Plant Waters Research Articles

EXAFS evidence of sorbed arsenic(V) and pharmacosiderite in a soil overlying the Echassières geochemical anomaly, Allier, France

Abstract At Echassières (Allier, France), arsenic speciation was determined in a soil developed over a micaschist where Hercynian hydrothermal mineralization, including arsenopyrite FeAsS and löllingite FeAs2, has lead to a regional As anomaly. The overlying soils which have developed from long term weathering exhibit As levels as high as 900 ppm in the richest area, where the saprolite contains up to 5200 ppm As. Analysis by powder XRD, μ-X-ray diffraction on the 20μm scale, SEM-EDS and electron micro-probe analyses revealed that As, released from arsenopyrite and/or löllingite alteration, is concentrated in a secondary iron arsenate, pharmacosiderite, (Bax,K2-2x) (Fe,Al)4 (AsO4)3 (OH)5 • 6H2O. Quantitative mineralogical analysis by Rietveld refinement indicates that the proportion of As hosted by this mineral decreases systematically from the saprolite to the topsoil (from 70 % to 30 % of the total bulk As content, respectively). EXAFS spectroscopy indicates that the main form of the As occurring with pharmacosiderite, consists of As(V) ions sorbed on iron oxides. Sorption processes, which dominate As speciation in the topsoil horizons, appear as a key mechanism able to delay As dissemination from soils to plant and surface waters, provided that pH and Eh conditions remain sufficiently acidic and oxidizing, respectively.

The oxygen isotopic compositions of silica phytoliths and plant water in grasses: implications for the study of paleoclimate

Information about climatic conditions during plant growth is preserved by the oxygen-isotope composition of biogenic silica (phytoliths) deposited in grasses. The oxygen-isotope composition of phytolith silica is dependent on soil-water δ 18O values, relative humidity and evapotranspiration, and temperature during plant growth. Phytolith and plant-water δ 18O values for C3 ( A. breviligulata) and C4 ( C. longifolia) grasses from natural and greenhouse sites in southwestern Ontario were used to compare the isotopic fractionation between biogenic silica and water in various parts of these living plants. For non or weakly transpiring tissues (rhizomes, stems, sheaths) in both grass species, the Δ 18O silica-plant water remained constant at ∼34‰, and the δ 18O and δD values of plant water collected from pre-dawn and mid-day samplings showed little variation. These plant waters were only slightly enriched in 18O and D relative to water provided to the grasses. Isotopic temperatures calculated from the silica and plant-water isotopic data matched measured growing temperatures for the region. By comparison, the upper leaf water was extremely enriched in oxygen-18 and deuterium at maximum rates of transpiration relative to water from non-transpiring tissues, as were the calculated, steady-state values for leaf-water δ 18O and δD. Silica produced in the transpiring tissues (leaf, inflorescence) has higher δ 18O values than silica from non-transpiring tissues, but the enrichment is modest compared to upper leaf water under mid-day conditions. Leaf phytoliths have formed from plant water typical of average conditions in the lower leaf, where the extreme 18O-enrichment is not encountered. C. longifolia was also collected from Alberta and Nebraska, where growing conditions are different from southwestern Ontario. Phytoliths at all three sites have a similar pattern of δ 18O values within the plants, but the isotopic separation between leaf and stem silica increases from 4 to 8‰ as average relative humidity decreases. The difference between actual growing temperature and that calculated using measured δ 18O values for stem silica and local meteoric water became progressively larger as relative humidity decreased, likely because of evaporative 18O-enrichment of soil water. Such effects are most pronounced in arid environments and pertinent in grasslands where much of the active rooting zone can be situated at the shallower depths most affected by the 18O-enrichment of soil water.

Trace metals in groundwater and treatment plant product water of the central region of Saudi Arabia

Trace metals were assessed in the raw and product waters of 8 water treatment plants in Riyadh, Buraydah and Unayzah (Saudi Arabia). Samples were analyzed for 12 trace metals by inductively coupled plasma spectrophotometer (ICP). All the detected metals were within the permissible limits of WHO. Cd, Ni and Se were absent in all plant waters. It was found that concentrations of metals like As, Fe and Mn decreased after various treatment processes compared to their levels in raw water. Al increased in all product waters of the plants that use chemicals in the softening process. The increase in Al levels is observed to take place after the softening process where sodium aluminate is used. However, most of Al is removed by sand filtration. Zn and Cu levels in the product water have increased in many cases, which may be attributed to the pipings. The removal of trace metals by reverse osmosis was in the range of 78.8–100%. Assessment of trace metals in the water distribution network is recommended.

Preconcentration determination of inorganic anions and organic acids in power plant waters separation optimization through control of column capacity and selectivity

An anion-exchange column has been developed for the separation of anions inpower plant waters. The column has been optimized, in terms of capacity and selectivity, to allow the isocratic separation of weakly retained organic and inorganic anions, in addition to more strongly retained anions. This new moderate capacity anion-exchange column was utilised for the preconcentration ion chromatography (IC) determination of key anions, at low μg/l levels, in a numver of power plant waters. Correlation coefficients obtained for linearity plots of fluoride, acetate, formate, chloride, nitrite, sulfate and oxalate in pure water, ammoniated and morpholinated waters were in the range 0.996–0.999. The correlation coefficients obtained for the seven anions in borated water were in the range 0.995–0.999, except for fluoride and chloride, which were 0.993 and 0.991, respectively.

Pre-concentration techniques for bromate analysis in ozonated waters

Ozonation of surface waters that contain bromide result in the formation of bromate which has been identified as a potential carcinogen. Regulation of bromate at the preferred concentration of less than 5 μg/1 is being delayed due to lack of a validated analytical method for quantification at this level. This paper describes the integrated use of a silver cation resin to reduce closely eluting chloride from aqueous samples followed by a chelation column to remove leached silver prior to pre-concentration of 4-ml samples on an anion-exchange column. A borate eluent used under gradient conditions allows for bromate determination at 0.5 μ/1 in treatment plant waters that, hitherto, were reported to be devoid of bromate.

Determination of 89Sr and 90Sr in highly radioactive water from a nuclear power plant

The main criterion in assaying strontium radionuclides is to obtain radiochemically pure strontium sources for beta-particle counting. Nuclear power plant waters contain both 89Sr and 90Sr accompanied by many beta-particle and gamma-ray emitting fission and neutron-activation products. The latter activities can sometimes exceed those of strontium by a factor of 10 7. Efficient purification procedures must be used to remove these products, preferably at an initial stage of analysis to reduce the radiation risk to personnel. A method has been developed in which a water sample is passed through a prefilter installed on top of an ion-exchange column filled with Dowex-50 resin in H + form. This prefilter is impregnated with ferrocyanides and manganese dioxide and retains most of the interfering radionuclides while the underlying cation-exchanger takes up strontium ions. A few additional purification steps result in a strontium salt that is free from other radioactivity.

Improved method for the determination of manganese in nuclear power plant waters

An improved method for manganese determination in nuclear power plant waters has been developed. This method combines a selective chelation concentration method with a unique analytical separation for manganese from the interfering matrix using a weak acid cation exchange column. The detection sensitivity by conventional post-column derivatization is improved with the combination of chemical eluent suppression and subsequent post-column derivatization. The detection limit for manganese in ammonium matrix is approximately 2 pg/ml and the limit of quantitation 10 pg/ml with 100 ml sample volume.

Solid Phase Spectrophotometric Microdetermination of Manganese

Abstract A method for the determination of microgram per litre level of manganese has been developed, based on Solid-Phase Spectrophotometry (SPS). Manganese reacts with 3-bromobenzohydroxamic acid to form a 1:3 anionic brown-reddish complex of Mn(III), which is fixed on a dextran-type anion-exchange resin. Resin phase absorbance is measured directly and allows the determination of manganese in the range 5–100 μg 1−1, with a RSD of 4%. The method has been applied to the determination of manganese in different samples, namely plant tissue extracts, active charcoals and waters.

Peak-shape analysis and noise evaluation in suppressed ion chromatography for ultra-trace ion analysis

Numerical analysis was used to study the performance of a suppressed ion chromatographic system with on-line preconcentration for ultra-trace ion determination in ultra-pure power plant waters. Peakshape analysis by the Edgeworth—Cramér series fitting method was applied in order to cheek non-linear concentration-dependent effects, so as to evaluate the best experimental practice with regard to the linear calibration range. Noise evaluation by Edgeworth-cramér fitting residuals and Fourier analysis is discussed in order to establish the detection limits. Results of the checks made for strictly linear conditions and determination of the quantification limits for sodium, chloride and sulphate ions are reported.

Separation and detection of group I and II cations by ion chromatography

Lithium, sodium, magnesium and calcium are routinely monitored in environmental samples and in analysis of ultrapure water for semiconductor and power generation facilities. The use of graphite furnace, atomic absorption and ICP have long been recognized as the analytical instruments of science for the detection and quantization of these cations. These spectral detectors detection method of choice of because of their inherent speed, sensitivity, and lack of interferences. This paper will present results of a recent advance using ion chromatography with chemical suppression and conductivity detection for group I and group II cations. The method allows the separation and detection of lithium, sodium, ammonium, potassium, magnesium, calcium and morpholine at the sub-μg/l levels in ultrapure water and common power plant waters.

Table-mountain geology and surficial geochemistry: Chimantá Massif, Venezuelan Guayana shield

The Chimantá Massif consists of eleven table-mountains (up to more than 2600 m in elevation), which are remnants of the Auyán-tepui planation surface (with a possible Cretaceous initial age) cut into siliceous sandstones of the Matauí Formation, the highest unit of the Precambrian Roraima Group. The sandstones are gently folded and several fracture systems control weathering and erosion. The Matauí Formation was intruded by Precambrian diabase dikes and sills. This relationship invalidates previous suggestions that the Roraima Group contained an unconformity separating Lower Precambrian from upper Mesozoic units. Ombrotrophic peat-bogs are conspicuous features on the summits of the table-mountains. Peat formation probably began in the early Holocene, initiated by algae and lichens, accumulation of humidity and detritus, plant colonization of weathered rock surfaces, a low rate of organic decomposition, and high rainfall. The geochemistry of Ca, K, Fe, Si, Cl, I, and Br is discussed. The nutrient cycle consists of sunlight, which contributes to photosynthetic processes, and rainwater, which partly provides the nutrients, dissolves the bedrock, and transports the nutrients from the bedrock and eventually out of the system as river or stream water. The natural waters (rain-, river and stream, peat, and plant waters) are acid (pH range 3.5–4.7) and act on the sandstone, dissolving the siliceous cement and liberating the sand grains. This is the primary weathering mechanism and produces the karst-like topography of the table-mountain summits. Through geologic time (probably up to about 70 million years), this weathering has produced the spectacular table-mountain and savanna landscape of the Gran Sabana.

BOD測定における硝化性酸素要求量（NOD）の寄与

BOD (Biochemical Oxygen Demand) is utilized widely as an index of water quality. However, nitrification is a cause of significant errors in measuring BOD, particularly when a large population of nitrifying organisms are existing in water such as effluents from biological treatment plants. In this case, the use of a nitrification inhibitor is recommended, but it is not used commonly. In order to investigate the amount of nitrogenous oxygen demand (NOD) which is caused by nitrification, BOD with and without inhibitor was measured as samples in the Kitakyushu area. About 70 percent of BOD from the effluents of biological treatment plants was NOD. In the case of influent of biological treatment plant and river waters, 0-39 percent of NOD was contained in BOD.

Adsorption of fatty acids on fine mineral particles as a purification method of industrial wastewaters

Abstract The problem of fines disposal and utilization that has to be faced from most of the mineral processing plants, in relation with the removal of fatty acids (reagents that constitute usual anionic collectors and could be possibly found in flotation plant waters) led to the study of the adsorption of later on fine particles, being in this case magnesite and dolomite. Another main application of this work is in the separation of fines (at sub‐sieve size range) by flotation. Sodium oleate and a commercial tall oil fatty acid were selected in the present. Common parameters and their effect on adsorption were carefully looked at, including the pH of solution and concentration. The presence of modifying reagents (as sodium hexametaphosphate, pyrophosphate and carboxymethyl cellulose) was also examined.

Environmental Status of Bismuth and its Trace Analysis in Alloys Plant Tissues, Animal Tissues and Waters as Ternary Complex with N-p-Methoxyphenyl-2-Furylacrylohydroxamic Acid and a Pyridylazo Reagent

Abstract A new series of reagents, N-phenyl-2-furylacrylohydroxamic acid and its eight analogues, together with eight pyridylazo reagents, were explored for the selective extraction and sensitive spectrophotometric determination of bismuth (III) in standard alloys and environmental matrices. Bismuth was first extracted with a hydroxamic acid into chloroform and a pyridylazo reagent was added to the extract to form an intensely coloured ternary complex for spectrophotometric analysis. The combination of N-p-methoxyphenyl-2-furylacrylohydroxamic acid (MFHA) and 5-iodo-5-(dimethylamino)-2-(2-pyridylazo) phenol (IDEPAP) provided the maximum selectivity and sensitivity (e=6.5 × 104 1 mol−1 cm−1 at 590 nm). The enrichment attained through solvent extraction together with the intense colour of the ternary complex enabled analysis of bismuth at levels of 1ppb (0.001 ppm) and lower.

The Precipitation of Calcium Carbonate from Coal Preparation Plant Circulating Waters

Water recirculation and the addition of lime as a pH modifier may lead to a build up of dissolved calcium salts in coal preparation plant waters. Under certain conditions precipitates may form on product filters or dewatering screens, with the possibility of serious operating difficulties, even to the extent of total plant shutdowns in extreme cases. In this paper the common causes of such precipitation are discussed. The application of Saturation and Stability Indices is demonstrated as a means of characterizing, and possibly predicting, from a basic water analysis, the behaviour of calcium carbonate salts in water. The chemical behaviour of calcium salts in solution is discussed and a number of options are described by which precipitation may be avoided. These include the addition of a prescribed calcite inhibitor, better pH control and the use of an alternative pH modifier.

Photosynthetic Rate Control in Sorghum: Stomatal and Nonstomatal Factors1

The purpose of this series of experiments was to determine the cause of photosynthetic rate responses to environmental effectors in one grain sorghumh ybrid [Sorghum bicolor (L.) Moench cv. ATX623 ✕ TX430]. Field experiments were conducted over a 4‐year period (1980–1983) at two locations using a range irrigation levels, to provide different degrees of plant waters tress. One site had a fine loamy sand soil (fine loamy, mixed, thermic family of Aridic Paleustaifs) with the second site having a clay loam (fine mixed, thermic family of Torrertic Paleustolls). Gas exchange rates of individual leaves were monitored on both a diurnal and seasonal basis. The results indicated that the primary cause of the photosynthetic rate changes due to leaf age, water stress, and photon flux density effects was related to mesophyll problems rather than due to stomatal conductance limitations. Increasing leaf age and environmental stress affected the photosynthetic processes by reducing the CO2 saturated rate (Amax) and the assimilation rate at all intercellular CO2 concentrations evaluated. The assimilation rate per unit photon flux density was also reduced in water‐stressed plants. Stomatal conductance responded to photosynthetic rate changes to maintain a relatively constant intercellular CO2 concentration at ambient CO2 levels. The primary control of photosynthetic carbon fixation in sorghum appears to be related to chloroplast activity rather than to CO2 supply due to stomatal conductance.

A re-investigation of phenol as a spectrophotometric reagent for the determination of nitrate-nitrogen

The advantages of phenol over isomers of dimethylphenol in the determination of nitrate-nitrogen are described. Linear calibration graphs are obtained for the ranges 0–100, 0–400 and 0–20 μg ml l-1 for nitrate-nitrogen; these ranges are suitable for analyses of plant materials, soil extracts and waters. For spiked samples, recoveries of 97.7 to 104.3% were obtained with relative standard deviations of 2.0 to 6.7%. Tolerance to chloride is good, and interferences by nitrite and hydrogen peroxide are easily controlled. A modified Markham microstill for use in automatic analyser systems is described.

Distribution of polychlorinated biphenyls in a municipal wastewater treatment plant and environs

Distribution of polychlorinated biphenyls (PCB) in sewage wastes at a municipal sewage treatment plant was studied, showing that the great bulk of PCBs entering such a treatment plant become adsorbed onto the grit chamber solids and the sludge that is passed from the anaerobic digesters. When appreciable quantities of PCBs are present in sewage, as was the case in this study, significant quantities can nevertheless pass with the effluents discharged from the treatment plant. The PCB concentrations in the treatment plant waters undergoing secondary and tertiary treatment tend to be consistent with the limited solubility properties of the PCBs. However, appreciably higher concentrations can be found in the sediments of waters receiving treatment plant discharges and bioaccumulation in fish is demonstrated readily. Also described are quantitative data on PCBs in soils fertilized with PCB-contaminated sludge.

A critical examination of the curcumin method foe boron analysis of plant tissues, waters and soil extracts. I. Sample size

Abstract The apparent boron content of plant tissues was found to vary with the amount of tissue used. The effect was observed in both ashed and acid extracted plant tissue and is related to the salt content of the material which affects the value of boron obtained in the absence of salts.

New Methods for the Colorimetric Determination of Halogen Residuals. Part II. Free and Total Chlorine

This article discusses a method for the determination of free chlorine using leuco crystal violet as the indicator. It provides accurate and reproducible results with minimal interference from combined chlorine at relatively high water temperatures. The method is very rapid, taking only a matter of seconds to develop the test color, and the stability of the developed color allows ample time for accurate color matching with standards. The effect of sample temperature on the accuracy of the method is negligible over a wide range and constituents normally present in water do not interfere. The oxidized forms of manganese produce the only serious interference found, and in the relatively few waters presenting this problem, it can be solved by using a suitable arsenite modification. Application of the test method in field studies involving swimming pool and treatment plant waters gave results very similar to those obtained by amperometric titration. All reagents were easily prepared and demonstrate exceptional stability in solution form. The test method is successfully used with free‐chlorine concentrations of 2 mg/l or less, but may be extended greater than this concentration by appropriate dilution methods. A very sensitive method for total chlorine is presented and when used in conjunction with the free‐chlorine test, will permit the determination of a combined chlorine residual by difference.