation for 30 d after the incomplete suppression of microbial activity caused a drop in Eh. However, this decline in Eh did not induce the transformation of As(V) to As(III) in either the soil solid or solution phases, and the dissolution of As was limited. Microbial activity was necessary for the reductive reaction of As(V) to As(III) even when Eh reached the condition necessary for the dominance of As(III). Ratios of released As to Fe from the soils were decreased with incubation time during both anaerobic incubation and abiotic dissolution by sodium ascorbate, suggesting that a larger amount of As was associated with an easily soluble fraction of Fe (hydr) oxide in amorphous phase and/or smaller particles. PMID

  12. Differential response of archaeal and bacterial communities to nitrogen inputs and pH changes in upland pasture rhizosphere soil.

    PubMed

    Nicol, Graeme W; Webster, Gordon; Glover, L Anne; Prosser, James I

    2004-08-01

    Grassland management regimens influence the structure of archaeal communities in upland pasture soils, which appear to be dominated by as yet uncultivated non-thermophilic Crenarchaeota. In an attempt to determine which grassland management factors select for particular crenarchaeal community structures, soil microcosm experiments were performed examining the effect of increased pH, application of inorganic fertilizer (ammonium nitrate) and sheep urine deposition on both archaeal and bacterial communities in unmanaged grassland soil. As grassland management typically increases pH, a further experiment examined the effect of a reduction in pH, to that typical of unimproved grassland soils, on archaeal and bacterial communities. The RT-PCR amplification of 16S rRNA followed by denaturing gradient gel electrophoresis analysis demonstrated a distinct and reproducible effect on bacterial communities after incubation for 28 or 30 days. In contrast, none of the treatments had a significant effect on the structure of the crenarchaeal community, indicating that these factors are not major drivers of crenarchaeal community structures in grassland soils.

  13. Seasonal Belowground Ecosystem and Eco-enzymatic Responses to Soil pH and Phosphorus Availability in Temperate Hardwood Forests

    NASA Astrophysics Data System (ADS)

    Smemo, K. A.; Deforest, J. L.; Petersen, S. L.; Burke, D.; Hewins, C.; Kluber, L. A.; Kyker, S. R.

    2013-12-01

    Atmospheric acid deposition can increase phosphorus (P) limitation in temperate hardwood forests by increasing N availability, and therefore P demand, and/or by decreasing pH and occluding inorganic P. However, only recently have studies demonstrated that P limitation can occur in temperate forests and very little is known about the temporal aspects of P dynamics in acidic forest soils and how seasonal shifts in nutrient availability and demand influence microbial investment in extracellular enzymes. The objectives of this study were to investigate how P availability and soil pH influence seasonal patterns of nutrient cycling and soil microbial activity in hardwood forests that experience chronic acid deposition. We experimentally manipulated soil pH, P, or both for three years and examined soil treatment responses in fall, winter, spring, early summer, and late summer. We found that site (glaciated versus unglaciated) and treatment had the most significant influence on nutrient pools and cycling. In general, nutrient pools were higher in glaciated soils than unglaciated for measured nutrients, including total C and N (2-3 times higher), extractable inorganic nitrogen, and readily available P. Treatment had no impact on total C and N pools in either region, but did affect other measured nutrients such as ammonium, which was greatest in the elevated pH treatment for both sites. As expected, readily available P pools were highest in the elevated P treatments (3 fold increase in both sites), but raising pH decreased available P pools in the glaciated site. Raising soil pH increased both net N mineralization rates and net P mineralization rates, regardless of site. Nitrification responses were complex, but we observed an overall significant nitrification increase under elevated pH, particularly in the growing season. Extracellular enzyme activity showed more seasonal patterns than site and treatment effects, exhibiting significant growing season activity reductions for

  14. Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH.

    PubMed

    Uchimiya, Minori; Bannon, Desmond I

    2013-08-14

    Biochar is often considered a strong heavy metal stabilizing agent. However, biochar in some cases had no effects on, or increased the soluble concentrations of, heavy metals in soil. The objective of this study was to determine the factors causing some biochars to stabilize and others to dissolve heavy metals in soil. Seven small arms range soils with known total organic carbon (TOC), cation exchange capacity, pH, and total Pb and Cu contents were first screened for soluble Pb and Cu concentrations. Over 2 weeks successive equilibrations using weak acid (pH 4.5 sulfuric acid) and acetate buffer (0.1 M at pH 4.9), Alaska soil containing disproportionately high (31.6%) TOC had nearly 100% residual (insoluble) Pb and Cu. This soil was then compared with sandy soils from Maryland containing significantly lower (0.5-2.0%) TOC in the presence of 10 wt % (i) plant biochar activated to increase the surface-bound carboxyl and phosphate ligands (PS450A), (ii) manure biochar enriched with soluble P (BL700), and (iii) unactivated plant biochars produced at 350 °C (CH350) and 700 °C (CH500) and by flash carbonization (corn). In weak acid, the pH was set by soil and biochar, and the biochars increasingly stabilized Pb with repeated extractions. In pH 4.9 acetate buffer, PS450A and BL700 stabilized Pb, and only PS450A stabilized Cu. Surface ligands of PS450A likely complexed and stabilized Pb and Cu even under acidic pH in the presence of competing acetate ligand. Oppositely, unactivated plant biochars (CH350, CH500, and corn) mobilized Pb and Cu in sandy soils; the putative mechanism is the formation of soluble complexes with biochar-borne dissolved organic carbon. In summary, unactivated plant biochars can inadvertently increase dissolved Pb and Cu concentrations of sandy, low TOC soils when used to stabilize other contaminants.

  15. The molecular composition of dissolved organic matter in forest soils as a function of pH and temperature.

    PubMed

    Roth, Vanessa-Nina; Dittmar, Thorsten; Gaupp, Reinhard; Gleixner, Gerd

    2015-01-01

    We examined the molecular composition of forest soil water during three different seasons at three different sites, using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS). We examined oxic soils and tested the hypothesis that pH and season correlate with the molecular composition of dissolved organic matter (DOM). We used molecular formulae and their relative intensity from ESI-FT-ICR-MS for statistical analysis. Applying unconstrained and constrained ordination methods, we observed that pH, dissolved organic carbon (DOC) concentration and season were the main factors correlating with DOM molecular composition. This result is consistent with a previous study where pH was a main driver of the molecular differences between DOM from oxic rivers and anoxic bog systems in the Yenisei River catchment. At a higher pH, the molecular formulae had a lower degree of unsaturation and oxygenation, lower molecular size and a higher abundance of nitrogen-containing compounds. These characteristics suggest a higher abundance of tannin connected to lower pH that possibly inhibited biological decomposition. Higher biological activity at a higher pH might also be related to the higher abundance of nitrogen-containing compounds. Comparing the seasons, we observed a decrease in unsaturation, molecular diversity and the number of nitrogen-containing compounds in the course of the year from March to November. Temperature possibly inhibited biological degradation during winter, which could cause the accumulation of a more diverse compound spectrum until the temperature increased again. Our findings suggest that the molecular composition of DOM in soil pore waters is dynamic and a function of ecosystem activity, pH and temperature.

  16. The Molecular Composition of Dissolved Organic Matter in Forest Soils as a Function of pH and Temperature

    PubMed Central

    Roth, Vanessa-Nina; Dittmar, Thorsten; Gaupp, Reinhard; Gleixner, Gerd

    2015-01-01

    We examined the molecular composition of forest soil water during three different seasons at three different sites, using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS). We examined oxic soils and tested the hypothesis that pH and season correlate with the molecular composition of dissolved organic matter (DOM). We used molecular formulae and their relative intensity from ESI-FT-ICR-MS for statistical analysis. Applying unconstrained and constrained ordination methods, we observed that pH, dissolved organic carbon (DOC) concentration and season were the main factors correlating with DOM molecular composition. This result is consistent with a previous study where pH was a main driver of the molecular differences between DOM from oxic rivers and anoxic bog systems in the Yenisei River catchment. At a higher pH, the molecular formulae had a lower degree of unsaturation and oxygenation, lower molecular size and a higher abundance of nitrogen-containing compounds. These characteristics suggest a higher abundance of tannin connected to lower pH that possibly inhibited biological decomposition. Higher biological activity at a higher pH might also be related to the higher abundance of nitrogen-containing compounds. Comparing the seasons, we observed a decrease in unsaturation, molecular diversity and the number of nitrogen-containing compounds in the course of the year from March to November. Temperature possibly inhibited biological degradation during winter, which could cause the accumulation of a more diverse compound spectrum until the temperature increased again. Our findings suggest that the molecular composition of DOM in soil pore waters is dynamic and a function of ecosystem activity, pH and temperature. PMID:25793306

  17. Caribbean mangroves adjust to rising sea level through biotic controls on change in soil elevation

    USGS Publications Warehouse

    McKee, K.L.; Cahoon, D.R.; Feller, Ilka C.

    2007-01-01

    Aim The long-term stability of coastal ecosystems such as mangroves and salt marshes depends upon the maintenance of soil elevations within the intertidal habitat as sea level changes. We examined the rates and processes of peat formation by mangroves of the Caribbean Region to better understand biological controls on habitat stability. Location Mangrove-dominated islands on the Caribbean coasts of Belize, Honduras and Panama were selected as study sites. Methods Biological processes controlling mangrove peat formation were manipulated (in Belize) by the addition of nutrients (nitrogen or phosphorus) to Rhizophora mangle (red mangrove), and the effects on the dynamics of soil elevation were determined over a 3-year period using rod surface elevation tables (RSET) and marker horizons. Peat composition and geological accretion rates were determined at all sites using radiocarbon-dated cores. Results The addition of nutrients to mangroves caused significant changes in rates of mangrove root accumulation, which influenced both the rate and direction of change in elevation. Areas with low root input lost elevation and those with high rates gained elevation. These findings were consistent with peat analyses at multiple Caribbean sites showing that deposits (up to 10 m in depth) were composed primarily of mangrove root matter. Comparison of radiocarbon-dated cores at the study sites with a sea-level curve for the western Atlantic indicated a tight coupling between peat building in Caribbean mangroves and sea-level rise over the Holocene. Main conclusions Mangroves common to the Caribbean region have adjusted to changing sea level mainly through subsurface accumulation of refractory mangrove roots. Without root and other organic inputs, submergence of these tidal forests is inevitable due to peat decomposition, physical compaction and eustatic sea-level rise. These findings have relevance for predicting the effects of sea-level rise and biophysical processes on tropical

  18. The effect of pH and natural microbial phosphatase activity on the speciation of uranium in subsurface soils

    NASA Astrophysics Data System (ADS)

    Beazley, Melanie J.; Martinez, Robert J.; Webb, Samuel M.; Sobecky, Patricia A.; Taillefert, Martial

    2011-10-01

    The biomineralization of U(VI) phosphate as a result of microbial phosphatase activity is a promising new bioremediation approach to immobilize uranium in both aerobic and anaerobic conditions. In contrast to reduced uranium minerals such as uraninite, uranium phosphate precipitates are not susceptible to changes in oxidation conditions and may represent a long-term sink for uranium in contaminated environments. So far, the biomineralization of U(VI) phosphate has been demonstrated with pure cultures only. In this study, two uranium contaminated soils from the Department of Energy Oak Ridge Field Research Center (ORFRC) were amended with glycerol phosphate as model organophosphate source in small flow-through columns under aerobic conditions to determine whether natural phosphatase activity of indigenous soil bacteria was able to promote the precipitation of uranium(VI) at pH 5.5 and 7.0. High concentrations of phosphate (1-3 mM) were detected in the effluent of these columns at both pH compared to control columns amended with U(VI) only, suggesting that phosphatase-liberating microorganisms were readily stimulated by the organophosphate substrate. Net phosphate production rates were higher in the low pH soil (0.73 ± 0.17 mM d -1) compared to the circumneutral pH soil (0.43 ± 0.31 mM d -1), suggesting that non-specific acid phosphatase activity was expressed constitutively in these soils. A sequential solid-phase extraction scheme and X-ray absorption spectroscopy measurements were combined to demonstrate that U(VI) was primarily precipitated as uranyl phosphate minerals at low pH, whereas it was mainly adsorbed to iron oxides and partially precipitated as uranyl phosphate at circumneutral pH. These findings suggest that, in the presence of organophosphates, microbial phosphatase activity can contribute to uranium immobilization in both low and circumneutral pH soils through the formation of stable uranyl phosphate minerals.

  19. Importance of inoculum properties on the structure and growth of bacterial communities during Recolonisation of humus soil with different pH.

    PubMed

    Pettersson, Marie; Bååth, Erland

    2013-08-01

    The relationship between community structure and growth and pH tolerance of a soil bacterial community was studied after liming in a reciprocal inoculum study. An unlimed (UL) humus soil with a pH of 4.0 was fumigated with chloroform for 4 h, after which < 1 % of the initial bacterial activity remained. Half of the fumigated soil was experimentally limed (EL) to a pH of 7.6. Both the UL and the EL soil were then reciprocally inoculated with UL soil or field limed (FL) soil with a pH of 6.2. The FL soil was from a 15-year-old experiment. The structural changes were measured on both bacteria in soil and on bacteria able to grow on agar plates using phospholipids fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analysis. The developing community pH tolerance and bacterial growth were also monitored over time using thymidine incorporation. The inoculum source had a significant impact on both growth and pH tolerance of the bacterial community in the EL soil. These differences between the EL soil inoculated with UL soil and FL soil were correlated to structural changes, as evidenced by both PLFA and DGGE analyses on the soil. Similar correlations were seen to the fraction of the community growing on agar plates. There were, however, no differences between the soil bacterial communities in the unlimed soils with different inocula. This study showed the connection between the development of function (growth), community properties (pH tolerance) and the structure of the bacterial community. It also highlighted the importance of both the initial properties of the community and the selection pressure after environmental changes in shaping the resulting microbial community.

  20. Contrasting effects of manure and compost on soil pH, heavy metal availability and growth of Chenopodium album L. in a soil contaminated by pyritic mine waste.

    PubMed

    Walker, David J; Clemente, Rafael; Bernal, M Pilar

    2004-10-01

    Chenopodium album L. was found to be one of the initial plant species colonising a heavy metal-contaminated site, polluted by pyritic (sulphide-rich) waste from the Aznalcóllar mine spill (South-western Spain). This indicates its importance in the re-vegetation of this soil. In a pot experiment, C. album was sown in soil collected from the contaminated site, either non-amended or amended with cow manure or compost produced from olive leaves and olive mill wastewater, in order to study the effect on heavy metal bioavailability and soil pH. In non-amended and compost-amended soils, soil acidification, probably resulting from oxidation and hydrolysis of sulphide, led to increases in the concentrations of soluble sulphate and plant-available Cu, Zn and Mn in the soil (extractable with 0.1 M CaCl(2)). Under these conditions, shoot growth of C. album was negligible and shoot concentrations of Zn (2,420-5,585 microg g(-1)) and Mn (5,513-8,994 microg g(-1)) were phytotoxic. Manure application greatly increased shoot growth and reduced the shoot concentrations of Cu, Zn, and Mn, and their plant-available concentrations in the soil. These effects appeared to be related to an increase of soil pH, due to an inhibition of sulphide oxidation/hydrolysis, relative to the non-amended soil. For metal sulphides-contaminated soil, liable to acidification, manure application appears to be able to enhance the initial stages of re-vegetation, by species such as C. album. PMID:15312738

  1. Influence of soil pH and application rate on the oxidation of calcium sulfite derived from flue gas desulfurization

    SciTech Connect

    Lee, Y.B.; Bigham, J.M.; Dick, W.A.; Jones, E.S.; Ramsier, C.

    2007-01-15

    Calcium sulfite hemihydrate (CaSO{sub 3} {center_dot} 0.5H{sub 2}O), a common byproduct of coal-fired utilities, is fairly insoluble and can decompose to release toxic SO{sub 2} under highly acidic soil conditions; however, it can also oxidize to form gypsum. The objective of this study was to examine the effects of application rate and soil pH on the oxidation of calcium sulfite under laboratory conditions. Oxidation rates measured by release of SO{sub 4}-S to solution decreased with increasing application rate. Leachate SO{sub 4}-S from soils amended with 1.0 to 3.0 g kg{sup -1} CaSO{sub 3} increased over a 21 to 28 d period before reaching a plateau. At 4 g kg{sup -1}, maximum SO{sub 4}-S release was delayed until Week 7. Oxidation and release of SO{sub 4}-S from soil amended with 3.0 g kg{sup -1} calcium sulfite increased markedly with decreasing soil pH. After only 3 d incubation, the concentrations of SO{sub 4}-S in aqueous leachates were 77, 122, 1709 220, and 229 mg L{sup -1} for initial soil pH values of 7.8, 6.5, 5.5, 5.1, and 4.0, respectively. At an initial soil pH value of 4.0, oxidation/dissolution did not increase much after 3 d. At higher pH values, oxidation was maximized after 21 d. These results suggest that autumn surface applications of calcium sulfite in no-till systems should permit ample time for oxidation/dissolution reactions to occur without introducing biocidal effects related to oxygen scavenging. Soil and annual crops can thus benefit from additions of soluble Ca and SO{sub 4} if calcium sulfite is applied in advance of spring planting.

  2. Influence of pH and soil copper on adsorption of metalaxyl and penconazole by the surface layer of vineyard soils.

    PubMed

    Arias, M; Paradelo, M; López, E; Simal-Gándara, J

    2006-10-18

    The upper horizons of old vineyard soils have substantial copper contents due to the traditional use of copper-based fungicides. Total copper levels in eight vineyard soils in the Rías Baixas area of Galicia (northwestern Spain) ranged from 60 to 560 mg kg(-1) (mean +/- SD = 206 +/- 170 mg kg(-1)). The adsorption of the fungicides metalaxyl (pK(a) = 1.41) and penconazole (pK(a) = 2.83) by these soils was determined using fungicide solutions of pH 2.5 and 5.5, and desorption of fungicide adsorbed at pH 5.5 was also determined. In all cases, Freundlich equations were fitted to the data with R (2) > 0.96. Penconazole was adsorbed and retained more strongly than metalaxyl, with K(F) values more than an order of magnitude greater. In the desorption experiments, both fungicides exhibited hysteresis. Soil copper content hardly affected the adsorption of metalaxyl, but K(F) values for adsorption of penconazole increased at a rate of about 0.1 mL(n) (microg of penconazole)(1-n) (microg of Cu)(-1), which is attributed to the formation of Cu(2+)-penconazole complexes with greater affinity for soil colloids than penconazole itself. Because the dependence of K(F) for penconazole adsorption on copper content was the same at both pH values, complex formation appears not to have been affected by the solubilization of 6-17% of soil copper at pH 2.5. A similar copper dependence, or lack of dependence, was observed when 100-1000 mg kg(-1) of copper was added as Cu(NO(3))(2).2H(2)O to the solutions from which the fungicides were adsorbed.

  3. Influence of Soil and Irrigation Water pH on the Availability of Phosphorus in Struvite Derived from Urine through a Greenhouse Pot Experiment.

    PubMed

    Liu, Xiaoning; Tao, Yi; Wen, Guoqi; Kong, Fanxin; Zhang, Xihui; Hu, Zhengyi

    2016-05-01

    One greenhouse pot experiment was used to investigate the availability of phosphorus in struvite derived from urine affected by soil pH (cinnamon soil, pH 7.3; paddy soil, pH 5.3) and irrigation water (pH 6.0 and 7.5) with bird rapeseed (Brassica campestris L.). The biomass of applied struvite in paddy soil was significantly greater than that of applied calcium superphosphate. However, statistically significant differences were not observed in cinnamon soil. Soil-applied struvite had a higher Olsen P compared to soil-applied calcium superphosphate irrespective of soil type. The biomass of applied struvite and irrigation with pH 6.0 water was greater compared to that with irrigation with pH 7.3 water irrespective of soil type, accompanied with significantly higher leaf chlorophyll concentration. Therefore, struvite has the potential to be an effective P fertilizer, and acidic irrigation water has greater influence on the availability of phosphorus in struvite than does acidic soil. PMID:27078189

  4. Influence of Soil and Irrigation Water pH on the Availability of Phosphorus in Struvite Derived from Urine through a Greenhouse Pot Experiment.

    PubMed

    Liu, Xiaoning; Tao, Yi; Wen, Guoqi; Kong, Fanxin; Zhang, Xihui; Hu, Zhengyi

    2016-05-01

    One greenhouse pot experiment was used to investigate the availability of phosphorus in struvite derived from urine affected by soil pH (cinnamon soil, pH 7.3; paddy soil, pH 5.3) and irrigation water (pH 6.0 and 7.5) with bird rapeseed (Brassica campestris L.). The biomass of applied struvite in paddy soil was significantly greater than that of applied calcium superphosphate. However, statistically significant differences were not observed in cinnamon soil. Soil-applied struvite had a higher Olsen P compared to soil-applied calcium superphosphate irrespective of soil type. The biomass of applied struvite and irrigation with pH 6.0 water was greater compared to that with irrigation with pH 7.3 water irrespective of soil type, accompanied with significantly higher leaf chlorophyll concentration. Therefore, struvite has the potential to be an effective P fertilizer, and acidic irrigation water has greater influence on the availability of phosphorus in struvite than does acidic soil.

  5. Optimal Soil Eh, pH, and Water Management for Simultaneously Minimizing Arsenic and Cadmium Concentrations in Rice Grains.

    PubMed

    Honma, Toshimitsu; Ohba, Hirotomo; Kaneko-Kadokura, Ayako; Makino, Tomoyuki; Nakamura, Ken; Katou, Hidetaka

    2016-04-19

    Arsenic (As) and cadmium (Cd) concentrations in rice grains are a human health concern. We conducted field experiments to investigate optimal conditions of Eh and pH in soil for simultaneously decreasing As and Cd accumulation in rice. Water managements in the experiments, which included continuous flooding and intermittent irrigation with different intervals after midseason drainage, exerted striking effects on the dissolved As and Cd concentrations in soil through changes in Eh, pH, and dissolved Fe(II) concentrations in the soil. Intermittent irrigation with three-day flooding and five-day drainage was found to be effective for simultaneously decreasing the accumulation of As and Cd in grain. The grain As and Cd concentrations were, respectively, linearly related to the average dissolved As and Cd concentrations during the 3 weeks after heading. We propose a new indicator for expressing the degree to which a decrease in the dissolved As or Cd concentration is compromised by the increase in the other. For minimizing the trade-off relationship between As and Cd in rice grains in the field investigated, water management strategies should target the realization of optimal soil Eh of -73 mV and pH of 6.2 during the 3 weeks after heading. PMID:26999020

  6. Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH

    SciTech Connect

    Komonweeraket, Kanokwan; Cetin, Bora; Benson, Craig H.; Aydilek, Ahmet H.; Edil, Tuncer B.

    2015-04-15

    Highlights: • The impact of pH on the leaching of elements and metals from fly ash mixed soils. • Generally Ca, Cd, Mg, and Sr follows a cationic leaching pattern. • The leaching of As and Se shows an oxyanionic leaching pattern. • The leaching behavior of elements does not change based on material type. • Different fly ash types show different abilities in immobilizing trace elements. - Abstract: Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, were studied at a pH range of 2–14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into.

  7. A simple model for assessing ammonia emission from ammoniacal fertilisers as affected by pH and injection into soil

    NASA Astrophysics Data System (ADS)

    Nyord, T.; Schelde, K. M.; Søgaard, H. T.; Jensen, L. S.; Sommer, S. G.

    Ammonia (NH 3) volatilisation following the application of ammoniacal fertilisers and liquid manure to agricultural land is a significant source of atmospheric NH 3, which not only poses a risk to the environment, but may also result in a loss of plant available nitrogen (N). This study examined the potential for reducing NH 3 emission through acidifying an ammoniacal solution and by injecting the solution. The combination of the two technologies was studied and a model for predicting the most optimal treatment was developed. In the laboratory, ammonium (NH 4+) hydroxide (aqueous NH 3) was dissolved in water (pH 11) and injected into a loamy sand soil. The NH 3 emission was measured with a dynamic chamber technology. Injecting the solution to 10 mm below the soil surface reduced NH 3 emission by 10% compared to surface application, and injection to 30 mm reduced emission by 20% compared to surface application. Acidifying the ammoniacal solution by adding sulphuric acid and reducing pH to 10 reduced the emission by 60% at a 10 mm injection depth and 90% at 30 mm compared with non-acidified and surface-spread ammoniacal solution. The results show that there is an important interaction of pH and injection depth and that there is a need for models predicting a combined effect. This type of model could contribute to reduce cost and energy (traction force) by providing the optimal combination of acidifying and injection depth that gives a specific reduction in NH 3 emission, which in this study was reducing pH to 10 and inject the fertiliser to 30 mm below surface. This study showed that relatively simple models can predict the NH 3 emission from injected ammoniacal fertilisers, but that there is still a need for developing algorithms that predict the effect of pH, including the pH buffering capacity of the fertiliser and the soil.

  8. Uptake of cadmium, zinc, lead, and copper by earthworms near a zinc-smelting complex: influence of soil pH and organic matter

    SciTech Connect

    Ma, W.; Edelman, T.; van Beersum, I.; Jans, T.

    1983-04-01

    Soil samples were taken from 31 sites near Eindhoven, The Netherlands, mainly along transects of 1 to 15 km from the nearest zinc smelter. Earthworms (Lumbricus rubellus) were taken from the upper 20 cm soil layer and analyzed from accumulation of Cd, Zn, Pb and Cu by atomic absorption spectrophotometry. Cd, Zn, and Pb appeared to be more strongly accumulated by L. rubellus when present in soil with a low pH value. Cu was the only exception in this regard; its uptake by L. rubellus was not significantly influenced by soil pH. The organic matter content of the soil played a significant role only in the worm uptake of Pb. Soil Pb content, soil pH, and soil organic matter content together accounted for almost 70% of the variance in worm Pb content. The results indicate that L. rubellus accumulates Pb more strongly in soil with a low pH and low organic matter content than in soil with higher values of these parameters. The demonstrated influence of pH and organic matter content on element concentration in earthworms emphasizes the importance of soil factors in governing the entrance of toxic metal elements into the food web. (JMT)

  9. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils

    PubMed Central

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2) were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH) were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH. PMID:26397367

  10. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils.

    PubMed

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2) were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH) were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH.

  11. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils.

    PubMed

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2) were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH) were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH. PMID:26397367

  12. Changes in metal speciation and pH in olive processing waste and sulphur-treated contaminated soil.

    PubMed

    de la Fuente, C; Clemente, R; Bernal, M P

    2008-06-01

    Degradation of organic matter from olive mill waste and changes in the heavy metal fractionation of a metal-contaminated calcareous soil were studied in a laboratory experiment, in which the olive mill waste was mixed with the soil and then incubated under aerobic conditions. The soil was calcareous (15% CaCO(3)) with high Zn and Pb concentrations (2058 and 2947 mg kg(-1), respectively). The organic amendment was applied at a rate equivalent to 20 g kg(-1) soil, and unamended soil was run as a control. To discern if changes in metal solubility were due to the acidic character of the waste, elemental sulphur was applied to soil as a non-organic acidifying material. The S(0) rates used were 3.14, 4.71 and 6.28 g kg(-1). The mineralisation of total organic-C (TOC) from the waste reached 14.8% of the original TOC concentration after 56 days of incubation. The CO(2)-C produced from S(0)-treated soils showed the carbonate destruction by the H(2)SO(4) formed through S(0) oxidation. The organic waste increased EDTA-extractable Zn and Pb concentrations and CaCl(2)-extractable Mn levels in soil after two days of incubation. The changes in metal availability with time indicated that the oxidation of phenols from the waste reduced Mn (IV) oxides, releasing Zn and Pb associated with this mineral phase. Organic waste addition did not decrease soil pH; the acidifying effect of S(0) did not change metal fractionation in the soil. PMID:17659778

  13. Litter quality and pH are strong drivers of carbon turnover and distribution in alpine grassland soils

    NASA Astrophysics Data System (ADS)

    Budge, K.; Leifeld, J.; Hiltbrunner, E.; Fuhrer, J.

    2010-08-01

    Alpine soils are expected to contain large amounts of labile carbon (C) which may become a further source of atmospheric CO2 as a of global warming. However, there is little data available on these soils, and understanding of the influence of environmental factors on soil organic matter (SOM) turnover is limited. We extracted 30 cm deep cores from five grassland sites along a small elevation gradient from 2285 to 2653 m above sea level (a.s.l.) in the central Swiss Alps. Our aim was to determine the quantity, degree of stabilization and mean residence time (MRT) of SOM in relation to site factors such as temperature, soil pH, vegetation, and organic matter (OM) structure. Soil fractions obtained by size and density fractionation revealed a high proportion of labile particulate organic matter C (POM C %) mostly in the uppermost soil layers. POM C in the top 20 cm across the gradient ranged from 39.6-57.6% in comparison to 7.2-29.6% reported in previous studies for lower elevation soils (810-1960 m a.s.l.). At the highest elevation, MRTs measured by means of radiocarbon dating and turnover modelling, increased between fractions of growing stability from 90 years in free POM (fPOM) to 534 years in the mineral-associated fraction (mOM). Depending on elevation and pH, plant community data indicated considerable variation in the quantity and quality of litter input, and these patterns could be reflected in the dynamics of soil C. 13C NMR data confirmed the direct relationship of OM composition to MRT. While temperature is likely to be a major cause for the slow turnover rate observed, other factors such as litter quality and soil pH, as well as the combination of all factors, play an important role in causing small-scale variability of SOM turnover. Ignoring this interplay of controlling factors may impair the performance of models to project SOM responses to environmental change.

  14. Growing up or growing out? How soil pH and light affect seedling growth of a relictual rainforest tree.

    PubMed

    Offord, Catherine A; Meagher, Patricia F; Zimmer, Heidi C

    2014-01-01

    Seedling growth rates can have important long-term effects on forest dynamics. Environmental variables such as light availability and edaphic factors can exert a strong influence on seedling growth. In the wild, seedlings of Wollemi pine (Wollemia nobilis) grow on very acid soils (pH ∼4.3) in deeply shaded sites (∼3 % full sunlight). To examine the relative influences of these two factors on the growth of young W. nobilis seedlings, we conducted a glasshouse experiment growing seedlings at two soil pH levels (4.5 and 6.5) under three light levels: low (5 % full sun), medium (15 %) and high (50 %). Stem length and stem diameter were measured, stem number and branch number were counted, and chlorophyll and carotenoid content were analysed. In general, increased plant growth was associated with increased light, and with low pH irrespective of light treatment, and pigment content was higher at low pH. Maximum stem growth occurred in plants grown in the low pH/high light treatment combination. However, stem number was highest in low pH/medium light. We hypothesize that these differences in stem development of W. nobilis among light treatments were due to this species' different recruitment strategies in response to light: greater stem growth at high light and greater investment in multiple stem production at low light. The low light levels in the W. nobilis habitat may be a key limitation on stem growth and hence W. nobilis recruitment from seedling to adult. Light and soil pH are two key factors in the growth of this threatened relictual rainforest species.

  15. Growing up or growing out? How soil pH and light affect seedling growth of a relictual rainforest tree

    PubMed Central

    Offord, Catherine A.; Meagher, Patricia F.; Zimmer, Heidi C.

    2014-01-01

    Seedling growth rates can have important long-term effects on forest dynamics. Environmental variables such as light availability and edaphic factors can exert a strong influence on seedling growth. In the wild, seedlings of Wollemi pine (Wollemia nobilis) grow on very acid soils (pH ∼4.3) in deeply shaded sites (∼3 % full sunlight). To examine the relative influences of these two factors on the growth of young W. nobilis seedlings, we conducted a glasshouse experiment growing seedlings at two soil pH levels (4.5 and 6.5) under three light levels: low (5 % full sun), medium (15 %) and high (50 %). Stem length and stem diameter were measured, stem number and branch number were counted, and chlorophyll and carotenoid content were analysed. In general, increased plant growth was associated with increased light, and with low pH irrespective of light treatment, and pigment content was higher at low pH. Maximum stem growth occurred in plants grown in the low pH/high light treatment combination. However, stem number was highest in low pH/medium light. We hypothesize that these differences in stem development of W. nobilis among light treatments were due to this species' different recruitment strategies in response to light: greater stem growth at high light and greater investment in multiple stem production at low light. The low light levels in the W. nobilis habitat may be a key limitation on stem growth and hence W. nobilis recruitment from seedling to adult. Light and soil pH are two key factors in the growth of this threatened relictual rainforest species. PMID:24790132

  16. Behavior of Engineered Nanomaterials in Unsaturated Soil: Transport, Effects on pH, and Interactions with Phosphorous

    NASA Astrophysics Data System (ADS)

    Conway, J.; Keller, A. A.

    2013-12-01

    Recent life cycle assessments have predicted that soils will be the primary non-landfill sink for many engineered nanomaterials (ENMs), and as their production and use increases annually it becomes increasingly relevant to understand their behavior in the unsaturated surface layers of soil. In this series of experiments, the transport and interactions of three common ENMs, TiO2, CeO2, and CuOH, were measured in an unsaturated potting soil with and without humic acid as a stabilizing agent. Transport was measured in loosely packed soil columns at two concentrations (10 and 100 ppm) with three exposure methods: through the application of contaminated biosolids to the top of the column with subsequent irrigation, by watering with an ENM suspension, and by mixing ENMs homogeneously into the soil and irrigating. Transport was also measured in soil containing intact root structures for the latter two exposure methods at 10 ppm ENM concentration. Soil columns were dried and 3 cm segments were acid digested and measured with inductively coupled plasma atomic emission spectroscopy (ICS-AES). The effect of these ENMs on soil pH was tested after mixing ENM suspensions into soil at four concentrations (0, 1, 10, and 100 mg kg-1). The bioavailability of PO4 in the presence of ENMs was measured by quantifying the soluble, bioavailable (i.e., extractable by Bray No. 1 solution), and tightly bound fractions of P in 0, 1, 10, and 100 mg kg-1 spiked soils via ICP-AES. We found that these three ENMs exhibit limited transport in all exposure scenarios and so will likely remain near the source zone in an environmental exposure. Additionally, these ENMs were seen to decrease soil pH by up to 0.5 in the highest concentrations, which has consequences for plant growth and nutrient mobility. TiO2 and CeO2 also decreased the soluble and bioavailable fractions of P, and so could inhibit the uptake of this limiting nutrient by organisms.

  17. Soil pH, total phosphorus, climate and distance are the major factors influencing microbial activity at a regional spatial scale

    PubMed Central

    Cao, Haichuan; Chen, Ruirui; Wang, Libing; Jiang, Lanlan; Yang, Fen; Zheng, Shixue; Wang, Gejiao; Lin, Xiangui

    2016-01-01

    Considering the extensive functional redundancy in microbial communities and great difficulty in elucidating it based on taxonomic structure, studies on the biogeography of soil microbial activity at large spatial scale are as important as microbial community structure. Eighty-four soil samples were collected across a region from south to north China (about 1,000 km) to address the questions if microbial activity displays biogeographic patterns and what are driving forces. These samples represented different soil types, land use and climate. Redundancy analysis and nonmetric multidimensional scaling clearly revealed that soil microbial activities showed distinct differentiation at different sites over a regional spatial scale, which were strongly affected by soil pH, total P, rainfall, temperature, soil type and location. In addition, microbial community structure was greatly influenced by rainfall, location, temperature, soil pH and soil type and was correlated with microbial activity to some extent. Our results suggest that microbial activities display a clear geographic pattern that is greatly altered by geographic distance and reflected by climate, soil pH and total P over large spatial scales. There are common (distance, climate, pH and soil type) but differentiated aspects (TP, SOC and N) in the biogeography of soil microbial community structure and activity. PMID:27170469

  18. Soil pH, total phosphorus, climate and distance are the major factors influencing microbial activity at a regional spatial scale.

    PubMed

    Cao, Haichuan; Chen, Ruirui; Wang, Libing; Jiang, Lanlan; Yang, Fen; Zheng, Shixue; Wang, Gejiao; Lin, Xiangui

    2016-05-12

    Considering the extensive functional redundancy in microbial communities and great difficulty in elucidating it based on taxonomic structure, studies on the biogeography of soil microbial activity at large spatial scale are as important as microbial community structure. Eighty-four soil samples were collected across a region from south to north China (about 1,000 km) to address the questions if microbial activity displays biogeographic patterns and what are driving forces. These samples represented different soil types, land use and climate. Redundancy analysis and nonmetric multidimensional scaling clearly revealed that soil microbial activities showed distinct differentiation at different sites over a regional spatial scale, which were strongly affected by soil pH, total P, rainfall, temperature, soil type and location. In addition, microbial community structure was greatly influenced by rainfall, location, temperature, soil pH and soil type and was correlated with microbial activity to some extent. Our results suggest that microbial activities display a clear geographic pattern that is greatly altered by geographic distance and reflected by climate, soil pH and total P over large spatial scales. There are common (distance, climate, pH and soil type) but differentiated aspects (TP, SOC and N) in the biogeography of soil microbial community structure and activity.

  19. Metsulfuron-methyl sorption/desorption behavior on volcanic ash-derived soils. effect of phosphate and pH.

    PubMed

    Cáceres, Lizethly; Fuentes, Roxana; Escudey, Mauricio; Fuentes, Edwar; Báez, María E

    2010-06-01

    Metsulfuron-methyl sorption/desorption behavior was studied through batch sorption experiments in three typical volcanic ash-derived soils belonging to Andisol and Ultisol orders. Their distinctive physical and chemical properties are acidic pH and variable surface charge. Organic matter content and mineral composition affected in different ways sorption of metsulfuron-methyl (K(OC) ranging from 113 to 646 mL g(-1)): organic matter and iron and aluminum oxides mainly through hydrophilic rather than hydrophobic interactions in Andisols, and Kaolinite group minerals, as major constituents of Ultisols, and iron and aluminum oxides only through hydrophilic interactions. The Freundlich model described metsulfuron-methyl behavior in all cases (R(2) > 0.992). K(f) values (3.1-14.4 microg(1-1/n) mL(1/n) g(-1)) were higher than those reported for different class of soils including some with variable charge. Hysteresis was more significant in Ultisols. A strong influence of pH and phosphate was established for both kinds of soil, intensive soil fertilization and liming being the most probable scenario for leaching of metsulfuron-methyl, particularly in Ultisols.

  20. Suitability of the normalized difference vegetation index and the adjusted transformed soil-adjusted vegetation index for spatially characterizing loggerhead shrike habitats in North American mixed prairie

    NASA Astrophysics Data System (ADS)

    Shen, Li; He, Yuhong; Guo, Xulin

    2013-01-01

    Habitat loss has become one major cause of prairie loggerhead shrike population decline, which is associated with some important grassland biophysical features. However, our understanding of what and how biophysical variables can spatially characterize shrike habitats is poor. The purpose of this study is to investigate the suitability of two vegetation indices (VIs) for spatially characterizing shrike habitats in North American mixed prairies. Our research, conducted in Grasslands National Park of Canada, is based on the normalized difference vegetation index (NDVI) and the adjusted transformed soil-adjusted vegetation index (ATSAVI) as derived from both in situ measurements and SPOT imagery for three types of nesting categories at three spatial scales. Our results demonstrated that shrikes in mixed North American prairies prefer sparsely vegetated areas with a leaf area index less than 2.01 and shrub cover of around 25%. Our results also demonstrated that ATSAVI is superior to NDVI in estimating vegetation abundance and structure. Loggerhead shrikes seems to prefer habitats characterized by NDVI ranging from 0.562 to 0.616 and ATSAVI ranging from 0.319 to 0.372 with the spatial scale varying from 100 to 20 m. ATSAVI also had better performance in detecting the spatial variation of shrike habitats due to its higher sensitivity to background information.

  1. Transcription of denitrification genes and kinetics of NO, N2O and N2 by soil bacteria as affected by pH

    NASA Astrophysics Data System (ADS)

    Liu, B.; Bakken, L. R.; Frostegard, A.

    2010-12-01

    Nitrous oxide (N2O), which is to a large part derived from denitrification in soil, is a major greenhouse gas and was also recently shown to be the single most important ozone-depleting substance. Previous studies demonstrate that the N2O/N2 product ratio of denitrification is strongly dependent on pH, increasing with decreasing soil pH. The mechanisms involved are, however, poorly understood. We here present an investigation of soils from a long-term liming experiment. Since it is difficult to control which pH is actually experienced by bacterial cells in intact soils, we extracted cells on a Nycodenz gradient and exposed them to different pH levels. Bacteria extracted from soils of 3 different pHs (4.0, 6.1 and 8.0) were incubated in minimal medium supplemented with nitrate (2mM) and glutamic acid (5 mM), buffered at three pH levels (5.7, 6.1 and 7.6). Both the pH of the medium and original soil pH showed profound effect on the denitrification activity in terms of gas emission kinetics. N2O reductase (N2OR) activity was only present when cells from the high pH soils (pH 6.1 and 8.0) were exposed to high pH medium (pH 7.6). Functional genes (nirS, nirK and nosZ) and their transcripts were quantified in the extracts from pH6.1-soil. A 10-25 fold higher expression of nosZ vs nirS was found when incubated at pH 7.6 compared to pH 6.1 and 5.7. The low but significant transcription of nosZ at pH 6.1 and 5.7 did not result in detectable N2O reduction however. Cells that had been allowed to assemble their proteome while growing in pH7 medium showed N2OR activity which was practically unaffected by pH within the range 5-7. On the contrary, no N2OR activity was detected if the proteome had been formed at pH 6. The cells extracted from acid soils (pH 5.8 and 6.1) showed very low nosZ transcritption and no N2OR activity if exposed to pH 7 during the transition from oxic to anoxic conditions, suggesting an adaptation to low pH in the sense that they do not transcribe the gene

  2. Sulfate reduction in sulfuric material after re-flooding: Effectiveness of organic carbon addition and pH increase depends on soil properties.

    PubMed

    Yuan, Chaolei; Fitzpatrick, Rob; Mosley, Luke M; Marschner, Petra

    2015-11-15

    Sulfuric material is formed upon oxidation of sulfidic material; it is extremely acidic, and therefore, an environmental hazard. One option for increasing pH of sulfuric material may be stimulation of bacterial sulfate reduction. We investigated the effects of organic carbon addition and pH increase on sulfate reduction after re-flooding in ten sulfuric materials with four treatments: control, pH increase to 5.5 (+pH), organic carbon addition with 2% w/w finely ground wheat straw (+C), and organic carbon addition and pH increase (+C+pH). After 36 weeks, in five of the ten soils, only treatment +C+pH significantly increased the concentration of reduced inorganic sulfur (RIS) compared to the control and increased the soil pore water pH compared to treatment+pH. In four other soils, pH increase or/and organic carbon addition had no significant effect on RIS concentration compared to the control. The RIS concentration in treatment +C+pH as percentage of the control was negatively correlated with soil clay content and initial nitrate concentration. The results suggest that organic carbon addition and pH increase can stimulate sulfate reduction after re-flooding, but the effectiveness of this treatment depends on soil properties. PMID:26024614

  3. Sulfate reduction in sulfuric material after re-flooding: Effectiveness of organic carbon addition and pH increase depends on soil properties.

    PubMed

    Yuan, Chaolei; Fitzpatrick, Rob; Mosley, Luke M; Marschner, Petra

    2015-11-15

    Sulfuric material is formed upon oxidation of sulfidic material; it is extremely acidic, and therefore, an environmental hazard. One option for increasing pH of sulfuric material may be stimulation of bacterial sulfate reduction. We investigated the effects of organic carbon addition and pH increase on sulfate reduction after re-flooding in ten sulfuric materials with four treatments: control, pH increase to 5.5 (+pH), organic carbon addition with 2% w/w finely ground wheat straw (+C), and organic carbon addition and pH increase (+C+pH). After 36 weeks, in five of the ten soils, only treatment +C+pH significantly increased the concentration of reduced inorganic sulfur (RIS) compared to the control and increased the soil pore water pH compared to treatment+pH. In four other soils, pH increase or/and organic carbon addition had no significant effect on RIS concentration compared to the control. The RIS concentration in treatment +C+pH as percentage of the control was negatively correlated with soil clay content and initial nitrate concentration. The results suggest that organic carbon addition and pH increase can stimulate sulfate reduction after re-flooding, but the effectiveness of this treatment depends on soil properties.

  4. Urea Fertilizer and pH Influence on Sorption Process of Flumetsulam and MCPA Acidic Herbicides in a Volcanic Soil.

    PubMed

    Palma, Graciela; Jorquera, Milko; Demanet, Rolando; Elgueta, Sebastian; Briceño, Gabriela; de la Luz Mora, María

    2016-01-01

    The aim of this study was to evaluate the influence of urea fertilizer and pH on the sorption process of two acidic herbicides, flumetsulam (2',6'-difluoro-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonanilide) and MCPA (4-chloro--tolyloxyacetic acid), on an Andisol. Urea reduced the adsorption of MCPA but not that of flumetsulam. The Freundlich parameter of MCPA decreased from 8.5 to 5.1 mg L kg. This finding could be attributed to an increase in dissolved organic C due to an initial increase in soil pH for urea application. The higher acidic character of MCPA compared with that of flumetsulam produced a greater hydrolysis of urea, leading to a further pH increase. A marked effect of pH on the adsorption of both herbicides was observed. The organic C distribution coefficient () values for flumetsulam were in the range of 74 to 10 L kg, while those of MCPA were in the range of 208 to 45 L kg. In the kinetic studies, the pseudo-second-order model appeared to fit the data best ( > 0.994). The initial adsorption rates () ranged from 20.00 to 4.59 mg kg h for flumetsulam and from 125.00 to 25.60 mg kg hfor MCPA. Both herbicides were adsorbed rapidly during the first stage of the sorption process, and the rates of sorption were dependent on pH. The application of the Elovich and Weber-Morris models led us to conclude that mass transfer through the boundary layer and, to a lesser degree, intraparticle diffusion were influenced by the chemical character of the herbicide. These results suggest that urea application could increase leaching of acid herbicides in soils.

  5. Lack of correlation between turnover of low-molecular-weight dissolved organic carbon and differences in microbial community composition or growth across a soil pH gradient.

    PubMed

    Rousk, Johannes; Brookes, Philip C; Glanville, Helen C; Jones, David L

    2011-04-01

    We studied how soil pH (pHs 4 to 8) influenced the mineralization of low-molecular-weight (LMW)-dissolved organic carbon (DOC) compounds, and how this compared with differences in microbial community structure. The mineralization of LMW-DOC compounds was not systematically connected to differences in soil pH, consistent with soil respiration. In contrast, the microbial community compositions differed dramatically. This suggests that microbial community composition data will be of limited use in improving the predictive power of soil C models.

  6. The effect of heavy metal concentration and soil pH on the abundance of selected microbial groups within ArcelorMittal Poland steelworks in Cracow.

    PubMed

    Lenart, Anna; Wolny-Koładka, Katarzyna

    2013-01-01

    The present study aimed to identify the effect of heavy metal concentration and soil pH on the abundance of the selected soil microorganisms within ArcelorMittal Poland steelworks, Cracow. The analysis included 20 soil samples, where the concentration of Fe, Zn, Cd, Pb, Ni, Cu, Mn, Cr and soil pH were evaluated together with the number of mesophilic bacteria, fungi, Actinomycetes and Azotobacter spp. In the majority of samples soil pH was alkaline. The limits of heavy metals exceeded in eight samples and in one sample, the concentration of Zn exceeded 31-fold. Chromium was the element which most significantly limited the number of bacteria and Actinomycetes.

  7. Spatial distribution of pH and organic matter in urban soils and its implications on site-specific land uses in Xuzhou, China.

    PubMed

    Mao, Yingming; Sang, Shuxun; Liu, Shiqi; Jia, Jinlong

    2014-05-01

    The spatial variation of soil pH and soil organic matter (SOM) in the urban area of Xuzhou, China, was investigated in this study. Conventional statistics, geostatistics, and a geographical information system (GIS) were used to produce spatial distribution maps and to provide information about land use types. A total of 172 soil samples were collected based on grid method in the study area. Soil pH ranged from 6.47 to 8.48, with an average of 7.62. SOM content was very variable, ranging from 3.51 g/kg to 17.12 g/kg, with an average of 8.26 g/kg. Soil pH followed a normal distribution, while SOM followed a log-normal distribution. The results of semi-variograms indicated that soil pH and SOM had strong (21%) and moderate (44%) spatial dependence, respectively. The variogram model was spherical for soil pH and exponential for SOM. The spatial distribution maps were achieved using kriging interpolation. The high pH and high SOM tended to occur in the mixed forest land cover areas such as those in the southwestern part of the urban area, while the low values were found in the eastern and the northern parts, probably due to the effect of industrial and human activities. In the central urban area, the soil pH was low, but the SOM content was high, which is mainly attributed to the disturbance of regional resident activities and urban transportation. Furthermore, anthropogenic organic particles are possible sources of organic matter after entering the soil ecosystem in urban areas. These maps provide useful information for urban planning and environmental management. PMID:24841960

  8. A new method to control electrolytes pH by circulation system in electrokinetic soil remediation.

    PubMed

    Lee, H H; Yang, J W

    2000-10-01

    To simultaneously avoid a decrease of electro-osmotic flow by hydrogen ions and to increase heavy metal precipitation due to hydroxide ions, simulated electrokinetic remediation was conducted in saturated kaolinite specimens loaded with lead(II) using an electrolyte circulation method to control electrolyte pH. At an electrolyte circulation rate of 1.1 ml/min, it was possible to increase the anolyte pH from 2 to 4 and decrease the catholyte pH from 12 to 8. Using electrolyte circulation, it was observed that the rate of decrease of clay pH due to the change of electrolyte pH was reduced. As a result, the operable period was extended and the removal efficiency for lead(II) was also increased. It was observed that most of the effluent lead(II) from the cathode compartment was electroplated onto the cathode and that residual effluent lead(II) did not precipitate onto, or adsorb to, the clay at the anode compartment during circulation. Therefore, there was no need to treat the electrolyte because there was virtually no effluent from the cathode compartment in the circulation system. It was also found that the electrolyte volume required to sustain the electrolytic reaction was sufficient for the whole electrokinetic remediation process. PMID:10946130

  9. Effect of soil organic matter content and pH on the toxicity of ZnO nanoparticles to Folsomia candida.

    PubMed

    Waalewijn-Kool, Pauline L; Rupp, Svenja; Lofts, Stephen; Svendsen, Claus; van Gestel, Cornelis A M

    2014-10-01

    Organic matter (OM) and pH may influence nanoparticle fate and effects in soil. This study investigated the influence of soil organic matter content and pH on the toxicity of ZnO-NP and ZnCl2 to Folsomia candida in four natural soils, having between 2.37% and 14.7% OM and [Formula: see text] levels between 5.0 and 6.8. Porewater Zn concentrations were much lower in ZnO-NP than in ZnCl2 spiked soils, resulting in higher Freundlich sorption constants for ZnO-NP. For ZnCl2 the porewater Zn concentrations were significantly higher in less organic soils, while for ZnO-NP the highest soluble Zn level (23mgZn/l) was measured in the most organic soil, which had the lowest pH. Free Zn(2+) ion concentrations were higher for ZnCl2 than for ZnO-NP and were greatly dependent on pH (pHpw) and dissolved organic carbon content of the pore water. The 28-d EC50 values for the effect of ZnCl2 on the reproduction of F. candida increased with increasing OM content from 356 to 1592mgZn/kg d.w. For ZnO-NP no correlation between EC50 values and OM content was found and EC50 values ranged from 1695 in the most organic soil to 4446mgZn/kg d.w. in the higher pH soil. When based on porewater and free Zn(2+) concentrations, EC50 values were higher for ZnCl2 than for ZnO-NP, and consistently decreased with increasing pHpw. This study shows that ZnO-NP toxicity is dependent on soil properties, but is mainly driven by soil pH.

  10. The large-scale distribution of ammonia oxidizers in paddy soils is driven by soil pH, geographic distance, and climatic factors.

    PubMed

    Hu, Hang-Wei; Zhang, Li-Mei; Yuan, Chao-Lei; Zheng, Yong; Wang, Jun-Tao; Chen, Deli; He, Ji-Zheng

    2015-01-01

    Paddy soils distribute widely from temperate to tropical regions, and are characterized by intensive nitrogen fertilization practices in China. Mounting evidence has confirmed the functional importance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in soil nitrification, but little is known about their biogeographic distribution patterns in paddy ecosystems. Here, we used barcoded pyrosequencing to characterize the effects of climatic, geochemical and spatial factors on the distribution of ammonia oxidizers from 11 representative rice-growing regions (75-1945 km apart) of China. Potential nitrification rates varied greatly by more than three orders of magnitude, and were significantly correlated with the abundances of AOA and AOB. The community composition of ammonia oxidizer was affected by multiple factors, but changes in relative abundances of the major lineages could be best predicted by soil pH. The alpha diversity of AOA and AOB displayed contrasting trends over the gradients of latitude and atmospheric temperature, indicating a possible niche separation between AOA and AOB along the latitude. The Bray-Curtis dissimilarities in ammonia-oxidizing community structure significantly increased with increasing geographical distance, indicating that more geographically distant paddy fields tend to harbor more dissimilar ammonia oxidizers. Variation partitioning analysis revealed that spatial, geochemical and climatic factors could jointly explain majority of the data variation, and were important drivers defining the ecological niches of AOA and AOB. Our findings suggest that both AOA and AOB are of functional importance in paddy soil nitrification, and ammonia oxidizers in paddy ecosystems exhibit large-scale biogeographic patterns shaped by soil pH, geographic distance, and climatic factors.

  11. The large-scale distribution of ammonia oxidizers in paddy soils is driven by soil pH, geographic distance, and climatic factors

    PubMed Central

    Hu, Hang-Wei; Zhang, Li-Mei; Yuan, Chao-Lei; Zheng, Yong; Wang, Jun-Tao; Chen, Deli; He, Ji-Zheng

    2015-01-01

    Paddy soils distribute widely from temperate to tropical regions, and are characterized by intensive nitrogen fertilization practices in China. Mounting evidence has confirmed the functional importance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in soil nitrification, but little is known about their biogeographic distribution patterns in paddy ecosystems. Here, we used barcoded pyrosequencing to characterize the effects of climatic, geochemical and spatial factors on the distribution of ammonia oxidizers from 11 representative rice-growing regions (75–1945 km apart) of China. Potential nitrification rates varied greatly by more than three orders of magnitude, and were significantly correlated with the abundances of AOA and AOB. The community composition of ammonia oxidizer was affected by multiple factors, but changes in relative abundances of the major lineages could be best predicted by soil pH. The alpha diversity of AOA and AOB displayed contrasting trends over the gradients of latitude and atmospheric temperature, indicating a possible niche separation between AOA and AOB along the latitude. The Bray–Curtis dissimilarities in ammonia-oxidizing community structure significantly increased with increasing geographical distance, indicating that more geographically distant paddy fields tend to harbor more dissimilar ammonia oxidizers. Variation partitioning analysis revealed that spatial, geochemical and climatic factors could jointly explain majority of the data variation, and were important drivers defining the ecological niches of AOA and AOB. Our findings suggest that both AOA and AOB are of functional importance in paddy soil nitrification, and ammonia oxidizers in paddy ecosystems exhibit large-scale biogeographic patterns shaped by soil pH, geographic distance, and climatic factors. PMID:26388866

  12. Diversity and food web structure of nematode communities under high soil salinity and alkaline pH.

    PubMed

    Salamún, Peter; Kucanová, Eva; Brázová, Tímea; Miklisová, Dana; Renčo, Marek; Hanzelová, Vladimíra

    2014-10-01

    A long-term and intensive magnesium (Mg) ore processing in Slovenské Magnezitové Závody a.s. in Jelšava has resulted in a high Mg content and alkaline pH of the soil environment, noticeable mainly in the close vicinity of the smelter. Nematode communities strongly reacted to the contamination mostly by a decrease in abundance of the sensitive groups. Nematodes from c-p 1 group and bacterivores, tolerant to pollution played a significant role in establishing the dominance at all sites. With increasing distance from the pollution source, the nematode communities were more structured and complex, with an increase in proportion of sensitive c-p 4 and 5 nematodes, composed mainly of carnivores and omnivores. Various ecological indices (e.g. MI2-5, SI, H') indicated similar improvement of farther soil ecosystems.

  13. Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils.

    PubMed

    Najafi, Sarvenaz; Jalali, Mohsen

    2016-06-01

    In many parts of the world, soil acidification and heavy metal contamination has become a serious concern due to the adverse effects on chemical properties of soil and crop yield. The aim of this study was to investigate the effect of pH (in the range of 1 to 3 units above and below the native pH of soils) on calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) solubility in non-spiked and heavy metal-spiked soil samples. Spiked samples were prepared by cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) as chloride salts and incubating soils for 40 days. The pH buffering capacity (pHBC) of each sample was determined by plotting the amount of H(+) or OH(-) added (mmol kg(-1)) versus the related pH value. The pHBC of soils ranged from 47.1 to 1302.5 mmol kg(-1) for non-spiked samples and from 45.0 to 1187.4 mmol kg(-1) for spiked soil samples. The pHBC values were higher in soil 2 (non-spiked and spiked) which had higher calcium carbonate content. The results indicated the presence of heavy metals in soils generally decreased the solution pH and pHBC values in spiked samples. In general, solubility of Ca, Mg, and K decreased with increasing equilibrium pH of non-spiked and spiked soil samples. In the case of P, increasing the pH to about 7, decreased the solubility in all soils but further increase of pH from 7, enhanced P solubility. The solubility trends and values for Ca, Mg, and K did not differed significantly in non-spiked and spiked samples. But in the case of P, a reduction in solubility was observed in heavy metal-spiked soils. The information obtained in this study can be useful to make better estimation of the effects of soil pollutants on anion and cation solubility from agricultural and environmental viewpoints. PMID:27168329

  14. Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils.

    PubMed

    Najafi, Sarvenaz; Jalali, Mohsen

    2016-06-01

    In many parts of the world, soil acidification and heavy metal contamination has become a serious concern due to the adverse effects on chemical properties of soil and crop yield. The aim of this study was to investigate the effect of pH (in the range of 1 to 3 units above and below the native pH of soils) on calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) solubility in non-spiked and heavy metal-spiked soil samples. Spiked samples were prepared by cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) as chloride salts and incubating soils for 40 days. The pH buffering capacity (pHBC) of each sample was determined by plotting the amount of H(+) or OH(-) added (mmol kg(-1)) versus the related pH value. The pHBC of soils ranged from 47.1 to 1302.5 mmol kg(-1) for non-spiked samples and from 45.0 to 1187.4 mmol kg(-1) for spiked soil samples. The pHBC values were higher in soil 2 (non-spiked and spiked) which had higher calcium carbonate content. The results indicated the presence of heavy metals in soils generally decreased the solution pH and pHBC values in spiked samples. In general, solubility of Ca, Mg, and K decreased with increasing equilibrium pH of non-spiked and spiked soil samples. In the case of P, increasing the pH to about 7, decreased the solubility in all soils but further increase of pH from 7, enhanced P solubility. The solubility trends and values for Ca, Mg, and K did not differed significantly in non-spiked and spiked samples. But in the case of P, a reduction in solubility was observed in heavy metal-spiked soils. The information obtained in this study can be useful to make better estimation of the effects of soil pollutants on anion and cation solubility from agricultural and environmental viewpoints.

  15. Use of precision agriculture technologies in studying the relationships among soil pH, calcium carbonate equivalent, soybean cyst nematode population density, and soybean yield

    NASA Astrophysics Data System (ADS)

    Rogovska, Natalia

    Iron deficiency chlorosis (IDC) and soybean cyst nematode (SCN; Heterodera glycines) infestation are major factors that contribute to soybean (Glycine max Merr.) yield reduction in the Midwest. The IDC is often associated with soybean grown on high pH, calcareous soils. In addition, it was documented that SCN population density is higher in high pH soils. The objectives of this paper were to assess the proportion of within-field soybean yield and SCN variability that could be explained by soil pH, calcium carbonate equivalent (CCE), and a previously defined alkalinity stress index (ASI). Aerial images from 21 fields planted to SCN-resistant or susceptible soybean varieties were collected from 2001 through 2005 and used as a guide for soil and grain sampling. Ten to 16 sampling sites were selected on each field. Regression analyses within and across sites were used to study relationships between the measured variables. The SCN population density increased and yield decreased with increasing pH, CCE, and ASI across the fields. The percentage of yield variability across fields explained by soil pH, CCE, ASI, and SCN was 13%, 15%, 18%, and 1%, respectively, for resistant soybean varieties and 37%, 24%, 39%, and 10%, respectively, for susceptible varieties. The yield reduction due to high pH, CCE, and ASI was greater for SCN-susceptible varieties in field areas heavily infested with SCN.

  16. Influence of soil pH on the fractionation of Cr, Cu and Zn in solid phases from a landfill site.

    PubMed

    Muñoz-Meléndez, G; Korre, A; Parry, S J

    2000-12-01

    The spatial variability of soil pH for engineered Weathered Oxford Clay is described using 35 samples collected from the base of a new cell in an existing landfill. Soil pH variability influences the reactivity of Cr, Cu and Zn in the site. The reactivity of these metals as natural components was determined using a sequential extraction method. The total concentration of Cr, Cu and Zn and the mineralogical composition were also determined. The results showed that due to the presence of a layer rich in pyrite in the base, a natural acidification may occur which can produce a soil pH as low as 2.7. The spatial variability of soil pH in this area has been described with an anisotropical variogram model and the estimation of its values at unsampled locations was carried out using the ordinary kriging algorithm. From the spatial modelling of the soil pH, it was found that the metals in the soil solid phases follow a similar distribution. PMID:15092828

  17. Sorption-desorption and transport of trimethoprim and sulfonamide antibiotics in agricultural soil: effect of soil type, dissolved organic matter, and pH.

    PubMed

    Zhang, Ya-Lei; Lin, Shuang-Shuang; Dai, Chao-Meng; Shi, Lu; Zhou, Xue-Fei

    2014-05-01

    Use of animal manure is a main source of veterinary pharmaceuticals (VPs) in soil and groundwater through a series of migration processes. The sorption-desorption and transport of four commonly used VPs including trimethoprim (TMP), sulfapyridine, sulfameter, and sulfadimethoxine were investigated in three soil layers taken from an agricultural field in Chongming Island China and two types of aqueous solution (0.01 M CaCl2 solution and wastewater treatment plant effluent). Results from sorption-desorption experiments showed that the sorption behavior of selected VPs conformed to the Freundlich isotherm equation. TMP exhibited higher distribution coefficients (K d = 6.73-9.21) than other sulfonamides (K d = 0.03-0.47), indicating a much stronger adsorption capacity of TMP. The percentage of desorption for TMP in a range of 8-12 % is not so high to be considered significant. Low pH (soil organic matter (e.g., 0-20 cm soil sample) had a positive impact on sorption of VPs. Slightly lower distribution coefficients were obtained for VPs in wastewater treatment plant (WWTP) effluent, which suggested that dissolved organic matter might affect their sorption behavior. Column studies indicated that the transport of VPs in the soil column was mainly influenced by sorption capacity. The weakly adsorbed sulfonamides had a high recovery rate (63.6-98.0 %) in the leachate, while the recovery rate of TMP was only 4.2-10.4 %. The sulfonamides and TMP exhibited stronger retaining capacity in 20-80 cm and 0-20 cm soil samples, respectively. The transport of VPs was slightly higher in the columns leached by WWTP effluent than by CaCl2 solution (0.01 M) due to their sorption interactions. PMID:24443047

  18. Sorption-desorption and transport of trimethoprim and sulfonamide antibiotics in agricultural soil: effect of soil type, dissolved organic matter, and pH.

    PubMed

    Zhang, Ya-Lei; Lin, Shuang-Shuang; Dai, Chao-Meng; Shi, Lu; Zhou, Xue-Fei

    2014-05-01

    Use of animal manure is a main source of veterinary pharmaceuticals (VPs) in soil and groundwater through a series of migration processes. The sorption-desorption and transport of four commonly used VPs including trimethoprim (TMP), sulfapyridine, sulfameter, and sulfadimethoxine were investigated in three soil layers taken from an agricultural field in Chongming Island China and two types of aqueous solution (0.01 M CaCl2 solution and wastewater treatment plant effluent). Results from sorption-desorption experiments showed that the sorption behavior of selected VPs conformed to the Freundlich isotherm equation. TMP exhibited higher distribution coefficients (K d = 6.73-9.21) than other sulfonamides (K d = 0.03-0.47), indicating a much stronger adsorption capacity of TMP. The percentage of desorption for TMP in a range of 8-12 % is not so high to be considered significant. Low pH (soil organic matter (e.g., 0-20 cm soil sample) had a positive impact on sorption of VPs. Slightly lower distribution coefficients were obtained for VPs in wastewater treatment plant (WWTP) effluent, which suggested that dissolved organic matter might affect their sorption behavior. Column studies indicated that the transport of VPs in the soil column was mainly influenced by sorption capacity. The weakly adsorbed sulfonamides had a high recovery rate (63.6-98.0 %) in the leachate, while the recovery rate of TMP was only 4.2-10.4 %. The sulfonamides and TMP exhibited stronger retaining capacity in 20-80 cm and 0-20 cm soil samples, respectively. The transport of VPs was slightly higher in the columns leached by WWTP effluent than by CaCl2 solution (0.01 M) due to their sorption interactions.

  19. Adjustments of molecular key components of branchial ion and pH regulation in Atlantic cod (Gadus morhua) in response to ocean acidification and warming.

    PubMed

    Michael, Katharina; Kreiss, Cornelia M; Hu, Marian Y; Koschnick, Nils; Bickmeyer, Ulf; Dupont, Sam; Pörtner, Hans-O; Lucassen, Magnus

    2016-03-01

    Marine teleost fish sustain compensation of extracellular pH after exposure to hypercapnia by means of efficient ion and acid-base regulation. Elevated rates of ion and acid-base regulation under hypercapnia may be stimulated further by elevated temperature. Here, we characterized the regulation of transepithelial ion transporters (NKCC1, NBC1, SLC26A6, NHE1 and 2) and ATPases (Na(+)/K(+) ATPase and V-type H(+) ATPase) in gills of Atlantic cod (Gadus morhua) after 4 weeks of exposure to ambient and future PCO2 levels (550 μatm, 1200 μatm, 2200 μatm) at optimum (10 °C) and summer maximum temperature (18 °C), respectively. Gene expression of most branchial ion transporters revealed temperature- and dose-dependent responses to elevated PCO2. Transcriptional regulation resulted in stable protein expression at 10 °C, whereas expression of most transport proteins increased at medium PCO2 and 18 °C. mRNA and protein expression of distinct ion transport proteins were closely co-regulated, substantiating cellular functional relationships. Na(+)/K(+) ATPase capacities were PCO2 independent, but increased with acclimation temperature, whereas H(+) ATPase capacities were thermally compensated but decreased at medium PCO2 and 10 °C. When functional capacities of branchial ATPases were compared with mitochondrial F1Fo ATP-synthase strong correlations of F1Fo ATP-synthase and ATPase capacities generally indicate close coordination of branchial aerobic ATP demand and supply. Our data indicate physiological plasticity in the gills of cod to adjust to a warming, acidifying ocean within limits. In light of the interacting and non-linear, dose-dependent effects of both climate factors the role of these mechanisms in shaping resilience under climate change remains to be explored.

  20. Cadmium Accumulation and Pathological Alterations in the Midgut Gland of Terrestrial Snail Helix pomatia L. from a Zinc Smelter Area: Role of Soil pH.

    PubMed

    Włostowski, Tadeusz; Kozłowski, Paweł; Łaszkiewicz-Tiszczenko, Barbara; Oleńska, Ewa

    2016-04-01

    The purpose of this study was to determine whether cadmium (Cd) accumulation and toxicity in the midgut gland of Helix pomatia snails living in a Cd-contaminated area were related to soil pH. Toxic responses in the midgut gland (i.e., increased vacuolization and lipid peroxidation) occurred in H. pomatia snails exhibiting the highest Cd levels in the gland (265-274 µg/g dry wt) and living on acidic soil (pH 5.3-5.5), while no toxicity was observed in snails accumulating less Cd (90 µg/g) and ranging on neutral soil (pH 7.0), despite the fact that total soil Cd was similar in the two cases. The accumulation of Cd in the gland was directly related to the water extractable Cd in soil, which in turn correlated inversely with soil pH, indicating that this factor had a significant effect on tissue Cd. It appeared further that the occurrence of Cd toxicity was associated with low levels of metallothionein in the gland of snails ranging on acidic soil.

  1. High-Resolution Denitrification Kinetics in Pasture Soils Link N2O Emissions to pH, and Denitrification to C Mineralization.

    PubMed

    Samad, Md Sainur; Bakken, Lars R; Nadeem, Shahid; Clough, Timothy J; de Klein, Cecile A M; Richards, Karl G; Lanigan, Gary J; Morales, Sergio E

    2016-01-01

    Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N2O and N2. It is known that N2O reduction to N2 is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N2O emissions in response to carbon (C) mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand) using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N2O production index (IN2O) and N2O/(N2O+N2) product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N2O+N2 μmol N/h/vial) were significantly associated with C mineralization (CO2 μmol/h/vial) measured both under oxic (r2 = 0.62, p = 0.0015) and anoxic (r2 = 0.89, p<0.0001) conditions.

  2. High-Resolution Denitrification Kinetics in Pasture Soils Link N2O Emissions to pH, and Denitrification to C Mineralization

    PubMed Central

    Samad, Md Sainur; Bakken, Lars R.; Nadeem, Shahid; Clough, Timothy J.; de Klein, Cecile A. M.; Richards, Karl G.; Lanigan, Gary J.; Morales, Sergio E.

    2016-01-01

    Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N2O and N2. It is known that N2O reduction to N2 is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N2O emissions in response to carbon (C) mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand) using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N2O production index (IN2O) and N2O/(N2O+N2) product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N2O+N2 μmol N/h/vial) were significantly associated with C mineralization (CO2 μmol/h/vial) measured both under oxic (r2 = 0.62, p = 0.0015) and anoxic (r2 = 0.89, p<0.0001) conditions. PMID:26990862

  3. An evaluation of remote sensing derived soil pH and average spring groundwater table for ecological assessments

    NASA Astrophysics Data System (ADS)

    Roelofsen, Hans D.; van Bodegom, Peter M.; Kooistra, Lammert; van Amerongen, Jorg J.; Witte, Jan-Philip M.

    2015-12-01

    Ecological assessments such as species distribution modelling and benchmarking site quality towards regulations often rely on full spatial coverage information of site factors such as soil acidity, moisture regime or nutrient availability. To determine if remote sensing (RS) is a viable alternative to traditional data sources of site factor estimates, we analysed the accuracy (using ground truth validation measurements) of traditional and RS sources of pH and mean spring groundwater level (MSL, in m) estimates. Traditional sources were a soil map and hydrological model. RS estimates were obtained using vegetation indicator values (IVs) from a Dutch national system as an intermediate between site factors and spectral response. IVs relate to those site factors that dictate vegetation occurrence, whilst also providing a robust link to canopy spectra. For pH, the soil map and the RS estimate were nearly as accurate. For MSL, the RS estimates were much closer to the observed groundwater levels than the hydrological model, but the error margin of the estimates still exceeded the tolerance range of moisture sensitive vegetation. The relatively high accuracy of the RS estimates was made possible by the availability of local calibration points and large environmental gradients in the study site. In addition, the error composition of the RS estimates could be analysed step-by-step, whereas the traditional sources had to be accepted 'as-is'. Also considering that RS offers high spatial and temporal resolution at low costs, RS offered advantages over traditional sources. This will likely hold true for any other situation where prerequisites of accurate RS estimates have been met.

  4. Characterization of Growing Soil Bacterial Communities across a pH gradient Using H218O DNA-Stable Isotope Probing

    NASA Astrophysics Data System (ADS)

    Welty-Bernard, A. T.; Schwartz, E.

    2014-12-01

    Recent studies have established consistent relationships between pH and bacterial diversity and community structure in soils from site-specific to landscape scales. However, these studies rely on DNA or PLFA extraction techniques from bulk soils that encompass metabolically active and inactive, or dormant, communities, and loose DNA. Dormant cells may comprise up to 80% of total live cells. If dormant cells dominate a particular environment, it is possible that previous interpretations of the soil variables assumed to drive communities could be profoundly affected. We used H218O stable isotope probing and bar-coded illumina sequencing of 16S rRNA genes to monitor the response of actively growing communities to changes in soil pH in a soil microcosm over 14 days. This substrate-independent approach has several advantages over 13C or 15N-labelled molecules in that all growing bacteria should be able to make use of water, allowing characterization of whole communities. We hypothesized that Acidobacteria would increasingly dominate the growing community and that Actinobacteria and Bacteroidetes would decline, given previously established responses by these taxa to soil pH. Instead, we observed the reverse. Actinobacteria abundance increased three-fold from 26 to 76% of the overall community as soil pH fell from pH 5.6 to pH 4.6. Shifts in community structure and decreases in diversity with declining soil pH were essentially driven by two families, Streptomyceaca and Microbacteracea, which collectively increased from 2 to 40% of the entire community. In contrast, Acidobacteria as a whole declined although numbers of subdivision 1 remained stable across all soil pH levels. We suggest that the brief incubation period in this SIP study selected for growth of acid-tolerant Actinobacteria over Acidobacteria. Taxa within Actinomycetales have been readily cultured over short time frames, suggesting rapid growth patterns. Conversely, taxa within Acidobacteria have been

  5. Sorption of dissolved lead from shooting range soils using hydroxyapatite amendments synthesized from industrial byproducts as affected by varying pH conditions.

    PubMed

    Hashimoto, Yohey; Taki, Tomohiro; Sato, Takeshi

    2009-04-01

    For immobilization technologies to be successful, the use of readily available and cost advantageous amendment is important when the remediation targets vast amounts of contaminated soils. The objectives of this study were to investigate whether the byproduct-synthesized hydroxyapatite can be used as an immobilizing amendment for dissolved Pb from a shooting range soil, and to model the kinetic data collected from dissolution experiments. A soil-solution kinetic experiment was conducted under fixed pH conditions as a function of time. A Pb-contaminated soil was reacted with various hydroxyapatite amendments to determine the dissolution rate and mineral products of soil Pb. Three types of amendments used were pure hydroxyapatite (HA), and poorly crystalline hydroxyapatites synthesized from gypsum waste (CHA), and synthesized from incinerated poultry litter (PHA). The dissolved Pb concentration decreased with the addition of amendments at pH 3-7. Both CHA and PHA were more effective than HA for attenuating Pb dissolution at pH 6 and above. According to the thermodynamic calculation at pH 6, the dissolved Pb concentration for CHA and PHA treatments was predicted to be 66% and 50% lower than that of HA treatment, respectively. A better Pb immobilization effect demonstrated by CHA and PHA resulted in their greater solubility at higher pH, which may promote the formation of chloropyromorphite precipitates. Dissolution kinetics of soil Pb was adequately explained by pseudo-first order and pseudo-second order equations in acid pH ranges. According to the ion exchange model, an adequate agreement between the experimental data and regression curves was shown in the initial 40 min of the reaction process, but the accuracy of model predictability decreased thereafter. According to kinetic models and dissolution phenomena, CHA and PHA amendments had better Pb sorption capacity with rapid kinetics than pure hydroxyapatite at weak acid to neutral pH.

  6. A review of metal (Pb and Zn) sensitive and pH tolerant bioassay organisms for risk screening of metal-contaminated acidic soils.

    PubMed

    Chapman, E Emily V; Dave, Göran; Murimboh, John D

    2013-08-01

    To improve risk estimates at the screening stage of Ecological Risk Assessment (ERA), short duration bioassays tailored to undisturbed soil cores from the contaminated site could be useful. However, existing standardized bioassays use disturbed soil samples and often pH sensitive organisms. This is a problem as naturally acidic soils are widespread. Changing soil properties to suit the test organism may change metal bioavailability, leading to erroneous risk estimates. For bioassays in undisturbed soil cores to be effective, species able to withstand natural soil properties must be identified. This review presents a critical examination of bioassay species' tolerance of acidic soils and sensitivity to metal contaminants such as Pb and Zn. Promising organisms include; Dendrobaena octaedra, Folsomia candida, Caenorhabditis elegans, Oppia nitens, Brassica rapa, Trifolium pratense, Allium cepa, Quercus rubra and Acer rubrum. The MetSTICK test and the Bait lamina test were also identified as suitable microorganism tests.

  7. A review of metal (Pb and Zn) sensitive and pH tolerant bioassay organisms for risk screening of metal-contaminated acidic soils.

    PubMed

    Chapman, E Emily V; Dave, Göran; Murimboh, John D

    2013-08-01

    To improve risk estimates at the screening stage of Ecological Risk Assessment (ERA), short duration bioassays tailored to undisturbed soil cores from the contaminated site could be useful. However, existing standardized bioassays use disturbed soil samples and often pH sensitive organisms. This is a problem as naturally acidic soils are widespread. Changing soil properties to suit the test organism may change metal bioavailability, leading to erroneous risk estimates. For bioassays in undisturbed soil cores to be effective, species able to withstand natural soil properties must be identified. This review presents a critical examination of bioassay species' tolerance of acidic soils and sensitivity to metal contaminants such as Pb and Zn. Promising organisms include; Dendrobaena octaedra, Folsomia candida, Caenorhabditis elegans, Oppia nitens, Brassica rapa, Trifolium pratense, Allium cepa, Quercus rubra and Acer rubrum. The MetSTICK test and the Bait lamina test were also identified as suitable microorganism tests. PMID:23688951

  8. Stability and mobility of cerium oxide nanoparticles in soils: effects of humic substances, pH and ionic strength

    NASA Astrophysics Data System (ADS)

    Chen, Yirui; Mu, Linlin; Li, Chunyan; Bai, Lingyun; Jacobson, Astrid; Darnault, Christophe

    2015-04-01

    Among the large number of types of nanomaterials used in the field of nanotechnology, cerium oxide nanoparticles (CeO2 NPs) are among the top five most commonly utilized by industry, agriculture and nanomedicine for their unique physico-chemical properties. They are used, for example, in the production of catalysts, as fuel additives, and as polishing agents. Therefore, the release and encounter of CeO2 NPs in the environment following their application, waste disposal, life-cycle and accidents is inevitable. It is critical to examine the behavior of CeO2 NPs released in the environment to assess the risk they pose to the environmental and public health. In particular, little is known about the fate and transport of CeO2 NPs in soils and groundwater. To assess the behavior of CeO2 NPs, it is important to investigate the factors that affect their stability and mobility. Humic substances are a major component of soils and have been shown to have the potential to impact the transport and retention of nanoparticles in soils. Consequently, our study characterizes the impacts of humic and fulvic acids on the stability and mobility of cerium oxides in model porous media under various pH and ionic strength conditions. Batch experiments conducted at various concentrations of humic and fulvic acids coupled with a wide range of pHs and ionic strengths were investigated. Selected parameters from these batch studies were then used as experimental conditions representative of environmental systems to perform column transport experiments to assess of the mobility of CeO2 NPs in saturated porous media, which is the first step in simulating their behavior in soil and groundwater systems.

  9. Active microorganisms in forest soils differ from the total community yet are shaped by the same environmental factors: the influence of pH and soil moisture.

    PubMed

    Romanowicz, Karl J; Freedman, Zachary B; Upchurch, Rima A; Argiroff, William A; Zak, Donald R

    2016-10-01

    Predicting the impact of environmental change on soil microbial functions requires an understanding of how environmental factors shape microbial composition. Here, we investigated the influence of environmental factors on bacterial and fungal communities across an expanse of northern hardwood forest in Michigan, USA, which spans a 500-km regional climate gradient. We quantified soil microbial community composition using high-throughput DNA sequencing on coextracted rDNA (i.e. total community) and rRNA (i.e. active community). Within both bacteria and fungi, total and active communities were compositionally distinct from one another across the regional gradient (bacteria P = 0.01; fungi P < 0.01). Taxonomically, the active community was a subset of the total community. Compositional differences between total and active communities reflected changes in the relative abundance of dominant taxa. The composition of both the total and active microbial communities varied by site across the gradient (P < 0.01) and was shaped by differences in soil moisture, pH, SOM carboxyl content, as well as C and N concentration. Our study highlights the importance of distinguishing between metabolically active microorganisms and the total community, and emphasizes that the same environmental factors shape the total and active communities of bacteria and fungi in this ecosystem.

  10. Fate of cadmium at the soil-solution interface: a thermodynamic study as influenced by varying pH at South 24 Parganas, West Bengal, India.

    PubMed

    Karak, Tanmoy; Paul, Ranjit Kumar; Das, Sampa; Das, Dilip K; Dutta, Amrit Kumar; Boruah, Romesh K

    2015-11-01

    A study on the sorption kinetics of Cd from soil solution to soils was conducted to assess the persistence of Cd in soil solution as it is related to the leaching, bioavailability, and potential toxicity of Cd. The kinetics of Cd sorption on two non-contaminated alkaline soils from Canning (22° 18' 48.02″ N and 88° 39' 29.0″ E) and Lakshmikantapur (22° 06' 16.61″ N and 88° 19' 08.66″ E) of South 24 Parganas, West Bengal, India, were studied using conventional batch experiment. The variable soil suspension parameters were pH (4.00, 6.00, 8.18, and 9.00), temperatures (308, 318, and 328 K) and Cd concentrations (5-100 mg L(-1)). The average rate coefficient (kavg) and half-life (t1/2) values indicate that the persistence of Cd in soil solution is influenced by both temperature and soil suspension pH. The concentration of Cd in soil solution decreases with increase of temperature; therefore, Cd sorption on the soil-solution interface is an endothermic one. Higher pH decreases the t 1/2 of Cd in soil solution, indicating that higher pH (alkaline) is not a serious concern in Cd toxicity than lower pH (acidic). Based on the energy of activation (Ea) values, Cd sorption in acidic pH (14.76±0.29 to 64.45±4.50 kJ mol(-1)) is a surface control phenomenon and in alkaline pH (9.33±0.09 to 44.60±2.01 kJ mol(-1)) is a diffusion control phenomenon The enthalpy of activation (ΔH∓) values were found to be between 7.28 and 61.73 kJ mol(-1). Additionally, higher positive energy of activation (ΔG∓) values (46.82±2.01 to 94.47±2.36 kJ mol(-1)) suggested that there is an energy barrier for product formation. PMID:26514796

  11. Fate of cadmium at the soil-solution interface: a thermodynamic study as influenced by varying pH at South 24 Parganas, West Bengal, India.

    PubMed

    Karak, Tanmoy; Paul, Ranjit Kumar; Das, Sampa; Das, Dilip K; Dutta, Amrit Kumar; Boruah, Romesh K

    2015-11-01

    A study on the sorption kinetics of Cd from soil solution to soils was conducted to assess the persistence of Cd in soil solution as it is related to the leaching, bioavailability, and potential toxicity of Cd. The kinetics of Cd sorption on two non-contaminated alkaline soils from Canning (22° 18' 48.02″ N and 88° 39' 29.0″ E) and Lakshmikantapur (22° 06' 16.61″ N and 88° 19' 08.66″ E) of South 24 Parganas, West Bengal, India, were studied using conventional batch experiment. The variable soil suspension parameters were pH (4.00, 6.00, 8.18, and 9.00), temperatures (308, 318, and 328 K) and Cd concentrations (5-100 mg L(-1)). The average rate coefficient (kavg) and half-life (t1/2) values indicate that the persistence of Cd in soil solution is influenced by both temperature and soil suspension pH. The concentration of Cd in soil solution decreases with increase of temperature; therefore, Cd sorption on the soil-solution interface is an endothermic one. Higher pH decreases the t 1/2 of Cd in soil solution, indicating that higher pH (alkaline) is not a serious concern in Cd toxicity than lower pH (acidic). Based on the energy of activation (Ea) values, Cd sorption in acidic pH (14.76±0.29 to 64.45±4.50 kJ mol(-1)) is a surface control phenomenon and in alkaline pH (9.33±0.09 to 44.60±2.01 kJ mol(-1)) is a diffusion control phenomenon The enthalpy of activation (ΔH∓) values were found to be between 7.28 and 61.73 kJ mol(-1). Additionally, higher positive energy of activation (ΔG∓) values (46.82±2.01 to 94.47±2.36 kJ mol(-1)) suggested that there is an energy barrier for product formation.

  12. Low pH, Aluminum, and Phosphorus Coordinately Regulate Malate Exudation through GmALMT1 to Improve Soybean Adaptation to Acid Soils1[W][OA

    PubMed Central

    Liang, Cuiyue; Piñeros, Miguel A.; Tian, Jiang; Yao, Zhufang; Sun, Lili; Liu, Jiping; Shaff, Jon; Coluccio, Alison; Kochian, Leon V.; Liao, Hong

    2013-01-01

    Low pH, aluminum (Al) toxicity, and low phosphorus (P) often coexist and are heterogeneously distributed in acid soils. To date, the underlying mechanisms of crop adaptation to these multiple factors on acid soils remain poorly understood. In this study, we found that P addition to acid soils could stimulate Al tolerance, especially for the P-efficient genotype HN89. Subsequent hydroponic studies demonstrated that solution pH, Al, and P levels coordinately altered soybean (Glycine max) root growth and malate exudation. Interestingly, HN89 released more malate under conditions mimicking acid soils (low pH, +P, and +Al), suggesting that root malate exudation might be critical for soybean adaptation to both Al toxicity and P deficiency on acid soils. GmALMT1, a soybean malate transporter gene, was cloned from the Al-treated root tips of HN89. Like root malate exudation, GmALMT1 expression was also pH dependent, being suppressed by low pH but enhanced by Al plus P addition in roots of HN89. Quantitative real-time PCR, transient expression of a GmALMT1-yellow fluorescent protein chimera in Arabidopsis protoplasts, and electrophysiological analysis of Xenopus laevis oocytes expressing GmALMT1 demonstrated that GmALMT1 encodes a root cell plasma membrane transporter that mediates malate efflux in an extracellular pH-dependent and Al-independent manner. Overexpression of GmALMT1 in transgenic Arabidopsis, as well as overexpression and knockdown of GmALMT1 in transgenic soybean hairy roots, indicated that GmALMT1-mediated root malate efflux does underlie soybean Al tolerance. Taken together, our results suggest that malate exudation is an important component of soybean adaptation to acid soils and is coordinately regulated by three factors, pH, Al, and P, through the regulation of GmALMT1 expression and GmALMT1 function. PMID:23341359

  13. Cold, pH and salt tolerant Penicillium spp. inhabit the high altitude soils in Himalaya, India.

    PubMed

    Dhakar, Kusum; Sharma, Avinash; Pandey, Anita

    2014-04-01

    Twenty five fungal cultures (Penicillium spp.), isolated from soil samples from the high altitudes in the Indian Himalayan region, have been characterized following polyphasic approach. Colony morphology performed on five different media gave varying results; potato dextrose agar being the best for the vegetative growth and sporulation as well. Microscopic observations revealed 18 isolates to be biverticillate and 7 monoverticillate. Based on the phenotypic characters (colony morphology and microscopy), all the isolates were designated to the genus Penicillium. Exposure to low temperature resulted in enhanced sporulation in 23 isolates, while it ceased in case of two. The fungal isolates produced watery exudates in varying amount that in many cases increased at low temperature. All the isolates could grow between 4 and 37 °C, (optimum 24 °C), hence considered psychrotolerant. While all the isolates could tolerate pH from 2 to 14 (optimum 5-9), 7 isolates tolerated pH 1.5 as well. While all the fungal isolates tolerated salt concentration above 10 %; 10 isolates showed tolerance above 20 %. Based on ITS region (ITS1-5.8S-ITS2) analysis the fungal isolates belonged to 25 different species of Penicillium (showing similarity between 95 and 100 %). Characters like tolerance for low temperature, wide range of pH, and high salt concentration, and enhancement in sporulation and production of secondary metabolites such as watery exudates at low temperature can be attributed to the ecological resilience possessed by these fungi for survival under low temperature environment of mountain ecosystem.

  14. Effectiveness of the bran media and bacteria inoculum treatments in increasing pH and reducing sulfur-total of acid sulfate soils

    NASA Astrophysics Data System (ADS)

    Taufieq, Nur Anny Suryaningsih; Rahim, Sahibin Abdul; Jamil, Habibah

    2013-11-01

    This study was carried out to determine the effectiveness ofsulfate reducing bacteria (SRB) in using bran as a source of food and energy, and to see the effectiveness of the bran media and bacteria inoculums treatments for pH and sulfur-total of acid sulfate reduction insoils. This study used two factors in group random designs with four treatments for bacteria inoculum of B1 (1%), B2 (5%), B3 (10%), B4 (15%) and two treatments for organic media (bran) of D1 (1:1) and D2 (1:19). Based on three replications, the combination resulted in a total of 24 treatments. Soil pH was measured using the Duddridge and Wainright method and determination of sulfate content in soil was conducted by the spectrophotometry method. The data obtained was analyzed for significance by Analysis of Variance and the Least Significant Difference Test. The pH of the initial acid sulfate soils ranged from 3 to 4 and the soil sulfur-total ranged from 1.4% to 10%. After mixing sulfate reducing bacteria with the bran mediaand incubated for four days, the pH of the acid sulfate soils increased from 3.67 to 4.20, while the soil sulfur-total contents had been reduced by 2.85% to 0.35%. This experiment has proven that an acid sulfate soil with low pH is a good growth medium for the sulfate reducing bacteria. The bestincubation period to achieve an effective bioremediation resultthrough sulfate percentage reduction by sulfate reducing bacteria was 10 days, while the optimum bran media dose was 1:19, and the bacteria inoculums dose was 10%.

  15. Stereoselective Degradation and Molecular Ecological Mechanism of Chiral Pesticides Beta-Cypermethrin in Soils with Different pH Values.

    PubMed

    Yang, Zhong-Hua; Ji, Guo-Dong

    2015-12-15

    For decades, pesticides have been widely used for agricultural activities around the world, and the environmental problems caused by these compounds have raised widespread concern. However, the different enantioselective behaviors of chiral pesticide enantiomers are often ignored. Here, the selective degradation patterns and mechanisms of chiral pesticide enantiomers were successfully investigated for the first time in the soils of three cultivation areas with different pH values. Beta-cypermethrin was chosen as the target analyte. We found that the degradation rates of the four isomers of beta-cypermethrin were different. We used stepwise regression equations between degradation rates and functional genes to quantitatively study their relationships. Quantitative response analysis revealed that different isomers have different equations even under identical conditions. The results of path analysis showed that a single functional gene can make different direct and indirect contributions to the degradation of different isomers. Finally, the high-throughput technology was used to analysis the genome of the three tested soils and then compared the main microbial communities in them. We have successfully devised a method to investigate the molecular biological mechanisms of the selective degradation behavior of chiral compounds, thus enabling us to better understand these mechanisms.

  16. Cadmium and Zn availability as affected by pH manipulation and its assessment by soil extraction, DGT and indicator plants.

    PubMed

    Muhammad, Iqbal; Puschenreiter, Markus; Wenzel, Walter W

    2012-02-01

    Manipulation of soil pH by soil additives and / or rhizosphere processes may enhance the efficiency of metal phytoextraction. Here we report on the effect of nitric acid additions to four polluted soils on Cd and Zn concentrations in soil solution (C(soln)) and 0.005M Ca(NO(3))(2) extracts, and related changes in the diffusive fluxes and resupply of the metals as assessed by diffusive gradients in thin films (DGT). The responses of these chemical indicators of bioavailability were compared to metal uptake in two indicator plant species, common dandelion (Taraxacum officinale F.H. Wigg) and narrow leaf plantain (Plantago lanceolata L.) grown for 75days in a pot experiment. Lowering soil pH increased C(soln), the 0.005M Ca(NO(3))(2)-soluble fractions and the DGT-measured Cd and Zn concentrations (C(DGT)) in the experimental soils. This was associated with enhanced uptake of Cd and Zn on soils acidified to pH 4.5 whereas plants did not survive at pH 3.5. Toxicity along with decreased kinetics of metal resupply (calculated by the 2D DIFS model) in the strong acidification treatment suggests that moderate acidification is more appropriate to enhance the phytoextraction process. Each of the chemical indicators of bioavailability predicted well (R(2)>0.70) the Cd and Zn concentrations in plantain shoots but due to metal toxicity not for dandelion. Concentration factors, i.e. the ratio between metal concentrations in shoots and in soil solution (CF) indicate that Cd and Zn uptake in plantain was not limited by diffusion which may explain that DGT did not perform better than C(soln). However, DGT is expected to predict plant uptake better in diffusion-limited conditions such as in the rhizosphere of metal-accumulating phytoextraction crops. PMID:22177029

  17. Effect of short-chain organic acids and pH on the behaviors of pyrene in soil-water system.

    PubMed

    An, Chunjiang; Huang, Guohe; Yu, Hui; Wei, Jia; Chen, Wei; Li, Gongchen

    2010-12-01

    The effects of five short-chain organic acids (SCOAs) on the behaviors of pyrene in soil-water system were investigated. The influences of the quantity and species of organic acids, pH, and soil dissolved organic matter were considered. The results showed the presence of SCOAs inhibited the adsorption and promoted the desorption of pyrene in the following order: citric acid>oxalic acid>tartaric acid>lactic acid>acetic acid. The decreased extents of pyrene adsorption performance enhanced with increasing SCOA concentrations, while the decreasing rate became less pronounced at high SCOA concentrations. In the presence of organic acids, the adsorption ability of pyrene decreased with increasing pH. However, there was a slight increase of pyrene adsorption with the addition of oxalic acid, tartaric acid and citric acid above pH 8. The capacity for pyrene retention differentiated significantly between the soils with and without dissolved organic matter. The presence of SCOAs was also favorable for the decrease of pyrene adsorption on soil without dissolved organic matter. The results of this study have important implications for the remediation of persistent organic pollutants in soil and groundwater.

  18. Influence of Ca and pH on the uptake and effects of Cd in Folsomia candida exposed to simplified soil solutions.

    PubMed

    Ardestani, Masoud M; Ortiz, Maria Diez; van Gestel, Cornelis A M

    2013-08-01

    The present study sought to quantify the components of a biotic ligand model (BLM) for the effects of Cd on Folsomia candida (Collembola). Assuming that soil porewater is the main route of exposure and to exclude the effects of soil particles on metal availability, animals were exposed for 7 d to different Cd concentrations between 0.1 mM and 100 mM in simplified soil solutions at different Ca concentrations (0.2 mM, 0.8 mM, 3.2 mM, and 12.8 mM) or at different pH (5.0, 6.0, and 7.0). Higher Ca concentrations decreased the toxicity of Cd (adult survival) in test solutions, whereas toxicity was slightly lower at pH 7 and 6 than at pH 5, suggesting a mitigating effect of Ca and to a lesser extent pH on Cd toxicity to F. candida. Internal Cd concentrations in the animals increased with increasing exposure level but were significantly reduced by increasing Ca concentrations and were not significantly affected by pH. By using Langmuir isotherms, binding constants for Cd, Ca, and protons and the fraction of binding sites occupied by Cd were calculated and used to predict effects of Cd on survival. Predicted toxicity showed a good agreement with measured responses when Ca and pH were used as separate factors or combined together. The present study shows indications of protective effects of Ca but less of protons on the toxicity and uptake of Cd in F. candida on exposure to simplified soil solutions, which can be described using the principles of a biotic ligand model.

  19. Solid-solution partitioning of organic matter in soils as influenced by an increase in pH or Ca concentration.

    PubMed

    Oste, L A; Temminghoff, E J M; van Riemsdijk, W H

    2002-01-15

    Organic matter is an important component of soil with regard to the binding of contaminants. Hence, the partitioning of organic matter influences the partitioning of soil contaminants. The partitioning of organic matter is, among other factors, influenced by the ionic composition and ionic strength of the soil solution. This study focuses on the behavior of organic matter after a change in the ionic composition of the soil solution, particularly in Ca concentration and pH. Different amounts of Ca(NO3)2 and NaOH were added to soil suspensions. The dissolved organic carbon (DOC) concentration increased with increasing pH (addition of NaOH), whereas an increase in Ca (addition of Ca(NO3)2) had the opposite effect. A stronger increase in DOC was observed if a single dose of NaOH was added, compared to a gradual addition of the same amount of NaOH. Cation binding by organic matter in the supernatant was calculated using the NICA-Donnan model. The log DOC concentration appeared to be correlated to the Donnan potential, calculated under the assumption that all DOC equals humic acid. This correlation was found for all eight neutral to acidic soils used in this study, although the slopes and elevations of the regression lines varied. The slope varied by a factor of 2 and the elevation appeared to be strongly influenced by the DOC concentration in the untreated soils, which is related to the total organic matter in the soil. Finally, we predicted the Donnan potential on the basis of an extraction of untreated soil with 0.03 M NaNO3, and the total additions of Ca(NO3)2 and NaOH. Comparison of these predictions with speciation calculations in solution showed a good correlation, indicating that a combination of one batch experiment and the presented calculation procedure can provide good estimations of DOC concentrations after addition of chemicals. PMID:11831217

  20. Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

    PubMed

    Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

    2016-02-01

    Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising. PMID:26629644

  1. Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

    PubMed

    Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

    2016-02-01

    Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising.

  2. Soil pH effects on the comparative toxicity of dissolved zinc, non-nano and nano ZnO to the earthworm Eisenia fetida.

    PubMed

    Heggelund, Laura R; Diez-Ortiz, Maria; Lofts, Stephen; Lahive, Elma; Jurkschat, Kerstin; Wojnarowicz, Jacek; Cedergreen, Nina; Spurgeon, David; Svendsen, Claus

    2014-08-01

    To determine how soil properties influence nanoparticle (NP) fate, bioavailability and toxicity, this study compared the toxicity of nano zinc oxide (ZnO NPs), non-nano ZnO and ionic ZnCl2 to the earthworm Eisenia fetida in a natural soil at three pH levels. NP characterisation indicated that reaction with the soil media greatly controls ZnO properties. Three main conclusions were drawn. First that Zn toxicity, especially for reproduction, was influenced by pH for all Zn forms. This can be linked to the influence of pH on Zn dissolution. Secondly, that ZnO fate, toxicity and bioaccumulation were similar (including relationships with pH) for both ZnO forms, indicating the absence of NP-specific effects. Finally, earthworm Zn concentrations were higher in worms exposed to ZnO compared to ZnCl2, despite the greater toxicity of the ionic form. This observation suggests the importance of considering the relationship between uptake and toxicity in nanotoxicology studies.

  3. Aluminium Uptake and Translocation in Al Hyperaccumulator Rumex obtusifolius Is Affected by Low-Molecular-Weight Organic Acids Content and Soil pH

    PubMed Central

    Vondráčková, Stanislava; Száková, Jiřina; Drábek, Ondřej; Tejnecký, Václav; Hejcman, Michal; Müllerová, Vladimíra; Tlustoš, Pavel

    2015-01-01

    Background and Aims High Al resistance of Rumex obtusifolius together with its ability to accumulate Al has never been studied in weakly acidic conditions (pH > 5.8) and is not sufficiently described in real soil conditions. The potential elucidation of the role of organic acids in plant can explain the Al tolerance mechanism. Methods We established a pot experiment with R. obtusifolius planted in slightly acidic and alkaline soils. For the manipulation of Al availability, both soils were untreated and treated by lime and superphosphate. We determined mobile Al concentrations in soils and concentrations of Al and organic acids in organs. Results Al availability correlated positively to the extraction of organic acids (citric acid < oxalic acid) in soils. Monovalent Al cations were the most abundant mobile Al forms with positive charge in soils. Liming and superphosphate application were ambiguous measures for changing Al mobility in soils. Elevated transport of total Al from belowground organs into leaves was recorded in both lime-treated soils and in superphosphate-treated alkaline soil as a result of sufficient amount of Ca available from soil solution as well as from superphosphate that can probably modify distribution of total Al in R. obtusifolius as a representative of “oxalate plants.” The highest concentrations of Al and organic acids were recorded in the leaves, followed by the stem and belowground organ infusions. Conclusions In alkaline soil, R. obtusifolius is an Al-hyperaccumulator with the highest concentrations of oxalate in leaves, of malate in stems, and of citrate in belowground organs. These organic acids form strong complexes with Al that can play a key role in internal Al tolerance but the used methods did not allow us to distinguish the proportion of total Al-organic complexes to the free organic acids. PMID:25880431

  4. In situ production of bacterial branched tetraether lipids in the lower Yangtze River: Implications for soil-derived pH and temperature proxies

    NASA Astrophysics Data System (ADS)

    He, L.; Li, C.; Yang, S.; Zhang, C.

    2013-12-01

    Large rivers play a major role in transporting terrestrial material to the ocean and deposits on continental margins can serve as archives for paleo continental climate studies. Branched glycerol diakly glycerol tetraethers (bGDGTs) are predominantly found in soil, which can serve as proxies for paleo continental air temperature and paleo soil pH. Recently, however, in situ production of bGDGTs in aquatic systems has been observed. The goal of this study was to evaluate whether bGDGTs are produced in situ in the lower Yangtze River and how this in situ production might affect the temperature and pH proxies derived from the soil bGDGTs. Suspended particulate matter (SPM) was collected at three depth locations (left, central, right) of the river (<0.5 m depth) on a biweekly basis between December 2010 and July 2011 at the Datong hydrological station, which is about 600 km upstream of the Yangtze River mouth. Branched GDGTs from the SPM were extracted as core lipids (C-bGDGTs representing fossil lipids from soil)- and polar lipids (P-bGDGTs representing in situ production of lipids in the river water) using liquid chromatography-mass spectrometry. Our results showed that P-bGDGTs account for 4.2-10.6% of total bGDGTs. The flux of P-bGDGTs remained relatively constant in winter (December-January) and summer (June and July) (2.47-5.29 g/day) with higher values (12.39-14.67 g/day) occurred in April and May; whereas the flux of C-bGDGTs increased steady from January (19.21 g/day) to May (175 g/day) followed by an decrease to 122.15 g/day in July. The C- and P-bGDGT derived proxies showed large differences in mean annual air temperature (MAAT) and pH. Comparison with soil samples collected at the Datong station indicates that the C-bGDGTs in the river water reflected the MAAT and soil pH of the region whereas the P-bGDGT-derived values did not. These results suggest that there may be a constant portion of in situ production of bGDGTs in the lower Yangtze River. That

  5. Enriched Seawater Delivery System to Support In Situ Ocean Acidification Experiments using Carbon Dioxide for pH Adjustment of Seawater

    NASA Astrophysics Data System (ADS)

    Kirkwood, W. J.; Peltzer, E. T.; Walz, P. M.; Shane, F.; Kecy, C.; Headley, K. L.; Herlien, B.; Maughan, T.; Scholfield, J.; Salamy, K. A.; O'Reilly, T.; Brewer, P. G.

    2011-12-01

    A series of Free Ocean CO2 Enrichment (FOCE) experiments are underway or are in planning to perform in situ ocean acidification research at a number of locations around the world. One of the most challenging locations is in Monterey Bay at the site of the Monterey Accelerated Research System, the United States test facility for cabled observatories. This site is located at 890 m deep and 4 0C within the local oxygen minimum zone and approximately 50 kilometers from shore. At this depth and temperature the behavior of liquid CO2 presents various challenges that had to be addressed in order to provide the low pH seawater needed for the FOCE apparatus to perform as desired. To solve this challenge a team of engineers and scientists at the Monterey Bay Aquarium Research Institute (MBARI) have developed a standalone device referred to as the Enriched Seawater Delivery System. Simple injections of seawater saturated at one atmosphere with CO2 demonstrated that the FOCE unit itself performs as designed. However, providing a consistent source of CO2 enriched pH altered seawater within the design criteria proved to be an imposing problem which when solved could have a broader impact in the oceanographic community. The decision was made to build a stand-alone device separate from the FOCE flume to perform in situ CO2 experiments in conditions where CO2 hydrate can form. Challenges to be over-come by this work included: (1) liquid CO2 is buoyant at the prescribed depth; (2) minimizing the formation of hydrates while manufacturing the CO2 enriched seawater. Because CO2 hydrate is denser than seawater, management of the phases and stability of liquid CO2 was necessary to prevent clogging within the delivery system. Our earliest field experiments demonstrated that containing and controlling the CO2 and the CO2-enriched seawater is difficult and makes the metering of the enriched fluid with on demand milliliter per second precision an extremely challenging problem. The Enriched

  6. [X-ray absorption fine structure (XAFS) study of the effects of pH on Pb(II) sorption by soil].

    PubMed

    Hu, Ning-Jing; Huang, Peng; Luo, Yong-Ming; Hu, Tian-Dou; Xie, Ya-Ning; Wu, Zi-Yu

    2010-12-01

    Combined batch sorption and in situ X-ray absorption fine structure (XAFS) provide direct assessment of the mechanisms for Pb(II) sorption at the soil-water interface under different pH conditions. The XAFS data indicated that the innersphere Pb sorption complex with ionic character (Pb4 (OH)4(4+)) dominated the Pb surface speciation, and the outer-sphere Pb sorption complex and the precipitation of calcium carbonate containing Pb(PbCaCO3) were also involved in the adsorption samples. Coordination number and radial distance of the first-shell Pb-O decreased from 0.172 7 to 0.166 6 nm and the percentage of inner-sphere complexes increased when the initial pH changed from 6.0 to 8.5, indicating that the mechanism of Pb(II) sorption by the soil was pH-dependent. PMID:21322254

  7. Influence of In Vitro Assay pH and Extractant Composition on As Bioaccessibility in Contaminated Soils

    EPA Science Inventory

    In vitro bioaccessibility assays are often utilised to determine the potential human exposure to soil contaminants through soil ingestion. Comparative studies have identified inconsistencies in the results obtained with different in vitro assays. In this study we investigated the...

  8. The gamma dose assessment and pH correlation for various soil types at Batu Pahat and Kluang districts, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Johar, Saffuwan Mohamed; Embong, Zaidi; Tajudin, Saiful Azhar Ahmad

    2016-01-01

    An assessment of absorbed dose and radiation hazard index as well as its relationship with soil pH was performed in this study. The area was chosen due to its variety of soil types from the Alluvial and the Sedentary group. The radioactivity concentration levels and the soil acidity were measured using the Canberra GC3518 high pure germanium with a relative efficiency of 35% at 1.3 MeV and the Takemura Soil pH and Moisture Tester (DM15), respectively. Overall results show the Holyrood-Lunas soil of Alluvial group recorded the highest external terrestrial gamma radiation dose rate (TGRD) of 286.4±37.9 nGy h-1 and radioactivity concentrations of 78.1±8.9 Bq kg-1 (226Ra), 410.5±55.4 Bq kg-1 (232Th) and 56.4±8.8 Bq kg-1 (40K), respectively, while the Peat soil of Alluvial group recorded the lowest TGRD of 4.4±2.7 nGy h-1 and radioactivity concentrations of 4.8±1.7 Bq kg-1 (226Ra), 3.1±1.1 Bq kg-1 (232Th) and 6.1±2.0 Bq kg-1 (40K), respectively. The estimated mean outdoor annual effective dose, the mean radium equivalent activity (Req) and the mean external (Hext) and internal hazard index (Hint) associated with the alluvial and sedentary soil group were evaluated at 0.15 and 0.20 mSv, 280 and 364 Bq kg-1, Hext = 0.78 and 1.01, and Hint = 0.93 and 1.26, respectively. Correlation analysis between 238U, 232Th and 40K with soil pH level for alluvial group was r = +0.68, +0.48 and 0, respectively, while for sedentary soil, the Pearson's, r = -0.30, -0.90 and +0.14, respectively.

  9. Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

    NASA Astrophysics Data System (ADS)

    Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

    2014-05-01

    Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

  10. The influence of long-term copper contaminated agricultural soil at different pH levels on microbial communities and springtail transcriptional regulation.

    PubMed

    de Boer, Tjalf E; Taş, Neslihan; Braster, Martin; Temminghoff, Erwin J M; Röling, Wilfred F M; Roelofs, Dick

    2012-01-01

    Copper has long been applied for agricultural practises. Like other metals, copper is highly persistent in the environment and biologically active long after its use has ceased. Here we present a unique study on the long-term effects (27 years) of copper and pH on soil microbial communities and on the springtail Folsomia candida an important representative of the soil macrofauna, in an experiment with a full factorial, random block design. Bacterial communities were mostly affected by pH. These effects were prominent in Acidobacteria, while Actinobacteria and Gammaroteobacteria communities were affected by original and bioavailable copper. Reproduction and survival of the collembolan F. candida was not affected by the studied copper concentrations. However, the transcriptomic responses to copper reflected a mechanism of copper transport and detoxification, while pH exerted effects on nucleotide and protein metabolism and (acute) inflammatory response. We conclude that microbial community structure reflected the history of copper contamination, while gene expression analysis of F. candida is associated with the current level of bioavailable copper. The study is a first step in the development of a molecular strategy aiming at a more comprehensive assessment of various aspects of soil quality and ecotoxicology. PMID:21882881

  11. The influence of calcium and pH on the uptake and toxicity of copper in Folsomia candida exposed to simplified soil solutions.

    PubMed

    Ardestani, Masoud M; Verweij, Rudo A; van Gestel, Cornelis A M

    2013-10-15

    The aim of the present study was to investigate the influence of Ca and pH on the uptake and effects of Cu in Folsomia candida (Collembola). Assuming that soil pore water is the main route of exposure, F. candida were exposed for seven days to Cu in simplified soil solutions at different Ca concentrations and different pH levels. A hormetic-type effect was seen for the effect of Cu on F. candida survival. Toxicity of Cu was slightly decreased and Cu uptake increased at the highest Ca concentrations. Cu toxicity and uptake were not significantly affected by pH. Conditional binding constants for Cu(2+), Ca(2+) and H(+), calculated with a Langmuir isotherm, were used to relate Cu toxicity to the fraction of occupied binding sites (BL). The estimated 50% effect level (fCu-BL50) was 0.14 when all data were combined. To verify the Langmuir parameters, binding constants calculated based on internal Cu concentrations were used to estimate predicted effects and compared with the measured values. A good correlation between predicted and measured survival indicated that the principles of a biotic ligand model may be applicable to explain Cu toxicity to F. candida in simplified soil solutions. PMID:23973473

  12. Hierarchical control of porous silica by pH adjustment: Alkyl polyamines as surfactants for bimodal silica synthesis and its carbon replica

    NASA Astrophysics Data System (ADS)

    Abellán, G.; Carrillo, A. I.; Linares, N.; Serrano, E.; García-Martínez, J.

    2009-08-01

    Bimodal macro-mesoporous silica networks have been prepared in a simple one-pot synthesis using an inexpensive tetramine surfactant and tetraethoxysilane as a silica precursor. These novel materials show high pore volumes and templated mesopores (average pore size 3.0 nm) embedded in 20 nm thick walls forming interparticle large meso/macropores. The judicious control of the pH during the silica formation allows for the precise control of the interparticle condensation, likely due to the change in the interaction between the tetramine surfactant and the silica precursors. Finally, a highly porous carbon replica with bimodal porosity was prepared by using the bimodal silica as a hard sacrificial template. The microstructure of the silica template was accurately transferred to the carbon material obtaining high surface areas (up to 1300 m 2 g -1) and total pore volumes ≥2 cm 3 g -1.

  13. Short-column anion-exchange chromatography for soil and peat humic substances profiling by step-wise gradient of high pH aqueous sodium ethylenediaminetetraacetate.

    PubMed

    Hutta, Milan; Ráczová, Janka; Góra, Róbert; Pessl, Juraj

    2015-08-21

    Novel anion-exchange liquid chromatographic method with step gradient of aqueous EDTA(4-) based mobile phase elution has been developed to profile available Slovak soil humic substances and alkaline extracts of various soils. The method utilize short glass column (30mm×3mm) filled in with hydrolytically stable particles (60μm diameter) Separon HEMA-BIO 1000 having (diethylamino)ethyl functional groups. Step gradient was programmed by mixing mobile phase composed of aqueous solution of sodium EDTA (pH 12.0; 5mmolL(-1)) and mobile phase constituted of aqueous solution of sodium EDTA (pH 12.0, 500mmolL(-1)). The FLD of HSs was set to excitation wavelength 480nm and emission wavelength 530nm (λem). Separation mechanism was studied by use of selected aromatic acids related to humic acids with the aid of UV spectrophotometric detection at 280nm. The proposed method benefits from high ionic strength (I=5molL(-1)) of the end mobile phase buffer and provides high recovery of humic acids (98%). Accurate and reproducible profiling of studied humic substances, alkaline extracts of various types of soils enables straightforward characterization and differentiation of HSs in arable and forest soils. Selected model aromatic acids were used for separation mechanism elucidation.

  14. Sorption behavior of 17 phthalic acid esters on three soils: effects of pH and dissolved organic matter, sorption coefficient measurement and QSPR study.

    PubMed

    Yang, Fen; Wang, Meng; Wang, Zunyao

    2013-09-01

    This work studies the sorption behaviors of phthalic acid esters (PAEs) on three soils by batch equilibration experiments and quantitative structure property relationship (QSPR) methodology. Firstly, the effects of soil type, dissolved organic matter and pH on the sorption of four PAEs (DMP, DEP, DAP, DBP) are investigated. The results indicate that the soil organic carbon content has a crucial influence on sorption progress. In addition, a negative correlation between pH values and the sorption capacities was found for these four PAEs. However, the effect of DOM on PAEs sorption may be more complicated. The sorption of four PAEs was promoted by low concentrations of DOM, while, in the case of high concentrations, the influence of DOM on the sorption was complicated. Then the organic carbon content normalized sorption coefficient (logKoc) values of 17 PAEs on three soils were measured, and the mean values ranged from 1.50 to 7.57. The logKoc values showed good correlation with the corresponding logKow values. Finally, two QSPR models were developed with 13 theoretical parameters to get reliable logKoc predictions. The leave-one-out cross validation (CV-LOO) indicated that the internal predictive power of the two models was satisfactory.

  15. The Community Structures of Prokaryotes and Fungi in Mountain Pasture Soils are Highly Correlated and Primarily Influenced by pH

    PubMed Central

    Lanzén, Anders; Epelde, Lur; Garbisu, Carlos; Anza, Mikel; Martín-Sánchez, Iker; Blanco, Fernando; Mijangos, Iker

    2015-01-01

    Traditionally, conservation and management of mountain pastures has been managed solely on the basis of visible biota. However, microorganisms play a vital role for the functioning of the soil ecosystem and, hence, pasture sustainability. Here, we studied the links between soil microbial (belowground) community structure (using amplicon sequencing of prokaryotes and fungi), other soil physicochemical and biological properties and, finally, a variety of pasture management practices. To this aim, during two consecutive years, we studied 104 environmental sites characterized by contrasting elevation, habitats, bedrock, and pasture management; located in or near Gorbeia Natural Park (Basque Country/Spain). Soil pH was found to be one of the most important factors in structuring soil microbial diversity. Interestingly, we observed a striking correlation between prokaryotic, fungal and macrofauna diversity, likely caused by interactions between these life forms. Further studies are needed to better understand such interactions and target the influence of different management practices on the soil microbial community, in face of the significant heterogeneity present. However, clearing of bushes altered microbial community structure, and in sites with calcareous bedrock also the use of herbicide vs. mechanical clearing of ferns. PMID:26640462

  16. Hierarchical control of porous silica by pH adjustment: Alkyl polyamines as surfactants for bimodal silica synthesis and its carbon replica

    SciTech Connect

    Abellan, G.; Carrillo, A.I.; Linares, N.; Serrano, E.

    2009-08-15

    Bimodal macro-mesoporous silica networks have been prepared in a simple one-pot synthesis using an inexpensive tetramine surfactant and tetraethoxysilane as a silica precursor. These novel materials show high pore volumes and templated mesopores (average pore size 3.0 nm) embedded in 20 nm thick walls forming interparticle large meso/macropores. The judicious control of the pH during the silica formation allows for the precise control of the interparticle condensation, likely due to the change in the interaction between the tetramine surfactant and the silica precursors. Finally, a highly porous carbon replica with bimodal porosity was prepared by using the bimodal silica as a hard sacrificial template. The microstructure of the silica template was accurately transferred to the carbon material obtaining high surface areas (up to 1300 m{sup 2} g{sup -1}) and total pore volumes >=2 cm{sup 3} g{sup -1}. - Graphical abstract: Hierarchical bimodal porous silica and its carbon replica prepared by nanocasting.

  17. Destabilization dynamics of clay and acid-free polymers of ferric and magnesium salts in AMD without pH adjustment.

    PubMed

    Ntwampe, I O; Waanders, F B; Bunt, J R

    2016-01-01

    The physicochemical treatment was employed to treat acid mine drainage (AMD) in the removal of turbid materials using clay only (exp A) and a combination of clay, FeCl3 and Mg(OH)2 (exp B) to form a polymer. A 5 g sample of clay (bentonite) was added to 1.2 L of AMD and treated in a jar test at 250 rpm for 2 min and reduced to 100 rpm for 10 min. A 200 mL sub-sample from the 1.2 L mother liquor was poured into five 500 mL glass beakers, and 20 mL dosages of a polymer of 0.1 M Fe(3+) in (FeCl3) and 0.1 M Mg(2+) in (Mg(OH)2) was added to the beakers. The samples were allowed to settle for 1 h, after which the supernatant was analyzed for pH, total suspended solids (TSS), dissolved oxygen (DO) and oxidation-reduction potential (ORP) (exp A). A similar set of experiments was conducted where 200 mL of the AMD sample was poured into 500 mL glass beakers and (20-60 mL) dosages of a combination of 5 g clay, 0.1 M Fe(3+) (FeCl3) and Mg(2+) (Mg(OH)2) polymer was added and similar mixing, settling time and measurements were conducted (exp B). The polymers used in exp A exhibited TSS removal efficiency (E%) which was slightly lower compared with the polymer used in exp B, above 90%. Clay has a high TSS removal efficiency in the treatment of the AMD, indicating that adsorption was a predominant process in exps A and B. The scanning electron microscope (SEM) micrographs of the AMD sludge of both exps A and B, with a rigid and compacted structure consisting of dense flocs surrounded by the smaller flocs bound together, corroborate the fact that adsorption is a predominant process.

  18. Destabilization dynamics of clay and acid-free polymers of ferric and magnesium salts in AMD without pH adjustment.

    PubMed

    Ntwampe, I O; Waanders, F B; Bunt, J R

    2016-01-01

    The physicochemical treatment was employed to treat acid mine drainage (AMD) in the removal of turbid materials using clay only (exp A) and a combination of clay, FeCl3 and Mg(OH)2 (exp B) to form a polymer. A 5 g sample of clay (bentonite) was added to 1.2 L of AMD and treated in a jar test at 250 rpm for 2 min and reduced to 100 rpm for 10 min. A 200 mL sub-sample from the 1.2 L mother liquor was poured into five 500 mL glass beakers, and 20 mL dosages of a polymer of 0.1 M Fe(3+) in (FeCl3) and 0.1 M Mg(2+) in (Mg(OH)2) was added to the beakers. The samples were allowed to settle for 1 h, after which the supernatant was analyzed for pH, total suspended solids (TSS), dissolved oxygen (DO) and oxidation-reduction potential (ORP) (exp A). A similar set of experiments was conducted where 200 mL of the AMD sample was poured into 500 mL glass beakers and (20-60 mL) dosages of a combination of 5 g clay, 0.1 M Fe(3+) (FeCl3) and Mg(2+) (Mg(OH)2) polymer was added and similar mixing, settling time and measurements were conducted (exp B). The polymers used in exp A exhibited TSS removal efficiency (E%) which was slightly lower compared with the polymer used in exp B, above 90%. Clay has a high TSS removal efficiency in the treatment of the AMD, indicating that adsorption was a predominant process in exps A and B. The scanning electron microscope (SEM) micrographs of the AMD sludge of both exps A and B, with a rigid and compacted structure consisting of dense flocs surrounded by the smaller flocs bound together, corroborate the fact that adsorption is a predominant process. PMID:27533861

  19. Char-amended farm soils – effects on soil chemistry and wheat growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On-farm gasification of agricultural residues, the non-food byproducts from crop harvests, could provide a means to generate value-added income from the production of fuel or electrical generation. Char produced during the process also has potential value as a soil amendment to adjust acid soil pH (...

  20. Predicting Soluble Nickel in Soils Using Soil Properties and Total Nickel.

    PubMed

    Zhang, Xiaoqing; Li, Jumei; Wei, Dongpu; Li, Bo; Ma, Yibing

    2015-01-01

    Soil soluble nickel (Ni) concentration is very important for determining soil Ni toxicity. In the present study, the relationships between soil properties, total and soluble Ni concentrations in soils were developed in a wide range of soils with different properties and climate characteristics. The multiple regressions showed that soil pH and total soil Ni concentrations were the most significant parameters in predicting soluble Ni concentrations with the adjusted determination coefficients (Radj2) values of 0.75 and 0.68 for soils spiked with soluble Ni salt and the spiked soils leached with artificial rainwater to mimic field conditions, respectively. However, when the soils were divided into three categories (pH < 7, 7-8 and > 8), they obtained better predictions with Radj2 values of 0.78-0.90 and 0.79-0.94 for leached and unleached soils, respectively. Meanwhile, the other soil properties, such as amorphous Fe and Al oxides and clay, were also found to be important for determining soluble Ni concentrations, indicating that they were also presented as active adsorbent surfaces. Additionally, the whole soil speciation including bulk soil properties and total soils Ni concentrations were analyzed by mechanistic speciation models WHAM VI and Visual MINTEQ3.0. It was found that WHAM VI provided the best predictions for the soils with pH < 7, was relatively reasonable for pH 7 to 8, and gave an overestimation for pH > 8. The Visual MINTEQ3.0 could provide better estimation for pH < 8 and meanwhile quite reasonable results for pH > 8. These results indicated the possibility and applicability of these models to predict soil soluble Ni concentration by soil properties.

  1. Predicting Soluble Nickel in Soils Using Soil Properties and Total Nickel

    PubMed Central

    Zhang, Xiaoqing; Li, Jumei; Wei, Dongpu; Li, Bo; Ma, Yibing

    2015-01-01

    Soil soluble nickel (Ni) concentration is very important for determining soil Ni toxicity. In the present study, the relationships between soil properties, total and soluble Ni concentrations in soils were developed in a wide range of soils with different properties and climate characteristics. The multiple regressions showed that soil pH and total soil Ni concentrations were the most significant parameters in predicting soluble Ni concentrations with the adjusted determination coefficients (Radj2) values of 0.75 and 0.68 for soils spiked with soluble Ni salt and the spiked soils leached with artificial rainwater to mimic field conditions, respectively. However, when the soils were divided into three categories (pH < 7, 7–8 and > 8), they obtained better predictions with Radj2 values of 0.78–0.90 and 0.79–0.94 for leached and unleached soils, respectively. Meanwhile, the other soil properties, such as amorphous Fe and Al oxides and clay, were also found to be important for determining soluble Ni concentrations, indicating that they were also presented as active adsorbent surfaces. Additionally, the whole soil speciation including bulk soil properties and total soils Ni concentrations were analyzed by mechanistic speciation models WHAM VI and Visual MINTEQ3.0. It was found that WHAM VI provided the best predictions for the soils with pH < 7, was relatively reasonable for pH 7 to 8, and gave an overestimation for pH > 8. The Visual MINTEQ3.0 could provide better estimation for pH < 8 and meanwhile quite reasonable results for pH > 8. These results indicated the possibility and applicability of these models to predict soil soluble Ni concentration by soil properties. PMID:26217951

  2. Past and future seasonal variation in pH and metal concentrations in runoff from river basins on acid sulphate soils in Western Finland.

    PubMed

    Saarinen, Tuomas S; Kløve, Bjørn

    2012-01-01

    Drainage of acid sulphate soils (ASS) increases oxidation, leading to extensive leaching of acidity and metals to rivers (Al, Cd, Cr, Fe, Ni and Zn). This is often apparent during high runoff periods in spring and autumn after long dry periods with low groundwater levels and associated ASS oxidation. Regression models were used to study changes in these water quality variables according to various discharge scenarios. The knowledge of seasonal patterns of water quality variables in future is important for planning land use of the catchments in relation to WFD of European Union. The data showed that river water acidity (pH and metals) increased with discharge, with the correlation being strongest in low runoff periods in winter and summer and less clear in spring. With future climate change, river acidity can increase radically, especially during winters following extremely dry summers, and pH and metal peaks may occur even during winter.

  3. Influence of CO2 exposure on pH value, electrochemical properties, and the formation of calcium-phosphate on Ti-6Al-4V under adjusted in vitro conditions in DMEM

    NASA Astrophysics Data System (ADS)

    Höhn, Sarah; Virtanen, Sannakaisa

    2015-06-01

    Immersion tests for studying biomaterials surface reactions should be carried out at a pH value of 7.4 and an adjusted blood physiological electrolyte to simulate as far as possible in vivo conditions. The present work deals with surface reactivity of the biocompatible Ti-6Al-4V alloy in Dulbecco's Modified Eagle Medium (DMEM) and the influence of different immersion conditions on the pH value of solution and thus on the surface charge and calcium-phosphate formation on the oxide covered alloy surface. More specifically, the influence of the temperature (room temperature vs. 37 °C) and atmospheric exposure (solution open-to-air vs. solution exposed to 5% CO2 in air) was investigated. Electrochemical measurements, XPS and ATR-IR studies were carried out for interface characterization. Precipitations of calcium-phosphate (Ca-P) on Ti-6Al-4V in DMEM are formed depending on the atmospheric conditions (presence or absence of CO2). In the absence of CO2 strong coverage of the surface by a Ca-P layer takes place; in solution exposed to 5% CO2, however, only minor amounts of Ca-P are found on the surface. This drastically different behavior can be explained by different surface terminations of OH and TiO2, induced by atmosphere-dependent pH change in solution. In consequence, different surface charges on Ti-6Al-4V can be formed at the interface depending on the type of hydroxides after contact with the electrolyte. Hence, the surface charge influences the interaction with adsorption of charged species and further modifies the oxide properties. The adsorption of the charged cations (Ca2 +) and anions (PO43 -, HPO42 -, H2PO4 -) leads to the formation of additional calcium phosphate layers. The pH of the solution is also important. At higher pH the titanium surface is more negatively charged leading to an increased electrostatic interaction with Ca2 + and reduced solubility of the calcium phosphates. Additional experiments indicate that the CO2 content in the atmosphere is

  4. Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties

    PubMed Central

    Boguta, Patrycja; Sokołowska, Zofia

    2016-01-01

    The main aim of this study was the analysis of the interaction between humic acids (HAs) from different soils and Zn(II) ions at wide concentration ranges and at two different pHs, 5 and 7, by using fluorescence and FTIR spectroscopy, as well as potentiometric measurements. The presence of a few areas of HAs structures responsible for Zn(II) complexing was revealed. Complexation at α-sites (low humified structures of low-molecular weight and aromatic polycondensation) and β-sites (weakly humified structures) was stronger at pH 7 than 5. This trend was not observed for γ-sites (structures with linearly-condensed aromatic rings, unsaturated bonds and large molecular weight). The amount of metal complexed at pH5 and 7 by α and γ-structures increased with a decrease in humification and aromaticity of HAs, contrary to β-areas where complexation increased with increasing content of carboxylic groups. The stability of complexes was higher at pH 7 and was the highest for γ-structures. At pH 5, stability decreased with C/N increase for α-areas and -COOH content increase for β-sites; stability increased with humification decrease for γ-structures. The stability of complexes at α and β-areas at pH 7 decreased with a drop in HAs humification. FTIR spectra at pH 5 revealed that the most-humified HAs tended to cause bidentate bridging coordination, while in the case of the least-humified HAs, Zn caused bidentate bridging coordination at low Zn additions and bidentate chelation at the highest Zn concentrations. Low Zn doses at pH 7 caused formation of unidentate complexes while higher Zn doses caused bidentate bridging. Such processes were noticed for HAs characterized by high oxidation degree and high oxygen functional group content; where these were low, HAs displayed bidentate bridging or even bidentate chelation. To summarize, the above studies have showed significant impact of Zn concentration, pH and some properties of HAs on complexation reactions of humic

  5. Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties.

    PubMed

    Boguta, Patrycja; Sokołowska, Zofia

    2016-01-01

    The main aim of this study was the analysis of the interaction between humic acids (HAs) from different soils and Zn(II) ions at wide concentration ranges and at two different pHs, 5 and 7, by using fluorescence and FTIR spectroscopy, as well as potentiometric measurements. The presence of a few areas of HAs structures responsible for Zn(II) complexing was revealed. Complexation at α-sites (low humified structures of low-molecular weight and aromatic polycondensation) and β-sites (weakly humified structures) was stronger at pH 7 than 5. This trend was not observed for γ-sites (structures with linearly-condensed aromatic rings, unsaturated bonds and large molecular weight). The amount of metal complexed at pH5 and 7 by α and γ-structures increased with a decrease in humification and aromaticity of HAs, contrary to β-areas where complexation increased with increasing content of carboxylic groups. The stability of complexes was higher at pH 7 and was the highest for γ-structures. At pH 5, stability decreased with C/N increase for α-areas and -COOH content increase for β-sites; stability increased with humification decrease for γ-structures. The stability of complexes at α and β-areas at pH 7 decreased with a drop in HAs humification. FTIR spectra at pH 5 revealed that the most-humified HAs tended to cause bidentate bridging coordination, while in the case of the least-humified HAs, Zn caused bidentate bridging coordination at low Zn additions and bidentate chelation at the highest Zn concentrations. Low Zn doses at pH 7 caused formation of unidentate complexes while higher Zn doses caused bidentate bridging. Such processes were noticed for HAs characterized by high oxidation degree and high oxygen functional group content; where these were low, HAs displayed bidentate bridging or even bidentate chelation. To summarize, the above studies have showed significant impact of Zn concentration, pH and some properties of HAs on complexation reactions of humic

  6. Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties.

    PubMed

    Boguta, Patrycja; Sokołowska, Zofia

    2016-01-01

    The main aim of this study was the analysis of the interaction between humic acids (HAs) from different soils and Zn(II) ions at wide concentration ranges and at two different pHs, 5 and 7, by using fluorescence and FTIR spectroscopy, as well as potentiometric measurements. The presence of a few areas of HAs structures responsible for Zn(II) complexing was revealed. Complexation at α-sites (low humified structures of low-molecular weight and aromatic polycondensation) and β-sites (weakly humified structures) was stronger at pH 7 than 5. This trend was not observed for γ-sites (structures with linearly-condensed aromatic rings, unsaturated bonds and large molecular weight). The amount of metal complexed at pH5 and 7 by α and γ-structures increased with a decrease in humification and aromaticity of HAs, contrary to β-areas where complexation increased with increasing content of carboxylic groups. The stability of complexes was higher at pH 7 and was the highest for γ-structures. At pH 5, stability decreased with C/N increase for α-areas and -COOH content increase for β-sites; stability increased with humification decrease for γ-structures. The stability of complexes at α and β-areas at pH 7 decreased with a drop in HAs humification. FTIR spectra at pH 5 revealed that the most-humified HAs tended to cause bidentate bridging coordination, while in the case of the least-humified HAs, Zn caused bidentate bridging coordination at low Zn additions and bidentate chelation at the highest Zn concentrations. Low Zn doses at pH 7 caused formation of unidentate complexes while higher Zn doses caused bidentate bridging. Such processes were noticed for HAs characterized by high oxidation degree and high oxygen functional group content; where these were low, HAs displayed bidentate bridging or even bidentate chelation. To summarize, the above studies have showed significant impact of Zn concentration, pH and some properties of HAs on complexation reactions of humic

  7. Predicting where enhanced atrazine degradation will occur based on soil pH and herbicide use history

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil bacteria on all continents except Antartica have developed the ability to rapidly degrade the herbicide atrazine, a phenomenon referred to as enhanced degradation. The agronomic significance of enhanced degradation is the potential for reduced residual weed control with atrazine in Corn, Sorgh...

  8. Urea hydrolysis rates in soil toposequences as influenced by pH, carbon, nitrogen, and soluble metals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simultaneous increase in the use of urea fertilizer and the incidence of harmful algal blooms worldwide has generated research on potential loss pathways of unhydrolyzed urea from agricultural areas. The objective of this research was to study the dynamics of urea hydrolysis in soil profile topos...

  9. Evaluation of a commercial multi-sensor system for soil electrical conductivity, organic matter, and pH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efficient and accurate spatial quantification of soil properties is recognized as an important aspect of precision agriculture. With the current standard practice of in-field sample collection and subsequent laboratory analysis it is often prohibitively expensive to obtain data at the spatial densit...

  10. Effects of Temperature and pH on the Activities of Catechol 2,3-dioxygenase Obtained from Crude Oil Contaminated Soil in Ilaje, Ondo State, Nigeria

    PubMed Central

    Olukunle, O.F.; Babajide, O.; Boboye, B.

    2015-01-01

    Enrichment technique was employed for the isolation of the crude oil degrading bacteria. The isolated bacteria were screened for their degradative ability and the best degrading bacteria were selected based on their growth. Specific activities of Catechol-2,3-dioxygenase and effects of temperature and pH and their stabilities on the enzyme relative activities were observed. Bacteria isolated from the soil sample include; Bacillus cereus, B. amyloliquficiens, B. firmus, Acinetobacter calcoaceticus, Pseudomonas sp. P. fluorescens, P.putida, P.aeruginosa, Achromobacter xylosoxidans and Achromobacter sp. Screening of the degradative ability of the bacteria revealed P. aeruginosa, Bacillus cereus, Acinetobacter calcoaceticus and Achromobacter sp. to be the best degraders. The pH and temperature range with time for the enzyme activity were 6.0-8.0 and 30oC-50oC respectively. The enzyme exhibited activity that was slightly more tolerant to alkaline pH. Therefore, engineering of Catechol 2,3-dioxygenase may be employed for application on bioremediation of polluted sites. PMID:26464607

  11. Effects of Temperature and pH on the Activities of Catechol 2,3-dioxygenase Obtained from Crude Oil Contaminated Soil in Ilaje, Ondo State, Nigeria.

    PubMed

    Olukunle, O F; Babajide, O; Boboye, B

    2015-01-01

    Enrichment technique was employed for the isolation of the crude oil degrading bacteria. The isolated bacteria were screened for their degradative ability and the best degrading bacteria were selected based on their growth. Specific activities of Catechol-2,3-dioxygenase and effects of temperature and pH and their stabilities on the enzyme relative activities were observed. Bacteria isolated from the soil sample include; Bacillus cereus, B. amyloliquficiens, B. firmus, Acinetobacter calcoaceticus, Pseudomonas sp. P. fluorescens, P.putida, P.aeruginosa, Achromobacter xylosoxidans and Achromobacter sp. Screening of the degradative ability of the bacteria revealed P. aeruginosa, Bacillus cereus, Acinetobacter calcoaceticus and Achromobacter sp. to be the best degraders. The pH and temperature range with time for the enzyme activity were 6.0-8.0 and 30(o)C-50(o)C respectively. The enzyme exhibited activity that was slightly more tolerant to alkaline pH. Therefore, engineering of Catechol 2,3-dioxygenase may be employed for application on bioremediation of polluted sites. PMID:26464607

  12. Sorption, dissolution and pH determine the long-term equilibration and toxicity of coated and uncoated ZnO nanoparticles in soil.

    PubMed

    Waalewijn-Kool, Pauline L; Diez Ortiz, Maria; van Straalen, Nico M; van Gestel, Cornelis A M

    2013-07-01

    To assess the effect of long-term dissolution on bioavailability and toxicity, triethoxyoctylsilane coated and uncoated zinc oxide nanoparticles (ZnO-NP), non-nano ZnO and ZnCl2 were equilibrated in natural soil for up to twelve months. Zn concentrations in pore water increased with time for all ZnO forms but peaked at intermediate concentrations of ZnO-NP and non-nano ZnO, while for coated ZnO-NP such a clear peak only was seen after 12 months. Dose-related increases in soil pH may explain decreased soluble Zn levels due to fixation of Zn released from ZnO at higher soil concentrations. At T = 0 uncoated ZnO-NP and non-nano ZnO were equally toxic to the springtail Folsomia candida, but not as toxic as coated ZnO-NP, and ZnCl2 being most toxic. After three months equilibration toxicity to F. candida was already reduced for all Zn forms, except for coated ZnO-NP which showed reduced toxicity only after 12 months equilibration. PMID:23542444

  13. Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ application of heavy metal stabilizing agents has in some cases increased the mobility of target metal contaminants. Mechanistic understandings are necessary to better predict (1) the dynamic short- and long-term response to soil amendments, and (2) the utility of biochars in nonremoval and...

  14. Observation of pH Value in Electrokinetic Remediation using various electrolyte (MgSO4, KH2PO4 and Na(NO3)) for Barren Acidic Soil at Ayer Hitam, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Norashira, J.; Zaidi, E.; Aziman, M.; Saiful Azhar, A. T.

    2016-07-01

    Barren acidic soil collected at Ayer Hitam, Johor Malaysia was recorded at pH value of 2.36 with relative humidity of 86%. This pH value is not suitable for the growth of any plants especially for the soil stabilization purposes. Gradation weathering within the range of 4 to 6 indicates an incomplete/partial weathering process. The soil grade in this range is known as a black shale mudstone. Beside, this also influences to a factor of the high surface water runoff at this particular soil species. As the acidic pH become a major problem for soil fertilizing hence an appropriate technique was implemented known as using ‘Electrokinetic Remediation’, EKR. This technique has a great potential in changing the soil pH value from acidic to less acidic and also kept maintain the pH at the saturated rate of electrochemical process. This research study presents the monitoring data of pH value due to the effect of various electrolyte consist of 0.5M of MgSO4, KH2PO4, and Na(NO3). Here, the distilled water (DW) was used as reference solution. The electric field was provided by dipping two pieces of identical rectangular aluminum foil as anode and cathode. The EKR was conducted under a constant voltage gradient of 50 V/m across the sample bulk at 0.14 m length measured between both electrodes. The data collection was conducted during the total period of 7 days surveillance. The variation of pH values at the remediation area between anode and cathode for various type of electrolyte indicates that there are a significant saturated value as it reaches 7 days of treatment. During the analysis, it is found that the highest pH value at the remediation area after 7 days treatment using Na(NO3), KH2PO4 and MgSO4 was 3.93, 3.33 and 3.39 respectively. Hence from the last stage of pH value observation, it can be conclude that the best electrolyte for barren soil treatment is Na(NO3) whereby it contribute to highest pH value and turn the soil to be less acidic.

  15. Vertical structure and pH as factors for chitinolytic and pectinolytic microbial community of soils and terrestrial ecosystems of different climatic zones

    NASA Astrophysics Data System (ADS)

    Lukacheva, Evgeniya; Natalia, Manucharova

    2016-04-01

    Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower animals similar to that of cellulose in plants. Also it's a compound of cell walls of fungi. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues; it is the second most abundant organic compound in nature, after cellulose. Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. Roots of the plants and root crops contain pectin. Chitin and pectin are widely distributed throughout the natural world. Structural and functional features of the complex microbial degradation of biopolymers one of the most important direction in microbial ecology. But there is no a lot of data concerns degradation in vertical structure of terrestrial ecosystems and detailed studies concerning certain abiotic features as pH. Microbial complexes of natural areas were analyzed only as humus horizons (A1) of the soil profile. Only small part of microbial community could be studied with this approach. It is known that ecosystems have their own structure. It is possible to allocate some vertical tiers: phylloplane, litter (soil covering), soil. We investigated chitinolytic and pectinolytic microbial communities dedicated to different layers of the ecosystems. Also it was described depending on pH dominated in certain ecosystem with certain conditions. Quantity of eukaryote and procaryote organisms increased in the test samples with chitin and pectin. Increasing of eukaryote in samples with pectin was more then in samples with chitin. Also should be noted the significant increasing of actinomycet's quantity in the samples with chitin in comparison with samples with pectin. The variety and abundance of bacteria in the litter samples increased an order of magnitude as compared to other probes. Further prokaryote community was investigated by method FISH (fluorescence in situ hybridization). FISH is a cytogenetic

  16. [Effects of simulated acid rain on decomposition of soil organic carbon and crop straw].

    PubMed

    Zhu, Xue-Zhu; Huang, Yao; Yang, Xin-Zhong

    2009-02-01

    To evaluate the effects of acid rain on the organic carbon decomposition in different acidity soils, a 40-day incubation test was conducted with the paddy soils of pH 5.48, 6.70 and 8.18. The soils were amended with 0 and 15 g x kg(-1) of rice straw, adjusted to the moisture content of 400 g x kg(-1) air-dried soil by using simulated rain of pH 6.0, 4.5, and 3.0, and incubated at 20 degrees C. The results showed that straw, acid rain, and soil co-affected the CO2 emission from soil system. The amendment of straw increased the soil CO2 emission rate significantly. Acid rain had no significant effects on soil organic carbon decomposition, but significantly affected the straw decomposition in soil. When treated with pH 3.0 acid rain, the amount of decomposed straw over 40-day incubation in acid (pH 5.48) and alkaline (pH 8.18) soils was 8% higher, while that in neutral soil (pH 6.70) was 15% lower, compared to the treatment of pH 6.0 rain. In the treatment of pH 3.0 acid rain, the decomposition rate of soil organic C in acid (pH 5.48) soil was 43% and 50% (P < 0.05) higher than that in neutral (pH 6.70) and alkaline (pH 8.18) soils, while the decomposition rate of straw in neutral soil was 17% and 16% (P < 0.05) lower than that in acid and alkaline soils, respectively.

  17. [Effects of simulated acid rain on decomposition of soil organic carbon and crop straw].

    PubMed

    Zhu, Xue-Zhu; Huang, Yao; Yang, Xin-Zhong

    2009-02-01

    To evaluate the effects of acid rain on the organic carbon decomposition in different acidity soils, a 40-day incubation test was conducted with the paddy soils of pH 5.48, 6.70 and 8.18. The soils were amended with 0 and 15 g x kg(-1) of rice straw, adjusted to the moisture content of 400 g x kg(-1) air-dried soil by using simulated rain of pH 6.0, 4.5, and 3.0, and incubated at 20 degrees C. The results showed that straw, acid rain, and soil co-affected the CO2 emission from soil system. The amendment of straw increased the soil CO2 emission rate significantly. Acid rain had no significant effects on soil organic carbon decomposition, but significantly affected the straw decomposition in soil. When treated with pH 3.0 acid rain, the amount of decomposed straw over 40-day incubation in acid (pH 5.48) and alkaline (pH 8.18) soils was 8% higher, while that in neutral soil (pH 6.70) was 15% lower, compared to the treatment of pH 6.0 rain. In the treatment of pH 3.0 acid rain, the decomposition rate of soil organic C in acid (pH 5.48) soil was 43% and 50% (P < 0.05) higher than that in neutral (pH 6.70) and alkaline (pH 8.18) soils, while the decomposition rate of straw in neutral soil was 17% and 16% (P < 0.05) lower than that in acid and alkaline soils, respectively. PMID:19459394

  18. Stability and Mobility of CdSe/ZnS Quantum Dots in Soils: Effects of Organic Ligands, pH and Ionic Strength

    NASA Astrophysics Data System (ADS)

    Li, C.; Darnault, C. J. G.; Snee, P. T.

    2015-12-01

    Quantum dots (QDs) are the key enablers in the domain of nanoscience and have found many applications due to their physico-chemical and optical properties. For example, they are used in solar cells, lighting technologies, and biomedical imaging. Their presence in the environment following their application and life-cycle is inevitable. Therefore, it is critical to understand their behavior in the soil water system to assess the risks they may pose to natural systems and to public health. Assessing the factors that impact the stability and mobility of QDs in the soil water system is important. Natural organic ligands occur in subsurface environments and alter chemical processes in soils through complex reactions with metal ions in solution and ligand exchange reactions on soil surfaces. Consequently, the presence of ligands may alter the surface properties of QDs and impact their stability and mobility in saturated porous media. In this study, characteristics and stability of CdSe/ZnS QDs in water solutions are tested in batch experiments. The impacts of organic ligands (acetate, oxalate, and citrate) on the stability of QDs under various pH (5, 7 and 9) and ionic strength (0.05 and 0.1 M) conditions were investigated. The stability and aggregation kinetics of QDs were examined using UV-vis and DLS methods. Selected parameters from batch experiments were then used as study conditions to perform column transport experiments to generate breakthrough curves and retention profiles to assess the fate and transport of QDs in saturated porous media, which is the first phase in simulating their behavior in the subsurface.

  19. Occurrence of salt, pH, and temperature-tolerant, phosphate-solubilizing bacteria in alkaline soils

    PubMed

    Johri; Surange; Nautiyal

    1999-08-01

    An ecological survey was conducted to characterize 4800 bacterial strains isolated from the root-free soil, rhizosphere, and rhizoplane of Prosopis juliflora growing in alkaline soils. Of the 4800 bacteria, 857 strains were able to solubilize phosphate on plates. The incidence of phosphate-solubilizing bacteria (PSB) in the rhizoplane was highest, followed by rhizosphere and root-free soil. Eighteen bacterial strains out of 857 PSB were able to produce halo at 30 degrees C in a plate assay in the presence of 5% salt (NaCl) and solubilize tricalcium phosphate in National Botanical Research Institute's phosphate growth medium (NBRIP) broth, in the presence of various salts, pHs, and temperatures. Among the various bacteria tested, NBRI4 and NBRI7 did not produced halo in a plate assay at 30 degrees C in the absence of salt. Contrary to indirect measurement of phosphate solubilization by plate assay, the direct measurement of phosphate solubilization in NBRIP broth assay always resulted in reliable results. The phosphate solubilization ability of NBRI4 was higher than in the control in the presence of salts (NaCl, CaCl2, and KCl) at 30 degrees C. Phosphate solubilization further increased in the presence of salts at 37 degrees C as compared with 30 degrees C. At 37 degrees C, CaCl2 reduced phosphate solubilization ability of NBRI4 compared with the control. The results indicated the role of calcium salt in the phosphate solubilization ability of NBRI4.http://link.springer-ny. com/link/service/journals/00284/bibs/39n2p89.html PMID:10398833

  20. Effect of Cultural Practices, Soil Phosphorus, Potassium, and pH on the Incidence of Fusarium Head Blight and Deoxynivalenol Levels in Wheat

    PubMed Central

    Teich, A. H.; Hamilton, J. R.

    1985-01-01

    In a survey conducted in 1984 in Essex, Lambton, and Middlesex Counties of Ontario, Canada, greater incidences of head blight and greater concentrations of deoxynivalenol in grain were observed in fields of winter wheat planted after corn than in those planted after soybeans, barley, and mixed grains. Neither head blight nor deoxynivalenol level were correlated significantly with soil P, K, or pH. Head blight was reduced in wheat planted after corn where the residues from a preceding corn crop were plowed down or where seed was treated with Vitaflo 280. However, head blight and deoxynivalenol levels were not affected significantly by the level of N application, cultivar, other diseases or herbicides. PMID:16346808

  1. [Structural adjustment, cultural adjustment?].

    PubMed

    Dujardin, B; Dujardin, M; Hermans, I

    2003-12-01

    Over the last two decades, multiple studies have been conducted and many articles published about Structural Adjustment Programmes (SAPs). These studies mainly describe the characteristics of SAPs and analyse their economic consequences as well as their effects upon a variety of sectors: health, education, agriculture and environment. However, very few focus on the sociological and cultural effects of SAPs. Following a summary of SAP's content and characteristics, the paper briefly discusses the historical course of SAPs and the different critiques which have been made. The cultural consequences of SAPs are introduced and are described on four different levels: political, community, familial, and individual. These levels are analysed through examples from the literature and individual testimonies from people in the Southern Hemisphere. The paper concludes that SAPs, alongside economic globalisation processes, are responsible for an acute breakdown of social and cultural structures in societies in the South. It should be a priority, not only to better understand the situation and its determining factors, but also to intervene and act with strategies that support and reinvest in the social and cultural sectors, which is vital in order to allow for individuals and communities in the South to strengthen their autonomy and identify.

  2. Terrestrial soil pH and MAAT records based on the MBT/CBT in the southern South China Sea: implications for the atmospheric CO2 evolution in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Dong, L.; Li, L.; Li, Q.; Zhang, C.

    2013-12-01

    Liang Dong1, Li Li1, Qianyu Li1,2, Chuanlun L. Zhang1,3 1State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 2School of Earth and Environment Sciences, University of Adelaide, SA 5005, Australia 3Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA The methylation index of branched tetraethers (MBT) and/or the cyclization ratio of branched tetraethers (CBT) are derived from the branched glycerol dialkyl Glycerol tetraethers (GDGTs) of bacterial origin and are widely used to reconstruct the terrestrial soil pH and mean annual air temperature (MAAT); however, these proxies are less frequently used in the oceanic settings. Here we provide the first high resolution records of soil pH and MAAT since the last glacial maximum based on the sedimentary core of MD05-2896 in the southern South China Sea. The MAAT record exhibited typical glacial and interglacial cycles and was consistent with the winter insolation variation. The pH values were lower (6.4-7) in the glacial time and higher (7-8.4) in the interglacial time. Changes in soil pH allowed the evaluation of changes in soil CO2 based on the atmosphere-soil CO2 balance. The results imply that the lower winter MAAT variation with a lower winter atmospheric CO2 concentration might have resulted in a higher pH in the interglacial period. Our records provide a new insight into the evolution of atmospheric CO2 between glacial and interglacial cycles in East Asia. Key words: South China Sea, MBT/CBT, b-GDGTs, MAAT, pH

  3. Lysine and novel hydroxylysine lipids in soil bacteria: amino acid membrane lipid response to temperature and pH in Pseudopedobacter saltans

    PubMed Central

    Moore, Eli K.; Hopmans, Ellen C.; Rijpstra, W. Irene C.; Sánchez-Andrea, Irene; Villanueva, Laura; Wienk, Hans; Schoutsen, Frans; Stams, Alfons J. M.; Sinninghe Damsté, Jaap S.

    2015-01-01

    Microbial decomposition of organic matter is an essential process in the global carbon cycle. The soil bacteria Pseudopedobacter saltans and Flavobacterium johnsoniae are both able to degrade complex organic molecules, but it is not fully known how their membrane structures are adapted to their environmental niche. The membrane lipids of these species were extracted and analyzed using high performance liquid chromatography-electrospray ionization/ion trap/mass spectrometry (HPLC-ESI/IT/MS) and high resolution accurate mass/mass spectrometry (HRAM/MS). Abundant unknown intact polar lipids (IPLs) from P. saltans were isolated and further characterized using amino acid analysis and two dimensional nuclear magnetic resonance (NMR) spectroscopy. Ornithine IPLs (OLs) with variable (hydroxy) fatty acid composition were observed in both bacterial species. Lysine-containing IPLs (LLs) were also detected in both species and were characterized here for the first time using HPLC-MS. Novel LLs containing hydroxy fatty acids and novel hydroxylysine lipids with variable (hydroxy) fatty acid composition were identified in P. saltans. The confirmation of OL and LL formation in F. johnsoniae and P. saltans and the presence of OlsF putative homologs in P. saltans suggest the OlsF gene coding protein is possibly involved in OL and LL biosynthesis in both species, however, potential pathways of OL and LL hydroxylation in P. saltans are still undetermined. Triplicate cultures of P. saltans were grown at three temperature/pH combinations: 30°C/pH 7, 15°C/pH 7, and 15°C/pH 9. The fractional abundance of total amino acid containing IPLs containing hydroxylated fatty acids was significantly higher at higher temperature, and the fractional abundance of lysine-containing IPLs was significantly higher at lower temperature and higher pH. These results suggest that these amino acid-containing IPLs, including the novel hydroxylysine lipids, could be involved in temperature and pH stress

  4. Surface Crack Growth Behavior of Pipeline Steel Under Disbonded Coating at Free Corrosion Potential in Near-Neutral pH Soil Environments

    NASA Astrophysics Data System (ADS)

    Egbewande, Afolabi; Chen, Weixing; Eadie, Reg; Kania, Richard; Van Boven, Greg; Worthingham, Robert; Been, Jenny

    2014-10-01

    Crack growth behavior of X65 pipeline steel at free corrosion potential in near-neutral pH soil environment under a CO2 concentration gradient inside a disbonded coating was studied. Growth rates were found to be highest at the open mouth of the simulated disbondment where CO2 concentrations, hence local hydrogen concentration in the local environment, was highest. Careful analysis of growth rate data using a corrosion-fatigue model of the form Δ K α / K {max/ β }/ f γ , where (1/ f γ ) models environmental contribution to growth, revealed that environmental contribution could vary by up to a factor of three. Such intense environmental contribution at the open mouth kept the crack tip atomically sharp despite the simultaneous occurrence of low-temperature creep and crack tip dissolution, which are the factors that blunt the crack tip. At other locations where environmental enhancement was lower, significant crack tip blunting attributed to both low-temperature creep and crack tip dissolution was observed. These factors both led to lower crack growth rates away from the open mouth.

  5. pH tolerance in freshwater bacterioplankton: trait variation of the community as measured by leucine incorporation.

    PubMed

    Bååth, Erland; Kritzberg, Emma

    2015-11-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) instantaneously after pH adjustment. The resulting unimodal response curves, reflecting community tolerance to pH, were well modeled with a double logistic equation (mean R(2) = 0.97). The optimal pH for growth (pHopt) among the bacterial communities was closely correlated with in situ pH, with a slope (0.89 ± 0.099) close to unity. The pH interval, in which growth was ≥90% of that at pHopt, was 1.1 to 3 pH units wide (mean 2.0 pH units). Tolerance response curves of communities originating from circum-neutral pH were symmetrical, whereas in high-pH (8.9) and especially in low-pH (<5.5) waters, asymmetric tolerance curves were found. In low-pH waters, decreasing pH was more detrimental for bacterial growth than increasing pH, with a tendency for the opposite for high-pH waters. A pH tolerance index, using the ratio of growth at only two pH values (pH 4 and 8), was closely related to pHopt (R(2) = 0.83), allowing for easy determination of pH tolerance during rapid changes in pH. PMID:26276108

  6. pH tolerance in freshwater bacterioplankton: trait variation of the community as measured by leucine incorporation.

    PubMed

    Bååth, Erland; Kritzberg, Emma

    2015-11-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) instantaneously after pH adjustment. The resulting unimodal response curves, reflecting community tolerance to pH, were well modeled with a double logistic equation (mean R(2) = 0.97). The optimal pH for growth (pHopt) among the bacterial communities was closely correlated with in situ pH, with a slope (0.89 ± 0.099) close to unity. The pH interval, in which growth was ≥90% of that at pHopt, was 1.1 to 3 pH units wide (mean 2.0 pH units). Tolerance response curves of communities originating from circum-neutral pH were symmetrical, whereas in high-pH (8.9) and especially in low-pH (<5.5) waters, asymmetric tolerance curves were found. In low-pH waters, decreasing pH was more detrimental for bacterial growth than increasing pH, with a tendency for the opposite for high-pH waters. A pH tolerance index, using the ratio of growth at only two pH values (pH 4 and 8), was closely related to pHopt (R(2) = 0.83), allowing for easy determination of pH tolerance during rapid changes in pH.

  7. pH Tolerance in Freshwater Bacterioplankton: Trait Variation of the Community as Measured by Leucine Incorporation

    PubMed Central

    Kritzberg, Emma

    2015-01-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) instantaneously after pH adjustment. The resulting unimodal response curves, reflecting community tolerance to pH, were well modeled with a double logistic equation (mean R2 = 0.97). The optimal pH for growth (pHopt) among the bacterial communities was closely correlated with in situ pH, with a slope (0.89 ± 0.099) close to unity. The pH interval, in which growth was ≥90% of that at pHopt, was 1.1 to 3 pH units wide (mean 2.0 pH units). Tolerance response curves of communities originating from circum-neutral pH were symmetrical, whereas in high-pH (8.9) and especially in low-pH (<5.5) waters, asymmetric tolerance curves were found. In low-pH waters, decreasing pH was more detrimental for bacterial growth than increasing pH, with a tendency for the opposite for high-pH waters. A pH tolerance index, using the ratio of growth at only two pH values (pH 4 and 8), was closely related to pHopt (R2 = 0.83), allowing for easy determination of pH tolerance during rapid changes in pH. PMID:26276108

  8. The pH Game.

    ERIC Educational Resources Information Center

    Chemecology, 1996

    1996-01-01

    Describes a game that can be used to teach students about the acidity of liquids and substances around their school and enable them to understand what pH levels tell us about the environment. Students collect samples and measure the pH of water, soil, plants, and other natural material. (DDR)

  9. NaRALF, a peptide signal essential for the regulation of root hair tip apoplastic pH in Nicotiana attenuata, is required for root hair development and plant growth in native soils.

    PubMed

    Wu, Jinsong; Kurten, Erin L; Monshausen, Gabriele; Hummel, Grégoire M; Gilroy, Simon; Baldwin, Ian T

    2007-12-01

    Rapid alkalinization factor (RALF) is a 49-amino-acid peptide that rapidly alkalinizes cultivated tobacco cell cultures. In the native tobacco Nicotiana attenuata, NaRALF occurs as a single-copy gene and is highly expressed in roots and petioles. Silencing the NaRALF transcript by transforming N. attenuata with an inverted-repeat construct generated plants (irRALF) with normal wild-type (WT) above-ground parts, but with roots that grew longer and produced trichoblasts that developed into abnormal root hairs. Most trichoblasts produced a localized 'bulge' without commencing root hair tip growth; fewer trichoblasts grew, but were only 10% as long as those of WT plants. The root hair phenotype was associated with slowed apoplastic pH oscillations, increased pH at the tips of trichoblasts and decreased accumulation of reactive oxygen species in the root hair initiation zone. The root hair growth phenotype was partially restored when irRALF lines were grown in a low-pH-buffered medium, and reproduced in WT plants grown in a high-pH-buffered medium. When irRALF plants were grown in pH 5.6, 6.7 and 8.1 soils together with WT plants in glasshouse experiments, they were out-competed by WT plants in basic, but not acidic, soils. When WT and irRALF lines were planted into the basic soils of the native habitat of N. attenuata in the Great Basin Desert, irRALF plants had smaller leaves, shorter stalks, and produced fewer flowers and seed capsules than did WT plants. We conclude that NaRALF is required for regulating root hair extracellular pH, the transition from root hair initiation to tip growth and plant growth in basic soils.

  10. Modeling soil climate controls on the exchange of trace gases between the terrestrial biosphere and the atmosphere. Ph.D. Thesis

    SciTech Connect

    Frolking, S.E.

    1993-12-31

    Soil temperature and moisture profiles (soil climate) have a strong influence on the rate of trace gas exchange between the terrestrial biosphere and the atmosphere through the controls exerted on microbial processes and the physical exchange of gases. Principal controls of biological denitrification in mineral soils are the availability of carbon and nitrogen substrates and the soil anaerobic status. A process-oriented model of decomposition and denitrification in soils (DNDC) was modified to have a more detailed portrayal of these controls. In particular, a diffusive soil gas phase was added, along with a method for determining anaerobic and aerobic fractional volume within a soil profile. The model generally overestimated N2O fluxes when compared to field data from a sandy soil in Costa Rica, but captured the timing and shape of the brief flux episodes. Several modelling shortcomings are discussed, including the nature of the carbon substrates and the nature and dynamics of soil anaerobic fractional volume. Methane flux from wetland soils is generally correlated with soil temperature and depth to water table. A model of peat soil climate was developed and applied to a small, poor fen in southern New Hampshire. Temperature profiles and ice depth are in good agreement with field data, but depth to water table is more problematic. Field-based flux correlations to soil temperature, depth to water table, and weighted recent precipitation were developed. When used with the wetland soil climate model, much of the seasonal and shorter period flux variability was captured. The model was then driven by local weather data for 1926-1986; flux variability was dependent on both summer season temperatures and summer precipitation patterns. It is estimated that a five-year field study would capture most of the inter-annual variability.

  11. Impact of Inoculation Protocols, Salinity, and pH on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) and Survival of PAH-Degrading Bacteria Introduced into Soil

    PubMed Central

    Kästner, Matthias; Breuer-Jammali, Maren; Mahro, Bernd

    1998-01-01

    Degradation of polycyclic aromatic hydrocarbons (PAHs) and survival of bacteria in soil was investigated by applying different inoculation protocols. The soil was inoculated with Sphingomonas paucimobilis BA 2 and strain BP 9, which are able to degrade anthracene and pyrene, respectively. CFU of soil bacteria and of the introduced bacteria were monitored in native and sterilized soil at different pHs. Introduction with mineral medium inhibited PAH degradation by the autochthonous microflora and by the strains tested. After introduction with water (without increase of the pore water salinity), no inhibition of the autochthonous microflora was observed and both strains exhibited PAH degradation. PMID:9435090

  12. Effects of combinations of simulated acid rain and cadmium or zinc on microbial activity in soil.

    PubMed

    Bewley, R J; Stotzky, G

    1983-08-01

    There was little effect on the rate of CO2 evolution from glucose-supplemented soil, adjusted to pH 3.2 with a 2:1 combination of H2SO4 and fuming HNO3, and concomitant additions of 100 or 1000 ppm Cd or of 1000 or 10,000 ppm Zn (as sulfates) were no more inhibitory than in soil untreated with acid. In soil adjusted to pH 2.8, the lag in CO2 evolution was increased by 1 day, and was extended further by the concomitant addition of 10,000 but not 1000 ppm Zn or of 1000 but not 100 ppm Cd. The growth of Aspergillus niger in soil acidified to pH levels of 3.6 to 4.2 was further reduced by the addition of either 100 or 250 ppm Cd or of 1000 ppm Zn.

  13. Last-Century Increases in Intrinsic Water-Use Efficiency of Grassland Communities Have Occurred over a Wide Range of Vegetation Composition, Nutrient Inputs, and Soil pH1[OPEN

    PubMed Central

    Köhler, Iris H.; Macdonald, Andy J.; Schnyder, Hans

    2016-01-01

    Last-century climate change has led to variable increases of the intrinsic water-use efficiency (Wi; the ratio of net CO2 assimilation to stomatal conductance for water vapor) of trees and C3 grassland ecosystems, but the causes of the variability are not well understood. Here, we address putative drivers underlying variable Wi responses in a wide range of grassland communities. Wi was estimated from carbon isotope discrimination in archived herbage samples from 16 contrasting fertilizer treatments in the Park Grass Experiment, Rothamsted, England, for the 1915 to 1929 and 1995 to 2009 periods. Changes in Wi were analyzed in relation to nitrogen input, soil pH, species richness, and functional group composition. Treatments included liming as well as phosphorus and potassium additions with or without ammonium or nitrate fertilizer applications at three levels. Wi increased between 11% and 25% (P < 0.001) in the different treatments between the two periods. None of the fertilizers had a direct effect on the change of Wi (ΔWi). However, soil pH (P < 0.05), species richness (P < 0.01), and percentage grass content (P < 0.01) were significantly related to ΔWi. Grass-dominated, species-poor plots on acidic soils showed the largest ΔWi (+14.7 μmol mol−1). The ΔWi response of these acidic plots was probably related to drought effects resulting from aluminum toxicity on root growth. Our results from the Park Grass Experiment show that Wi in grassland communities consistently increased over a wide range of nutrient inputs, soil pH, and plant community compositions during the last century. PMID:26620525

  14. Last-Century Increases in Intrinsic Water-Use Efficiency of Grassland Communities Have Occurred over a Wide Range of Vegetation Composition, Nutrient Inputs, and Soil pH.

    PubMed

    Köhler, Iris H; Macdonald, Andy J; Schnyder, Hans

    2016-02-01

    Last-century climate change has led to variable increases of the intrinsic water-use efficiency (Wi; the ratio of net CO2 assimilation to stomatal conductance for water vapor) of trees and C3 grassland ecosystems, but the causes of the variability are not well understood. Here, we address putative drivers underlying variable Wi responses in a wide range of grassland communities. Wi was estimated from carbon isotope discrimination in archived herbage samples from 16 contrasting fertilizer treatments in the Park Grass Experiment, Rothamsted, England, for the 1915 to 1929 and 1995 to 2009 periods. Changes in Wi were analyzed in relation to nitrogen input, soil pH, species richness, and functional group composition. Treatments included liming as well as phosphorus and potassium additions with or without ammonium or nitrate fertilizer applications at three levels. Wi increased between 11% and 25% (P < 0.001) in the different treatments between the two periods. None of the fertilizers had a direct effect on the change of Wi (ΔWi). However, soil pH (P < 0.05), species richness (P < 0.01), and percentage grass content (P < 0.01) were significantly related to ΔWi. Grass-dominated, species-poor plots on acidic soils showed the largest ΔWi (+14.7 μmol mol(-1)). The ΔWi response of these acidic plots was probably related to drought effects resulting from aluminum toxicity on root growth. Our results from the Park Grass Experiment show that Wi in grassland communities consistently increased over a wide range of nutrient inputs, soil pH, and plant community compositions during the last century.

  15. Last-Century Increases in Intrinsic Water-Use Efficiency of Grassland Communities Have Occurred over a Wide Range of Vegetation Composition, Nutrient Inputs, and Soil pH.

    PubMed

    Köhler, Iris H; Macdonald, Andy J; Schnyder, Hans

    2016-02-01

    Last-century climate change has led to variable increases of the intrinsic water-use efficiency (Wi; the ratio of net CO2 assimilation to stomatal conductance for water vapor) of trees and C3 grassland ecosystems, but the causes of the variability are not well understood. Here, we address putative drivers underlying variable Wi responses in a wide range of grassland communities. Wi was estimated from carbon isotope discrimination in archived herbage samples from 16 contrasting fertilizer treatments in the Park Grass Experiment, Rothamsted, England, for the 1915 to 1929 and 1995 to 2009 periods. Changes in Wi were analyzed in relation to nitrogen input, soil pH, species richness, and functional group composition. Treatments included liming as well as phosphorus and potassium additions with or without ammonium or nitrate fertilizer applications at three levels. Wi increased between 11% and 25% (P < 0.001) in the different treatments between the two periods. None of the fertilizers had a direct effect on the change of Wi (ΔWi). However, soil pH (P < 0.05), species richness (P < 0.01), and percentage grass content (P < 0.01) were significantly related to ΔWi. Grass-dominated, species-poor plots on acidic soils showed the largest ΔWi (+14.7 μmol mol(-1)). The ΔWi response of these acidic plots was probably related to drought effects resulting from aluminum toxicity on root growth. Our results from the Park Grass Experiment show that Wi in grassland communities consistently increased over a wide range of nutrient inputs, soil pH, and plant community compositions during the last century. PMID:26620525

  16. Copper, nickel and zinc speciation in a biosolid-amended soil: pH adsorption edge, μ-XRF and μ-XANES investigations.

    PubMed

    Mamindy-Pajany, Yannick; Sayen, Stéphanie; Mosselmans, J Frederick W; Guillon, Emmanuel

    2014-07-01

    Metal solid phase speciation plays an important role in the control of the long-term stability of metals in biosolid-amended soils. The present work used pH-adsorption edge experiments and synchrotron-based spectroscopy techniques to understand the solid phase speciation of copper, nickel and zinc in a biosolid-amended soil. Comparison of metal adsorption edges on the biosolid-amended soil and the soil sample showed that Cu, Ni, and Zn can be retained by both soil and biosolid components such as amorphous iron phases, organic matter and clay minerals. These data are combined with microscopic results to obtain structural information about the surface complexes formed. Linear combination fitting of K-edge XANES spectra of metal hot-spots indicated consistent differences in metal speciation between metals. While organic matter plays a dominant role in Ni binding in the biosolid-amended soil, it was of lesser importance for Cu and Zn. This study suggests that even if the metals can be associated with soil components (clay minerals and organic matter), biosolid application will increase metals retention in the biosolid-amended soil by providing reactive organic matter and iron oxide fractions. Among the studied metals, the long-term mobility of Ni could be affected by organic matter degradation while Cu and Zn are strongly associated with iron oxides.

  17. Shaft adjuster

    DOEpatents

    Harry, H.H.

    1988-03-11

    Abstract and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus. 3 figs.

  18. Shaft adjuster

    DOEpatents

    Harry, Herbert H.

    1989-01-01

    Apparatus and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus.

  19. Studies on the Effects of Certain Soil Properties on the Biodegradation of Oils Determined by the Manometric Respirometric Method

    PubMed Central

    Kaakinen, Juhani; Vähäoja, Pekka; Kuokkanen, Toivo; Roppola, Katri

    2007-01-01

    The biodegradability of certain biofuels was studied in the case of forest soils using the manometric respirometric technique, which was proved to be very suitable for untreated, fertilized as well as pH adjusted soils. Experiments carried out in infertile sandy forest soil gave a BOD/ThOD value of 45.1% for a typical model substance, that is, sodium benzoate after a period of 30 days and mineral addition improved the BOD/ThOD value to a value of 76.2%. Rapeseed oil-based chain oil almost did not biodegrade at all in 30 days in nonprocessed soil, and when pH was adjusted to 8.0, the BOD/ThOD value increased slightly to a value of 7.4%. Mineral addition improved the BOD/ThOD value on average to 43.2% after 30 days. The combined mineral addition and pH adjustment together increased the BOD/ThOD value to 75.8% in 30 days. The observations were similar with a rapeseed oil-based lubricating oil: after 30 days, the BOD/ThOD value increased from 5.9% to an average value of 51.9%, when the pH and mineral concentrations of the soil were optimized. The mineral addition and pH adjustment also improved the precision of the measurements significantly. PMID:18273392

  20. In-field spatial variability in the degradation of the phenyl-urea herbicide isoproturon is the result of interactions between degradative Sphingomonas spp. and soil pH.

    PubMed

    Bending, Gary D; Lincoln, Suzanne D; Sørensen, Sebastian R; Morgan, J Alun W; Aamand, Jens; Walker, Allan

    2003-02-01

    Substantial spatial variability in the degradation rate of the phenyl-urea herbicide isoproturon (IPU) [3-(4-isopropylphenyl)-1,1-dimethylurea] has been shown to occur within agricultural fields, with implications for the longevity of the compound in the soil, and its movement to ground- and surface water. The microbial mechanisms underlying such spatial variability in degradation rate were investigated at Deep Slade field in Warwickshire, United Kingdom. Most-probable-number analysis showed that rapid degradation of IPU was associated with proliferation of IPU-degrading organisms. Slow degradation of IPU was linked to either a delay in the proliferation of IPU-degrading organisms or apparent cometabolic degradation. Using enrichment techniques, an IPU-degrading bacterial culture (designated strain F35) was isolated from fast-degrading soil, and partial 16S rRNA sequencing placed it within the Sphingomonas group. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified bacterial community 16S rRNA revealed two bands that increased in intensity in soil during growth-linked metabolism of IPU, and sequencing of the excised bands showed high sequence homology to the Sphingomonas group. However, while F35 was not closely related to either DGGE band, one of the DGGE bands showed 100% partial 16S rRNA sequence homology to an IPU-degrading Sphingomonas sp. (strain SRS2) isolated from Deep Slade field in an earlier study. Experiments with strains SRS2 and F35 in soil and liquid culture showed that the isolates had a narrow pH optimum (7 to 7.5) for metabolism of IPU. The pH requirements of IPU-degrading strains of Sphingomonas spp. could largely account for the spatial variation of IPU degradation rates across the field.

  1. In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

    PubMed Central

    Bending, Gary D.; Lincoln, Suzanne D.; Sørensen, Sebastian R.; Morgan, J. Alun W.; Aamand, Jens; Walker, Allan

    2003-01-01

    Substantial spatial variability in the degradation rate of the phenyl-urea herbicide isoproturon (IPU) [3-(4-isopropylphenyl)-1,1-dimethylurea] has been shown to occur within agricultural fields, with implications for the longevity of the compound in the soil, and its movement to ground- and surface water. The microbial mechanisms underlying such spatial variability in degradation rate were investigated at Deep Slade field in Warwickshire, United Kingdom. Most-probable-number analysis showed that rapid degradation of IPU was associated with proliferation of IPU-degrading organisms. Slow degradation of IPU was linked to either a delay in the proliferation of IPU-degrading organisms or apparent cometabolic degradation. Using enrichment techniques, an IPU-degrading bacterial culture (designated strain F35) was isolated from fast-degrading soil, and partial 16S rRNA sequencing placed it within the Sphingomonas group. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified bacterial community 16S rRNA revealed two bands that increased in intensity in soil during growth-linked metabolism of IPU, and sequencing of the excised bands showed high sequence homology to the Sphingomonas group. However, while F35 was not closely related to either DGGE band, one of the DGGE bands showed 100% partial 16S rRNA sequence homology to an IPU-degrading Sphingomonas sp. (strain SRS2) isolated from Deep Slade field in an earlier study. Experiments with strains SRS2 and F35 in soil and liquid culture showed that the isolates had a narrow pH optimum (7 to 7.5) for metabolism of IPU. The pH requirements of IPU-degrading strains of Sphingomonas spp. could largely account for the spatial variation of IPU degradation rates across the field. PMID:12571001

  2. Copper removal from contaminated soils by soil washing process using camellian-derived saponin

    NASA Astrophysics Data System (ADS)

    Reyes, Arturo; Fernanda Campos, Maria; Videla, Álvaro; Letelier, María Victoria; Fuentes, Bárbara

    2015-04-01

    Antofagasta Region in North of Chile has been the main copper producer district in the world. As a consequence of a lack of mining closure regulation, a large number of abandon small-to-medium size metal-contaminated sites have been identified in the last survey performed by the Chilean Government. Therefore, more research development on sustainable reclamation technologies must be made in this extreme arid-dry zone. The objective of this study is to test the effectiveness of soil remediation by washing contaminated soil using camellian-derived saponin for the mobilization of copper. Soil samples were taken from an abandoned copper mine site located at 30 km North Antofagasta city. They were dried and sieved at 75 µm for physico-chemical characterization. A commercial saponin extracted from camellias seed was used as biosurfactant. The soil used contains 67.4 % sand, 26.3 % silt and 6.3 % clay. The soil is highly saline (electric conductivity, 61 mScm-1), with low organic matter content (0.41%), with pH 7.30, and a high copper concentration (2200 mg Kg-1 soil). According to the sequential extraction procedure of the whole soil, copper species are mainly as exchangeable fraction (608.2 mg Kg-1 soil) and reducible fraction (787.3 mg Kg-1 soil), whereas the oxidizable and residual fractions are around 205.7 and 598.8 mg Kg-1 soil, respectively. Soil particles under 75 µm contain higher copper concentrations (1242 mg Kg-1 soil) than the particle fraction over 75 µm (912 mg Kg-1 soil). All washing assays were conducted in triplicate using a standard batch technique with and without pH adjustment. The testing protocols includes evaluation of four solid to liquid ratio (0.5:50; 1.0:50; 2.0:50, and 5.0:50) and three saponin concentrations (0, 1, and 4 mg L-1). After shaking (24 h, 20±1 °C) and subsequently filtration (0.45 µm), the supernatants were analyzed for copper and pH. The removal efficiencies of copper by saponin solutions were calculated in according to the

  3. Function of peatland located on secondary transformed peat-moorsh soils on the purification processes of groundwater and the impact of pH on the rates of the elution of organic matter

    NASA Astrophysics Data System (ADS)

    Wojciech Szajdak, Lech; Szczepański, Marek

    2010-05-01

    The investigation of peatland is used to show the water quality functioning with respect to different forms of nitrogen and carbon. The purification of ground water by the transect of 4.5 km long consisting organic soils (peat-moorsh soils) was estimated. This transect is located in the Agroecological Landscape Park in Turew, 40 km South-West of Poznan, West Polish Lowland. There is this transect along Wyskoć ditch. pH, the contents of total and dissolved organic carbon, total nitrogen, N-NO3-, N-NH4+ was measured. Additionally C/N factors of peats were estimated. The investigation has shown the impact of the peatland located on the secondary transformed peat - moorsh soils on the lowering of total nitrogen, ammonium, and nitrates as well as total and dissolved organic carbon in ground water. Peat-moorsh soils were described and classified according to Polish hydrogenic soil classification and World Reference Base Soil Notation. There are four investigated points along to Wyskoc ditch. Two times a month during entire vegetation season the following material was taken from this four chosen sites: samples of peat, from the depth of 0-20 cm, samples of water from the ditch, samples of ground water from wells established for this investigation. Samples of peat-moorsh soils were collected at the depth 0-20 cm. Soils were sampled two times a month from 10 sites of each site. Samples were air dried and crushed to pass a 1 mm-mesh sieve. These 10 sub-samples were mixed for the reason of preparing a 'mean sample', which used for the determination of pH (in 1M KCl), dissolved organic carbon (DOC), total organic carbon (TOC), total nitrogen (Ntotal), and N-NO3- as well as N-NH4+. In water from Wyskoć ditch pH, Ntotal, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) was measured. Ground water samples were collected from four wells established for this investigation. The water was filtered by the middle velocity separation and pH, N-total, N

  4. EFFECTS OF PH AND PHOSPHATE ON METAL DISTRIBUTION WITH EMPHASIS ON AS SPECIATION AND MOBILIZATION IN SOILS FROM A LEAD SMELTING SITE

    EPA Science Inventory

    Arsenic in soils from the Asarco Lead Smelter in East Helena, Montana was characterized by X-ray absorption spectroscopy (XAS). As oxidation state and geochemical speciation were analyzed as a function of depth (two sampling sites) and surface distribution. These results were c...

  5. AS SPECIATION AND EFFECTS OF PH AND PHOSPHATE ON THE MOBILIZATION OF AS IN SOILS FROM A LEAD SMELTING SITE. PUBLISHED IN ADVANCED PHOTON SOURCE ACTIVITY REPORT 2003.

    EPA Science Inventory

    Arsenic in soils from the Asarco lead smelter in East Helena, Montana was characterized by X-ray absorption spectroscopy (XAS). Arsenic oxidation state and mineralogy were analyzed as a function of depth and surface distribution using bulk and microprobe XAS. These results were c...

  6. Remediation of PAHs in a saline-alkaline soil amended with wastewater sludge and the effect on dynamics of C and N.

    PubMed

    Fernández-Luqueño, F; Marsch, R; Espinosa-Victoria, D; Thalasso, F; Hidalgo Lara, M E; Munive, A; Luna-Guido, M L; Dendooven, L

    2008-08-25

    Contamination of soil with hydrocarbons occurs frequently and organic material, such as sludge, is often applied to accelerate their dissipation. Little is known, however, how sludge characteristics affect removal of polycyclic aromatic hydrocarbons (PAHs) from alkaline-saline soil. Soil of the former lake Texcoco with pH 9 and electrolytic conductivity 7 dS m(-1) was contaminated with phenanthrene and anthracene and amended with sludge, sterilized sludge, sludge adjusted to maintain pH in contaminated soil or glucose plus an inorganic N and P source while emission of CO2 and concentrations of NH4+, NO3-, NO2-, extractable P, phenanthrene and anthracene were monitored in an aerobic incubation experiment of 112 days. An agricultural soil from Acolman treated in the same way served as control. Contaminating the Texcoco soil increased emission of CO2 significantly, but not in the Acolman soil. After 112 days, the largest concentration of anthracene and phenanthrene was found in the Acolman soil added with glucose and the lowest in the sludge-amended soil. The largest concentration of anthracene in the Texcoco soil was found in soil added with sterile sludge and the lowest in the sludge-amended soil. The largest concentration of phenanthrene in the Texcoco soil was found in the glucose-amended soil and the lowest in the sludge-amended soil. It was found that addition of sludge removed more phenanthrene, but not anthracene from soil compared to the unamended contaminated soil, glucose inhibited dissipation of PAHs while microorganisms in the sludge contributed to their removal, and adjustment of soil pH had no effect. Organic material can be used to accelerate removal of hydrocarbons from soil, but the effect is controlled by soil type, contaminant and organic material characteristics. PMID:18538824

  7. Remediation of PAHs in a saline-alkaline soil amended with wastewater sludge and the effect on dynamics of C and N.

    PubMed

    Fernández-Luqueño, F; Marsch, R; Espinosa-Victoria, D; Thalasso, F; Hidalgo Lara, M E; Munive, A; Luna-Guido, M L; Dendooven, L

    2008-08-25

    Contamination of soil with hydrocarbons occurs frequently and organic material, such as sludge, is often applied to accelerate their dissipation. Little is known, however, how sludge characteristics affect removal of polycyclic aromatic hydrocarbons (PAHs) from alkaline-saline soil. Soil of the former lake Texcoco with pH 9 and electrolytic conductivity 7 dS m(-1) was contaminated with phenanthrene and anthracene and amended with sludge, sterilized sludge, sludge adjusted to maintain pH in contaminated soil or glucose plus an inorganic N and P source while emission of CO2 and concentrations of NH4+, NO3-, NO2-, extractable P, phenanthrene and anthracene were monitored in an aerobic incubation experiment of 112 days. An agricultural soil from Acolman treated in the same way served as control. Contaminating the Texcoco soil increased emission of CO2 significantly, but not in the Acolman soil. After 112 days, the largest concentration of anthracene and phenanthrene was found in the Acolman soil added with glucose and the lowest in the sludge-amended soil. The largest concentration of anthracene in the Texcoco soil was found in soil added with sterile sludge and the lowest in the sludge-amended soil. The largest concentration of phenanthrene in the Texcoco soil was found in the glucose-amended soil and the lowest in the sludge-amended soil. It was found that addition of sludge removed more phenanthrene, but not anthracene from soil compared to the unamended contaminated soil, glucose inhibited dissipation of PAHs while microorganisms in the sludge contributed to their removal, and adjustment of soil pH had no effect. Organic material can be used to accelerate removal of hydrocarbons from soil, but the effect is controlled by soil type, contaminant and organic material characteristics.

  8. [Effect of acid rain on mercury leaching from forest yellow soil in Jinyun Mountain].

    PubMed

    Li, Jing; Wei, Shiqiang; Yang, Xuechun

    2004-09-01

    Forest yellow soil and arable yellow soil in Jinyun Mountain were collected to study the effect of simulated acid rain(adjusted to pH 2.0, 3.0, 4.0 and 5.0) on the Hg leaching from soils by the methods of static extraction and dynamic leaching. The results showed that in forest yellow soils, surface accumulation of Hg occurred, and the accumulated Hg was easier to be leached out than that in arable yellow soil by acid rain. The amount of leached Hg was the largest at pH 4.0. To abate the risk of Hg pollution in water bodies by the Hg leaching from this forest soil, the Mountain should be closed, and timber-felling should be forbidden.

  9. pH. Agricultural Lesson Plans.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

    This lesson plan is intended for use in conducting classes on the effect of pH on plant growth. Presented first are an attention step/problem statement and a series of questions and answers designed to convey general information about soil pH and its effect on plants. The following topics are among those discussed: acidity and alkalinity; the…

  10. County-scale temporal-spatial distribution and variability tendency of heavy metals in arable soils influenced by policy adjustment during the last decade: a case study of Changxing, China.

    PubMed

    Li, Peng; Zhi, Yuyou; Shi, Jiachun; Zeng, Lingzao; Wu, Laosheng

    2015-11-01

    The widespread "pertinacious illness" for environmental management soil contamination by toxic metals has inevitably led to announcement of gradual adjustment for the local government to curb the notorious pollution. An extensive survey was conducted in Changxing County, Zhejiang Province, to investigate the contents of cadmium (Cd), arsenic (As), lead (Pb), and copper (Cu) and characterize the spatial-temporal change pattern to elucidate the current state and performance of policy adjustment. Geostatistic methods were applied in the mapping and characterizing processes to assess the concentrations of heavy metals at unsampled sites. Enrichment factor analysis indicated obvious Cd and As enrichment in the west and northwest of the county. Ordinary kriging interpolation combined with semivariogram revealed that the four heavy metals possessed distinct spatial distribution patterns. However, the distribution patterns for the elevated Cd and Pb concentrations exhibited a similar geographic drift, corresponding primarily to industrial distribution. Compared with the investigation findings in 2003, the results indicated an uptrend of Cd and As and downtrend of Cu, while Pb was a mixture of increase and decrease. However, strengthened actions aimed at restraining heavy metal contamination are still needed to establish a mechanism to secure residents' health and livelihood.

  11. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

    PubMed

    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  12. The remediation of the lead-polluted garden soil by natural zeolite.

    PubMed

    Li, Hua; Shi, Wei-yu; Shao, Hong-bo; Shao, Ming-an

    2009-09-30

    The current study investigated the remediation effect of lead-polluted garden soil by natural zeolite in terms of soil properties, Pb fraction of sequential extraction in soil and distribution of Pb in different parts of rape. Natural zeolite was added to artificially polluted garden soil to immobilize and limit the uptake of lead by rape through changing soil physical and chemical properties in the pot experiment under greenhouse conditions. Results indicated that the addition of natural zeolite could increase soil pH, CEC, content of soil organic matter and promote formation of soil aggregate. The application of zeolite decreased the available fraction of Pb in the garden soil by adjusting soil pH rather than CEC, and restrained the Pb uptake by rape. Data obtained suggested that the application of a dose of zeolite was adequate (>or=10 g kg(-1)) to reduce soluble lead significantly, even if lead pollution is severe in garden soil (>or=1000 mg kg(-1)). An appropriate dose of zeolite (20 g kg(-1)) could reduce the Pb concentration in the edible part (shoots) of rape up to 30% of Pb in the seriously polluted soil (2000 mg kg(-1)).

  13. Soil acidification as a confounding factor on metal phytotoxicity in soils spiked with copper-rich mine wastes.

    PubMed

    Ginocchio, Rosanna; De la Fuente, Luz María; Sánchez, Pablo; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Rodríguez, Patricio H

    2009-10-01

    Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino)ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests. PMID:19480535

  14. Steel slag raises pH of greenhouse substrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dolomitic lime (DL) is the primary liming agent used for increasing pH in peatmoss-based substrates. Steel slag (SS) is a byproduct of the steel manufacturing industry that has been used to elevate field soil pH. The objective of this research was to determine the pH response of a peatmoss-based g...

  15. Effect of inoculum conditioning on hydrogen fermentation and pH effect on bacterial community relevant to hydrogen production.

    PubMed

    Kawagoshi, Yasunori; Hino, Naoe; Fujimoto, Aya; Nakao, Masaharu; Fujita, Yukiko; Sugimura, Seiji; Furukawa, Kenji

    2005-11-01

    The effect of conditioning for a variety of inoculums on fermentative hydrogen production was investigated. In addition, the effects of pH condition on hydrogen fermentation and bacterial community were investigated. The effect of conditioning on hydrogen production was different depending on the inoculum types. An appreciable hydrogen production was shown with anaerobic digested sludge and lake sediment without conditioning, however, no hydrogen was produced when refuse compost and kiwi grove soil were used as inoculums without conditioning. The highest hydrogen production was obtained with heat-conditioned anaerobic digested sludge, almost the same production was also obtained with unconditioned digested sludge. The pH condition considerably affected hydrogen fermentation, hydrogen gas was efficiently produced with unconditioned anaerobic sludge when the pH was controlled at 6.0 throughout the culture period and not when only the initial pH was adjusted to 6.0 and 7.0. Hydrogen production decreased when the culture pH was only adjusted at the beginning of each batch in continuous batch culture, and additionally, bacterial community varied with the change in hydrogen production. It was suggested that Clostridium and Coprothermobacter species played important role in hydrogen fermentation, and Lactobacillus species had an adverse effect on hydrogen production.

  16. Feasibility of treating aged polycyclic aromatic hydrocarbons (PAHs)-contaminated soils using ethyl lactate-based Fenton treatment via parametric and kinetic studies.

    PubMed

    Yap, Chiew Lin; Gan, Suyin; Ng, Hoon Kiat

    2015-01-01

    This study focuses on the feasibility of treating aged polycyclic aromatic hydrocarbons (PAHs)-contaminated soils using ethyl lactate (EL)-based Fenton treatment via a combination of parametric and kinetic studies. An optimised operating condition was observed at 66.7 M H2O2 with H2O2/Fe(2+) of 40:1 for low soil organic carbon (SOC) content and mildly acidic soil (pH 6.2), and 10:1 for high SOC and very acidic soil (pH 4.4) with no soil pH adjustment. The desorption kinetic was only mildly shifted from single equilibrium to dual equilibrium of the first-order kinetic model upon ageing. Pretreatment with EL fc = 0.60 greatly reduced the mass transfer coefficient especially for the slow desorbed fraction (kslow) of high molecular weight (HMW) PAHs, largely contributed by the concentration gradient created by EL-enhanced solubility. As the major desorption obstacle was almost fully overcome by the pretreatment, the pseudo-first-order kinetic reaction rate constant of PAHs degradation of aged soils was statistically discernible from that of freshly contaminated soils but slightly reduced in high SOC and high acidity soil. Stabilisation of H2O2 by EL addition in combination with reduced Fe(2+) catalyst were able to slow the decomposition rate of H2O2 even at higher soil pH. PMID:25065478

  17. Feasibility of treating aged polycyclic aromatic hydrocarbons (PAHs)-contaminated soils using ethyl lactate-based Fenton treatment via parametric and kinetic studies.

    PubMed

    Yap, Chiew Lin; Gan, Suyin; Ng, Hoon Kiat

    2015-01-01

    This study focuses on the feasibility of treating aged polycyclic aromatic hydrocarbons (PAHs)-contaminated soils using ethyl lactate (EL)-based Fenton treatment via a combination of parametric and kinetic studies. An optimised operating condition was observed at 66.7 M H2O2 with H2O2/Fe(2+) of 40:1 for low soil organic carbon (SOC) content and mildly acidic soil (pH 6.2), and 10:1 for high SOC and very acidic soil (pH 4.4) with no soil pH adjustment. The desorption kinetic was only mildly shifted from single equilibrium to dual equilibrium of the first-order kinetic model upon ageing. Pretreatment with EL fc = 0.60 greatly reduced the mass transfer coefficient especially for the slow desorbed fraction (kslow) of high molecular weight (HMW) PAHs, largely contributed by the concentration gradient created by EL-enhanced solubility. As the major desorption obstacle was almost fully overcome by the pretreatment, the pseudo-first-order kinetic reaction rate constant of PAHs degradation of aged soils was statistically discernible from that of freshly contaminated soils but slightly reduced in high SOC and high acidity soil. Stabilisation of H2O2 by EL addition in combination with reduced Fe(2+) catalyst were able to slow the decomposition rate of H2O2 even at higher soil pH.

  18. ADJUSTABLE DOUBLE PULSE GENERATOR

    DOEpatents

    Gratian, J.W.; Gratian, A.C.

    1961-08-01

    >A modulator pulse source having adjustable pulse width and adjustable pulse spacing is described. The generator consists of a cross coupled multivibrator having adjustable time constant circuitry in each leg, an adjustable differentiating circuit in the output of each leg, a mixing and rectifying circuit for combining the differentiated pulses and generating in its output a resultant sequence of negative pulses, and a final amplifying circuit for inverting and square-topping the pulses. (AEC)

  19. Soil biotransformation of thiodiglycol, the hydrolysis product of mustard gas: understanding the factors governing remediation of mustard gas contaminated soil.

    PubMed

    Li, Hong; Muir, Robert; McFarlane, Neil R; Soilleux, Richard J; Yu, Xiaohong; Thompson, Ian P; Jackman, Simon A

    2013-02-01

    Thiodiglycol (TDG) is both the precursor for chemical synthesis of mustard gas and the product of mustard gas hydrolysis. TDG can also react with intermediates of mustard gas degradation to form more toxic and/or persistent aggregates, or reverse the pathway of mustard gas degradation. The persistence of TDG have been observed in soils and in the groundwater at sites contaminated by mustard gas 60 years ago. The biotransformation of TDG has been demonstrated in three soils not previously exposed to the chemical. TDG biotransformation occurred via the oxidative pathway with an optimum rate at pH 8.25. In contrast with bacteria isolated from historically contaminated soil, which could degrade TDG individually, a consortium of three bacterial strains isolated from the soil never contaminated by mustard gas was able to grow on TDG in minimal medium and in hydrolysate derived from an historical mustard gas bomb. Exposure to TDG had little impacts on the soil microbial physiology or on community structure. Therefore, the persistency of TDG in soils historically contaminated by mustard gas might be attributed to the toxicity of mustard gas to microorganisms and the impact to soil chemistry during the hydrolysis. TDG biodegradation may form part of a remediation strategy for mustard gas contaminated sites, and may be enhanced by pH adjustment and aeration. PMID:22752796

  20. Soil biotransformation of thiodiglycol, the hydrolysis product of mustard gas: understanding the factors governing remediation of mustard gas contaminated soil.

    PubMed

    Li, Hong; Muir, Robert; McFarlane, Neil R; Soilleux, Richard J; Yu, Xiaohong; Thompson, Ian P; Jackman, Simon A

    2013-02-01

    Thiodiglycol (TDG) is both the precursor for chemical synthesis of mustard gas and the product of mustard gas hydrolysis. TDG can also react with intermediates of mustard gas degradation to form more toxic and/or persistent aggregates, or reverse the pathway of mustard gas degradation. The persistence of TDG have been observed in soils and in the groundwater at sites contaminated by mustard gas 60 years ago. The biotransformation of TDG has been demonstrated in three soils not previously exposed to the chemical. TDG biotransformation occurred via the oxidative pathway with an optimum rate at pH 8.25. In contrast with bacteria isolated from historically contaminated soil, which could degrade TDG individually, a consortium of three bacterial strains isolated from the soil never contaminated by mustard gas was able to grow on TDG in minimal medium and in hydrolysate derived from an historical mustard gas bomb. Exposure to TDG had little impacts on the soil microbial physiology or on community structure. Therefore, the persistency of TDG in soils historically contaminated by mustard gas might be attributed to the toxicity of mustard gas to microorganisms and the impact to soil chemistry during the hydrolysis. TDG biodegradation may form part of a remediation strategy for mustard gas contaminated sites, and may be enhanced by pH adjustment and aeration.

  1. Biodegradation and Bioremediation of Petroleum Pollutants in Soil

    SciTech Connect

    Huesemann, Michael H.

    2004-08-02

    During bioremediation, petroleum hydrocarbons are converted by naturally occurring or indigenous soil microorganisms to carbon dioxide, water, bacterial cells (biomass), and humic materials. Numerous factors are known to affect both the rate and the extent of hydrocarbon biodegradation in contaminated soils. These include soil properties such as moisture content, aeration, nutrient status, pH, and temperature as well as waste characteristics such as the concentration and molecular structure of hydrocarbon compounds or classes, the presence of inhibitors and cometabolic substrates, and the degree of contaminant sequestration which often leads to serious bioavailability limitations, particularly in aged soils. It is the objective of this chapter to outline a strategy for optimizing the hydrocarbon bioremediation process by adjusting the various operational parameters so that none of them become a limiting factor during treatment.

  2. pH and the surface tension of water.

    PubMed

    Beattie, James K; Djerdjev, Alex M; Gray-Weale, Angus; Kallay, Nikola; Lützenkirchen, Johannes; Preočanin, Tajana; Selmani, Atiđa

    2014-05-15

    Despite the strong adsorption of hydroxide ions, the surface tension of water is almost independent of pH between pH 1 and 13 when the pH is adjusted by addition of HCl or NaOH. This is consistent with the Gibbs adsorption isotherm which measures the surface excess of all species in the double layer, if hydronium ions and hydroxide ions are adsorbed and sodium and chloride ions are not. The surface tension becomes pH dependent around pH 7 in millimolar NaCl or KCl solutions, for now sodium ions can replace hydronium ions as counterions to the adsorbed hydroxide ions.

  3. Nitrate and Anion Behavior in Alpine Tundra Soil in the Colorado Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Evans, A.; Janke, J. R.

    2014-12-01

    Anthropogenic nitrogen deposition can potentially alter soil biogeochemistry in alpine tundra ecosystems by soil acidification, resulting in accelerated nutrient leaching as well as reduced microbial and plant diversity. Several field studies have simulated various atmospheric nitrogen loading rates and observed changes in above ground biomass, species diversity, and soil buffering capacity. Few studies to date have examined the biogeochemical behavior and transport of nitrogen in alpine tundra soil. The objective of this study is to evaluate nitrate transport in soil and the chemical behavior of associated leached ionic species. To accomplish this, a soil leaching study was conducted using both composite soil columns and intact soil cores collected in Rocky Mountain National Park, CO, USA (3,658 m). Soil columns were leached in a temperature controlled environmental chamber with DI water adjusted for pH and ionic strength. Leachates were collected using a fraction collector and analyzed using IC and ICP-MS. Analysis of collected leachates for intact soil cores indicated a complex mixture of inorganic and organic anions moving in the soil wetting front, with elevated NO3- concentration > 15 mg/L. Nitrate concentration decreased rapidly after initial column breakthrough. Leaching of individual soil horizons indicated high NO3- concentrations > 15 mg/L in collected pore volumes for both the organic and subsurface horizons. Elevated concentrations of both inorganic (SO42-, F-) and organic anions (acetate, oxalate) were found in these horizons. Fluctuation of approximately 1-1.5 pH units for the intact soil column leachates and the anion elution order suggests possible complex anion exchange processes in the soil wetting front between various soil solid phases.

  4. Efficiency of hexane extraction of napropamide from Aldrich humic acid and soil solutions

    SciTech Connect

    Williams, C.F.; Letey, J.; Farmer, W.J.; Nelson, S.D.; Anderson, M.; Ben-Hur, M.

    1999-12-01

    Dissolved organic matter (DOM) has been shown to form a stable complex with napropamide [2({alpha}-naphthoxy)-N,N-diethyl propionamide] and to facilitate its transport through soil columns. Liquid-liquid extraction of organics is a common method to transfer napropamide from water into an organic phase for gas chromatography analysis. A study was conducted to determine the effect of Aldrich humic acid, soil-derived dissolved organic matter, electrical conductivity, and hydrogen ion activity on the ability of hexane to extract napropamide from solutions and from soil extracts. The electrical conductivity from solutions and from soil extracts. The electrical conductivity of Aldrich humic acid solutions were adjusted to 0.01, 0.97, and 1.69 dS m{sup {minus}1} by adding NaCl and CaCl{sub 2}, and pH was adjusted using HCl and NaOH. Electrical conductivity had no effect on extraction efficiency. In the absence of DOM pH had no effect on extraction efficiency. In the absence of DOM pH had no effect on extraction efficiency. Extraction efficiency decreased with increasing DOM concentration. Maximum reduction in extraction efficiency occurred in the presence of DOM when solution pH was near neutrality. A maximum extraction efficiency of 100% was observed in the absence of DOM and a minimum of 68% when napropamide was added to DOM solutions at pH 8.2 and then lowered to pH 5.6. Management practices such as liming and allowing napropamide to dry on the soil may increase environmental transport. Also quantification of napropamide in environmental samples can be affected by DOM.

  5. Soil and Water: Some Teaching Suggestions.

    ERIC Educational Resources Information Center

    Fischer, Richard B.

    1987-01-01

    Outlines six soil and water investigations that students can pursue outdoors, in nature centers, or in classrooms: soil characteristics; relationship between soil ph and plant life; what aggregates tell us; differences in soil structure; differences in rate of water absorption by soil; and soil exploration with a Berlesi funnel. (NEC)

  6. Effects of acidification on metal mobility in a papermill-ash amended soil

    SciTech Connect

    Chirenje, T.; Ma, L.Q.

    1999-05-01

    Elevated soil pH due to papermill ash application has adverse effects on forest soils. Column leaching studies were conducted to determine the effects of acidification on trace metal mobility in a papermill-ash amended soil. Two types of ash, aged and fresh, were used. The aged ash-soil profile was collected from the field where the ash was mixed with the surface soil to a depth of 47 cm at rates of 896 and 1,792 mt ha{sup {minus}1} and left to stand for 1.5 yr. The fresh ash-soil profile was prepared by mixing fresh ash with the surface soil at the same rates as the aged ash-soil profiles. The pHs of the ash-soil profiles were adjusted from 9--10 to 7 and 6 using dilute HNO{sub 3}. Leachate concentrations of As, Ca, Cd, Cr, Cu, Na, Ni, Se, and dissolved organic carbon (DOC), and pH were measured at the end of 7 and 35 d. Acidification of the aged ash-soil profiles elevated concentrations of Se, As, Cd, and Ni in leachate possibly due to the dissolution of CaCO{sub 3} and release of metals adsorbed to CaCO{sub 3}. Reduced Cu concentrations were possibly due to reduced DOC concentrations at reduced pH. On the other hand, acidification greatly reduced the amount of metals leached through the fresh ash-soil profiles (except Ca and Cd), mainly due to significant reduction in the mobilization/solubilization of organic matter. The high metal mobility in the unacidified fresh ash-soil profiles could have been due to DOC-facilitated metal migration.

  7. The effect of pH on metal accumulation in two Alyssum species.

    PubMed

    Kukier, Urszula; Peters, Carinne A; Chaney, Rufus L; Angle, J Scott; Roseberg, Richard J

    2004-01-01

    Nickel phytoextraction using hyperaccumulator plants offers a potential for profit while decontaminating soils. Although soil pH is considered a key factor in metal uptake by crops, little is known about soil pH effects on metal uptake by hyperaccumulator plants. Two Ni and Co hyperaccumulators, Alyssum murale and A. corsicum, were grown in Quarry muck (Terric Haplohemist) and Welland (Typic Epiaquoll) soils contaminated by a Ni refinery in Port Colborne, Ontario, Canada, and in the serpentine Brockman soil (Typic Xerochrepts) from Oregon, USA. Soils were acidified and limed to cover pH from strongly acidic to mildly alkaline. Alyssum grown in both industrially contaminated soils exhibited increased Ni concentration in shoots as soil pH increased despite a decrease in water-soluble soil Ni, opposite to that seen with agricultural crop plants. A small decrease in Alyssum shoot Ni concentration as soil pH increased was observed in the serpentine soil. The highest fraction of total soil Ni was phytoextracted from Quarry muck (6.3%), followed by Welland (4.7%), and Brockman (0.84%). Maximum Ni phytoextraction was achieved at pH 7.3, 7.7, and 6.4 in the Quarry, Welland, and Brockman soils, respectively. Cobalt concentrations in shoots increased with soil pH increase in the Quarry muck, but decreased in the Welland soil. Plants extracted 1.71, 0.83, and 0.05% of the total soil Co from Welland, Quarry, and Brockman, respectively. The differences in uptake pattern of Ni and Co by Alyssum from different soils and pH were probably related to the differences in organic matter and iron contents of the soils. PMID:15537931

  8. Tannic acid and saponin for removing arsenic from brownfield soils: Mobilization, distribution and speciation.

    PubMed

    Gusiatin, Zygmunt Mariusz

    2014-04-01

    Plant biosurfactants were used for the first time to remove As and co-existing metals from brownfield soils. Tannic acid (TA), a polyphenol, and saponin (SAP), a glycoside were tested. The soil washing experiments were performed in batch conditions at constant biosurfactant concentration (3%). Both biosurfactants differed in natural pH, surface tension, critical micelle concentration and content of functional groups. After a single washing, TA (pH 3.44) more efficiently mobilized As than SAP (pH 5.44). When both biosurfactants were used at the same pH (SAP adjusted to 3.44), arsenic mobilization was improved by triple washing. The process efficiency for TA and SAP was similar, and depending on the soil sample, ranged between 50%-64%. Arsenic mobilization by TA and SAP resulted mainly from decomposition of Fe arsenates, followed by Fe(3+) complexation with biosurfactants. Arsenic was efficiently released from reducible and partially from residual fractions. In all soils, As(V) was almost completely removed, whereas content of As(III) was decreased by 37%-73%. SAP and TA might be used potentially to remove As from contaminated soils.

  9. [Leaching behavior of Pb, Cd and Zn from soil stabilized by lime stabilized sludge].

    PubMed

    Li, Xiang; Song, Yun; Liu, Yong-Bing

    2014-05-01

    Stabilization of Pb, Cd and Zn spiked soil by using lime-stabilized sewage sludge( LSS) as amendment was investigated in this study, and the effectiveness was evaluated by using leaching tests ( TCLP, SPLP and de-ionized water) and modified BCR sequential extraction procedure. The results of TCLP indicated that the concentrations of heavy metals in TCLP leachate reduced significantly with the increase of the mass percentage of the LSS and the leaching reduction rates were as high as 99. 54% for Zn, 99. 60% for Pb, 99. 85% for Cd at 40% of LSS addition. When evaluated by SPLP and de-ionized water leaching method, the concentrations of Zn and Pb in leachate decreased obviously at 10% and 20% of LSS additions, but subsequently increased at 30% and 40% because of redissolution of Zn and Pb at strong base condition. After pH value of LLS-stabilized soil was adjusted by ferrous sulfate and phosphoric acid for recovering soil plantation function, the pH value of the soil decreased effectively, in the meantime promoting the stabilization effectiveness of Pb and Zn. The BCR test revealed that compared with the spiked soil exchangeable proportion of Zn, Pb, Cd in the soil and the soils adjusted by ferrous sulfate obviously declined, which implied the migration for Pb, Cd and Zn of contaminated soil could be confined. This study results show that municipal LSS can be reused in the stabilization of heavy metal contaminated soils and physical and chemical properties of LLS-stabilized soil are improved for plantation.

  10. Phenanthrene and pyrene oxidation in contaminated soils using Fenton's reagent.

    PubMed

    Silva, Paula Tereza de Souza E; Silva, Valdinete Lins da; Neto, Benício de Barros; Simonnot, Marie-Odile

    2009-01-30

    Fenton's reagent has shown its applicability to oxidizing these biorefractory organic contaminants. The purpose of this contribution was to investigate the influence of operating parameters on the process efficiency for soil highly contaminated by PAHs. Five variables were selected: pH, reaction time, UV irradiation, hydrogen peroxide concentration and Fe (II) amendment. Their effects on the oxidation of (i) phenanthrene and on (ii) phenanthrene and pyrene present in freshly contaminated soil samples were studied through batch reactor experiments following factorial designs. For phenanthrene oxidation run with a soil contaminated at 700 mg kg(-1), one set of variables enabled us to reach a residual concentration lower than 40 mg kg(-1) (Dutch legislation threshold). The most important factor was the reaction time, followed at a certain distance by UV irradiation, Fe (II), H(2)O(2) concentration and pH, this last variable being the least significant. The possibility of operating without pH adjustment is of importance in the treatment at the field scale. This shows the feasibility of photo-Fenton-like oxidation for the treatment of soil highly contaminated with PAH and the relative importance of the process variables. PMID:18524479

  11. SLIT ADJUSTMENT CLAMP

    DOEpatents

    McKenzie, K.R.

    1959-07-01

    An electrode support which permits accurate alignment and adjustment of the electrode in a plurality of planes and about a plurality of axes in a calutron is described. The support will align the slits in the electrode with the slits of an ionizing chamber so as to provide for the egress of ions. The support comprises an insulator, a leveling plate carried by the insulator and having diametrically opposed attaching screws screwed to the plate and the insulator and diametrically opposed adjusting screws for bearing against the insulator, and an electrode associated with the plate for adjustment therewith.

  12. Role of Osmotic Adjustment in Plant Productivity

    SciTech Connect

    Gebre, G.M.

    2001-01-11

    Successful implementation of short rotation woody crops requires that the selected species and clones be productive, drought tolerant, and pest resistant. Since water is one of the major limiting factors in poplar (Populus sp.) growth, there is little debate for the need of drought tolerant clones, except on the wettest of sites (e.g., lower Columbia River delta). Whether drought tolerance is compatible with productivity remains a debatable issue. Among the many mechanisms of drought tolerance, dehydration postponement involves the maintenance of high leaf water potential due to, for example, an adequate root system. This trait is compatible with productivity, but requires available soil moisture. When the plant leaf water potential and soil water content decline, the plant must be able to survive drought through dehydration tolerance mechanisms, such as low osmotic potential or osmotic adjustment. Osmotic adjustment and low osmotic potential are considered compatible with growth and yield because they aid in the maintenance of leaf turgor. However, it has been shown that turgor alone does not regulate cell expansion or stomatal conductance and, therefore, the role of osmotic adjustment is debated. Despite this finding, osmotic adjustment has been correlated with grain yield in agronomic crop species, and gene markers responsible for osmotic adjustment are being investigated to improve drought tolerance in productive progenies. Although osmotic adjustment and low osmotic potentials have been investigated in several forest tree species, few studies have investigated the relationship between osmotic adjustment and growth. Most of these studies have been limited to greenhouse or container-grown plants. Osmotic adjustment and rapid growth have been specifically associated in Populus and black spruce (Picea mariuna (Mill.) B.S.P.) progenies. We tested whether these relationships held under field conditions using several poplar clones. In a study of two hybrid poplar

  13. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign. PMID:26476769

  14. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign.

  15. Effect of biochar produced at different pyrolysis temperature on the soil respiration of abandoned mine soil

    NASA Astrophysics Data System (ADS)

    Kim, Yong Seong; Kim, Juhee; Hwang, Wonjae; Hyun, Seunghun

    2015-04-01

    Contaminated soils near an abandoned mine site included the high acidic mine tailing have received great interest due to potential risk to human health, because leachable elements in low pH continuously release from mine site soil with ground water and precipitation event. Biochar, which is the obtained pyrolysis process of biomass, is used as a soil amendments and carbon storage. Especially, many researchers report that the biochar application to soil show increasing soil pH, CEC, adsorption capacity of various elements, as well as, enhanced microbial activity. Therefore, biochar application to contaminated soil near abandoned mine site is expected to have a positive effects on management of these site and soils through the decreased leachability of contaminants. However, effects of biochar application to these site on the soil respiration, as a common measure of soil health, are poorly understood. The objective of this study is to evaluate the effects of biochar application to abandoned mine site soil on the microbial activity with soil respiration test. Biochar was obtained from giant Miscanthus in a slow pyrolysis process (heating rate of 10° C min-1 and N2 gas flow rate of 1.2 L min-1) at the temperature of 400° C (BC4) and 700° C (BC7), respectively. All biochar samples were prepared with grinding and sieving for particle size control (150~500μm). Soil sample was collected from abandoned mine site at Korea (36° 58'N, 128° 10'E). Main contaminants of this soil were As (12.5 g kg-1), Pb (7.3 g kg-1), and Zn (1.1 g kg-1). Biochars were applied (5% by dry weight) to the soil (final mixture weight were 800g), and then moisture contents were adjusted to 100% field capacity (-0.33 bar) in the respirometer with vacuum pump. CO2 efflux of each samples was continuously assessed using continuous aeration system (air flow rate 25 cc min-1) using air cylinder during 130hr (at 20° C and darkness condition). The CO2 emitted from the samples were carried to the

  16. Remotely Adjustable Hydraulic Pump

    NASA Technical Reports Server (NTRS)

    Kouns, H. H.; Gardner, L. D.

    1987-01-01

    Outlet pressure adjusted to match varying loads. Electrohydraulic servo has positioned sleeve in leftmost position, adjusting outlet pressure to maximum value. Sleeve in equilibrium position, with control land covering control port. For lowest pressure setting, sleeve shifted toward right by increased pressure on sleeve shoulder from servovalve. Pump used in aircraft and robots, where hydraulic actuators repeatedly turned on and off, changing pump load frequently and over wide range.

  17. Effect of biochar and liming on soil nitrous oxide emissions from a temperate maize cropping system

    NASA Astrophysics Data System (ADS)

    Hüppi, R.; Felber, R.; Neftel, A.; Six, J.; Leifeld, J.

    2015-12-01

    Biochar, a carbon-rich, porous pyrolysis product of organic residues may positively affect plant yield and can, owing to its inherent stability, promote soil carbon sequestration when amended to agricultural soils. Another possible effect of biochar is the reduction in emissions of nitrous oxide (N2O). A number of laboratory incubations have shown significantly reduced N2O emissions from soil when mixed with biochar. Emission measurements under field conditions however are more scarce and show weaker or no reductions, or even increases in N2O emissions. One of the hypothesised mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH following the application of alkaline biochar. To test the effect of biochar on N2O emissions in a temperate maize cropping system, we set up a field trial with a 20t ha-1 biochar treatment, a limestone treatment adjusted to the same pH as the biochar treatment (pH 6.5), and a control treatment without any addition (pH 6.1). An automated static chamber system measured N2O emissions for each replicate plot (n = 3) every 3.6 h over the course of 8 months. The field was conventionally fertilised at a rate of 160 kg N ha-1 in three applications of 40, 80 and 40 kg N ha-1 as ammonium nitrate. Cumulative N2O emissions were 52 % smaller in the biochar compared to the control treatment. However, the effect of the treatments overall was not statistically significant (p = 0.27) because of the large variability in the data set. Limed soils emitted similar mean cumulative amounts of N2O as the control. There is no evidence that reduced N2O emissions with biochar relative to the control is solely caused by a higher soil pH.

  18. Weighted triangulation adjustment

    USGS Publications Warehouse

    Anderson, Walter L.

    1969-01-01

    The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.

  19. Plant Habitat (PH)

    NASA Technical Reports Server (NTRS)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  20. Genesis of Cr(VI) in Sri Lankan soils and its adsorptive removal by calcined gibbsite

    NASA Astrophysics Data System (ADS)

    Rajapaksha, A. U.; Wijesundara, D. M.; Vithanage, M. S.; Ok, Y. S.

    2012-12-01

    Hexavalent chromium is highly toxic to biota and considered as a priority pollutant. Industrial sources of Cr(VI) include leather tanning, plating, electroplating, anodizing baths, rinse waters, etc. In addition, weathering of ultramafic rocks rich in chromium, such as serpentine, is known to Cr(VI) sources into natural water. The Cr(III) is the most stable in the environment, however, conversion of Cr(III) into Cr(VI) occurs in soil due to presence of naturally occurring minerals such as manganese dioxides. We investigated the amount of Cr(VI) recorded from the soils from anthropogenically and naturally contaminated soils (serpentine soils) in Sri Lanka and the removal efficacy of Cr(VI) by calcined gibbsite (Al oxides). The effect of pH on Cr(VI) adsorption was determined by adjusting the pH in the range of 4-10. In the experiments, the adsorbent concentration was kept at 1 g/l of solution containing 10 mg/l Cr(VI) at 25 0C. Total chromium recorded were around 11,000 mg kg-1 and 6,000 mg kg-1 for serpentine soil and tannery waste-contaminated soil, respectively. Although total Cr was high in the contaminated soils, Cr(VI) concentration was only about 28 mg kg-1 and 210 mg kg-1 in the serpentine and tannery soils, respectively. The calcined gibbsite has maximum adsorption of 85 % around pH 4 and adsorption generally decreased with increase of pH.

  1. Removal of arsenic from Janghang smelter site and energy crops-grown soil with soil washing using magnetic iron oxide

    NASA Astrophysics Data System (ADS)

    Han, Jaemaro; Zhao, Xin; Lee, Jong Keun; Kim, Jae Young

    2014-05-01

    Arsenic compounds are considered carcinogen and easily enter drinking water supplies with their natural abundance. US Environmental Protection Agency is finalizing a regulation to reduce the public health risks from arsenic in drinking water by revising the current drinking water standard for arsenic from 50 ppb to 10 ppb in 2001 (USEPA, 2001). Therefore, soil remediation is also growing field to prevent contamination of groundwater as well as crop cultivation. Soil washing is adjusted as ex-situ soil remediation technique which reduces volume of the contaminated soil. The technique is composed of physical separation and chemical extraction to extract target metal contamination in the soil. Chemical extraction methods have been developed solubilizing contaminants containing reagents such as acids or chelating agents. And acid extraction is proven as the most commonly used technology to treat heavy metals in soil, sediment, and sludge (FRTR, 2007). Due to the unique physical and chemical properties, magnetic iron oxide have been used in diverse areas including information technology and biomedicine. Magnetic iron oxides also can be used as adsorbent to heavy metal enhancing removal efficiency of arsenic concentration. In this study, magnetite is used as the washing agent with acid extraction condition so that the injected oxide can be separated by magnetic field. Soil samples were collected from three separate areas in the Janghang smelter site and energy crops-grown soil to have synergy effect with phytoremediation. Each sample was air-dried and sieved (2mm). Soil washing condition was adjusted on pH in the range of 0-12 with hydrogen chloride and sodium hydroxide. After performing soil washing procedure, arsenic-extracted samples were analyzed for arsenic concentration by inductively coupled plasma optical emission spectrometer (ICP-OES). All the soils have exceeded worrisome level of soil contamination for region 1 (25mg/kg) so the soil remediation techniques are

  2. Relation between Soil Order and Sorptive Capacity for Dissolved Organic Carbon

    SciTech Connect

    Heal, Katherine R; Brandt, Craig C; Mayes, Melanie; Phillips, Jana Randolph; Jardine, Philip M

    2012-01-01

    Soils have historically been considered a temporary sink for organic C, but deeper soils may serve as longer term C sinks due to the sorption of dissolved organic C (DOC) onto Fe- and clay-rich mineral soil particles. This project provides an improved understanding and predictive capability of the physical and chemical properties of deep soils that control their sorptive capacities for DOC. Two hundred thirteen subsurface soil samples (72 series from five orders) were selected from the eastern and central United States. A characterized natural DOC source was added to the soils, and the Langmuir sorption equation was fitted to the observed data by adjusting the maximum DOC sorption capacity (Q{sub max}) and the binding coefficient (k). Different isotherm shapes were observed for Ultisols, Alfisols, and Mollisols due to statistically significant differences in the magnitude of k, while Q{sub max} was statistically invariant among these three orders. Linear regressions were performed on the entire database and as a function of soil order to correlate Langmuir fitted parameters with measured soil properties, e.g., pH, clay content, total organic C (TOC), and total Fe oxide content. Together, textural clay and Fe oxide content accounted for 35% of the variation in Q{sub max} in the database, and clay was most important for Alfisols and Ultisols. The TOC content, however, accounted for 27% of the variation in Q{sub max} in Mollisols. Soil pH accounted for 45% of the variation in k for the entire database, 41% for Mollisols, and 22% for Alfisols. Our findings demonstrate that correlations between Langmuir parameters and soil properties are different for different soil orders and that k is a more sensitive parameter for DOC sorption than is Q{sub max} for temperate soils from the central and eastern United States.

  3. pH Basics

    ERIC Educational Resources Information Center

    Lunelli, Bruno; Scagnolari, Francesco

    2009-01-01

    The exposition of the pervasive concept of pH, of its foundations and implementation as a meaningful quantitative measurement, in nonspecialist university texts is often not easy to follow because too many of its theoretical and operative underpinnings are neglected. To help the inquiring student we provide a concise introduction to the depth just…

  4. pH optrode

    DOEpatents

    Northrup, M. Allen; Langry, Kevin C.

    1993-01-01

    A process is provided for forming a long-lasting, stable, pH-sensitive dye-acrylamide copolymer useful as a pH-sensitive material for use in an optrode or other device sensitive to pH. An optrode may be made by mechanically attaching the copolymer to a sensing device such as an optical fiber.

  5. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid.

    PubMed

    Donaldson, Melissa A; Bish, David L; Raff, Jonathan D

    2014-12-30

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼ 3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day.

  6. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid

    PubMed Central

    Donaldson, Melissa A.; Bish, David L.; Raff, Jonathan D.

    2014-01-01

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day. PMID:25512517

  7. Simple, Internally Adjustable Valve

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.

    1990-01-01

    Valve containing simple in-line, adjustable, flow-control orifice made from ordinary plumbing fitting and two allen setscrews. Construction of valve requires only simple drilling, tapping, and grinding. Orifice installed in existing fitting, avoiding changes in rest of plumbing.

  8. Self Adjusting Sunglasses

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Corning Glass Works' Serengeti Driver sunglasses are unique in that their lenses self-adjust and filter light while suppressing glare. They eliminate more than 99% of the ultraviolet rays in sunlight. The frames are based on the NASA Anthropometric Source Book.

  9. Rural to Urban Adjustment

    ERIC Educational Resources Information Center

    Abramson, Jane A.

    Personal interviews with 100 former farm operators living in Saskatoon, Saskatchewan, were conducted in an attempt to understand the nature of the adjustment process caused by migration from rural to urban surroundings. Requirements for inclusion in the study were that respondents had owned or operated a farm for at least 3 years, had left their…

  10. Self adjusting inclinometer

    DOEpatents

    Hunter, Steven L.

    2002-01-01

    An inclinometer utilizing synchronous demodulation for high resolution and electronic offset adjustment provides a wide dynamic range without any moving components. A device encompassing a tiltmeter and accompanying electronic circuitry provides quasi-leveled tilt sensors that detect highly resolved tilt change without signal saturation.

  11. Acid rain and soil.

    PubMed

    vanLoon, G W

    1984-08-01

    A summary of important chemical properties of soil is given and the way in which acid rain may affect these properties is discussed. Acid rain may suppress microbiological decomposition and nitrification processes, thus influencing the nutrient status of soils. It has also been found that soil organic matter is less soluble in more acid solutions. Changed nutrient availability patterns are predicted in a low pH environment and enhanced leaching of essential elements from the soil exchange complex has been observed. Increased solubility of potentially toxic elements such as aluminium may also occur from soils which have been exposed to acidified rainfall.

  12. Efficient remediation of pentachlorophenol contaminated soil with tetrapolyphosphate washing and subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Wang, Li; Ai, Zhihui; Zhang, Lizhi

    2015-07-15

    In this study, we demonstrate that pentachlorophenol contaminated soil can be efficiently remediated with tetrapolyphosphate washing and subsequent zerovalent iron (ZVI)/Air treatment. 2 mmol L(-1) of tetrapolyphosphate could wash away 52.8% of pentachlorophenol (PCP) at pH 7.0 and 84.2% of pentachlorophenol at pH 11.0 from contaminated soil owing to the promotion effect of tetrapolyphosphate on the soil matrix dispersion and the subsequent solubilization of pentachlorophenol. More importantly, tetrapolyphosphate ions remained in the washing effluent could greatly enhance the molecular oxygen activation by ZVI to oxidize the desorbed PCP without any pH adjustment, and also avoid the competitive consumption of reactive oxygen species, as caused by the common organic surfactants in the washing effluent. Therefore, 85.1% of pentachlorophenol could be aerobically removed from the washing effluent by merely using 5 g L(-1) of ZVI. We also interestingly found that the dissolved iron ions released from the soil could enhance the oxidation of pentachlorophenol in the washing effluent, but the dissolved organic matter had the opposite effect. This study suggests the coupling tetrapolyphosphate washing and subsequent ZVI/Air treatment is an optional approach to remediate pentachlorophenol contaminated soil in view of its low cost and environmental benign.

  13. 17-4 PH and 15-5 PH

    NASA Technical Reports Server (NTRS)

    Johnson, Howard T.

    1995-01-01

    17-4 PH and 15-5 PH are extremely useful and versatile precipitation-hardening stainless steels. Armco 17-4 PH is well suited for the magnetic particle inspection requirements of Aerospace Material Specification. Armco 15-5 PH and 17-4 PH are produced in billet, plate, bar, and wire. Also, 15-5 PH is able to meet the stringent mechanical properties required in the aerospace and nuclear industries. Both products are easy to heat treat and machine, making them very useful in many applications.

  14. Precision adjustable stage

    DOEpatents

    Cutburth, Ronald W.; Silva, Leonard L.

    1988-01-01

    An improved mounting stage of the type used for the detection of laser beams is disclosed. A stage center block is mounted on each of two opposite sides by a pair of spaced ball bearing tracks which provide stability as well as simplicity. The use of the spaced ball bearing pairs in conjunction with an adjustment screw which also provides support eliminates extraneous stabilization components and permits maximization of the area of the center block laser transmission hole.

  15. Adjustable vane windmills

    SciTech Connect

    Ducker, W.L.

    1982-09-14

    A system of rotatably and pivotally mounted radially extended bent supports for radially extending windmill rotor vanes in combination with axially movable radially extended control struts connected to the vanes with semi-automatic and automatic torque and other sensing and servo units provide automatic adjustment of the windmill vanes relative to their axes of rotation to produce mechanical output at constant torque or at constant speed or electrical quantities dependent thereon.

  16. Adjustable vane windmills

    SciTech Connect

    Ducker, W.L.

    1980-01-15

    A system of rotatably and pivotally mounted radially extended bent supports for radially extending windmill rotor vanes in combination with axially movable radially extended control struts connected to the vanes with semi-automatic and automatic torque and other sensing and servo units provide automatic adjustment of the windmill vanes relative to their axes of rotation to produce mechanical output at constant torque or at constant speed or electrical quantities dependent thereon.

  17. Adjustable vane windmills

    SciTech Connect

    Ducker, W.L.

    1982-09-07

    A system of rotatably and pivotally mounted radially extended bent supports for radially extending windmill rotor vanes in combination with axially movable radially extended control struts connected to the vanes with semi-automatic and automatic torque and other sensing and servo units provide automatic adjustment of the windmill vanes relative to their axes of rotation to produce mechanical output at constant torque or at constant speed or electrical quantities dependent thereon.

  18. Adjustable Autonomy Testbed

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Schrenkenghost, Debra K.

    2001-01-01

    The Adjustable Autonomy Testbed (AAT) is a simulation-based testbed located in the Intelligent Systems Laboratory in the Automation, Robotics and Simulation Division at NASA Johnson Space Center. The purpose of the testbed is to support evaluation and validation of prototypes of adjustable autonomous agent software for control and fault management for complex systems. The AA T project has developed prototype adjustable autonomous agent software and human interfaces for cooperative fault management. This software builds on current autonomous agent technology by altering the architecture, components and interfaces for effective teamwork between autonomous systems and human experts. Autonomous agents include a planner, flexible executive, low level control and deductive model-based fault isolation. Adjustable autonomy is intended to increase the flexibility and effectiveness of fault management with an autonomous system. The test domain for this work is control of advanced life support systems for habitats for planetary exploration. The CONFIG hybrid discrete event simulation environment provides flexible and dynamically reconfigurable models of the behavior of components and fluids in the life support systems. Both discrete event and continuous (discrete time) simulation are supported, and flows and pressures are computed globally. This provides fast dynamic simulations of interacting hardware systems in closed loops that can be reconfigured during operations scenarios, producing complex cascading effects of operations and failures. Current object-oriented model libraries support modeling of fluid systems, and models have been developed of physico-chemical and biological subsystems for processing advanced life support gases. In FY01, water recovery system models will be developed.

  19. Rhizosphere pH responses to simulated acid rain as measured with glass microelectrodes

    SciTech Connect

    Conkling, B.L.

    1988-01-01

    The objectives of this study were to develop a useful experimental system for studying the rhizosphere of growing roots, and to investigate the effects of bulk soil pH and foliar acid rain application on the rhizosphere pH of alfalfa, corn and soybeans. First, a study was done to compare soil pH measurements made with a standard glass pH electrode with those made using an antimony (Sb) microelectrode. Because of uncertainty with the Sb microelectrodes' response, glass pH-sensitive microelectrodes were made and tested for rhizosphere pH measurements. The influence of soil water pressure gradients in the range of {minus}10 to {minus}1500 kPa in the proximity of the pH and reference electrodes on pH measurements made with microelectrodes was studied. The effect of foliar acid rain application on the rhizosphere pH of alfalfa, corn, and soybean as a function of soil pH were studied. Alfalfa, corn, and soybean were grown into minirhizotrons containing reformed samples of both Seymour A and Bt soil horizons, and the rhizosphere pH measured. The measured in situ bulk soil pH ranged from 4.9 to 6.2 in the A horizon and from 4.0 to 5.7 in the Bt horizon. Plants received acid or non-acid foliar rain applications. Rhizosphere pH was measured using a glass pH-sensitive microelectrode. Acid rain applications caused foliar damage, but had little effect on the rhizosphere pH. The general trend was for the lateral root pH values to be slightly higher than the main root values.

  20. Mobilization of phenol and dichlorophenol in unsaturated soils by non-uniform electrokinetics.

    PubMed

    Luo, Qishi; Zhang, Xihui; Wang, Hui; Qian, Yi

    2005-06-01

    The poor mobility of organic pollutants in contaminated sites frequently results in slow remediation processes. Organics, especially hydrophobic compounds, are generally retained strongly in soil matrix as a result of sorption, sequestration, or even formation into non-aqueous-phase liquids and their mobility is thus greatly reduced. The objective of this study was to evaluate the feasibility of using non-uniform electrokinetic transport processes to enhance the mobility of organic pollutants in unsaturated soils with no injection reagents. Phenol and 2,4-dichlorophenol (2,4-DCP), and kaolin and a natural sandy loam soil were selected as model organics and soils, respectively. The results showed that non-uniform electrokinetics can accelerate the desorption and movement of phenol and 2,4-DCP in unsaturated soils. Electromigration and electroosmotic flow were the main driving forces, and their role in the mobilization of phenol and 2,4-DCP varied with soil pH. The movement of 2,4-DCP in the sandy loam towards the anode (about 1.0 cmd(-1)V(-1)) was 1.0-1.5 cmd(-1)V(-1) slower than that in the kaolin soil, but about 0.5 cmd(-1)V(-1) greater than that of phenol in the sandy loam. When the sandy loam was adjusted to pH 9.3, the movement of phenol and 2,4-DCP towards the anode was about twice and five times faster than that at pH 7.7, respectively. The results also demonstrated that the movement of phenol and 2,4-DCP in soils can be easily controlled by regulating the operational mode of electric field. It is believed that non-uniform electrokinetics has the potential for practical application to in situ remediation of organics-contaminated sites. PMID:15857640

  1. 76 FR 26759 - Rate Adjustments for Indian Irrigation Projects

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-09

    ... Federal Register on November 1, 2010 (75 FR 67095) to propose adjustments to the irrigation assessment..., Oregon 97232-4169, Telephone: (503) 231- 6702 Project Name Project/Agency Contacts Fort Hall Dean Fox..., PH: (406) 653-1752 602 6th Avenue North Wolf Point, MT 59201 Wind River Ed Lone Fight,...

  2. Impact of a Glycolic Acid-Containing pH 4 Water-in-Oil Emulsion on Skin pH.

    PubMed

    Behm, Barbara; Kemper, Michael; Babilas, Philipp; Abels, Christoph; Schreml, Stephan

    2015-01-01

    The skin pH is crucial for physiological skin functions. A decline in stratum corneum acidity, as observed in aged or diseased skin, may negatively affect physiological skin functions. Therefore, glycolic acid-containing water-in-oil (W/O) emulsions adjusted to pH 4 were investigated regarding their effect on normal or increased skin pH. A pH 4 W/O emulsion was applied on three areas with pathologically increased skin surface pH in diabetics (n = 10). Further, a 28-day half-side trial (n = 30) was performed to test the long-term efficacy and safety of a pH 4 W/O emulsion (n = 30). In summary, the application of a pH 4 W/O emulsion reduced the skin pH in healthy, elderly and diabetic subjects, which may improve epidermal barrier functions.

  3. Urine pH test

    MedlinePlus

    A urine pH test measures the level of acid in urine. ... pH - urine ... meat products, or cheese can decrease your urine pH. ... to check for changes in your urine acid levels. It may be done to ... more effective when urine is acidic or non-acidic (alkaline).

  4. Subsea adjustable choke valves

    SciTech Connect

    Cyvas, M.K. )

    1989-08-01

    With emphasis on deepwater wells and marginal offshore fields growing, the search for reliable subsea production systems has become a high priority. A reliable subsea adjustable choke is essential to the realization of such a system, and recent advances are producing the degree of reliability required. Technological developments have been primarily in (1) trim material (including polycrystalline diamond), (2) trim configuration, (3) computer programs for trim sizing, (4) component materials, and (5) diver/remote-operated-vehicle (ROV) interfaces. These five facets are overviewed and progress to date is reported. A 15- to 20-year service life for adjustable subsea chokes is now a reality. Another factor vital to efficient use of these technological developments is to involve the choke manufacturer and ROV/diver personnel in initial system conceptualization. In this manner, maximum benefit can be derived from the latest technology. Major areas of development still required and under way are listed, and the paper closes with a tabulation of successful subsea choke installations in recent years.

  5. Influence of the zinc hyperaccumulator Thlaspi caerulescens J. & C. Presl. and the nonmetal accumulator Trifolium pratense L. on soil microbial populations.

    PubMed

    Delorme, T A; Gagliardi, J V; Angle, J S; Chaney, R L

    2001-08-01

    Metal hyperaccumulator plants like Thlaspi caerulescens J. & C. Presl. are used for phytoremediation of contaminated soils. Since little is known about the rhizosphere of hyperaccumulators, the influence of T. caerulescens was compared with the effects of Trifolium pratense L. on soil microbes. High- and low-metal soils were collected near a zinc smelter in Palmerton, Penn. Soil pH was adjusted to 5.8 and 6.8 by the addition of Ca(OH)2. Liming increased bacterial populations and decreased metal toxicity to levels allowing growth of both plants. The effects of the plants on total (culturable) bacteria, total fungi, as well as cadmium- and zinc-resistant populations were assessed in nonrhizosphere and rhizosphere soil. Both plants increased microbial populations in rhizosphere soil compared with nonrhizosphere soil. Microbial populations were higher in soils planted with T. pratense, but higher ratios of metal-resistant bacteria were found in the presence of T. caerulescens. We hypothesize that T. caerutescens acidifies its rhizosphere. Soil acidification in the rhizosphere of T. caerulescens would affect metal uptake by increasing available metals around the roots and consequently, increase the selection for metal-resistant bacteria. Soil acidification may be part of the hyperaccumulation process enhancing metal uptake from soil.

  6. Investigating the effect of different minerals on biogeochemical interface formation in soil using artificial soil incubations

    NASA Astrophysics Data System (ADS)

    Pronk, G.; Heister, K.; Kögel-Knabner, I.

    2009-04-01

    The formation of soil interfaces is controlled by the type of particle surface(s) present and the assemblage of organic matter and mineral particles. We consider clay minerals, iron oxides and charcoal as major components controlling the formation of interfaces relevant for sorption of organic chemicals because they exhibit high surface area and microporosity. In order to study the formation of biogeochemical interfaces, batch incubation experiments were started with artificial soils consisting of model compounds (quartz, clay minerals, iron oxide and charcoal), stall manure as a carbon source and inoculated with soil bacteria derived from a Eutric Cambisol. The model materials were characterised and used to compose artificial soils with 8 different compositions. Samples were taken at the start of the incubation and pH, C and N content and specific surface area are measured. At regular time intervals, the water content is adjusted and carbon dioxide production is measured. Samples for determination of specific surface area and microporosity, surface morphology and elemental distribution, speciation of iron, characterisation of the organic material, sorption experiments with organic chemicals and microbial community analysis will be retrieved after 3, 6, 12 and 18 months. The duration of the incubation experiments is planned to be at least 18 months.

  7. Adolescent Mothers' Adjustment to Parenting.

    ERIC Educational Resources Information Center

    Samuels, Valerie Jarvis; And Others

    1994-01-01

    Examined adolescent mothers' adjustment to parenting, self-esteem, social support, and perceptions of baby. Subjects (n=52) responded to questionnaires at two time periods approximately six months apart. Mothers with higher self-esteem at Time 1 had better adjustment at Time 2. Adjustment was predicted by Time 2 variables; contact with baby's…

  8. Responses of microbial populations in the rhizosphere to deposition of simulated acidic rain onto foliage and/or soil.

    PubMed

    Shafer, S R

    1992-01-01

    Air pollutants or some chemicals applied to plant foliage can alter the ecology of the rhizosphere. Experiments were conducted to distinguish among possible foliage-mediated versus soil- or root-mediated effects of acid deposition on microorganism in the rhizosphere. Seedlings of a sorghum x sudangrass hybrid in pots of non-sterile soil-sand mix in a greenhouse were exposed to simulated rain solution adjusted with H2SO4 + HNO3 to pH 4.9, 4.2, 3.5 or 2.8. Solutions were applied as simulated rain to foliage and soil, foliage only (soil covered by plastic, and deionized water applied directly to the soil), or soil only (solution applied directly to the soil). Solutions were applied on 16 days during a 6-week period (1.5 cm deposition in 1 h per application). Plant shoot and root dry weights and population densities of selected types of bacteria, filamentous actinomycetes and fungi in the rhizosphere were quantified after exposures were completed. Deposition of simulated acidic rain onto foliage alone had no effect on plant biomass or microbial population densities in the rhizosphere (colony-forming units per gram of rhizosphere soil). However, plant growth was stimulated and all microbial populations in the rhizosphere increased 3- to 8-fold with increased solution acidity (relative to pH 4.9 solution) when solution penetrated the soil. Statistical analyses indicated that the acid dose-population response relationships for soil-only and foliage-and-soil applications were not different. Thus, no foliage-mediated effect of simulated acidic rain on rhizosphere ecology was detected.

  9. Effect of pH on biological phosphorus uptake.

    PubMed

    Serralta, J; Ferrer, J; Borrás, L; Seco, A

    2006-12-01

    An anaerobic aerobic laboratory scale sequencing batch reactor (SBR) was operated to study the effect of pH on enhanced biological phosphorus removal. Seven steady states were achieved under different operating conditions. In all of them, a slight variation in the pH value was observed during anaerobic phase. However, pH rose significantly during aerobic phase. The increase observed was due to phosphorus uptake and carbon dioxide stripping. When pH was higher than 8.2-8.25 the phosphorus uptake rate clearly decreased. The capability of Activated Sludge Model No. 2d (ASM2d) and Biological Nutrient Removal Model No. 1 (BNRM1) to simulate experimental results was evaluated. Both models successfully characterized the enhanced biological phosphorus removal performance of the SBR. Furthermore, BNRM1 also reproduced the pH variations observed and the decrease in the phosphorus uptake rate. This model includes a switch function in the kinetic expressions to represent the pH inhibition in biological processes. The pH inhibition constants related to polyphosphate storage process were obtained by adjusting model predictions to measured phosphorus concentrations. On the other hand, pH inhibition should be included in ASM2d to accurately simulate experimental phosphorus evolution observed in an A/O SBR.

  10. Selected Fe and Mn (nano)oxides as perspective amendments for the stabilization of As in contaminated soils.

    PubMed

    Michálková, Zuzana; Komárek, Michael; Veselská, Veronika; Číhalová, Sylva

    2016-06-01

    An amorphous Mn oxide (AMO), nanomaghemite, and nanomagnetite were used as potential amendments reducing the mobility of As in three contrasting contaminated soils differing in origin of As contamination. Adsorption experiments and XPS analyses combined with incubation batch experiments and pH-static leaching tests were used. The AMO showed excellent adsorption capacity for As(V) reaching a maximum of 1.79 mmol g(-1) at pH 7 and 8. Interestingly, the adsorption capacity in this case decreases with decreasing pH, probably as a result of AMO dissolution at lower pH values. Chemical sorption of As(V) onto AMO was further confirmed with XPS. Both Fe nano-oxides proved the highest adsorption capacity at pH 4 reaching 11 mg g(-1) of adsorbed As(V). The AMO was also the most efficient amendment for decreasing As concentrations in soil solutions during 8 weeks of incubation. Additionally, pH-static leaching tests were performed at pH 4, 5, 6, 7, and natural pH (not adjusted) and AMO again proved the highest ability to decrease As content in leachate. On the other hand, strong dissolution of this amendment at lower pH values (especially pH 4) was observed. For that reason, AMO appears as a promising stabilizing agent for As, especially in neutral, alkaline, or slightly acidic soils, where As(V) species are expected to be more mobile. PMID:26895725

  11. DISSOLVED ORGANIC MATTER AND METALS: EFFECTS OF PH ON PARTITIONING

    EPA Science Inventory

    Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb, and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was fractionated into three operationally defined fractions: hydrophilic acids (Hyd), fulvic acids (FA), an...

  12. Metal ion leaching from contaminated soils: Model calibration and application

    SciTech Connect

    Ganguly, C.; Rabideau, A.J.; Matsumoto, M.R.; Van Benschoten, J.E.

    1998-12-01

    A previously developed model that describes leaching of heavy metals from contaminated soils is applied to four hazardous-waste-site soils contaminated with Pb. Processes included in the model are intraparticle diffusion, rate expressions for irreversibly and reversibly sorbed fractions, and metal complexation by ions in solution. The model is calibrated using laboratory experimental data in the pH 1--3 range, liquid-to-solid mass ratios from 5 to 20, and leaching times of 24 h. Parameters for the model are estimated through a combination of independent experiments, literature correlations, and mathematical optimization. Equilibrium data were used to estimate site density and an adsorption equilibrium constant. Two kinetic rate coefficients, a particle tortuosity factor, and a distribution coefficient ({alpha}{sub a}) that defined the amount of Pb in two contaminant fractions were adjusted to match kinetic leaching data. Using one set of parameter estimates for each soil, the model successfully simulated experimental data collected under different leaching conditions. The fraction of Pb associated with easily leachable, irreversibly sorbed fraction (1 {minus} {alpha}{sub a}) provides some insight to the geochemical distribution of Pb in the soils tested. The model is used to explore effects of process variables such as liquid-to-solid ratio and sequential washes. The model should be useful for simulating ex-situ soil washing processes and may, with further development, have applications for in-situ flushing processes.

  13. Interactions of Soil Order and Land Use Management on Soil Properties in the Kukart Watershed, Kyrgyzstan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surveys of soil properties related to soil functioning for many regions of Kyrgyzstan are limited. This study established ranges of selected chemical [soil organic matter (SOM), pH and total N (TN)], physical (soil texture), and biochemical (six enzyme activities of C, N, P and S cycling) character...

  14. [Optimization of electrode configuration in soil electrokinetic remediation].

    PubMed

    Liu, Fang; Fu, Rong-Bing; Xu, Zhen

    2015-02-01

    Electric field distributions of several different electrode configurations in non-uniform electric field were simulated using MATLAB software, and the electrokinetic remediation device was constructed according to the best electrode configuration. The changes of soil pH and heavy metal residues in different parts of the device during the electrokinetic remediation were also studied. The results showed that, in terms of the effectiveness of the electric field strength, the square (1-D-1) and hexagonal (2-D-3) were the optimal electrode configurations for one-dimensional and two-dimensional respectively and the changes of soil pH, the removal of heavy metals and the distribution of electric field were closely related to one another. An acidic migration band, which could prevent premature precipitation of heavy metals to a certain extent and promote electrokinetic removal of heavy metals, was formed gradually along with the remediation in the whole hexagon device when the cathodic pH was controlled during the remediation of the four cationic metallic ions, Cd2+, Ni2+, Pb2+ and Cu2+. After 480-hour remediation, the total removals of Cd, Ni, Pb and Cu were 86.6%, 86.2%, 67.7% and 73.0%, respectively. Remediation duration and replacement frequency of the electrodes could be adjusted according to the repair target. PMID:26031098

  15. Surfactant adsorption to soil components and soils.

    PubMed

    Ishiguro, Munehide; Koopal, Luuk K

    2016-05-01

    Soils are complex and widely varying mixtures of organic matter and inorganic materials; adsorption of surfactants to soils is therefore related to the soil composition. We first discuss the properties of surfactants, including the critical micelle concentration (CMC) and surfactant adsorption on water/air interfaces, the latter gives an impression of surfactant adsorption to a hydrophobic surface and illustrates the importance of the CMC for the adsorption process. Then attention is paid to the most important types of soil particles: humic and fulvic acids, silica, metal oxides and layered aluminosilicates. Information is provided on their structure, surface properties and primary (proton) charge characteristics, which are all important for surfactant binding. Subsequently, the adsorption of different types of surfactants on these individual soil components is discussed in detail, based on mainly experimental results and considering the specific (chemical) and electrostatic interactions, with hydrophobic attraction as an important component of the specific interactions. Adsorption models that can describe the features semi-quantitatively are briefly discussed. In the last part of the paper some trends of surfactant adsorption on soils are briefly discussed together with some complications that may occur and finally the consequences of surfactant adsorption for soil colloidal stability and permeability are considered. When we seek to understand the fate of surfactants in soil and aqueous environments, the hydrophobicity and charge density of the soil or soil particles, must be considered together with the structure, hydrophobicity and charge of the surfactants, because these factors affect the adsorption. The pH and ionic strength are important parameters with respect to the charge density of the particles. As surfactant adsorption influences soil structure and permeability, insight in surfactant adsorption to soil particles is useful for good soil management. PMID

  16. Delay Adjusted Incidence Infographic

    Cancer.gov

    This Infographic shows the National Cancer Institute SEER Incidence Trends. The graphs show the Average Annual Percent Change (AAPC) 2002-2011. For Men, Thyroid: 5.3*,Liver & IBD: 3.6*, Melanoma: 2.3*, Kidney: 2.0*, Myeloma: 1.9*, Pancreas: 1.2*, Leukemia: 0.9*, Oral Cavity: 0.5, Non-Hodgkin Lymphoma: 0.3*, Esophagus: -0.1, Brain & ONS: -0.2*, Bladder: -0.6*, All Sites: -1.1*, Stomach: -1.7*, Larynx: -1.9*, Prostate: -2.1*, Lung & Bronchus: -2.4*, and Colon & Rectum: -3/0*. For Women, Thyroid: 5.8*, Liver & IBD: 2.9*, Myeloma: 1.8*, Kidney: 1.6*, Melanoma: 1.5, Corpus & Uterus: 1.3*, Pancreas: 1.1*, Leukemia: 0.6*, Brain & ONS: 0, Non-Hodgkin Lymphoma: -0.1, All Sites: -0.1, Breast: -0.3, Stomach: -0.7*, Oral Cavity: -0.7*, Bladder: -0.9*, Ovary: -0.9*, Lung & Bronchus: -1.0*, Cervix: -2.4*, and Colon & Rectum: -2.7*. * AAPC is significantly different from zero (p<.05). Rates were adjusted for reporting delay in the registry. www.cancer.gov Source: Special section of the Annual Report to the Nation on the Status of Cancer, 1975-2011.

  17. Excessive use of nitrogen in Chinese agriculture results in high N(2) O/(N(2) O+N(2) ) product ratio of denitrification, primarily due to acidification of the soils.

    PubMed

    Qu, Zhi; Wang, Jingguo; Almøy, Trygve; Bakken, Lars R

    2014-05-01

    China is the world's largest producer and consumer of fertilizer N, and decades of overuse has caused nitrate leaching and possibly soil acidification. We hypothesized that this would enhance the soils' propensity to emit N(2) O from denitrification by reducing the expression of the enzyme N(2) O reductase. We investigated this by standardized oxic/anoxic incubations of soils from five long-term fertilization experiments in different regions of China. After adjusting the nitrate concentration to 2 mM, we measured oxic respiration (R), potential denitrification (D), substrate-induced denitrification, and the denitrification product stoichiometry (NO, N(2) O, N(2) ). Soils with a history of high fertilizer N levels had high N(2) O/(N(2) O+N(2)) ratios, but only in those field experiments where soil pH had been lowered by N fertilization. By comparing all soils, we found a strong negative correlation between pH and the N(2) O/(N(2) O+N(2)) product ratio (r(2) = 0.759, P < 0.001). In contrast, the potential denitrification (D) was found to be a linear function of oxic respiration (R), and the ratio D/R was largely unaffected by soil pH. The immediate effect of liming acidified soils was lowered N(2) O/(N(2) O+N(2)) ratios. The results provide evidence that soil pH has a marginal direct effect on potential denitrification, but that it is the master variable controlling the percentage of denitrified N emitted as N(2) O. It has been known for long that low pH may result in high N(2) O/(N(2) O+N(2)) product ratios of denitrification, but our documentation of a pervasive pH-control of this ratio across soil types and management practices is new. The results are in good agreement with new understanding of how pH may interfere with the expression of N2 O reductase. We argue that the management of soil pH should be high on the agenda for mitigating N(2) O emissions in the future, particularly for countries where ongoing intensification of plant production is likely to acidify

  18. Excessive use of nitrogen in Chinese agriculture results in high N2O/(N2O+N2) product ratio of denitrification, primarily due to acidification of the soils

    PubMed Central

    Qu, Zhi; Wang, Jingguo; Almøy, Trygve; Bakken, Lars R

    2014-01-01

    China is the world's largest producer and consumer of fertilizer N, and decades of overuse has caused nitrate leaching and possibly soil acidification. We hypothesized that this would enhance the soils' propensity to emit N2O from denitrification by reducing the expression of the enzyme N2O reductase. We investigated this by standardized oxic/anoxic incubations of soils from five long-term fertilization experiments in different regions of China. After adjusting the nitrate concentration to 2 mM, we measured oxic respiration (R), potential denitrification (D), substrate-induced denitrification, and the denitrification product stoichiometry (NO, N2O, N2). Soils with a history of high fertilizer N levels had high N2O/(N2O+N2) ratios, but only in those field experiments where soil pH had been lowered by N fertilization. By comparing all soils, we found a strong negative correlation between pH and the N2O/(N2O+N2) product ratio (r2 = 0.759, P < 0.001). In contrast, the potential denitrification (D) was found to be a linear function of oxic respiration (R), and the ratio D/R was largely unaffected by soil pH. The immediate effect of liming acidified soils was lowered N2O/(N2O+N2) ratios. The results provide evidence that soil pH has a marginal direct effect on potential denitrification, but that it is the master variable controlling the percentage of denitrified N emitted as N2O. It has been known for long that low pH may result in high N2O/(N2O+N2) product ratios of denitrification, but our documentation of a pervasive pH-control of this ratio across soil types and management practices is new. The results are in good agreement with new understanding of how pH may interfere with the expression of N2O reductase. We argue that the management of soil pH should be high on the agenda for mitigating N2O emissions in the future, particularly for countries where ongoing intensification of plant production is likely to acidify the soils. PMID:24249526

  19. Influence of Soil Solution Salinity on Molybdenum Adsorption by Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molybdenum (Mo) adsorption on five arid-zone soils from California was investigated as a function of equilibrium solution Mo concentration (0-30 mg L-1), solution pH (4-8), and electrical conductivity (EC = 0.3 or 8 dS m-1). Molybdenum adsorption decreased with increasing pH. An adsorption maximum...

  20. Effect of different soil washing solutions on bioavailability of residual arsenic in soils and soil properties.

    PubMed

    Im, Jinwoo; Yang, Kyung; Jho, Eun Hea; Nam, Kyoungphile

    2015-11-01

    The effect of soil washing used for arsenic (As)-contaminated soil remediation on soil properties and bioavailability of residual As in soil is receiving increasing attention due to increasing interest in conserving soil qualities after remediation. This study investigates the effect of different washing solutions on bioavailability of residual As in soils and soil properties after soil washing. Regardless of washing solutions, the sequential extraction revealed that the residual As concentrations and the amount of readily labile As in soils were reduced after soil washing. However, the bioassay tests showed that the washed soils exhibited ecotoxicological effects - lower seed germination, shoot growth, and enzyme activities - and this could largely be attributed to the acidic pH and/or excessive nutrient contents of the washed soils depending on washing solutions. Overall, this study showed that treated soils having lower levels of contaminants could still exhibit toxic effects due to changes in soil properties, which highly depended on washing solutions. This study also emphasizes that data on the As concentrations, the soil properties, and the ecotoxicological effects are necessary to properly manage the washed soils for reuses. The results of this study can, thus, be utilized to select proper post-treatment techniques for the washed soils. PMID:26086811

  1. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  2. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium, and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  3. Modeling organic transformations by microorganisms of soils in six contrasting ecosystems: Validation of the MOMOS model

    NASA Astrophysics Data System (ADS)

    Pansu, M.; Sarmiento, L.; Rujano, M. A.; Ablan, M.; Acevedo, D.; Bottner, P.

    2010-03-01

    The Modeling Organic Transformations by Microorganisms of Soils (MOMOS) model simulates the growth, respiration, and mortality of soil microorganisms as main drivers of the mineralization and humification processes of organic substrates. Originally built and calibrated using data from two high-altitude sites, the model is now validated with data from a 14C experiment carried out in six contrasting tropical ecosystems covering a large gradient of temperature, rainfall, vegetation, and soil types from 65 to 3968 m asl. MOMOS enabled prediction of a greater number of variables using a lower number of parameter values than for predictions previously published on this experiment. The measured 14C mineralization and transfer into microbial biomass (MB) and humified compartments were accurately modeled using (1) temperature and moisture response functions to daily adjust the model responses to weather conditions and (2) optimization of only one parameter, the respiration rate kresp of soil microorganisms at optimal temperature and moisture. This validates the parameterization and hypotheses of the previous calibration experiment. Climate and microbial respiratory activity, related to soil properties, appear as the main factors that regulate the C cycle. The kresp rate was found to be negatively related to the fine textural fraction of soil and positively related to soil pH, allowing the proposition of two transfer functions that can be helpful to generalize MOMOS application at regional or global scale.

  4. Improved granular activated carbon for the stabilization of wastewater PH

    SciTech Connect

    Farmer, R.W.; Dussert, B.W.; Kovacic, S.L.

    1996-12-31

    Laboratory studies have identified the cause of the pH rise, which occurs during water treatment with activated carbon, as an interaction between the naturally occurring anions and protons in the water and the carbon surface. The interaction can be described as an ion exchange type of phenomenon, in which the carbon surface sorbs the anions and corresponding hydronium ions from the water. These studies have shown that the anion sorption and resulting pH increase is independent of the raw material used for the activated carbon production, e.g. bituminous or subbituminous coal, peat, wood or coconut. Also, the pH excursions occur with virgin, reactivated, and acid washed granular carbons. Current pH control technologies focus on adjustment of the wastewater pH prior to discharge or recycle of the initial effluent water until the pH increase abates. However, improved water pH control options have been realized by altering the carbon surface through controlled oxidation rather than the water chemistry or extended preprocessing at the treatment site.

  5. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - II

    EPA Science Inventory

    The bioabailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  6. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - I

    EPA Science Inventory

    The bioavailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  7. Transfer of cadmium from a sandy acidic soil to man: A population study

    SciTech Connect

    Staessen, J.A.; Celis, H.G.; Fagard, R.H.; Lijnen, P.J.; Thijs, L.B.; Amery, A.K. ); Vyncke, G. ); Lauwerys, R.R.; Roels, H.A. ); Claeys, F. ); Dondeyne, F. ); Ide, G. ); Rondia, D.; Sartor, F. )

    1992-06-01

    This population study included 230 subjects (age range 20-83 years) who consumed vegetables grown in kitchen gardens on a sandy acidic soil (mean pH {approximately}6.3). The study investigated the association between the Cd (cadmium) levels in blood and urine and the Cd concentration in the soil (range 0.2-44 ppm). Seventy-six subjects were current smokers and 122 participants lived in a district with known Cd pollution. Urinary Cd in the 230 subjects averaged 8.7 nmole/24 hr, (range 1.3 to 47 nmole/24 hr) after age adjustment positively correlated with the Cd level in the soil; a twofold increase of the Cd concentration in the soil was accompanied by a 7% rise in urinary Cd in men and by a 4% rise in women. Blood Cd averaged 11.5 nmole/liter (range 1.8-41 nmole/liter) and was negatively associated with the Cd level in the soil. After adjustment for significant covariates (smoking and serum {gamma}-glutamyl transpeptidase in both sexes, and age and serum ferritin in women), a twofold increase in the Cd concentration in the soil was accompanied by a 6% decrease in blood Cd in men and by a 10% decrease in women. In conclusion, in a rural population, consuming vegetables grown on a sandy acidic soil, 2 to 4% of the variance of urinary Cd was directly related to the Cd level in the soil. The negative correlation with blood Cd, a measure of more recent exposure, was biased by the implementation of preventive measures in the polluted district.

  8. Effect of pH on Paramagnetic Centers in Cladosporium cladosporioides Melanin

    NASA Astrophysics Data System (ADS)

    Pilawa, B.; Buszman, E.; Gondzik, A.; Wilczyński, S.; Zdybel, M.; Witoszyńska, T.; Wilczok, T.

    2006-07-01

    Paramagnetic centers in melanin existing in pigmented soil fungi Cladosporium cladosporioides cultured at acidic (4, 5, 6), neutral (7), and alkaline (8) pH were studied by EPR method. o-semiquinone free radicals (g: 2.0032-2.0040) concentration in melanin biopolymer increased for pH from 4 to 6, decreased at pH 7, and reached the maximum value at pH 8. It may be expected that melanin free radicals reactions with small molecules (metal ions, drugs) are the most effective at pH between 6 and 8. Slow spin-lattice relaxation processes exist in the all studied melanin samples.

  9. Enhancing electrokinetic remediation of cadmium- contaminated soils with stepwise moving anode method.

    PubMed

    Chen, Xue J; Shen, Zhe M; Yuan, Tao; Zheng, Shen S; Ju, Bing X; Wang, Wen H

    2006-01-01

    This paper proposed an innovative approach by stepwise moving anode towards cathode to enhance the cadmium (Cd) removal from soil during the process of electrokinetic (EK) remediation. Fixed anode tests and moving anode tests were carried out for 60 hours to compare their performances. The anode-cathode spacing was 21 cm. Constant voltage grade of 1.0 V cm(-1) was applied in this study. The parameters included pH, electrical conductivity, current, Cd concentration and speciation distributions, energy consumptions, etc. It was found that the pH values in the moving anode tests were relatively lower than those of the fixed tests. In the moving anode test, the removal efficiency of Cd in the soils at the fraction of S4 was enhanced by 54.9% compared with that of the fixed anode tests. After 60 hours of treatment, approximately 80% of the spiked soils (100.63 mg x kg(-1) of Cd) in the system were successfully remedied in the moving anode tests; and the mean removal efficiency was 73% for actual field-contaminated soil (54.26 mg x kg(-1) of Cd). It is effective to remedy actual contaminated soils. In addition, the cumulative energy consumptions were 59.29 kWhm(-3) and 31.52 kWhm(-3) for the fixed and moving tests, respectively. The results revealed that the Cd removal efficiency was improved by the moving anode method. Moreover, less energy was consumed in the moving test. The proposed approach does not need to introduce extra chemicals nor adjust the pH in the system to enhance the Cd removal by EK remediation. The basic idea proposed in this paper provides a novel and environmental friendly method to enhance the EK remediation of heavy metals contaminated soils. PMID:17000543

  10. Mood Adjustment via Mass Communication.

    ERIC Educational Resources Information Center

    Knobloch, Silvia

    2003-01-01

    Proposes and experimentally tests mood adjustment approach, complementing mood management theory. Discusses how results regarding self-exposure across time show that patterns of popular music listening among a group of undergraduate students differ with initial mood and anticipation, lending support to mood adjustment hypotheses. Describes how…

  11. Spousal Adjustment to Myocardial Infarction.

    ERIC Educational Resources Information Center

    Ziglar, Elisa J.

    This paper reviews the literature on the stresses and coping strategies of spouses of patients with myocardial infarction (MI). It attempts to identify specific problem areas of adjustment for the spouse and to explore the effects of spousal adjustment on patient recovery. Chapter one provides an overview of the importance in examining the…

  12. Parental Divorce and Children's Adjustment.

    PubMed

    Lansford, Jennifer E

    2009-03-01

    This article reviews the research literature on links between parental divorce and children's short-term and long-term adjustment. First, I consider evidence regarding how divorce relates to children's externalizing behaviors, internalizing problems, academic achievement, and social relationships. Second, I examine timing of the divorce, demographic characteristics, children's adjustment prior to the divorce, and stigmatization as moderators of the links between divorce and children's adjustment. Third, I examine income, interparental conflict, parenting, and parents well-being as mediators of relations between divorce and children's adjustment. Fourth, I note the caveats and limitations of the research literature. Finally, I consider notable policies related to grounds for divorce, child support, and child custody in light of how they might affect children s adjustment to their parents divorce.

  13. Modeling soil response to acidic deposition in nonsulfate adsorbing soils

    SciTech Connect

    Bloom, P.R.; Grigal, D.F.

    1985-01-01

    A simple semiempirical model for the prediction of changes in soil pH and base saturation with acidic deposition was developed. In steady-state ecosystems acidic deposition results in losses of basic cations from exchange sites. In the model, depletion of exchangeable bases is calculated from the difference between input acidity and output of H/sup +/ and Al/sup 3 +/ in water percolating through the solum. A correction for the decrease in bicarbonate weathering is made but sulfate adsorption is not considered. Estimates including the effect of increased mineral weathering with decreased pH can be made if the natural weathering rate is known and if the order with respect to H/sup +/ is known for the rate expression for soil weathering. The model predicted laboratory data for the acidification of samples for three soil horizons. For a fourth horizon, that was formed in contact with bedrock and high in weatherable minerals, the model overestimated the effect of the acid. Model predictions using soil data showed a slow decrease in soil pH and base saturation until the pH region of Al buffering was attained and then a new steady-state was achieved. The pH and base saturation in the Al buffering region was similar to that found in very acid soils under forest vegetation.

  14. Reclamation of a mine contaminated soil using biologically reactive organic matrices.

    PubMed

    Alvarenga, Paula; Gonçalves, Ana Paula; Fernandes, Rosa Maria; de Varennes, Amarillas; Duarte, Elizabeth; Cunha-Queda, Ana Cristina; Vallini, Giovanni

    2009-03-01

    Organic residues such as sewage sludge, biowastes and composts are increasingly used in land rehabilitation because they can improve the physical, chemical and biochemical properties of soil, and reduce the need for inorganic fertilization. Furthermore, their use contributes to an integrated approach to waste management by promoting recycling of nutrients and minimizing final disposal, especially of organic residues that, due to their composition, can pose problems to agricultural soils. In the present study, three different types of organic residues were considered as amendments to be used in the reclamation of a metal-contaminated mine soil from the Aljustrel mining area (a pyrite mine located in the SW Portugal in the Iberian Pyrite Belt), with high Cu, Pb and Zn total contents: sewage sludge from a municipal wastewater treatment plant (SS), compost from the organic fraction of unsorted municipal solid waste (MSWC), and garden waste compost (GWC), applied at 100 and 200 Mg ha(-1) . The soil and mixtures of soil and amendments were adjusted to 70% of the maximum water-holding capacity determined for each type of sample and incubated in a controlled-temperature room at 20 +/- 1 degrees C. Sub-samples were taken prior to wetting (time zero), and after 7, 14, 21 and 28 days of incubation, and analysed for pH, electrical conductivity, organic matter content, effectively bioavailable Cu, Zn and Pb (extracted with 0.01 mol L(- 1) calcium chloride) and potentially bioavailable metals (extracted with 0.5 mol L(-1) ammonium acetate, 0.5 mol L( -1) acetic acid and 0.01 mol L(- 1) EDTA, pH 4.7). In general, organic residues corrected soil acidity, and increased the total organic matter content of the soil. The SS and the MSWC amendments were roughly equivalent in their ability to correct soil acidity whereas the GWC had the smallest liming capacity and only with 200 Mg ha(-1) GWC did the soil pH reach acceptable values. As expected, all the tested organic residues, at both

  15. Adjustment versus no adjustment when using adjustable sutures in strabismus surgery

    PubMed Central

    Liebermann, Laura; Hatt, Sarah R.; Leske, David A.; Holmes, Jonathan M.

    2013-01-01

    Purpose To compare long-term postoperative outcomes when performing an adjustment to achieve a desired immediate postoperative alignment versus simply tying off at the desired immediate postoperative alignment when using adjustable sutures for strabismus surgery. Methods We retrospectively identified 89 consecutive patients who underwent a reoperation for horizontal strabismus using adjustable sutures and also had a 6-week and 1-year outcome examination. In each case, the intent of the surgeon was to tie off and only to adjust if the patient was not within the intended immediate postoperative range. Postoperative success was predefined based on angle of misalignment and diplopia at distance and near. Results Of the 89 patients, 53 (60%) were adjusted and 36 (40%) were tied off. Success rates were similar between patients who were simply tied off immediately after surgery and those who were adjusted. At 6 weeks, the success rate was 64% for the nonadjusted group versus 81% for the adjusted group (P = 0.09; difference of 17%; 95% CI, −2% to 36%). At 1 year, the success rate was 67% for the nonadjusted group versus 77% for the adjusted group (P = 0.3; difference of 11%; 95% CI, −8% to 30%). Conclusions Performing an adjustment to obtain a desired immediate postoperative alignment did not yield inferior long-term outcomes to those obtained by tying off to obtain that initial alignment. If patients were who were outside the desired immediate postoperative range had not been not adjusted, it is possible that their long-term outcomes would have been worse, therefore, overall, an adjustable approach may be superior to a nonadjustable approach. PMID:23415035

  16. Designer, acidic biochar influences calcareous soil characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 degrees celsius) and steam activation to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0, 1, 2, and 10 percent (by weight) to an eroded Portneuf soil (coarse-silty,...

  17. Exploring Soil Ecosystems.

    ERIC Educational Resources Information Center

    Finley, Deborah R.

    1991-01-01

    Describes a soil lab that can be performed with a minimum of equipment and time, utilizing a lawn, field, or woodlot. Students dig a 1-meter-deep pit and observe the litter and humus layers where most microbial and fungal decomposition occurs. Describes comparing different locations by pH level and concentration of potassium, phosphorous, and…

  18. Influence of pH on mobilization and formation of iron-dominated colloids in podzol

    NASA Astrophysics Data System (ADS)

    Neubauer, E.; Schenkeveld, W. D. C.; Kammer, F. v. D.; Kraemer, S. M.; Hofmann, T.

    2012-04-01

    Increasing evidence is found that naturally occurring nanoparticles (<20 nm), such as natural organic matter (NOM) and Fe-dominated colloids may play a key role in transport and retention of trace metals. These two colloid types have different affinities for trace elements. Extraction of colloids from soils indicates that both colloid types can contain iron, and that the extraction protocol itself may influence colloidal Fe-speciation. These interdependencies are therefore of particular interest for correctly understanding the fate of trace metals in the environment. In order to assess the influence of pH on mobilization and/or formation of iron-dominated colloids, we extracted the A-, E- and B-horizon of a podzol at 3 different pH levels (pH 4, pH 7 and pH 9, respectively). Flow Field-Flow Fractionation, coupled to ICP-MS, was used as a high-resolution size separation technique which allows the detection and quantification of colloids and associated metals. Iron-dominated colloids were only found in extracts from the E- and B-horizon with pH 7 and pH 9; in the other extracts all Fe was associated to NOM. The samples in which iron-dominated colloids were found exhibited a higher iron to DOC ratio than the samples without such colloids from the same soil horizon. The concentration and composition of the extracted NOM was pH dependent; at pH 4 it was dominated by fulvic acids and small organic ligands. The latter has a relatively low affinity for complexing iron, potentially contributing to the lower iron to DOC ratio. Iron-dominated colloids were present in pH 9-extracts that had equilibrated only one hour with soil from the B horizon; the resulting suspension was stable over several days. Upon lowering the pH to 4, dissolution kinetics of the iron dominated phase was slow. On the contrary, upon increasing the pH of the pH 4-extract of the same soil to pH 9, iron-dominated colloids readily formed. The results show that the extent to which iron is mobilized from soil

  19. Esophageal pH monitoring

    MedlinePlus

    pH monitoring - esophageal; Esophageal acidity test ... esophagitis You may need to have the following tests if your doctor suspects esophagitis : Barium swallow Esophagogastroduodenoscopy (also called upper GI endoscopy)

  20. Thermodynamic and kinetic study of the single extraction of mercury from soil using sodium-thiosulfate.

    PubMed

    Issaro, N; Besancon, S; Bermond, A

    2010-10-15

    The use of sodium-thiosulfate (Na-thiosulfate) as a reagent for the extraction of mercury (Hg) from soil was investigated. High organic matter content in soil plays a major role in retaining metals. It has previously been reported that using the cold vapour atomic absorption method, powerful reagents such as EDTA, DTPA and cysteine could not release Hg from soil samples. The optimal conditions for using Na-thiosulfate to extract soil-Hg are presented here. Our results show that 50±5% of total Hg was extracted from soil samples using 0.01molL(-1) of the reagent without pH adjustment. Increasing the reagent concentration above this level showed no significant change in Hg extraction. From this extraction three fractions of Hg were obtained, the labile, slowly labile and un-extractable. We further applied the use of a kinetic extraction approach that has never been applied for Hg. We observed a correlation between the first two fractions and the quantity of organic matter content in soils. The labile fraction could be released by using any concentration of the reagent. However, the slowly labile fraction was dependent on time and increased concentrations of Na-thiosulfate. Furthermore, our results suggest that the labile and slowly labile fractions involve two different sites of reduced sulphur groups contained in soil organic matter and Hg levels present in the soil samples did not appear high enough to saturate all these high affinity sulphur sites. The capacity of Na-thiosulfate to reduce (Hg(II)) to (Hg(0)), was determined to be negligible. Our results further suggest the implication of iron (Fe(II)) for reducing Hg(II) to Hg(0). Here we have demonstrated that Na-thiosulfate is an effective reagent in the extraction of Hg from soil, with the particular characteristic of its ability to remove strongly bound Hg from sulphur groups contained in soil organic matter.

  1. pH dependent salinity-boron interactions impact yield, biomass, evapotranspiration and boron uptake in broccoli (Brassica oleracea L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil pH is known to influence many important biochemical processes in plants and soils, however its role in salinity - boron interactions affecting plant growth and ion relations has not been examined. The purpose of this research was to evaluate the interactive effects of salinity, boron and soil ...

  2. PhEDEx Data Service

    NASA Astrophysics Data System (ADS)

    Egeland, Ricky; Wildish, Tony; Huang, Chih-Hao

    2010-04-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the "SiteDB" service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  3. Carbon Mineralizability Determines Interactive Effects on Mineralization of Pyrogenic Organic Matter and Soil Organic Carbon

    SciTech Connect

    Whitman, Thea L.; Zhu, Zihua; Lehmann, Johannes C.

    2014-10-31

    Soil organic carbon (SOC) is a critical and active pool in the global C cycle, and the addition of pyrogenic organic matter (PyOM) has been shown to change SOC cycling, increasing or decreasing mineralization rates (often referred to as priming). We adjusted the amount of easily mineralizable C in the soil, through 1-day and 6-month pre-incubations, and in PyOM made from maple wood at 350°C, through extraction. We investigated the impact of these adjustments on C mineralization interactions, excluding pH and nutrient effects and minimizing physical effects. We found short-term increases (+20-30%) in SOC mineralization with PyOM additions in the soil pre-incubated for 6 months. Over the longer term, both the 6-month and 1-day pre-incubated soils experienced net ~10% decreases in SOC mineralization with PyOM additions. This was possibly due to stabilization of SOC on PyOM surfaces, suggested by nanoscale secondary ion mass spectrometry. Additionally, the duration of pre-incubation affected priming interactions, indicating that there may be no optimal pre-incubation time for SOC mineralization studies. We show conclusively that relative mineralizability of SOC in relation to PyOM-24 C is an important determinant of the effect of PyOM additions on SOC mineralization.

  4. Carbon mineralizability determines interactive effects on mineralization of pyrogenic organic matter and soil organic carbon.

    PubMed

    Whitman, Thea; Zhu, Zihua; Lehmann, Johannes

    2014-12-01

    Soil organic carbon (SOC) is a critical and active pool in the global C cycle, and the addition of pyrogenic organic matter (PyOM) has been shown to change SOC cycling, increasing or decreasing mineralization rates (often referred to as priming). We adjusted the amount of easily mineralizable C in the soil, through 1-day and 6-month preincubations, and in PyOM made from maple wood at 350 °C, through extraction. We investigated the impact of these adjustments on C mineralization interactions, excluding pH and nutrient effects and minimizing physical effects. We found short-term increases (+20-30%) in SOC mineralization with PyOM additions in the soil preincubated for 6 months. Over the longer term, both the 6-month and 1-day preincubated soils experienced net ∼10% decreases in SOC mineralization with PyOM additions. Additionally, the duration of preincubation affected interactions, indicating that there may be no optimal preincubation time for SOC mineralization studies. We show conclusively that mineralizability of SOC in relation to PyOM-C is an important determinant of the effect of PyOM additions on SOC mineralization. PMID:25361379

  5. SOIL Geo-Wiki: A tool for improving soil information

    NASA Astrophysics Data System (ADS)

    Skalský, Rastislav; Balkovic, Juraj; Fritz, Steffen; See, Linda; van der Velde, Marijn; Obersteiner, Michael

    2014-05-01

    soil classification system) and allow experts to upload and share scientifically rigorous soil data; and an application oriented towards the general public, which will be more focused on describing well observed, individual soil properties using simplified classification keys. The latter application will avoid the use of soil science related terminology and focus on the most useful soil parameters such as soil surface features, stone content, soil texture, soil plasticity, calcium carbonate presence, soil color, soil pH, soil repellency, and soil depth. Collection of soil and landscape pictures will also be supported in Soil Geo-Wiki to allow for comprehensive data collection while simultaneously allowing for quality checking by experts.

  6. Insights into tetrabromobisphenol A adsorption onto soils: Effects of soil components and environmental factors.

    PubMed

    Tong, Fei; Gu, Xueyuan; Gu, Cheng; Ji, Rong; Tan, Yinyue; Xie, Jinyu

    2015-12-01

    Concerns regarding tetrabromobisphenol A (TBBPA), the most widely utilized brominated flame retardant in the world, are growing because of the wide application and endocrine-disrupting potential of this compound. To properly assess its environmental impacts, it is important to understand the mobility and fate of TBBPA in soil environments. In this study, the effects of soil components, dissolved organic carbon (DOC) and heavy metal cations on TBBPA adsorption onto two Chinese soils (red soil and black soil) were investigated using batch sorption experiments. The desorption behavior of TBBPA when the two soils are irrigated with eutrophicated river water was also investigated. The results showed that pH greatly affects the adsorptive behavior of TBBPA in soils. Iron oxide minerals and phyllosilicate minerals are both active surfaces for TBBPA sorption, in addition to soil organic matter (SOM). DOC (50 mg OC L(-1)) exhibited a limited effect on TBBPA sorption only under neutral conditions. TBBPA sorption was only minimally affected by the heavy metals (Cu2+, Pb2+ and Cd2+) in the studied pH range. Eutrophicated river water significantly enhanced the desorption of TBBPA from red soil due to the change in soil solution pH. These findings indicate that mobility of TBBPA in soils is mainly associated with soil pH, organic matter and clay fractions: it will be retained by soils or sediments with high organic matter and clay fractions under acidic conditions but becomes mobile under alkaline conditions. PMID:26247687

  7. Insights into tetrabromobisphenol A adsorption onto soils: Effects of soil components and environmental factors.

    PubMed

    Tong, Fei; Gu, Xueyuan; Gu, Cheng; Ji, Rong; Tan, Yinyue; Xie, Jinyu

    2015-12-01

    Concerns regarding tetrabromobisphenol A (TBBPA), the most widely utilized brominated flame retardant in the world, are growing because of the wide application and endocrine-disrupting potential of this compound. To properly assess its environmental impacts, it is important to understand the mobility and fate of TBBPA in soil environments. In this study, the effects of soil components, dissolved organic carbon (DOC) and heavy metal cations on TBBPA adsorption onto two Chinese soils (red soil and black soil) were investigated using batch sorption experiments. The desorption behavior of TBBPA when the two soils are irrigated with eutrophicated river water was also investigated. The results showed that pH greatly affects the adsorptive behavior of TBBPA in soils. Iron oxide minerals and phyllosilicate minerals are both active surfaces for TBBPA sorption, in addition to soil organic matter (SOM). DOC (50 mg OC L(-1)) exhibited a limited effect on TBBPA sorption only under neutral conditions. TBBPA sorption was only minimally affected by the heavy metals (Cu2+, Pb2+ and Cd2+) in the studied pH range. Eutrophicated river water significantly enhanced the desorption of TBBPA from red soil due to the change in soil solution pH. These findings indicate that mobility of TBBPA in soils is mainly associated with soil pH, organic matter and clay fractions: it will be retained by soils or sediments with high organic matter and clay fractions under acidic conditions but becomes mobile under alkaline conditions.

  8. Manganese-oxide-coated redox bars as an indicator of reducing conditions in soils.

    PubMed

    Dorau, Kristof; Mansfeldt, Tim

    2015-03-01

    Identification of reducing conditions in soils is of concern not only for pedogenesis but also for nutrient and pollutant dynamics. We manufactured manganese (Mn)-oxide-coated polyvinyl chloride bars and proved their suitability for the identification of reducing soil conditions. Birnessite was synthesized and coated onto white polyvinyl chloride bars. The dark brown coatings were homogenous and durable. As revealed by microcosm devices with adjusted redox potentials (E), under oxidizing conditions (E ∼450 mV at pH 7) there was no Mn-oxide removal. Reductive dissolution of Mn-oxides, which is expressed by the removal of the coatings, started under weakly reducing conditions (E ∼175 mV) and was more intensive under moderately reducing conditions (∼80 mV). According to thermodynamics, the removal of Mn-oxide coatings (225 mm d) exceeded the removal of iron (Fe)-oxide coatings (118 mm d) in soil column experiments. This was confirmed in a soil with a shallow and strongly fluctuating water table where both types of redox bars were inserted. Consequently, it was possible to identify reducing conditions in soils using Mn-oxide-coated bars. We recommend this methodology for short-term monitoring because tri- and tetravalent Mn is the preferred electron acceptor compared with trivalent Fe, and this additionally offers the possibility of distinguishing between weakly and moderately reducing conditions. If dissolved Fe is abundant in soils, the possibility of nonenzymatic reduction of Mn has to be taken into account.

  9. Environmental behaviors of phoxim with two formulations in bamboo forest under soil surface mulching.

    PubMed

    Liu, Yihua; Ni, Zhanglin; Mo, Runhong; Shen, Danyu; Zhong, Donglian; Tang, Fubin

    2015-09-01

    Phoxim (emulsifiable concentrate (EC) and granules (G)) has been widely used in bamboo forests. The persistence and magnitude of phoxim residues in the crop and soil must be investigated to ensure human and environmental safety. The environmental behaviors of the two formulations were investigated in a bamboo forest under soil surface mulching conditions (CP) and non-covered cultivation conditions (NCP). The half-lives of phoxim in soil under the two conditions in soil were 4.1-6.2days (EC) and 31.5-49.5days (G), respectively. Phoxim in EC could be leached from the topsoil into the subsoil. A minimized leaching effect was observed for G under NCP. Inversely, an enhanced leaching effect was observed for G under CP. The G formulation resulted in more parent compound (in bamboo shoots) and metabolite (in soil) residues of phoxim than in the case of EC, especially under CP conditions. In addition, the intensity and duration of the formulation effect on soil pH adjustment from G were more obvious than that from EC. Results showed that the environmental behaviors (distribution, degradation, residue) of phoxim in the bamboo forest were significantly influenced by the type of formulation. The prolongation effect from phoxim G might cause persistence and long-term environmental risk. However, bamboo shoot consumption could be considered relatively safe after applying the recommended dose of the two phoxim formulations.

  10. Biodegradation of di(2-ethylhexyl)phthalate in a typical tropical soil.

    PubMed

    Carrara, Silvia Marta Castelo de Moura; Morita, Dione Mari; Boscov, Maria Eugenia Gimenez

    2011-12-15

    The aim of this research was to evaluate the possibility of biodegradation of di(2-ethylhexyl)phthalate (DEHP), widely used as an industrial plasticizer and considered an endocrine-disrupting chemical included in the U.S. Environmental Protection Agency priority list, in a Brazilian tropical soil, which has not been previously reported in the literature, despite the geographic importance of tropical soils. Preliminary laboratory testing comprised respirometric, air and water permeability, and pilot scale infiltration tests. Standard respirometric tests were found inadequate for studying biodegradation in tropical contaminated soils, due to the effect of the addition of significant amounts of calcium carbonate, necessary to adjust soil pH. Pilot scale infiltration tests performed for 5 months indicated that DEHP was retained in the superficial layer of the soil, barely migrating downwards, whereas air and water permeability tests discarded in situ bioremediation. However, ex situ bioremediation was possible, using a slurry-phase reactor with acclimated microorganisms, in pilot scale tests conducted to remediate a total mass of 150 kg of contaminated soil with 100 mg DEHP/kg. The removal of DEHP in the slurry-phase reactor achieved the percentage of 99% in 49 days, with biodegradation following a first-order kinetic model with a biodegradation coefficient of 0.127 day(-1).

  11. Effect of pH control strategies and substrate concentration on the hydrogen yield from fermentative hydrogen production in large laboratory-scale.

    PubMed

    Mariakakis, I; Krampe, J; Steinmetz, H

    2012-01-01

    A series of batch experiments investigating two different pH control strategies, initial pH adjustment and continuous pH control, have been carried out in large laboratory-scale reactors with working volumes of 30 L. In both cases, pH was varied between 5 and 7.5. Sucrose concentrations were also varied starting from 0 up to 30 g/L. Higher hydrogen production yields can be achieved by batch experiments through continuous pH control than by simple initial pH adjustment. In the case of continuous pH control, maximization of hydrogen yield was acquired for slightly acidic pH of 6.5. Continuous pH control in the neutral pH range of 7.0 and in pH lower than 6.5, induced a reduction in the hydrogen production yield. Sucrose can be completely degraded only for a pH higher than 6. Lower pH values seem to inhibit the hydrogen-producing bacteria. Under the conditions of continuous pH adjustment at pH 6.5 and a sucrose concentration of 25 g/L the maximum hydrogen yield of 1.79 mol H(2)/mol hexose was obtained. These conditions could be applied for the batch start-up of large fermentors.

  12. Cadmium chemical speciation and absorption in plant in a polluted soil

    NASA Astrophysics Data System (ADS)

    Gigliotti, Giovanni; Massaccesi, Luisa

    2013-04-01

    Cadmium is a very toxic heavy metal presents in nature in small amounts, with an average content of 0.2 mg kg-1 in the geosphere. Nonetheless, anthropogenic activities such as industrial processes, large use of phosphate fertilizers and sewage sludge disposals may determine a massive accumulation of Cd in soil. Cd is considered a particularly interesting heavy metal as it can be accumulated by plants to levels that can be toxic to humans and animals, when consumed even in minor amounts. The aim of the present work was to study in a soil polluted with Cd for a long time i) the distribution of Cd in different chemical fractions by means of a sequential extraction procedure; ii) the adsorption of Cd by plants grown in this polluted soil; iii) the change in the distribution of Cd in the soil fractions possibly due to root exudates after plant growing. The chemical fractionation procedure used involved the following forms: a) exchangeable, b) bound to carbonates, c) bound to Fe-Mn oxides and hydroxides, d) bound to organic matter, e) residual part. The following reagents and extraction times were applied: a) 1 M CH3COONa (1:10, w/v; pH 8.2) for 16 h at room temperature; b) 0,1 M CH3COOH for 16 h at room temperature; c) 0,1 M NH2OH•HCl (1:10, w/v; adjusted to pH 2.0 with HNO3) for 16 h at room temperature; d) 30% H2O2 (adjusted to pH 2.0 with HNO3) at 85 °C, followed by extraction with 1 M CH3COONH4 (1:10, w/v; adjusted to pH 2.0 with HNO3) for 16 h at room temperature; e) acid digestion with concentrated HNO3 and 30% H2O2 for residue fraction. Festuca seeds were germinated in the contaminated soil in plastic flats and non-contaminated soil. After two days the seedling were submitted to day/night conditions. The seedlings were collected 6 weeks after seeding and divided in roots and shoots and analysed for Cd concentration. The polluted soil has average Cd content of 200 mg kg-1, instead, the Cd content in the same unpolluted soil was about 0.44 mg kg-1. The

  13. Freundlich and dual Langmuir isotherm models for predicting 137Cs binding on Savannah River Site soils.

    PubMed

    Goto, Momoko; Rosson, Robert; Wampler, J Marion; Elliott, W Crawford; Serkiz, Steven; Kahn, Bernd

    2008-01-01

    Distribution of 137Cs and stable cesium between aqueous solution and near-surface soil samples from five locations at the Savannah River Site was measured in order to develop a predictive model for 137Cs uptake by the soils. Sorption of 137Cs in these soils appears to be mostly by hydroxy-interlayered vermiculite. Batch sorption studies with 4 d for equilibration were conducted at three cesium concentrations and at two backing electrolyte (NaNO3) concentrations. The soil-solution mixtures were pH-adjusted to evaluate the effects of pH on cesium sorption. Sorbed cesium was related to the equilibrium aqueous cesium concentrations by a Freundlich isotherm model. Model fits on logarithmic scales have a common slope of 0.60 +/- 0.03 for acidic mixtures and 0.69 +/- 0.04 for neutralized mixtures but have unique intercepts that are influenced by backing electrolyte concentration and pH. An ion-exchange model is proposed that pertains to all five soils and relates the Freundlich isotherms to the cation exchange capacity of soil and the aqueous concentrations of cesium, sodium, and a third ionic species that was hydrogen in the acidic mixtures and potassium in the neutralized mixtures. Model fits are consistent with Kd values in the entire range of 5-2,300 L kg(-1) determined for the five soil types. As an alternate model, dual Langmuir isotherms were fitted to the data. The results suggest cesium sorption by (1) relatively few interlayer-wedge sites, highly selective for cesium, and (2) much more abundant but less selective sites on internal and external planar surfaces.

  14. Adjustable Induction-Heating Coil

    NASA Technical Reports Server (NTRS)

    Ellis, Rod; Bartolotta, Paul

    1990-01-01

    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  15. Time-adjusted variable resistor

    NASA Technical Reports Server (NTRS)

    Heyser, R. C.

    1972-01-01

    Timing mechanism was developed effecting extremely precisioned highly resistant fixed resistor. Switches shunt all or portion of resistor; effective resistance is varied over time interval by adjusting switch closure rate.

  16. 78 FR 62712 - Rate Adjustment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... noticing a recent Postal Service filing seeking postal rate adjustments based on exigent circumstances...,'' is ``premised on the recent recession as an exigent event.'' Id. at 1, 2. In Order No. 1059,...

  17. Influence of pH Regulation Mode in Glucose Fermentation on Product Selection and Process Stability.

    PubMed

    Mohd-Zaki, Zuhaida; Bastidas-Oyanedel, Juan R; Lu, Yang; Hoelzle, Robert; Pratt, Steven; Slater, Fran R; Batstone, Damien J

    2016-01-01

    Mixed culture anaerobic fermentation generates a wide range of products from simple sugars, and is potentially an effective process for producing renewable commodity chemicals. However it is difficult to predict product spectrum, and to control the process. One of the key control handles is pH, but the response is commonly dependent on culture history. In this work, we assess the impact of pH regulation mode on the product spectrum. Two regulation modes were applied: in the first, pH was adjusted from 4.5 to 8.5 in progressive steps of 0.5 and in the second, covered the same pH range, but the pH was reset to 5.5 before each change. Acetate, butyrate, and ethanol were produced throughout all pH ranges, but there was a shift from butyrate at pH < 6.5 to ethanol at pH > 6.5, as well as a strong and consistent shift from hydrogen to formate as pH increased. Microbial analysis indicated that progressive pH resulted in dominance by Klebsiella, while reset pH resulted in a bias towards Clostridium spp., particularly at low pH, with higher variance in community between different pH levels. Reset pH was more responsive to changes in pH, and analysis of Gibbs free energy indicated that the reset pH experiments operated closer to thermodynamic equilibrium, particularly with respect to the formate/hydrogen balance. This may indicate that periodically resetting pH conforms better to thermodynamic expectations. PMID:27681895

  18. Influence of pH Regulation Mode in Glucose Fermentation on Product Selection and Process Stability

    PubMed Central

    Mohd-Zaki, Zuhaida; Bastidas-Oyanedel, Juan R.; Lu, Yang; Hoelzle, Robert; Pratt, Steven; Slater, Fran R.; Batstone, Damien J.

    2016-01-01

    Mixed culture anaerobic fermentation generates a wide range of products from simple sugars, and is potentially an effective process for producing renewable commodity chemicals. However it is difficult to predict product spectrum, and to control the process. One of the key control handles is pH, but the response is commonly dependent on culture history. In this work, we assess the impact of pH regulation mode on the product spectrum. Two regulation modes were applied: in the first, pH was adjusted from 4.5 to 8.5 in progressive steps of 0.5 and in the second, covered the same pH range, but the pH was reset to 5.5 before each change. Acetate, butyrate, and ethanol were produced throughout all pH ranges, but there was a shift from butyrate at pH < 6.5 to ethanol at pH > 6.5, as well as a strong and consistent shift from hydrogen to formate as pH increased. Microbial analysis indicated that progressive pH resulted in dominance by Klebsiella, while reset pH resulted in a bias towards Clostridium spp., particularly at low pH, with higher variance in community between different pH levels. Reset pH was more responsive to changes in pH, and analysis of Gibbs free energy indicated that the reset pH experiments operated closer to thermodynamic equilibrium, particularly with respect to the formate/hydrogen balance. This may indicate that periodically resetting pH conforms better to thermodynamic expectations. PMID:27681895

  19. Influence of pH Regulation Mode in Glucose Fermentation on Product Selection and Process Stability

    PubMed Central

    Mohd-Zaki, Zuhaida; Bastidas-Oyanedel, Juan R.; Lu, Yang; Hoelzle, Robert; Pratt, Steven; Slater, Fran R.; Batstone, Damien J.

    2016-01-01

    Mixed culture anaerobic fermentation generates a wide range of products from simple sugars, and is potentially an effective process for producing renewable commodity chemicals. However it is difficult to predict product spectrum, and to control the process. One of the key control handles is pH, but the response is commonly dependent on culture history. In this work, we assess the impact of pH regulation mode on the product spectrum. Two regulation modes were applied: in the first, pH was adjusted from 4.5 to 8.5 in progressive steps of 0.5 and in the second, covered the same pH range, but the pH was reset to 5.5 before each change. Acetate, butyrate, and ethanol were produced throughout all pH ranges, but there was a shift from butyrate at pH < 6.5 to ethanol at pH > 6.5, as well as a strong and consistent shift from hydrogen to formate as pH increased. Microbial analysis indicated that progressive pH resulted in dominance by Klebsiella, while reset pH resulted in a bias towards Clostridium spp., particularly at low pH, with higher variance in community between different pH levels. Reset pH was more responsive to changes in pH, and analysis of Gibbs free energy indicated that the reset pH experiments operated closer to thermodynamic equilibrium, particularly with respect to the formate/hydrogen balance. This may indicate that periodically resetting pH conforms better to thermodynamic expectations.

  20. Soil cultivation in vineyards alters interactions between soil biota and soil physical and hydrological properties

    NASA Astrophysics Data System (ADS)

    Zaller, Johann G.; Buchholz, Jacob; Querner, Pascal; Winter, Silvia; Kratschmer, Sophie; Pachinger, Bärbel; Strauss, Peter; Bauer, Thomas; Stiper, Katrin; Potthoff, Martin; Guernion, Muriel; Scimia, Jennifer; Cluzeau, Daniel

    2016-04-01

    Several ecosystem services provided by viticultural landscapes result from interactions between soil organisms and soil parameters. However, to what extent different soil cultivation intensities in vineyards compromise soil organisms and their interactions between soil physical and hydrological properties is not well understood. In this study we examined (i) to what extent different soil management intensities affect the activity and diversity of soil biota (earthworms, Collembola, litter decomposition), and (ii) how soil physical and hydrological properties influence these interactions, or vice versa. Investigating 16 vineyards in Austria, earthworms were assessed by hand sorting, Collembola via pitfall trapping and soil coring, litter decomposition by using the tea bag method. Additionally, soil physical (water infiltration, aggregate stability, porosity, bulk density, soil texture) and chemical (pH, soil carbon content, cation exchange capacity, potassium, phosphorus) parameters were assessed. Results showed complex ecological interactions between soil biota and various soil characteristics altered by management intensity. These investigations are part of the transdisciplinary BiodivERsA project VineDivers and will ultimately lead into management recommendations for various stakeholders.

  1. Yogurt made from milk heated at different pH values.

    PubMed

    Ozcan, Tulay; Horne, David S; Lucey, John A

    2015-10-01

    Milk for yogurt manufacture is subjected to high heat treatment to denature whey proteins. Low milk pH values (≤ 6.5) at heating result in most denatured whey proteins becoming associated with casein micelles, whereas high milk pH values (≥ 7.0) at heating result in the formation of mostly soluble (nonmicellar) denatured whey protein complexes. There are conflicting reports on the relative importance of soluble and casein-bound whey protein aggregates on the properties of acid gels. Prior studies investigating the effect of pH of milk at heating used model gels in which milk was acidified by glucono-δ-lactone; in this study, we prepared yogurt gels using commercial starter cultures. Model acid gels can have very different texture and physical properties from those made by fermentation with starter cultures. In this study, we investigated the effects of different pH values of milk at heating on the rheological, light backscatter, and microstructural properties of yogurt gels. Reconstituted skim milk was adjusted to pH values 6.2, 6.7, and 7.2 and heated at 85°C for 30 min. A portion of the heated milk samples was readjusted back to pH 6.7 after heating. Milks were inoculated with 3% (wt/wt) yogurt starter culture and incubated at 40°C until pH 4.6. Gel formation was monitored using dynamic oscillatory rheology, and parameters measured included the storage modulus (G') and loss tangent (LT) values. Light-backscattering properties, such as the backscatter ratio (R) and the first derivative of light backscatter ratio (R'), were also monitored during fermentation. Fluorescence microscopy was used to observe gel microstructure. The G' values at pH 4.6 were highest in gels made from milk heated at pH 6.7 and lowest in milk heated at pH 6.2, with or without pH adjustment after heating. The G' values at pH 4.6 were lower in samples after adjustment back to pH 6.7 after heating. No maximum in the LT parameter was observed during gelation for yogurts made from milk

  2. Yogurt made from milk heated at different pH values.

    PubMed

    Ozcan, Tulay; Horne, David S; Lucey, John A

    2015-10-01

    Milk for yogurt manufacture is subjected to high heat treatment to denature whey proteins. Low milk pH values (≤ 6.5) at heating result in most denatured whey proteins becoming associated with casein micelles, whereas high milk pH values (≥ 7.0) at heating result in the formation of mostly soluble (nonmicellar) denatured whey protein complexes. There are conflicting reports on the relative importance of soluble and casein-bound whey protein aggregates on the properties of acid gels. Prior studies investigating the effect of pH of milk at heating used model gels in which milk was acidified by glucono-δ-lactone; in this study, we prepared yogurt gels using commercial starter cultures. Model acid gels can have very different texture and physical properties from those made by fermentation with starter cultures. In this study, we investigated the effects of different pH values of milk at heating on the rheological, light backscatter, and microstructural properties of yogurt gels. Reconstituted skim milk was adjusted to pH values 6.2, 6.7, and 7.2 and heated at 85°C for 30 min. A portion of the heated milk samples was readjusted back to pH 6.7 after heating. Milks were inoculated with 3% (wt/wt) yogurt starter culture and incubated at 40°C until pH 4.6. Gel formation was monitored using dynamic oscillatory rheology, and parameters measured included the storage modulus (G') and loss tangent (LT) values. Light-backscattering properties, such as the backscatter ratio (R) and the first derivative of light backscatter ratio (R'), were also monitored during fermentation. Fluorescence microscopy was used to observe gel microstructure. The G' values at pH 4.6 were highest in gels made from milk heated at pH 6.7 and lowest in milk heated at pH 6.2, with or without pH adjustment after heating. The G' values at pH 4.6 were lower in samples after adjustment back to pH 6.7 after heating. No maximum in the LT parameter was observed during gelation for yogurts made from milk

  3. Soil Properties Controlling Zn Speciation and Fractionation in Contaminated Soils

    SciTech Connect

    Jacquat, O.; Voegelin, A; Kretzschmar, R

    2009-01-01

    We determined the speciation of Zn in 49 field soils differing widely in pH (4.1-7.7) and total Zn content (251-30,090 mg/kg) by using extended X-ray absorption fine structure (EXAFS) spectroscopy. All soils had been contaminated since several decades by inputs of aqueous Zn with runoff-water from galvanized power line towers. Pedogenic Zn species identified by EXAFS spectroscopy included Zn in hydroxy-interlayered minerals (Zn-HIM), Zn-rich phyllosilicates, Zn-layered double hydroxide (Zn-LDH), hydrozincite, and octahedrally and tetrahedrally coordinated sorbed or complexed Zn. Zn-HIM was only observed in (mostly acidic) soils containing less than 2000 mg/kg of Zn, reflecting the high affinity but limited sorption capacity of HIM. Zn-bearing precipitates, such as Zn-LDH and Zn-rich trioctahedral phyllosilicates, became more dominant with increasing pH and increasing total Zn content relative to available adsorption sites. Zn-LDH was the most abundant Zn-precipitate and was detected in soils with pH > 5.2. Zn-rich phyllosilicates were detected even at lower soil pH, but were generally less abundant than Zn-LDH. Hydrozincite was only identified in two calcareous soils with extremely high Zn contents. In addition to Zn-LDH, large amounts of Zn in highly contaminated soils were mainly accumulated as sorbed/complexed Zn in tetrahedral coordination. Soils grouped according to their Zn speciation inferred from EXAFS spectroscopy mainly differed with respect to soil pH and total Zn content. Clear differences were observed with respect to Zn fractionation by sequential extraction: From Zn-HIM containing soils, most of the total Zn was recovered in the exchangeable and the most recalcitrant fractions. In contrast, from soils containing the highest percentage of Zn-precipitates, Zn was mainly extracted in intermediate extraction steps. The results of this study demonstrate that soil pH and Zn contamination level relative to available adsorption sites are the most important

  4. Relative bioaccessibility of Pb-based paint in soil.

    PubMed

    Hunt, Andrew

    2016-08-01

    The threat posed by lead (Pb) in soil for pediatric populations continues to be a public health issue. In long-established residential areas, a principal source of Pb in soil is likely to be old Pb-based paint originating from building surfaces. The health hazard posed by Pb from paint in soil will likely depend on quantity of paint incorporated, its Pb-mineral composition, whether the Pb is locked in some other material and the paint residence time in the soil (degree of aging). Here the relative bioavailability (RBA) of Pb in different types of Pb-bearing paint has been assessed. Tests were performed with individual paints, with paints mixed with a low-Pb soil, and with paints mixed with soil and the biogenic phosphate apatite II. Thirteen Pb-bearing paint samples were ground and passed through 250- and 100-µm screens. Samples nominally <100 µm from all the paints were analyzed, and six of the paints for which there was sufficient material in the 100- to 250-µm-size range were also tested. RBA extraction of Pb employed a simulated gastric fluid (SGF) of HCl and glycine adjusted to a pH of 1.5 in which samples were agitated (in an end-over-end rotator) for 2 h. Original paints were examined by SEM/EDX, and by XRD, residues collected after RBA extraction were examined by SEM/EDX. The concentration of Pb in the extraction fluid was measured by AAS. The quantity of Pb mobilized in each test batch was approximately an order of magnitude less in the paint-soil mix compared to the corresponding paint-only sample. The difference in the amount of Pb extracted from the paint-soil mix compared to the paint-soil-phosphate mix was minimal. However, in the post-RBA residues of the paint-soil mix, a PbCl precipitate was observed, and in the extraction residues of the paint-soil-apatite II mixes PbClP phases were recorded. Precipitation of these secondary phases obviously modified the amount of Pb in the extraction fluid, and this may need to be considered, i.e., under

  5. Relative bioaccessibility of Pb-based paint in soil.

    PubMed

    Hunt, Andrew

    2016-08-01

    The threat posed by lead (Pb) in soil for pediatric populations continues to be a public health issue. In long-established residential areas, a principal source of Pb in soil is likely to be old Pb-based paint originating from building surfaces. The health hazard posed by Pb from paint in soil will likely depend on quantity of paint incorporated, its Pb-mineral composition, whether the Pb is locked in some other material and the paint residence time in the soil (degree of aging). Here the relative bioavailability (RBA) of Pb in different types of Pb-bearing paint has been assessed. Tests were performed with individual paints, with paints mixed with a low-Pb soil, and with paints mixed with soil and the biogenic phosphate apatite II. Thirteen Pb-bearing paint samples were ground and passed through 250- and 100-µm screens. Samples nominally <100 µm from all the paints were analyzed, and six of the paints for which there was sufficient material in the 100- to 250-µm-size range were also tested. RBA extraction of Pb employed a simulated gastric fluid (SGF) of HCl and glycine adjusted to a pH of 1.5 in which samples were agitated (in an end-over-end rotator) for 2 h. Original paints were examined by SEM/EDX, and by XRD, residues collected after RBA extraction were examined by SEM/EDX. The concentration of Pb in the extraction fluid was measured by AAS. The quantity of Pb mobilized in each test batch was approximately an order of magnitude less in the paint-soil mix compared to the corresponding paint-only sample. The difference in the amount of Pb extracted from the paint-soil mix compared to the paint-soil-phosphate mix was minimal. However, in the post-RBA residues of the paint-soil mix, a PbCl precipitate was observed, and in the extraction residues of the paint-soil-apatite II mixes PbClP phases were recorded. Precipitation of these secondary phases obviously modified the amount of Pb in the extraction fluid, and this may need to be considered, i.e., under

  6. Amount of organic matter required to induce sulfate reduction in sulfuric material after re-flooding is affected by soil nitrate concentration.

    PubMed

    Yuan, Chaolei; Mosley, Luke M; Fitzpatrick, Rob; Marschner, Petra

    2015-03-15

    Acid sulfate soils (ASS) with sulfuric material can be remediated through microbial sulfate reduction stimulated by adding organic matter (OM) and increasing the soil pH to >4.5, but the effectiveness of this treatment is influenced by soil properties. Two experiments were conducted using ASS with sulfuric material. In the first experiment with four ASS, OM (finely ground mature wheat straw) was added at 2-6% (w/w) and the pH adjusted to 5.5. After 36 weeks under flooded conditions, the concentration of reduced inorganic sulfur (RIS) and pore water pH were greater in all treatments with added OM than in the control without OM addition. The RIS concentration increased with OM addition rate. The increase in RIS concentration between 4% and 6% OM was significant but smaller than that between 2% and 4%, suggesting other factors limited sulfate reduction. In the second experiment, the effect of nitrate addition on sulfate reduction at different OM addition rates was investigated in one ASS. Organic matter was added at 2 and 4% and nitrate at 0, 100, and 200 mg nitrate-N kg(-1). After 2 weeks under flooded conditions, soil pH and the concentration of FeS measured as acid volatile sulfur (AVS) were lower with nitrate added at both OM addition rates. At a given nitrate addition rate, pH and AVS concentration were higher at 4% OM than at 2%. It can be concluded that sulfate reduction in ASS at pH 5.5 can be limited by low OM availability and high nitrate concentrations. Further, the inhibitory effect of nitrate can be overcome by high OM addition rates. PMID:25600239

  7. Amount of organic matter required to induce sulfate reduction in sulfuric material after re-flooding is affected by soil nitrate concentration.

    PubMed

    Yuan, Chaolei; Mosley, Luke M; Fitzpatrick, Rob; Marschner, Petra

    2015-03-15

    Acid sulfate soils (ASS) with sulfuric material can be remediated through microbial sulfate reduction stimulated by adding organic matter (OM) and increasing the soil pH to >4.5, but the effectiveness of this treatment is influenced by soil properties. Two experiments were conducted using ASS with sulfuric material. In the first experiment with four ASS, OM (finely ground mature wheat straw) was added at 2-6% (w/w) and the pH adjusted to 5.5. After 36 weeks under flooded conditions, the concentration of reduced inorganic sulfur (RIS) and pore water pH were greater in all treatments with added OM than in the control without OM addition. The RIS concentration increased with OM addition rate. The increase in RIS concentration between 4% and 6% OM was significant but smaller than that between 2% and 4%, suggesting other factors limited sulfate reduction. In the second experiment, the effect of nitrate addition on sulfate reduction at different OM addition rates was investigated in one ASS. Organic matter was added at 2 and 4% and nitrate at 0, 100, and 200 mg nitrate-N kg(-1). After 2 weeks under flooded conditions, soil pH and the concentration of FeS measured as acid volatile sulfur (AVS) were lower with nitrate added at both OM addition rates. At a given nitrate addition rate, pH and AVS concentration were higher at 4% OM than at 2%. It can be concluded that sulfate reduction in ASS at pH 5.5 can be limited by low OM availability and high nitrate concentrations. Further, the inhibitory effect of nitrate can be overcome by high OM addition rates.

  8. Empirical algorithms to estimate water column pH in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Williams, N. L.; Juranek, L. W.; Johnson, K. S.; Feely, R. A.; Riser, S. C.; Talley, L. D.; Russell, J. L.; Sarmiento, J. L.; Wanninkhof, R.

    2016-04-01

    Empirical algorithms are developed using high-quality GO-SHIP hydrographic measurements of commonly measured parameters (temperature, salinity, pressure, nitrate, and oxygen) that estimate pH in the Pacific sector of the Southern Ocean. The coefficients of determination, R2, are 0.98 for pH from nitrate (pHN) and 0.97 for pH from oxygen (pHOx) with RMS errors of 0.010 and 0.008, respectively. These algorithms are applied to Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling floats, which include novel sensors (pH, nitrate, oxygen, fluorescence, and backscatter). These algorithms are used to estimate pH on floats with no pH sensors and to validate and adjust pH sensor data from floats with pH sensors. The adjusted float data provide, for the first time, seasonal cycles in surface pH on weekly resolution that range from 0.05 to 0.08 on weekly resolution for the Pacific sector of the Southern Ocean.

  9. 7 CFR 251.7 - Formula adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Formula adjustments. 251.7 Section 251.7 Agriculture... GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION THE EMERGENCY FOOD ASSISTANCE PROGRAM § 251.7 Formula adjustments. Formula adjustments. (a) Commodity adjustments. The Department will make annual adjustments...

  10. 12 CFR 1209.80 - Inflation adjustments.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Inflation adjustments. 1209.80 Section 1209.80... PROCEDURE Civil Money Penalty Inflation Adjustments § 1209.80 Inflation adjustments. The maximum amount of... thereafter adjusted in accordance with the Inflation Adjustment Act, on a recurring four-year cycle, is...

  11. 12 CFR 1209.80 - Inflation adjustments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Inflation adjustments. 1209.80 Section 1209.80... PROCEDURE Civil Money Penalty Inflation Adjustments § 1209.80 Inflation adjustments. The maximum amount of... thereafter adjusted in accordance with the Inflation Adjustment Act, on a recurring four-year cycle, is...

  12. 12 CFR 1209.80 - Inflation adjustments.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Inflation adjustments. 1209.80 Section 1209.80... PROCEDURE Civil Money Penalty Inflation Adjustments § 1209.80 Inflation adjustments. The maximum amount of... thereafter adjusted in accordance with the Inflation Adjustment Act, on a recurring four-year cycle, is...

  13. Soil and Surface Runoff Phosphorus Relationships for Five Typical USA Midwest Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessively high soil P can increase P loss with surface runoff. This study used indoor rainfall simulations to characterize soil and runoff P relationships for five Midwest soils (Argiudoll, Calciaquaoll, Hapludalf, and two Hapludolls). Topsoil (15-cm depth, 241–289 g clay kg–1 and pH 6.0–8.0) was ...

  14. pH Optrode Instrumentation

    NASA Technical Reports Server (NTRS)

    Tabacco, Mary Beth; Zhou, Quan

    1995-01-01

    pH-sensitive chromophoric reagents immobilized in porous optical fibers. Optoelectronic instrumentation system measures acidity or alkalinity of aqueous nutrient solution. Includes one or more optrodes, which are optical-fiber chemical sensors, in sense, analogous to electrodes but not subject to some of spurious effects distorting readings taken by pH electrodes. Concept of optrodes also described in "Ethylene-Vapor Optrodes" (KSC-11579). pH optrode sensor head, with lead-in and lead-out optical fibers, convenient for monitoring solutions located away from supporting electronic equipment.

  15. The potentiation of zinc toxicity by soil moisture in a boreal forest ecosystem.

    PubMed

    Owojori, Olugbenga J; Siciliano, Steven D

    2015-03-01

    Northern boreal forests often experience forest dieback as a result of metal ore mining and smelting. The common solution is to lime the soil, which increases pH, reducing metal toxicity and encouraging recovery. In certain situations, however, such as in Flin Flon, Manitoba, Canada, liming has yielded only moderate benefits, with some locations responding well to liming and other locations not at all. In an effort to increase the effectiveness of the ecorestoration strategy, the authors investigated if these differences in liming responsiveness were linked to differences in toxicity. Toxicity of metal-impacted Flin Flon soils on the oribatid mite Oppia nitens and the collembolan Folsomia candida was assessed, with a view toward identifying the metal of concern in the area. The effects of moisture content on metal sorption, uptake, and toxicity to the invertebrates were also investigated. Toxicity tests with the invertebrates were conducted using either Flin Flon soils or artificial soils with moisture content adjusted to 30%, 45%, 60%, or 75% of the maximum water-holding capacity of the soil samples. The Relative to Cd Toxicity Model identified Zn as the metal of concern in the area, and this was confirmed using validation tests with field contaminated soils. Furthermore, increasing the moisture content in soils increased the amount of mobile Zn available for uptake with the ion exchange resin. Survival and reproduction of both invertebrates were reduced under Zn exposure as moisture level increased. Thus, moisture-collecting landforms, which are often also associated with high Zn concentrations at Flin Flon, have, as a result, higher Zn toxicity to the soil ecosystem because of increases in soil moisture.

  16. The potentiation of zinc toxicity by soil moisture in a boreal forest ecosystem.

    PubMed

    Owojori, Olugbenga J; Siciliano, Steven D

    2015-03-01

    Northern boreal forests often experience forest dieback as a result of metal ore mining and smelting. The common solution is to lime the soil, which increases pH, reducing metal toxicity and encouraging recovery. In certain situations, however, such as in Flin Flon, Manitoba, Canada, liming has yielded only moderate benefits, with some locations responding well to liming and other locations not at all. In an effort to increase the effectiveness of the ecorestoration strategy, the authors investigated if these differences in liming responsiveness were linked to differences in toxicity. Toxicity of metal-impacted Flin Flon soils on the oribatid mite Oppia nitens and the collembolan Folsomia candida was assessed, with a view toward identifying the metal of concern in the area. The effects of moisture content on metal sorption, uptake, and toxicity to the invertebrates were also investigated. Toxicity tests with the invertebrates were conducted using either Flin Flon soils or artificial soils with moisture content adjusted to 30%, 45%, 60%, or 75% of the maximum water-holding capacity of the soil samples. The Relative to Cd Toxicity Model identified Zn as the metal of concern in the area, and this was confirmed using validation tests with field contaminated soils. Furthermore, increasing the moisture content in soils increased the amount of mobile Zn available for uptake with the ion exchange resin. Survival and reproduction of both invertebrates were reduced under Zn exposure as moisture level increased. Thus, moisture-collecting landforms, which are often also associated with high Zn concentrations at Flin Flon, have, as a result, higher Zn toxicity to the soil ecosystem because of increases in soil moisture. PMID:25502519

  17. Bacterial community structure and soil properties of a subarctic tundra soil in Council, Alaska.

    PubMed

    Kim, Hye Min; Jung, Ji Young; Yergeau, Etienne; Hwang, Chung Yeon; Hinzman, Larry; Nam, Sungjin; Hong, Soon Gyu; Kim, Ok-Sun; Chun, Jongsik; Lee, Yoo Kyung

    2014-08-01

    The subarctic region is highly responsive and vulnerable to climate change. Understanding the structure of subarctic soil microbial communities is essential for predicting the response of the subarctic soil environment to climate change. To determine the composition of the bacterial community and its relationship with soil properties, we investigated the bacterial community structure and properties of surface soil from the moist acidic tussock tundra in Council, Alaska. We collected 70 soil samples with 25-m intervals between sampling points from 0-10 cm to 10-20 cm depths. The bacterial community was analyzed by pyrosequencing of 16S rRNA genes, and the following soil properties were analyzed: soil moisture content (MC), pH, total carbon (TC), total nitrogen (TN), and inorganic nitrogen (NH4+ and NO3-). The community compositions of the two different depths showed that Alphaproteobacteria decreased with soil depth. Among the soil properties measured, soil pH was the most significant factor correlating with bacterial community in both upper and lower-layer soils. Bacterial community similarity based on jackknifed unweighted unifrac distance showed greater similarity across horizontal layers than through the vertical depth. This study showed that soil depth and pH were the most important soil properties determining bacterial community structure of the subarctic tundra soil in Council, Alaska.

  18. MCCB warm adjustment testing concept

    NASA Astrophysics Data System (ADS)

    Erdei, Z.; Horgos, M.; Grib, A.; Preradović, D. M.; Rodic, V.

    2016-08-01

    This paper presents an experimental investigation in to operating of thermal protection device behavior from an MCCB (Molded Case Circuit Breaker). One of the main functions of the circuit breaker is to assure protection for the circuits where mounted in for possible overloads of the circuit. The tripping mechanism for the overload protection is based on a bimetal movement during a specific time frame. This movement needs to be controlled and as a solution to control this movement we choose the warm adjustment concept. This concept is meant to improve process capability control and final output. The warm adjustment device design will create a unique adjustment of the bimetal position for each individual breaker, determined when the testing current will flow thru a phase which needs to trip in a certain amount of time. This time is predetermined due to scientific calculation for all standard types of amperages and complies with the IEC 60497 standard requirements.

  19. Making pH Tangible.

    ERIC Educational Resources Information Center

    McIntosh, Elizabeth; Moss, Robert

    1995-01-01

    Presents a laboratory exercise in which students test the pH of different substances, study the effect of a buffer on acidic solutions by comparing the behavior of buffered and unbuffered solutions upon the addition of acid, and compare common over-the-counter antacid remedies. (MKR)

  20. Soils as records of past and present environments

    NASA Astrophysics Data System (ADS)

    Sauer, Daniela

    2015-04-01

    This contribution reflects selected pedological concepts that are helpful for interpreting soil properties related to past and present environments. These concepts are illustrated by examples from various landscapes, and their combination finally leads to some further conclusions. The concept of Targulian and Gerasimova (2009) distinguishes soil system and soil body. Soil system is defined as "open multiphase system functioning in any solid-phase substrate at its interface with the atmosphere, hydrosphere and biota", and soil body as "solid-phase part of a soil system produced by its long-term functioning and composed of a vertical sequence of genetic horizons". Soil system functioning corresponds to the recent environmental factors and includes heat and moisture dynamics, biomass production, biogeochemical cycles, and other processes. In contrast, a soil body is a record of the long-term functioning of a soil system. It thus provides a record not only of the functioning of the soil system under the present environmental conditions but also under past, possibly different, conditions. Hence, Targulian and Goryachkin (2004) called it the "memory" of the landscape. Richter and Yaalon (2012) argued that most soils comprise both, features that developed under the present environmental conditions and features that reflect different conditions that the soils experienced in the past; they concluded that most soils are polygenetic. Although the current functioning of the soil system in the concept of Targulian and Gerasimova (2009) is mainly controlled by the present-day combination of environmental factors, it should be added that past processes also influence the soil system, because past processes changed the soil properties in a way that also the present-day functioning of the soil system is affected by these changes. Earlier, Yaalon (1971) had categorised soil properties according to the time-span required for their adjustment to the actual environment, distinguishing

  1. Convective adjustment in baroclinic atmospheres

    NASA Technical Reports Server (NTRS)

    Emanuel, Kerry A.

    1986-01-01

    Local convection in planetary atmospheres is generally considered to result from the action of gravity on small regions of anomalous density. That in rotating baroclinic fluids the total potential energy for small scale convection contains a centrifugal as well as a gravitational contribution is shown. Convective adjustment in such an atmosphere results in the establishment of near adiabatic lapse rates of temperature along suitably defined surfaces of constant angular momentum, rather than in the vertical. This leads in general to sub-adiabatic vertical lapse rates. That such an adjustment actually occurs in the earth's atmosphere is shown by example and the magnitude of the effect for several other planetary atmospheres is estimated.

  2. Carbon and nitrogen dynamics across a bedrock-regulated subarctic pH gradient

    NASA Astrophysics Data System (ADS)

    Tomczyk, N.; Heim, E. W.; Sadowsky, J.; Remiszewski, K.; Varner, R. K.; Bryce, J. G.; Frey, S. D.

    2014-12-01

    Bedrock geochemistry has been shown to influence landscape evolution due to nutrient limitation on primary production. There may also be less direct interactions between bedrock-derived chemicals and ecosystem function. Effects of calcium (Ca) and pH on soil carbon (C) and nitrogen (N) cycling have been shown in acid impacted forests o f North America. Understanding intrinsic factors that affect C and nutrient dynamics in subarctic ecosystems has implications for how these ecosystems will respond to a changing climate. How the soil microbial community allocates enzymes to acquire resources from the environment can indicate whether a system is nutrient or energy limited. This study examined whether bedrock geochemistry exerts pressure on nutrient cycles in the overlying soils. In thin, weakly developed soils, bedrock is the primary mineral material and is a source of vital nutrients. Nitrogen (N) and C are not derived from bedrock, but their cycling is still affected by reactions with geologically-derived chemicals. Our study sites near Abisko, Sweden (~68°N) were selected adjacent to five distinct bedrock outcrops (quartzite, slate, carbonate, and two different metasedimenty units). All sites were at a similar elevation (~700 m a.s.l.) and had similar vegetation (subarctic heath). Nutrient concentrations in bedrock and soils were measured in addition to soil microbial biomass and extracellular enzyme activity. We found a statistically significant correlation between soil Ca concentrations and soil pH (r = 0.88, p < 0.01). There were also significant relationships between soil pH and the ratio of C-acquiring to N-acquiring enzyme activity (r = -0.89, p < 0.01), soil pH and soil C-to-N ratio (r = -0.76, p < 0.01), and the ratio of C-acquiring to N-acquiring enzyme activity and soil C-to-N ratio (r = 0.78, p < 0.01). These results suggest that soil Ca concentrations influence C and N cycling dynamics in these soils through their effect on soil pH.

  3. Effect of soil coarseness on soil base cations and available micronutrients in a semi-arid sandy grassland

    NASA Astrophysics Data System (ADS)

    Lü, Linyou; Wang, Ruzhen; Liu, Heyong; Yin, Jinfei; Xiao, Jiangtao; Wang, Zhengwen; Zhao, Yan; Yu, Guoqing; Han, Xingguo; Jiang, Yong

    2016-04-01

    Soil coarseness is the main process decreasing soil organic matter and threatening the productivity of sandy grasslands. Previous studies demonstrated negative effect of soil coarseness on soil carbon storage, but less is known about how soil base cations (exchangeable Ca, Mg, K, and Na) and available micronutrients (available Fe, Mn, Cu, and Zn) response to soil coarseness. In a semi-arid grassland of Northern China, a field experiment was initiated in 2011 to mimic the effect of soil coarseness on soil base cations and available micronutrients by mixing soil with different mass proportions of sand: 0 % coarse elements (C0), 10 % (C10), 30 % (C30), 50 % (C50), and 70 % (C70). Soil coarseness significantly increased soil pH in three soil depths of 0-10, 10-20 and 20-40 cm with the highest pH values detected in C50 and C70 treatments. Soil fine particles (smaller than 0.25 mm) significantly decreased with the degree of soil coarseness. Exchangeable Ca and Mg concentrations significantly decreased with soil coarseness degree by up to 29.8 % (in C70) and 47.5 % (in C70), respectively, across three soil depths. Soil available Fe, Mn, and Cu significantly decreased with soil coarseness degree by 62.5, 45.4, and 44.4 %, respectively. As affected by soil coarseness, the increase of soil pH, decrease of soil fine particles (including clay), and decline in soil organic matter were the main driving factors for the decrease of exchangeable base cations (except K) and available micronutrients (except Zn) through soil profile. Developed under soil coarseness, the loss and redistribution of base cations and available micronutrients along soil depths might pose a threat to ecosystem productivity of this sandy grassland.

  4. Plant selenium from soil and the atmosphere

    SciTech Connect

    Haygarth, P.M.; Jones, K.C.; Harrison, A.F.

    1995-07-01

    Transfer of selenium (Se) to pasture is important for prevention of Se deficiency in livestock, yet little is known about the relative importance of inputs to pasture from soil and the atmosphere. An isotope dilution method was used to assess quantitatively the importance of these inputs to ryegrass. Soil was labelled with {sup 75}Se and subjected to two field treatments that were untreated (pH 6.0) and limed (pH 7.0). After an initial period of equilibration, the specific activity of Se associated with unwashed leaves became lower than that of soil. This indicated that atmospheric Se had been deposited onto and possibly incorporated into the ryegrass. The percent contribution of {sup 75}Se in pasture leaves derived from the soil was 47% (pH 6.0) and 70% (pH 7.0), with, by inference, the remainder coming from the atmosphere. 23 refs., 1 fig., 4 tabs.

  5. Adjustable-Angle Drill Block

    NASA Technical Reports Server (NTRS)

    Gallimore, F. H.

    1986-01-01

    Adjustable angular drill block accurately transfers hole patterns from mating surfaces not normal to each other. Block applicable to transfer of nonperpendicular holes in mating contoured assemblies in aircraft industry. Also useful in general manufacturing to transfer mating installation holes to irregular and angular surfaces.

  6. Economic Pressures and Family Adjustment.

    ERIC Educational Resources Information Center

    Haccoun, Dorothy Markiewicz; Ledingham, Jane E.

    The relationships between economic stress on the family and child and parental adjustment were examined for a sample of 199 girls and boys in grades one, four, and seven. These associations were examined separately for families in which both parents were present and in which mothers only were at home. Economic stress was associated with boys'…

  7. A global pattern of soil acidification caused by nitrogen deposition

    NASA Astrophysics Data System (ADS)

    Niu, S.; Tian, D., Sr.

    2014-12-01

    Nitrogen (N) deposition-induced soil acidification has become a global problem. However, the response patterns of soil acidification to N addition and the underlying mechanisms remain far from unclear. Here, we conducted a meta-analysis of 106 studies to reveal global patterns of soil acidification in responses to N addition. We found that N addition significantly reduced soil pH by 0.23 on average globally. However, the response ratio of soil pH varied with ecosystem types, N addition rate, N fertilization forms, and experimental durations. Soil pH decreased most in grassland, whereas boreal forest was insensitive to N addition in soil acidification. Soil pH decreased linearly with N addition rates. Addition of urea and NH4NO3 contributed more to soil acidification than NH4-form fertilizer. When experimental duration was longer than 20 years, N addition effects on soil acidification diminished. Environmental factors such as initial soil pH, soil carbon and nitrogen content, precipitation, and temperature all influenced the response ratio of soil pH. Base cations of Ca2+, Mg2+ and K+ were critical important in buffering against N-induced soil acidification at the early stage. However, N addition has shifted global soils into the Al3+ buffering phase. Overall, this study indicates that acidification in global soils is very sensitive to N deposition, which is greatly modified by biotic and abiotic factors. Global soils are now at a buffering transition from base cations (Ca2+, Mg2+ and K+) to non-base cations (Mn2+ and Al3+). This calls our attention to care about the limitation of base cations and the toxic impact of non-base cations for terrestrial ecosystems with N deposition.

  8. A global analysis of soil acidification caused by nitrogen addition

    NASA Astrophysics Data System (ADS)

    Tian, Dashuan; Niu, Shuli

    2015-02-01

    Nitrogen (N) deposition-induced soil acidification has become a global problem. However, the response patterns of soil acidification to N addition and the underlying mechanisms remain far from clear. Here, we conducted a meta-analysis of 106 studies to reveal global patterns of soil acidification in responses to N addition. We found that N addition significantly reduced soil pH by 0.26 on average globally. However, the responses of soil pH varied with ecosystem types, N addition rate, N fertilization forms, and experimental durations. Soil pH decreased most in grassland, whereas boreal forest was not observed a decrease to N addition in soil acidification. Soil pH decreased linearly with N addition rates. Addition of urea and NH4NO3 contributed more to soil acidification than NH4-form fertilizer. When experimental duration was longer than 20 years, N addition effects on soil acidification diminished. Environmental factors such as initial soil pH, soil carbon and nitrogen content, precipitation, and temperature all influenced the responses of soil pH. Base cations of Ca2+, Mg2+ and K+ were critical important in buffering against N-induced soil acidification at the early stage. However, N addition has shifted global soils into the Al3+ buffering phase. Overall, this study indicates that acidification in global soils is very sensitive to N deposition, which is greatly modified by biotic and abiotic factors. Global soils are now at a buffering transition from base cations (Ca2+, Mg2+ and K+) to non-base cations (Mn2+ and Al3+). This calls our attention to care about the limitation of base cations and the toxic impact of non-base cations for terrestrial ecosystems with N deposition.

  9. [Key microbial processes in nitrous oxide emissions of agricultural soil and mitigation strategies].

    PubMed

    Zhu, Yong-Guan; Wang, Xiao-Hui; Yang, Xiao-Ru; Xu, Hui-Juan; Jia, Yan

    2014-02-01

    Nitrous oxide (N2O) is a powerful atmospheric greenhouse gas, which does not only have a strong influence on the global climate change but also depletes the ozone layer and induces the enhancement of ultraviolet radiation to ground surface, so numerous researches have been focused on global climate change and ecological environmental change. Soil is the foremost source of N2O emissions to the atmosphere, and approximately two-thirds of these emissions are generally attributed to microbiological processes including bacterial and fungal denitrification and nitrification processes, largely as a result of the application of nitrogenous fertilizers. Here the available knowledge concerning the research progress in N2O production in agricultural soils was reviewed, including denitrification, nitrification, nitrifier denitrification and dissimilatory nitrate reduction to ammonium, and the abiotic (including soil pH, organic and inorganic nitrogen, organic matter, soil humidity and temperature) and biotic factors that have direct and indirect effects on N2O fluxes from agricultural soils were also summarized. In addition, the strategies for mitigating N2O emissions and the future research direction were proposed. Therefore, these studies are expected to provide valuable and scientific evidence for the study on mitigation strategies for the emission of greenhouse gases, adjustment of nitrogen transformation processes and enhancement of nitrogen use efficiency.

  10. [Key microbial processes in nitrous oxide emissions of agricultural soil and mitigation strategies].

    PubMed

    Zhu, Yong-Guan; Wang, Xiao-Hui; Yang, Xiao-Ru; Xu, Hui-Juan; Jia, Yan

    2014-02-01

    Nitrous oxide (N2O) is a powerful atmospheric greenhouse gas, which does not only have a strong influence on the global climate change but also depletes the ozone layer and induces the enhancement of ultraviolet radiation to ground surface, so numerous researches have been focused on global climate change and ecological environmental change. Soil is the foremost source of N2O emissions to the atmosphere, and approximately two-thirds of these emissions are generally attributed to microbiological processes including bacterial and fungal denitrification and nitrification processes, largely as a result of the application of nitrogenous fertilizers. Here the available knowledge concerning the research progress in N2O production in agricultural soils was reviewed, including denitrification, nitrification, nitrifier denitrification and dissimilatory nitrate reduction to ammonium, and the abiotic (including soil pH, organic and inorganic nitrogen, organic matter, soil humidity and temperature) and biotic factors that have direct and indirect effects on N2O fluxes from agricultural soils were also summarized. In addition, the strategies for mitigating N2O emissions and the future research direction were proposed. Therefore, these studies are expected to provide valuable and scientific evidence for the study on mitigation strategies for the emission of greenhouse gases, adjustment of nitrogen transformation processes and enhancement of nitrogen use efficiency. PMID:24812980

  11. Herbicide sorption coefficients in relation to soil properties and terrain attributes on a cultivated prairie

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sorption of the herbicides 2,4-D and glyphosate in soil was quantified for 286 surface soil samples (0-15 cm) collected in a 10 m X 10 m grid across a heavily-eroded undulating calcareous prairie landscape. At each sampling point soil organic carbon content, soil carbonate content, soil pH, till...

  12. Group 2 PH: Medical Therapy.

    PubMed

    Guazzi, Marco; Labate, Valentina

    2016-01-01

    Pulmonary hypertension (PH) secondary to left heart disease, classified as Group 2, is a widely underestimated target of therapy. Prevention and treatment of initial subclinical stages are not valued as a priority in the management of this chronic disease population, whereas attention is high for PH consequences in patients with advanced heart failure (HF) requiring a left ventricular mechanical assist device or heart transplant candidates. Even so, there is a growing interest toward the evidence of a clinical and prognostic role of PH in the elderly populations and in HF with preserved ejection fraction (HFpEF). Certainly, along with a prevalence definition not yet defined, the search for effective pharmacological approaches that might favorably affect the aging process and the natural history of HFpEF from earlier stages is not an easy task. Pharmacological studies that have tested some traditional pulmonary arterial hypertension approved drugs (i.e., prostanoids and endothelin-1 receptor blockers) primarily in PH and HF with reduced ejection fraction have not been positive, especially because of concomitant side effects, i.e., systemic hypotension, fluid retention and hepatic toxicity. In recent years, interest has moved toward drugs overexpressing the nitric oxide (NO)-cyclic guanosine monophosphate pathway with recent availability of well-tolerated selective pulmonary vasodilators, such as phosphodiesterase type 5 inhibitors and guanylate cyclase stimulators. Single center studies performed with these drugs have shown good tolerability and safety profile providing alternating hemodynamic results mainly because of recruitment of patients at different stages of the pulmonary vascular disease. Nonetheless, the overexpression of NO pathway appears to remain the most solid background for targeting lung microvessel dysfunction and treating RV dysfunction since the earliest stages of the disease. PMID:27389809

  13. Availability of iron to Pseudomonas fluorescens in rhizosphere and bulk soil evaluated with an ice nucleation reporter gene.

    PubMed Central

    Loper, J E; Henkels, M D

    1997-01-01

    The biological availability of iron in the rhizosphere was assessed by evaluating ice nucleation activity (INA) expressed in situ by Pseudomonas fluorescens Pf-5 containing a transcriptional fusion (pvd-inaZ) of an iron-regulated promoter to an ice nucleation reporter gene (inaZ). Pf-5 containing pvd-inaZ expresses INA that is inversely related to the iron availability of a growth medium (J. E. Loper and S. E. Lindow, Appl. Environ. Microbiol. 60:1934-1941, 1994). INA expressed by rhizosphere populations of Pf-5 containing pvd-inaZ was at a maximum within 12 to 24 h following inoculation of the bacterium onto bean roots and typically decreased gradually during the following 4 days. Iron availability in the soil, which was altered by the addition of chelators, influenced INA expressed by rhizosphere populations of Pf-5 containing pvd-inaZ. In soil adjusted to a pH of 7.0 or 8.0 by adding Ca(OH)2, rhizosphere populations of Pf-5 containing pvd-inaZ expressed greater INA, indicating lower iron availability, than they did in the nonamended soil at a pH of 5.4. Similarly, rhizosphere populations of Pf-5 containing pvd-inaZ expressed less INA in an agricultural soil of pH 5.4 than in other agricultural soils ranging in pH from 6.4 to 7.7. These results conform to the predictions of chemical models stating that pH is a major factor influencing iron availability in soil solutions. The results of this study indicate that P. fluorescens Pf-5 encountered an iron-limited environment immediately after it was inoculated onto bean roots planted in agricultural field soils. One to two days after the bacterium was inoculated onto root surfaces, however, iron became more available to rhizosphere populations of Pf-5. We speculate that iron acquisition systems of plants and other rhizosphere organisms may provide available sources of iron to established rhizosphere populations of P. fluorescens. PMID:8979343

  14. 40 CFR 796.3500 - Hydrolysis as a function of pH at 25 °C.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... dihydrogen phosphate; 145 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (3) pH 11.00: use 250 mL of 0.0500M sodium bicarbonate; 113 mL of 0.100M sodium hydroxide; and adjust... phthalate; 113 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (2) pH...

  15. 40 CFR 796.3500 - Hydrolysis as a function of pH at 25 °C.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... dihydrogen phosphate; 145 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (3) pH 11.00: use 250 mL of 0.0500M sodium bicarbonate; 113 mL of 0.100M sodium hydroxide; and adjust... phthalate; 113 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (2) pH...

  16. 40 CFR 796.3500 - Hydrolysis as a function of pH at 25 °C.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... dihydrogen phosphate; 145 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (3) pH 11.00: use 250 mL of 0.0500M sodium bicarbonate; 113 mL of 0.100M sodium hydroxide; and adjust... phthalate; 113 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (2) pH...

  17. 40 CFR 796.3500 - Hydrolysis as a function of pH at 25 °C.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... dihydrogen phosphate; 145 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (3) pH 11.00: use 250 mL of 0.0500M sodium bicarbonate; 113 mL of 0.100M sodium hydroxide; and adjust... phthalate; 113 mL of 0.100M sodium hydroxide; and adjust volume to 500 mL with reagent-grade water. (2) pH...

  18. The Methods Behind PH WINS

    PubMed Central

    Leider, Jonathon P.; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers—a nationally representative data set for permanently employed state health agency central office employees comprising over 10 000 responses, and a pilot data set with approximately 12 000 local and regional health department staff responses. PMID:26422490

  19. Long-term tobacco plantation induces soil acidification and soil base cation loss.

    PubMed

    Zhang, Yuting; He, Xinhua; Liang, Hong; Zhao, Jian; Zhang, Yueqiang; Xu, Chen; Shi, Xiaojun

    2016-03-01

    Changes in soil exchangeable cations relative to soil acidification are less studied particularly under long-term cash crop plantation. This study investigated soil acidification in an Ali-Periudic Argosols after 10-year (2002-2012) long-term continuous tobacco plantation. Soils were respectively sampled at 1933 and 2143 sites in 2002 and 2012 (also 647 tobacco plants), from seven tobacco plantation counties in the Chongqing Municipal City, southwest China. After 10-year continuous tobacco plantation, a substantial acidification was evidenced by an average decrease of 0.20 soil pH unit with a substantial increase of soil sites toward the acidic status, especially those pH ranging from 4.5 to 5.5, whereas 1.93 kmol H(+) production ha(-1) year(-1) was mostly derived from nitrogen (N) fertilizer input and plant N uptake output. After 1 decade, an average decrease of 27.6 % total exchangeable base cations or of 0.20 pH unit occurred in all seven tobacco plantation counties. Meanwhile, for one unit pH decrease, 40.3 and 28.3 mmol base cations kg(-1) soil were consumed in 2002 and 2012, respectively. Furthermore, the aboveground tobacco biomass harvest removed 339.23 kg base cations ha(-1) year(-1) from soil, which was 7.57 times higher than the anions removal, leading to a 12.52 kmol H(+) production ha(-1) year(-1) as the main reason inducing soil acidification. Overall, our results showed that long-term tobacco plantation not only stimulated soil acidification but also decreased soil acid-buffering capacity, resulting in negative effects on sustainable soil uses. On the other hand, our results addressed the importance of a continuous monitoring of soil pH changes in tobacco plantation sites, which would enhance our understanding of soil fertility of health in this region. PMID:26566613

  20. 20 CFR 345.118 - Adjustments.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... calendar year because of an error that does not constitute a compensation adjustment as defined in... compensation adjustment as defined in paragraph (b) of this section, the employer shall adjust the error by... compensation, proper adjustments with respect to the contributions shall be made, without interest,...

  1. 20 CFR 345.118 - Adjustments.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... calendar year because of an error that does not constitute a compensation adjustment as defined in... compensation adjustment as defined in paragraph (b) of this section, the employer shall adjust the error by... compensation, proper adjustments with respect to the contributions shall be made, without interest,...

  2. Adjusting to University: The Hong Kong Experience

    ERIC Educational Resources Information Center

    Yau, Hon Keung; Sun, Hongyi; Cheng, Alison Lai Fong

    2012-01-01

    Students' adjustment to the university environment is an important factor in predicting university outcomes and is crucial to their future achievements. University support to students' transition to university life can be divided into three dimensions: academic adjustment, social adjustment and psychological adjustment. However, these…

  3. 12 CFR 19.240 - Inflation adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b)...

  4. 12 CFR 19.240 - Inflation adjustments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b)...

  5. 12 CFR 19.240 - Inflation adjustments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b)...

  6. Extracellular pH modulates the activity of cultured human osteoblasts.

    PubMed

    Kaysinger, K K; Ramp, W K

    1998-01-01

    The effect of medium pH on the activity of cultured human osteoblasts was investigated in this study. Osteoblasts derived from explants of human trabecular bone were grown to confluence and subcultured. The first-pass cells were incubated in Hepes-buffered media at initial pHs adjusted from 7.0 to 7.8. Osteoblast function was evaluated by measuring lactate production, alkaline phosphatase activity, proline hydroxylation, DNA content, and thymidine incorporation. Changes in medium pH were determined from media pHs recorded at the beginning and end of the final 48 h incubation period. As medium pH increased through pH 7.6, collagen synthesis, alkaline phosphatase activity, and thymidine incorporation increased. DNA content increased from pH 7.0 to 7.2, plateaued from pH 7.2 to 7.6, and increased again from pH 7.6 to 7.8. The changes in the medium pH were greatest at pHs 7.0 and 7.8, modest at pHs 7.4 and 7.6, and did not change at 7.2, suggesting that the pHs are migrating towards pH 7.2. Lactate production increased at pH 7.0 but remained constant from 7.2 to 7.8. These results suggest that in the pH range from 7.0-7.6 the activity of human osteoblasts increases with increasing pH, that this increase in activity does not require an increase in glycolytic activity, and that pH 7.2 may be the optimal pH for these cells.

  7. Uptakes of Cs and Sr on San Joaquin soil measured following ASTM method C1733.

    SciTech Connect

    Ebert, W.L.; Petri, E.T.

    2012-04-04

    x 10{sup -5} m, 1 x 10{sup -4} m, and 5 x 10{sup -4} m to measure the effects of the Cs and Sr concentrations on their uptake by the soil. The pH values of all solutions were adjusted to about pH 8.5 so that the effects of pH and concentration could be measured separately. The 1 x 10{sup -4} m solutions were used to measure the repeatability of the test and the effects of duration, scale, and imposed pH on the test response.

  8. Phosphorus Solubility in Response to Acidification of Dairy Manure Amended Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) additions from animal manure beyond plant needs results in accumulated soil calcium phosphate (Ca-P). Although stable near neutral pH levels, there is concern about the solubility of accumulated soil Ca-P when soil pH conditions become acidic, potentially releasing water soluble P (WS...

  9. Alkaline pH sensor molecules.

    PubMed

    Murayama, Takashi; Maruyama, Ichiro N

    2015-11-01

    Animals can survive only within a narrow pH range. This requires continual monitoring of environmental and body-fluid pH. Although a variety of acidic pH sensor molecules have been reported, alkaline pH sensor function is not well understood. This Review describes neuronal alkaline pH sensors, grouped according to whether they monitor extracellular or intracellular alkaline pH. Extracellular sensors include the receptor-type guanylyl cyclase, the insulin receptor-related receptor, ligand-gated Cl- channels, connexin hemichannels, two-pore-domain K+ channels, and transient receptor potential (TRP) channels. Intracellular sensors include TRP channels and gap junction channels. Identification of molecular mechanisms underlying alkaline pH sensing is crucial for understanding how animals respond to environmental alkaline pH and how body-fluid pH is maintained within a narrow range.

  10. [Effects of soil factors on arbuscular mycorrhizae (AM) fungi around roots of wild plants].

    PubMed

    Gai, Jingping; Liu, Runjin

    2003-03-01

    150 rhizospheric soil samples were collected from 45 wild plants distributed in Shandong Province during 1995-1997. More than forty species of AM fungi were isolated, and the effects of some soil factors on AM fungi were also investigated. It was proved that soil conditions were important factors to the colonization, growth, and distribution of AM fungi. Spore numbers were highest in brown earth, and lowest in alkali-saline soil. Glomus occurred in all types of soil. The occurrence frequency of Gigaspora and Scutellospora was much higher in brown earth. The distribution of AM fungi was also affected by soil pH. Glomus occurred in soil with a wide pH range. The greater of soil alkalinity, the more Glomus were found, while the greater of soil acidity, the more Acaulospora were isolated. Scutellospora occurred mostly in soil with pH of 6.0-7.0, and Gigaspora distributed mainly in acid soil. PMID:12836565

  11. How mangrove forests adjust to rising sea level

    USGS Publications Warehouse

    Krauss, Ken W.; McKee, Karen L.; Lovelock, Catherine E.; Cahoon, Donald R.; Saintilan, Neil; Reef, Ruth; Chen, Luzhen

    2014-01-01

    Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to sea-level rise. To persist, mangrove ecosystems must adjust to rising sea level by building vertically or become submerged. Mangroves may directly or indirectly influence soil accretion processes through the production and accumulation of organic matter, as well as the trapping and retention of mineral sediment. In this review, we provide a general overview of research on mangrove elevation dynamics, emphasizing the role of the vegetation in maintaining soil surface elevations (i.e. position of the soil surface in the vertical plane). We summarize the primary ways in which mangroves may influence sediment accretion and vertical land development, for example, through root contributions to soil volume and upward expansion of the soil surface. We also examine how hydrological, geomorphological and climatic processes may interact with plant processes to influence mangrove capacity to keep pace with rising sea level. We draw on a variety of studies to describe the important, and often under-appreciated, role that plants play in shaping the trajectory of an ecosystem undergoing change.

  12. How mangrove forests adjust to rising sea level.

    PubMed

    Krauss, Ken W; McKee, Karen L; Lovelock, Catherine E; Cahoon, Donald R; Saintilan, Neil; Reef, Ruth; Chen, Luzhen

    2014-04-01

    Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to sea-level rise. To persist, mangrove ecosystems must adjust to rising sea level by building vertically or become submerged. Mangroves may directly or indirectly influence soil accretion processes through the production and accumulation of organic matter, as well as the trapping and retention of mineral sediment. In this review, we provide a general overview of research on mangrove elevation dynamics, emphasizing the role of the vegetation in maintaining soil surface elevations (i.e. position of the soil surface in the vertical plane). We summarize the primary ways in which mangroves may influence sediment accretion and vertical land development, for example, through root contributions to soil volume and upward expansion of the soil surface. We also examine how hydrological, geomorphological and climatic processes may interact with plant processes to influence mangrove capacity to keep pace with rising sea level. We draw on a variety of studies to describe the important, and often under-appreciated, role that plants play in shaping the trajectory of an ecosystem undergoing change.

  13. Environmentally adjusted productivity measurement: an Australian case study.

    PubMed

    Nanere, Marthin; Fraser, Iain; Quazi, Ali; D'Souza, Clare

    2007-10-01

    This paper critically examines various methods for estimating productivity incorporating environmental effects for the Australian agricultural sector. The agricultural sector has been selected because of its strategic position in the economy of Australia. The findings of this study indicate that the application of environmentally adjusted productivity methods is a credible approach to measure productivity, in the context of sustainable development. Although the empirical findings of this research are case study specific, the results provide evidence supporting the adoption of these techniques to other sectors of the economy when measuring productivity and needing to be cognisant of sustainable development. The findings suggest that adjusting for the environmental impacts of soil erosion can result in higher or lower agricultural productivity depending on the assumptions we make regarding damage costs of erosion. It is argued in this paper that, for soil erosion in Australia, assumptions yielding higher productivity (i.e., upwardly adjusted) are justified. Finally, the findings of this study and the use of the methods presented point to important gaps in data availability. This gap needs to be addressed by policy makers if sustainable development objectives are to be credibly assessed using these techniques.

  14. Inoculating plants with the endophytic bacterium Pseudomonas sp. Ph6-gfp to reduce phenanthrene contamination.

    PubMed

    Sun, Kai; Liu, Juan; Gao, Yanzheng; Sheng, Yuehui; Kang, Fuxing; Waigi, Michael Gatheru

    2015-12-01

    Plant organic contamination poses a serious threat to the safety of agricultural products and human health worldwide, and the association of endophytic bacteria with host plants may decrease organic pollutants in planta. In this study, we firstly determined the growth response and biofilm formation of endophytic Pseudomonas sp. Ph6-gfp, and then systematically evaluated the performance of different plant colonization methods (seed soaking (SS), root soaking (RS), leaf painting (LP)) for circumventing the risk of plant phenanthrene (PHE) contamination. After inoculation for 48 h, strain Ph6-gfp grew efficiently with PHE, oxalic acid, or malic acid as the sole sources of carbon and energy. Moreover, strain Ph6-gfp could form robust biofilms in LB medium. In greenhouse hydroponic experiments, strain Ph6-gfp could actively colonize inoculated plants internally, and plants colonized with Ph6-gfp showed a higher capacity for PHE removal. Compared with the Ph6-gfp-free treatment, the accumulations of PHE in Ph6-gfp-colonized plants via SS, RS, and LP were 20.1, 33.1, and 7.1 %, respectively, lower. Our results indicate that inoculating plants with Ph6-gfp could lower the risk of plant PHE contamination. RS was most efficient for improving PHE removal in whole plant bodies by increasing the cell numbers of Ph6-gfp in plant roots. The findings in this study provide an optimized method to strain Ph6-gfp reduce plant PAH residues, which may be applied to agricultural production in PAH-contaminated soil.

  15. A surface complexation and ion exchange model of Pb and Cd competitive sorption on natural soils

    NASA Astrophysics Data System (ADS)

    Serrano, Susana; O'Day, Peggy A.; Vlassopoulos, Dimitri; García-González, Maria Teresa; Garrido, Fernando

    2009-02-01

    The bioavailability and fate of heavy metals in the environment are often controlled by sorption reactions on the reactive surfaces of soil minerals. We have developed a non-electrostatic equilibrium model (NEM) with both surface complexation and ion exchange reactions to describe the sorption of Pb and Cd in single- and binary-metal systems over a range of pH and metal concentration. Mineralogical and exchange properties of three different acidic soils were used to constrain surface reactions in the model and to estimate surface densities for sorption sites, rather than treating them as adjustable parameters. Soil heterogeneity was modeled with >FeOH and >SOH functional groups, representing Fe- and Al-oxyhydroxide minerals and phyllosilicate clay mineral edge sites, and two ion exchange sites (X - and Y -), representing clay mineral exchange. An optimization process was carried out using the entire experimental sorption data set to determine the binding constants for Pb and Cd surface complexation and ion exchange reactions. Modeling results showed that the adsorption of Pb and Cd was distributed between ion exchange sites at low pH values and specific adsorption sites at higher pH values, mainly associated with >FeOH sites. Modeling results confirmed the greater tendency of Cd to be retained on exchange sites compared to Pb, which had a higher affinity than Cd for specific adsorption on >FeOH sites. Lead retention on >FeOH occurred at lower pH than for Cd, suggesting that Pb sorbs to surface hydroxyl groups at pH values at which Cd interacts only with exchange sites. The results from the binary system (both Pb and Cd present) showed that Cd retained in >FeOH sites decreased significantly in the presence of Pb, while the occupancy of Pb in these sites did not change in the presence of Cd. As a consequence of this competition, Cd was shifted to ion exchange sites, where it competes with Pb and possibly Ca (from the background electrolyte). Sorption on >SOH

  16. An invisible soil acidification: Critical role of soil carbonate and its impact on heavy metal bioavailability.

    PubMed

    Wang, Cheng; Li, Wei; Yang, Zhongfang; Chen, Yang; Shao, Wenjing; Ji, Junfeng

    2015-01-01

    It is well known that carbonates inhibit heavy metals transferring from soil to plants, yet the mechanism is poorly understood. Based on the Yangtze River delta area, we investigated bioaccumulation of Ni and Cd in winter wheat as affected by the presence of carbonates in soil. This study aimed to determine the mechanism through which soil carbonates restrict transport and plant uptake of heavy metals in the wheat cropping system. The results indicate that soil carbonates critically influenced heavy metal transfer from soil to plants and presented a tipping point. Wheat grains harvested from carbonates-depleted (due to severe leaching) soils showed Ni and Cd concentrations 2-3 times higher than those of the wheat grains from carbonates-containing soils. Correspondingly, the incidence of Ni or Cd contamination in the wheat grain samples increased by about three times. With the carbonate concentration >1% in soil, uptake and bioaccumulation of Ni and Cd by winter wheat was independent with the soil pH and carbonate content. The findings suggest that soil carbonates play a critical role in heavy metal transfer from soil to plants, implying that monitoring soil carbonate may be necessary in addition to soil pH for the evaluating soil quality and food safety. PMID:26227091

  17. An invisible soil acidification: Critical role of soil carbonate and its impact on heavy metal bioavailability

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Li, Wei; Yang, Zhongfang; Chen, Yang; Shao, Wenjing; Ji, Junfeng

    2015-07-01

    It is well known that carbonates inhibit heavy metals transferring from soil to plants, yet the mechanism is poorly understood. Based on the Yangtze River delta area, we investigated bioaccumulation of Ni and Cd in winter wheat as affected by the presence of carbonates in soil. This study aimed to determine the mechanism through which soil carbonates restrict transport and plant uptake of heavy metals in the wheat cropping system. The results indicate that soil carbonates critically influenced heavy metal transfer from soil to plants and presented a tipping point. Wheat grains harvested from carbonates-depleted (due to severe leaching) soils showed Ni and Cd concentrations 2-3 times higher than those of the wheat grains from carbonates-containing soils. Correspondingly, the incidence of Ni or Cd contamination in the wheat grain samples increased by about three times. With the carbonate concentration >1% in soil, uptake and bioaccumulation of Ni and Cd by winter wheat was independent with the soil pH and carbonate content. The findings suggest that soil carbonates play a critical role in heavy metal transfer from soil to plants, implying that monitoring soil carbonate may be necessary in addition to soil pH for the evaluating soil quality and food safety.

  18. Evaluating Metal Probe Meters for Soil Testing.

    ERIC Educational Resources Information Center

    Hershey, David R.

    1992-01-01

    Inexpensive metal probe meters that are sold by garden stores can be evaluated by students for their accuracy in measuring soil pH, moisture, fertility, and salinity. The author concludes that the meters are inaccurate and cannot be calibrated in standard units. However, the student evaluations are useful in learning the methods of soil analysis…

  19. Effect of Dead Algae on Soil Permeability

    SciTech Connect

    Harvey, R.S.

    2003-02-21

    Since existing basins support heavy growths of unicellular green algae which may be killed by temperature variation or by inadvertent pH changes in waste and then deposited on the basin floor, information on the effects of dead algae on soil permeability was needed. This study was designed to show the effects of successive algal kills on the permeability of laboratory soil columns.

  20. Soil carbon stock and soil characteristics at Tasik Chini Forest Reserve, Pahang, Malaysia

    NASA Astrophysics Data System (ADS)

    Nur Aqlili Riana, R.; Sahibin A., R.

    2015-09-01

    This study was carried out to determine soil carbon stock and soil characteristic at Tasik Chini Forest Reserve (TCFR), Pahang. A total of 10 (20 m x 25 m) permanent sampling plot was selected randomly within the area of TCFR. Soil samples were taken from all subplots using dutch auger based on soil depth of 0-20cm, 20-40cm, 40-60cm. Soil parameters determined were size distribution, soil water content, bulk density, organic matter, organic carbon content, pH and electrical conductivity. All parameters were determined following their respective standard methods. Results obtained showed that the soil in TCFR was dominated by clay texture (40%), followed by sandy clay loam (30%), loam (20%). Silty clay, clay loam and sandy loam constitutes about 10% of the soil texture. Range of mean percentage of organic matter and bulk density are from 2.42±0.06% to 11.64±0.39% and 1.01 to 1.04 (gcm-ł), respectively. Soil pH are relatively very acidic and mean of electrical conductivity is low. Soil carbon content ranged from 0.83±0.03 to 1.87±0.41%. All soil parameter showed a decreasing trend with depth except electrical conductivity. ANOVA test of mean percentage of organic matter, soil water content, soil pH and electrical conductivity showed a significant difference between plot (p<0.05). However there are no significant difference of mean bulk density between plots (p>0.05). There are no significant difference in mean percentage of soil water content, organic matter and bulk density between three different depth (p>0.05). There were a significant difference on percentage of soil carbon organic between plots and depth. The mean of soil organic carbon stock in soil to a depth of 60 cm calculated was 35.50 t/ha.

  1. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, Layton C.

    1997-01-01

    An adjustable link for kinematic mounting systems. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two.

  2. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, L.C.

    1997-07-01

    An adjustable link for kinematic mounting systems is disclosed. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two. 3 figs.

  3. Adsorption and desorption of ammonium by maple wood biochar as a function of oxidation and pH.

    PubMed

    Wang, Bing; Lehmann, Johannes; Hanley, Kelly; Hestrin, Rachel; Enders, Akio

    2015-11-01

    The objective of this work was to investigate the retention mechanisms of ammonium in aqueous solution by using progressively oxidized maple wood biochar at different pH values. Hydrogen peroxide was used to oxidize the biochar to pH values ranging from 8.1 to 3.7, with one set being adjusted to a pH of 7 afterwards. Oxidizing the biochars at their lowered pH did not increase their ability to adsorb ammonium. However, neutralizing the oxygen-containing surface functional groups on oxidized biochar to pH 7 increased ammonia adsorption two to three-fold for biochars originally at pH 3.7-6, but did not change adsorption of biochars oxidized to pH 7 and above. The adsorption characteristics of ammonium are well described by the Freundlich equation. Adsorption was not fully reversible in water, and less than 27% ammonium was desorbed in water in two consecutive steps than previously adsorbed, for biochars with a pH below 7, irrespective of oxidation. Recovery using an extraction with 2M KCl increased from 34% to 99% of ammonium undesorbed by both preceding water extractions with increasing oxidation, largely irrespective of pH adjustment. Unrecovered ammonium in all extractions and residual biochar was negligible at high oxidation, but increased to 39% of initially adsorbed amounts at high pH, likely due to low amounts adsorbed and possible ammonia volatilization losses.

  4. Key soil functional properties affected by soil organic matter - evidence from published literature

    NASA Astrophysics Data System (ADS)

    Murphy, Brian

    2015-07-01

    The effect of varying the amount of soil organic matter on a range of individual soil properties was investigated using a literature search of published information largely from Australia, but also included relevant information from overseas. Based on published pedotransfer functions, soil organic matter was shown to increase plant available water by 2 to 3 mm per 10 cm for each 1% increase in soil organic carbon, with the largest increases being associated with sandy soils. Aggregate stability increased with increasing soil organic carbon, with aggregate stability decreasing rapidly when soil organic carbon fell below 1.2 to 1.5 5%. Soil compactibility, friability and soil erodibility were favourably improved by increasing the levels of soil organic carbon. Nutrient cycling was a major function of soil organic matter. Substantial amounts of N, P and S become available to plants when the soil organic matter is mineralised. Soil organic matter also provides a food source for the microorganisms involved in the nutrient cycling of N, P, S and K. In soils with lower clay contents, and less active clays such as kaolinites, soil organic matter can supply a significant amount of the cation exchange capacity and buffering capacity against acidification. Soil organic matter can have a cation exchange capacity of 172 to 297 cmol(+)/kg. As the cation exchange capacity of soil organic matter varies with pH, the effectiveness of soil organic matter to contribute to cation exchange capacity below pH 5.5 is often minimal. Overall soil organic matter has the potential to affect a range of functional soil properties.

  5. Hydroxyatrazine in soils and sediments

    USGS Publications Warehouse

    Lerch, R.N.; Thurman, E.M.; Blanchard, P.E.

    1999-01-01

    Hydroxyatrazine (HA) is the major metabolite of atrazine in most surface soils. Knowledge of HA sorption to soils, and its pattern of stream water contamination suggest that it is persistent in the environment. Soils with different atrazine use histories were collected from four sites, and sediments were collected from an agricultural watershed. Samples were exhaustively extracted with a mixed-mode extractant, and HA was quantitated using high performance liquid chromatography with UV detection. Atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were also measured in all samples. Concentrations of HA were considerably greater than concentrations of atrazine, DEA, and DIA in all soils and sediments studied. Soil concentrations of HA ranged from 14 to 640 ??g/kg with a median concentration of 84 ??g/kg. Sediment concentrations of HA ranged from 11 to 96 ??g/kg, with a median concentration of 14 ??g/kg. Correlations of HA and atrazine concentrations to soil properties indicated that HA levels in soils were controlled by sorption of atrazine. Because atrazine hydrolysis is known to be enhanced by sorption and pH extremes, soils with high organic matter (OM) and clay content and low pH will result in greater atrazine sorption and subsequent hydrolysis. Significant correlation of HA concentrations to OM, pH, and cation exchange capacity of sediments indicated that mixed-mode sorption (i.e., binding by cation exchange and hydrophobic interactions) was the mechanism controlling HA levels in sediment. The presence of HA in soils and stream sediments at the levels observed support existing hypotheses regarding its transport in surface runoff. These results also indicated that persistence of HA in terrestrial and aquatic ecosystems is an additional risk factor associated with atrazine usage.

  6. Evaluation the anaerobic hydrolysis acidification stage of kitchen waste by pH regulation.

    PubMed

    Wang, Yaya; Zang, Bing; Li, Guoxue; Liu, Yu

    2016-07-01

    This study analyzed the composition and characteristic of kitchen waste (KW) from closed cleaning sta