Single Water Extraction Research Articles

Temporal variations of disinfection byproduct precursors in wildfire detritus

The Rim Fire ignited on August 17, 2013 and became the third largest wildfire in California history. The fire consumed 104,131 ha of forested watersheds that were the drinking water source for 2.6 million residents in the San Francisco Bay area. To understand temporal variations in dissolved organic matter (DOM) after the wildfire and its potential impacts on disinfection byproduct (DBP) formation in source water supply, we collected the 0–5 cm ash/soil layer with surface deposits of white ash (high burn severity) and black ash (moderate burn severity) within the Rim Fire perimeter in Oct 2013 (pre-rainfall) for five sequential extractions, and in Dec 2013 (∼87 mm cumulative precipitation) and Aug 2014 (∼617 mm cumulative precipitation) for a single water extraction. Water-extractable DOM was characterized by absorption and fluorescence spectroscopy and DBP formation tests. Both increasing cumulative precipitation in the field or number of extractions in the lab resulted in a significant decrease in specific conductivity, dissolved organic carbon, and DBP formation potential, but an increase in DOM aromaticity (reflected by specific UV absorbance). However, the lab sequential leaching failed to capture the increase of the NOx−-N/NH4+-N ratio and the decrease in pH and dissolved organic carbon/nitrogen ratio of ash/soil extracts from Oct 2013 to Aug 2014. Increasing cumulative precipitation, inferring an increase in leaching after fire, led to an increase in DOM reactivity to form trihalomethanes, haloacetic acids, and chloral hydrate, but not for haloketones, haloacetonitrile, or N-nitrosodimethylamine, which were more related to the original burn severity. This study highlights that fire-affected DBP precursors for different DBP species have distinct temporal variation possibly due to their various sensitivity to biogeochemical alterations.

Land subsidence caused by a single water extraction well and rapid water infiltration

Abstract. Nowadays several parts of the world suffer from land subsidence. This setting of the earth surface occurs due to different factors such as earth quakes, mining activities, and gas, oil and water withdrawal. This research presents a numerical study of the influence of land subsidence caused by a single water extraction well and rapid water infiltration into structural soil discontinuities. The numerical simulation of the infiltration was based on a two-phase flow-model for porous media, and for the deformation a Mohr–Coulomb model was used. A two-layered system with a fault zone is presented. First a single water extraction well is simulated producing a cone-shaped (conical) water level depletion, which can cause land subsidence. Land Subsidence can be further increased if a hydrological barrier as a result of a discontinuity, exists. After water extraction a water column is applied on the top boundary for one hours in order to represent a strong storm which produces rapid water infiltration through the discontinuity as well as soil deformation. Both events are analysed and compared in order to characterize deformation of both elements and to get a better understanding of the land subsidence and new fracture formations.

Measurement of the maximum amount of water-extractable phosphorus in animal manure compost by continuous and sequential water extraction

Measuring the phosphorus (P) solubility in animal manure compost (AMC) is important to estimate both the risk of P loss from agricultural land and the P availability for crops in agriculture that use AMC as fertilizer. Water-extractable phosphorus (WEP) has most often been used to estimate P solubility in AMC. A single water extraction with a high ratio of compost to water is usually used to determine WEP, but in many cases, this may not evaluate the maximum WEP. In this study, we extracted the P included in AMC by using a continuous extraction method with a large amount of water, and tested this approach for 16 AMCs: four cattle manure composts, five swine manure composts, five layer (chicken) manure composts, and two broiler (chicken) litter composts. The P dissolution patterns were fitted to kinetic models, and the maximum WEP (WEPmax) was determined by the coefficient of the non-linear regression equation. The WEPmax values corresponded to the sum of H2O- and sodium bicarbonate (NaHCO3)-extractable P measured using the modified Hedley sequential extraction method. The result also suggests that the maximum amount of WEP from AMC can be estimated rapidly using a sequential extraction (the Hedley method) that has been widely used to characterize P in manure or AMC. The maximum water-extractable magnesium (Mg) (WEMgmax) was significantly positively correlated with WEPmax (r = 0.854, P < 0.01). This suggests that WEPmax in the AMCs is affected by water-soluble magnesium compounds.

Effect of mass extractions and injections on the performance of a fixed-size humidification–dehumidification desalination system

The impact of mass extractions and injections as a method for increasing the energetic performance of fixed-size humidification–dehumidification desalination systems is examined. Whereas previous studies of this problem have been restricted to thermodynamic models, the use of a more complete model that includes transport provides the ability to quantify the impact of mass extractions/injections on a realizable, fixed-size system. For a closed air, open water cycle, the results show that a single water extraction from the dehumidifier to the humidifier increases the gained output ratio by up to 10%, with extractions higher in the cycle proving more effective. The sizing problem for the humidifier and dehumidifier under thermodynamically optimized conditions found in literature is also discussed, as is the impact of system size on overall performance of a system without extractions/injections. For a range of sizes, it is shown that a rough doubling of both dehumidifier and humidifier size results in a two- to three-fold increase in gained output ratio, with diminishing returns as the absolute sizes increase.

Metabolite extraction from suspension-cultured mammalian cells for global metabolite profiling

Metabolite profiling of industrially important suspension-cultured mammalian cells is being increasingly used for rational improvement of bioprocesses. This requires the generation of global metabolite profiles that cover a broad range of metabolites and that are representative of the cells at the time of sampling. The protocol described here is a validated method for recovery of physiologically relevant amounts of key metabolites from suspension-cultured mammalian cells. The method is a two-step process consisting of initial quenching of the cells (to stop cellular metabolism and allow isolation of the cells) followed by extraction of the metabolites. The cells are quenched in 60% methanol supplemented with 0.85% (wt/vol) ammonium bicarbonate at -40 °C. Metabolites are then extracted from the quenched cells using two 100% methanol extractions followed by a single water extraction. Metabolite samples generated using this protocol are amenable to analysis by mass spectrometry-based techniques (e.g., gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry), NMR spectroscopy and enzymatic assays.

Influence of soil type and extraction conditions on perchlorate analysis by ion chromatography

Perchlorate is a stable anion that has been introduced into the environment through activities related to its production and use as a solid rocket propellant. Perchlorate is thought to transport through soils without being adsorbed; thus, for determination of perchlorate in soil, samples are typically extracted with water prior to analysis. The completeness of extraction depends on perchlorate existing as a free ion within the soil matrix. In this study, perchlorate extraction efficiency was evaluated with five soil types under two different oxygen states. For each soil, 30% (w/w) slurries were prepared and equilibrated under either oxic or anoxic conditions prior to spiking with a stock solution of sodium perchlorate, and the slurries were then maintained for 1-week or 1-month. At the end of the exposure, slurries were centrifuged and separated into aqueous and soil phases. After phase separation, the soil was washed first with deionized water and then with 50 mM NaOH, producing second and third aqueous phases, respectively. Perchlorate concentrations in the three aqueous phases were determined using ion chromatography. The results obtained from this study suggest that matrix interference and signal suppression due to high conductivity have greater effects upon observed perchlorate concentrations by ion chromatography than does perchlorate interaction with soil. Thus, a single water extraction is sufficient for quantitative determination of perchlorate in soil.

COMPARING DIFFERENT EXTRACTION METHODS FOR ESTIMATING PHOSPHORUS SOLUBILITY IN VARIOUS SOIL TYPES

In areas with intensive animal livestock farming, agricultural soils are enriched with phosphorus (P). These soils exhibit an increased risk for P transfer to the sub-soil and surface water via leaching. Besides the presence of hydrological pathways between a field and surface water, P in soil solution should be studied for evaluating the environmental risk. For this purpose, soil P extraction methods can be used. In this study, we tested the relation between various extraction methods and P in soil solution, simulated by a water extraction at a soil-to-solution ratio of 1:2 (w/v) using field-moist topsoils sampled from the major Dutch soil types (noncalcareous and calcareous sand and clay, reclaimed peat, and peat). The following methods were used: Pw (1:60 [v/v] water-extractable P), 0.01 M CaCl2 (1:10 [v/v]), FeO-strip, and acid ammonium oxalate-extractable P, Al, and Fe. Phosphorus in the 1:2 water extracts was mainly present as molybdate-reactive P (MRP). Extraction methods with the highest ability to predict MRP in 1:2 water extracts across different soil types were CaCl2, Pw, and FeO-strip, the latter two normalized for [Al + Fe]ox. However, for the peat and noncalcareous clay soils, also estimation of molybdate-unreactive P (MUP) is important because MUP dominates in the 1:2 water extracts of these soils. Thus, an extraction method that only determines MRP will not suffice, and further research is needed on the environmental risk of MUP in soil solution from these soil types. The calcareous sandy soils deviated significantly from the above mentioned relationships. For this soil type, it should be tested whether a single water extraction (e.g., Pw) suffices for determining the environmental risk.

Determinação de ácidos carboxílicos em composto de resíduos sólidos urbanos por cromatografia gasosa com detector de ionização em chama

Um método simples e eficiente para determinação simultânea de quatro ácidos carboxílicos de cadeia curta (acético, propiônico, butírico e valérico) em resíduos sólidos urbanos (RSU) é descrito no presente trabalho. Estes ácidos são considerados fitotóxicos na literatura e a variabilidade das suas concentrações durante o processo pode ser usada como parâmetro da maturação do composto de resíduos sólidos urbanos (RSU). A determinação dos ácidos carboxílicos presentes no composto de RSU envolve uma extração em água e filtração em membranas de polifluoreto de vinilideno (PVDF), seguida da injeção direta em um cromatográfo a gás com detector por ionização em chama (CG-DIC). Foram analisados três tipos de leira. Boas linearidades e coeficientes de correlação foram obtidas para todos os ácidos, e os limites de detecção e quantificação foram baixos, resultando em um método sensível para monitoramento desses ácidos em composto de RSU.

Lixiviation as a tool for radionuclide fractionation in holm oak leaves

A sequential extraction scheme, using distilled water and chloroform: hexane (1∶2), was applied in a study of radionuclide retention by holm oak leaves. To perform this study, holm oak leaves were contaminated by dry deposition using a thermogenerated radioactive aerosol containing134Cs,85Sr and110mAg. The experimental parameters tested were: type and time of shaking, number of successive extractions in each step, and the volume of extractans. From the results obtained, two schemes which give complementary information about radionuclide retention are proposed. The first scheme, using a single water extraction with mechanical shaking, allows us to define two fractions: the fraction removed by water, which is related to total radionuclide retention on leaf surfaces, and the residual fraction, which is associated with radionuclides incorporated into the leaves. The second scheme is based on a two-step extraction with manual shaking using water and chloroform: hexane, and permits us to distinguish among three fractions: the fraction removed by water (which is related to the radionuclide fraction easily leached by rain), the fraction removed by organic solvent (which is associated with the radionuclide fraction strongly retained on leaf surface), and the residual fraction, which may represent the absorbed radionuclide content. Since our objective was to study the retention of134Cs,85Sr and110mAg, simultaneously, the experimental conditions chosen were a compromise of individual suitable conditions for each radionuclide.