scholarly journals Caffeine vs. carbamazepine as indicators of wastewater pollution in a karst aquifer

2018 ◽  
Vol 22 (12) ◽  
pp. 6371-6381 ◽  
Author(s):  
Noam Zach Dvory ◽  
Yakov Livshitz ◽  
Michael Kuznetsov ◽  
Eilon Adar ◽  
Guy Gasser ◽  
...  
Keyword(s):  
Vadose Zone ◽  
Karst Aquifer ◽  
Aquifer System ◽  
High Attenuation ◽  
Low Concentrations ◽  
Caffeine Degradation ◽  
Linear Sorption ◽  
The Matrix ◽  
Sewage Contamination ◽  
Wastewater Pollution

Abstract. This paper presents the analysis of caffeine and carbamazepine transport in the subsurface as a result of wastewater release in the Sorek creek over the outcrops of the carbonate, Yarkon-Taninim, aquifer in Israel. Both caffeine and carbamazepine were used as indicators of sewage contamination in the subsurface. While carbamazepine is considered conservative, caffeine is subject to sorption and degradation. The objective of the study was to quantify differences in their transport under similar conditions in the karst aquifer. Water flow and pollutant transport in a “vadose zone–aquifer” system were simulated by a quasi-3-D dual permeability numerical model. The results of this study show that each of these two pollutants can be considered effective tracers for characterization and assessment of aquifer contamination. Carbamazepine was found to be more suitable for assessing the contamination boundaries, while caffeine can be used as a contaminant tracer only briefly after contamination occurs. In instances where there are low concentrations of carbamazepine which appear as background contamination in an aquifer, caffeine might serve as a better marker for detecting new contamination events, given its temporal nature. The estimated caffeine degradation rate and the distribution coefficient of a linear sorption isotherm were 0.091 d−1 and 0.1 L kg−1, respectively, which imply a high attenuation capacity. The results of the simulation indicate that by the end of the year most of the carbamazepine mass (approximately 95 %) remained in the matrix of the vadose zone, while all of the caffeine was completely degraded a few months after the sewage was discharged.

scholarly journals Caffeine vs Carbamazepine as indicators for wastewater pollution in a karst aquifer

2018 ◽  
Author(s):  
Noam Zach Dvory ◽  
Yakov Livshitz ◽  
Michael Kuznetsov ◽  
Eilon Adar ◽  
Guy Gasser ◽  
...  
Keyword(s):  
Karst Aquifer ◽  
Porous Matrix ◽  
Aquifer System ◽  
High Attenuation ◽  
Low Concentrations ◽  
Caffeine Degradation ◽  
Linear Sorption ◽  
Sewage Contamination ◽  
Wastewater Pollution ◽  
Contamination Events

Abstract. This paper presents the analysis of caffeine and carbamazepine transport in the subsurface during and after sewage discharge in the Sorek creek over outcrops of the Western Mountain Aquifer (Yarkon-Taninim) in Israel. Both caffeine and carbamazepine were used as indicators for sewage contamination in the subsurface. While carbamazepine is considered conservative, caffeine is subject to sorption and degradation. The objective of the study was to quantify differences in their transport under conditions in the carbonate aquifer. A quasi-3D dual permeability numerical model was used to simulate water flow and transport of both pollutants in a vadose zone – aquifer system. The results of this study show that each of these two pollutants can be considered as effective tracers for characterization and assessment of aquifer contamination. Carbamazepine was found to be more suitable to assess the contamination boundaries, while caffeine can be used as a contaminant tracer only briefly after contamination occurred. In instances when there are low concentrations of carbamazepine which appear as background contamination in an aquifer, caffeine might serve as a better marker for detect new contamination events given its temporal nature. The estimated caffeine degradation rate and the distribution coefficient of linear sorption isotherm were 0.091 d−1 and 0.1 L/kg, respectively, which imply a high attenuation capacity. The results of the simulation indicate that around 95 % of carbamazepine mass was retained in the porous matrix of the unsaturated zone by the end of the year, while all of the caffeine was completely degraded a few months after the sewage was discharged.

Leach Behavior of SRL TDS-131 Defense Waste Glass in Water at High&Low Flow Rates

1983 ◽  
Vol 26 ◽  
Author(s):  
Aaron Barkatt ◽  
William Sousanpour ◽  
Alisa Barkatt ◽  
Morad A. Boroomand ◽  
Pedro B. Macedo
Keyword(s):  
Contact Time ◽  
Protective Layer ◽  
High Flow ◽  
Low Flow ◽  
Matrix Elements ◽  
Flow Rates ◽  
Low Concentrations ◽  
Controlling Mechanism ◽  
The Matrix ◽  
Leach Behavior

ABSTRACTLeach tests carried out on SRL TDS-131 Defense Waste Class indicate that at high flow rates the controlling mechanism is simple corrosion. The matrix elements (Si, Al) are leached out at rates similar to those of the leaching of the alkalis and of boron, and the leaching process is nearly linear with time. At slow flow rates (below 1 m/yr) leaching becomes controlled by the build-up of a protective layer. Al and most of the Si remain in the leached surface layer. The leach rates decrease in the course of the test before leveling off at constant values which are almost inversely proportional to the contact time, indicating that leachate concentrations have become solubility-limited. The low concentrations observed at this stage indicate the formation of alteration products.

scholarly journals Simulation of Regional Karst Aquifer System and Assessment of Groundwater Resources in Manatí-Vega Baja, Puerto Rico

2015 ◽  
Vol 07 (12) ◽  
pp. 909-922 ◽  
Author(s):  
Balati Maihemuti ◽  
Reza Ghasemizadeh ◽  
Xue Yu ◽  
Ingrid Padilla ◽  
Akram N. Alshawabkeh
Keyword(s):  
Puerto Rico ◽  
Groundwater Resources ◽  
Karst Aquifer ◽  
Aquifer System ◽  
Karst Aquifer System ◽  
Vega Baja

scholarly journals Potentiometric Determination of Chlorate Impurities in Hypochlorite Solutions

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Dmitry V. Girenko ◽  
Al’ona A. Gyrenko ◽  
Nikolai V. Nikolenko
Keyword(s):  
Sodium Hypochlorite ◽  
Sodium Sulfite ◽  
Systematic Errors ◽  
Expanded Uncertainty ◽  
Iodide Ions ◽  
Low Concentrations ◽  
Sophisticated Equipment ◽  
The Matrix ◽  
Fold Excess

The method of iodometric determination of chlorates impurities in sodium hypochlorite solutions for medical and veterinary purposes was developed. This method does not require sophisticated equipment and can be implemented directly where the solutions are used. The method is based on the different rates of interaction of ClO- and ClO3- with iodide ions depending on the acidity of the medium. We have shown that blank titration is advisable to improve the accuracy of the determination of low concentrations of chlorates in the matrix of hypochlorite which is present in excess since in this case possible systematic errors due to the presence of oxidizing impurities in the reagents are prevented. To quantify the low concentrations of chlorates, we proposed to remove 85-95% of hypochlorite ions by means of reducing their excess with sodium sulfite at pH 10.5. The solution of sodium sulfite does not require standardization before each analysis in the proposed procedure. The possibility of quantitative determination of chlorate impurities in the range of 2-50 mg/L in the presence of 50-500–fold excess of sodium hypochlorite with an error of 5% has been proved. The expanded uncertainty of chlorate determination did not exceed 0.6 mg/L.

scholarly journals Taking into Account both Explicit Conduits and the Unsaturated Zone in Karst Reservoir Hybrid Models: Impact on the Outlet Hydrograph

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3221
Author(s):  
Lucie Dal Soglio ◽  
Charles Danquigny ◽  
Naomi Mazzilli ◽  
Christophe Emblanch ◽  
Gérard Massonnat
Keyword(s):  
Unsaturated Zone ◽  
Numerical Models ◽  
Karst Aquifer ◽  
Hybrid Models ◽  
Model Parameters ◽  
Transit Times ◽  
The Matrix ◽  
Karst Reservoir ◽  
Karst Systems ◽  
The One

The main outlets of karst systems are springs, the hydrographs of which are largely affected by flow processes in the unsaturated zone. These processes differ between the epikarst and transmission zone on the one hand and the matrix and conduit on the other hand. However, numerical models rarely consider the unsaturated zone, let alone distinguishing its subsystems. Likewise, few models represent conduits through a second medium, and even fewer do this explicitly with discrete features. This paper focuses on the interest of hybrid models that take into account both unsaturated subsystems and discrete conduits to simulate the reservoir-scale response, especially the outlet hydrograph. In a synthetic karst aquifer model, we performed simulations for several parameter sets and showed the ability of hybrid models to simulate the overall response of complex karst aquifers. Varying parameters affect the pathway distribution and transit times, which results in a large variety of hydrograph shapes. We propose a classification of hydrographs and selected characteristics, which proves useful for analysing the results. The relationships between model parameters and hydrograph characteristics are not all linear; some of them have local extrema or threshold limits. The numerous simulations help to assess the sensitivity of hydrograph characteristics to the different parameters and, conversely, to identify the key parameters which can be manipulated to enhance the modelling of field cases.

Ultrasonic measurements of attenuation and velocity of compressional and shear waves in partially frozen unconsolidated sediment and synthetic porous rock

Geophysics ◽  
2016 ◽  
Vol 81 (2) ◽  
pp. D141-D153 ◽  
Author(s):  
Jun Matsushima ◽  
Makoto Suzuki ◽  
Yoshibumi Kato ◽  
Shuichi Rokugawa
Keyword(s):  
Freezing Point ◽  
Velocity Versus ◽  
Porous Rock ◽  
S Waves ◽  
High Attenuation ◽  
Unconsolidated Material ◽  
Unconsolidated Sediment ◽  
The Matrix ◽  
Attenuation Mechanism ◽  
The Difference

The presence of partially frozen liquid in the pore spaces of porous materials has significant effects on elastic wave propagation. Although the characterization of partially frozen systems using velocity information has been well developed, application of the attenuation information is limited because the attenuation mechanisms in partially frozen systems are poorly understood. We have conducted ultrasonic wave transmission measurements with changing temperatures from 0°C to [Formula: see text] to estimate the effect of partially frozen liquids grown in unconsolidated (unconsolidated sediment) and consolidated (synthetic porous rock) materials on the velocity and attenuation of P- and S-waves. Our experimental results determined that the existence of partially frozen liquid in the unconsolidated and consolidated materials increases the velocity and attenuation for temperatures of 0°C to around the freezing point (i.e., [Formula: see text]), thus experimentally validating the unintuitive observations of high velocity and high attenuation. We interpreted the differences in velocity-versus-temperature curves as both the difference in inherent stiffness between the matrix of the consolidated material and the ice frame of the partially frozen unconsolidated material and the microscale ice distribution in pore spaces. We have also attributed the difference in the attenuation-versus-temperature curves in the unconsolidated and consolidated materials between the P- and S-waves to the difference of attenuation mechanism between the P- and S-waves. Our findings can be used for interpreting the velocity and attenuation results from the sonic logging measurements.

Analytical validation of eight methods of thyroglobulin measurement in fine-needle aspiration washouts

2020 ◽  
pp. 000456322096836
Author(s):  
Florence Boux de Casson ◽  
Rémi Beloeil ◽  
Anne-Sophie Gauchez ◽  
Charlotte Oris ◽  
Monique Leban ◽  
...  
Keyword(s):  
Matrix Effect ◽  
Limit Of Detection ◽  
Needle Aspiration ◽  
Decision Threshold ◽  
Serum Samples ◽  
Cervical Lymph Nodes ◽  
Analytical Error ◽  
Low Concentrations ◽  
The Matrix ◽  
Assay Methods

Background Thyroglobulin (Tg) assay in washout fluids of fine needles, after cervical lymph nodes aspiration, is used for detecting metastases from differentiated thyroid carcinomas. Assay methods are the same as for Tg in serum. However, with non-serum samples, methods require extensive validation to notably check for the absence of matrix effect. This study fits this context. Our objectives were to assess analytic performances, in washout fluid, of eight different Tg assay methods and to compare them to validated data in serum. Methods Eleven medical laboratories participated in this study. The matrix tested was phosphate-buffer saline containing 1% bovine serum albumin (PBS-1% BSA). Samples used were dilutions, in this buffer, of Certified Reference Material (CRM 457). We verified, for all methods, the limit of detection, precision, linearity, trueness and accuracy. Results In PBS-1% BSA, the functional sensitivities (FS) were comparable to those expected for serum. All the methods were linear. The relative biases of trueness were between –24.5 and 10.2% around 1  µg/L. Total analytical error was ≤40% near the functional sensitivity values. Conclusion No quantitatively important matrix effect was observed. All the methods showed their ability to measure Tg in PBS-1% BSA, over the concentration range of interest, with acceptable total analytical error. We validated the functional sensitivity value as a decision threshold in thyroidectomized patients after treatment and with low concentrations of serum Tg.

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