scholarly journals I-129 AND TC-99 DISTRIBUTION COEFFICIENTS OF SUBSURFACE SEDIMENTS COLLECTED FROM THE PROPOSED SITE OF THE ENVIRONMENTAL MANAGE DISPOSAL FACILITY

2021 ◽  
Author(s):  
DANIEL KAPLAN ◽  
KIMBERLY ROBERTS
Keyword(s):  
Distribution Coefficients ◽  
Disposal Facility ◽  
Subsurface Sediments

Atomic absorption determination of Hg (II), Cd (II), and As (III) in natural and waste water after preliminary group preconcentration

2019 ◽  
Vol 85 (2) ◽  
pp. 12-16
Author(s):  
I. V. Saunina ◽  
E. N. Gribanov ◽  
E. R. Oskotskaya
Keyword(s):  
Waste Water ◽  
Atomic Absorption ◽  
High Sensitivity ◽  
Distribution Coefficients ◽  
Neutral Medium ◽  
Atomic Absorption Determination ◽  
Absorption Determination ◽  
Relative Standard ◽  
Preliminary Group

The sorption of Hg (II), Cd (II), and As (III) by natural aluminosilicate is studied. It is shown that the mineral absorbs those toxicants in a rather wide pH range, quantitative extraction of analytes being achieved in a neutral or close to neutral medium (pH values range within 7.0 - 8.0; 6.3 - 7.5; 7.4 - 8.5 for Hg (II), As (III), and Cd (II), respectively). The effect of the time of phase contact on the degree of extraction of elements is shown. The sorption capacity of the mineral in optimal conditions of the medium acidity (0.06 mmol/g for mercury, 0.31 mmol/g for cadmium, and 0.52 mmol/g for arsenic) is determined. The distribution coefficients attain values of aboutnX 103-nX 104. A new combined method for determination of Hg (II), Cd (II), and As (III) in natural and waste water is developed and tested. The method consists in a preliminary group sorption concentration of the analytes by aluminosilicate, desorption of the analytes from the surface of the mineral and their subsequent atomic absorption determination. The correctness of the method is verified in analysis of spiked samples. The method is easy to use and exhibits high sensitivity, reproducibility and accuracy of analyte determination. The relative standard deviation does not exceed 0.13. Economic availability and possibility of using domestic sorption materials are the important advantages of the proposed procedure which can be used in the practice of laboratories monitoring the quality and safety of environmental objects.

Quantification of excess 231Pa in late Quaternary igneous baddeleyite

2020 ◽  
Vol 105 (12) ◽  
pp. 1830-1840 ◽  
Author(s):  
Yi Sun ◽  
Axel K. Schmitt ◽  
Lucia Pappalardo ◽  
Massimo Russo
Keyword(s):  
Late Quaternary ◽  
Central Italy ◽  
Direct Analysis ◽  
Weight Percent ◽  
Volcanic Field ◽  
Distribution Coefficients ◽  
Secular Equilibrium ◽  
Melt Distribution ◽  
D Values ◽  
Significant Figures

Abstract Initial excess protactinium (231Pa) is a frequently suspected source of discordance in baddeleyite (ZrO2) geochronology, which limits accurate U/Pb dating, but such excesses have never been directly demonstrated. In this study, Pa incorporation in late Holocene baddeleyite from Somma-Vesuvius (Campanian Volcanic Province, central Italy) and Laacher See (East Eifel Volcanic Field, western Germany) was quantified by U-Th-Pa measurements using a large-geometry ion microprobe. Baddeleyite crystals isolated from subvolcanic syenites have average U concentrations of ~200 ppm and are largely stoichiometric with minor abundances of Nb, Hf, Ti, and Fe up to a few weight percent. Measured (231Pa)/(235U) activity ratios are significantly above the secular equilibrium value of unity and range from 3.4(8) to 14.9(2.6) in Vesuvius baddeleyite and from 3.6(9) to 8.9(1.4) in Laacher See baddeleyite (values within parentheses represent uncertainties in the last significant figures reported as 1σ throughout the text). Crystallization ages of 5.12(56) ka (Vesuvius; MSWD = 0.96, n = 12) and 15.6(2.0) ka (Laacher See; MSWD = 0.91, n = 10) were obtained from (230Th)/(238U) disequilibria for the same crystals, which are close to the respective eruption ages. Applying a corresponding age correction indicates average initial (231Pa)/(235U)0 of 8.8(1.0) (Vesuvius) and 7.9(5) (Laacher See). For reasonable melt activities, model baddeleyite-melt distribution coefficients of DPa/DU = 5.8(2) and 4.1(2) are obtained for Vesuvius and Laacher See, respectively. Speciation-dependent (Pa4+ vs. Pa5+) partitioning coefficients (D values) from crystal lattice strain models for tetra- and pentavalent proxy ions significantly exceed DPa/DU inferred from direct analysis of 231Pa for Pa5+. This is consistent with predominantly reduced Pa4+ in the melt, for which D values similar to U4+ are expected. Contrary to common assumptions, baddeleyite-crystallizing melts from Vesuvius and Laacher See appear to be dominated by Pa4+ rather than Pa5+. An initial disequilibrium correction for baddeleyite geochronology using DPa/DU = 5 ± 1 is recommended for oxidized phonolitic melt compositions.

Cumulative Effects of Multiple Contaminants on Caged Fish

2006 ◽  
Vol 41 (3) ◽  
pp. 244-255 ◽  
Author(s):  
Jack F. Klaverkamp ◽  
Vince P. Palace ◽  
Christopher L. Baron ◽  
Robert E. Evans ◽  
Kerry G. Wautier
Keyword(s):  
Municipal Wastewater ◽  
Cumulative Effects ◽  
Disposal Site ◽  
Garbage Disposal ◽  
Disposal Facility ◽  
Multiple Contaminants ◽  
Wastewater Effluents ◽  
Liver Tissues

Abstract Pearl dace (Semotilus margarita) were held in cages and exposed to mine effluents, municipal wastewater effluents, a combination of the two, or to the combination in addition to runoff from a garbage disposal facility. Fish exposed to mining effluents only had the lowest mean lengths and weights but highest concentrations of As, Ni and Hg and lowest Zn in their viscera. Fish exposed to municipal wastewater effluents only had the highest concentrations of Cd and metallothionein in their viscera. Histopathological analyses of gill and liver tissues revealed a higher incidence of lesions in fish exposed to municipal wastewater effluents. These fish also had the highest LSIs, condition factors and mean vitellogenin concentrations in plasma from males. Fish exposed near the garbage disposal site had the highest concentrations of Pb and Se in their viscera.

MOBILIZATION OF NATURALLY OCCURRING URANIUM IN RESPONSE TO THE INFLUX OF NITRATE INPUTS INTO SUBSURFACE SEDIMENTS

2017 ◽  
Author(s):  
Jeffrey P. Westrop ◽  
◽  
Jason P. Nolan ◽  
Olivia M. Healy ◽  
Sharon Bone ◽  
...  
Keyword(s):  
Naturally Occurring ◽  
Subsurface Sediments

Isomorphic Co-Crystallization of Ammonium and Rubidium Bromocarnallites

1994 ◽  
Vol 59 (8) ◽  
pp. 1815-1819 ◽  
Author(s):  
Christomir Christov ◽  
Christo Balarew ◽  
Stefka Tepavitcharova
Keyword(s):  
Distribution Coefficients ◽  
Mixed Crystals ◽  
Solubility Isotherm ◽  
Continuous Series ◽  
Liquid Phases

The solubility isotherm of the system NH4Br.MgBr2.6 H2O - RbBr.MgBr2.6 H2O - H2O has been investigated at 75 °C and formation of a continuous series of mixed crystals is established. The factors determining the values of the distribution coefficients of the components between the crystalline and liquid phases are discussed.

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

scholarly journals Simultaneous Visualization of 161Tb- and 177Lu-Labeled Somatostatin Analogues Using Dual-Isotope SPECT Imaging

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 536
Author(s):  
Francesca Borgna ◽  
Patrick Barritt ◽  
Pascal V. Grundler ◽  
Zeynep Talip ◽  
Susan Cohrs ◽  
...  
Keyword(s):  
Pharmacokinetic Profile ◽  
Somatostatin Analogues ◽  
Distribution Coefficients ◽  
Spect Imaging ◽  
Cell Uptake ◽  
Organ Distribution ◽  
Dual Isotope ◽  
Biodistribution Studies ◽  
Simultaneous Visualization

The decay of terbium-161 results in the emission of β¯-particles as well as conversion and Auger electrons, which makes terbium-161 interesting for therapeutic purposes. The aim of this study was to use dual-isotope SPECT imaging in order to demonstrate visually that terbium-161 and lutetium-177 are interchangeable without compromising the pharmacokinetic profile of the radiopharmaceutical. The 161Tb- and 177Lu-labeled somatostatin (SST) analogues DOTATOC (agonist) and DOTA-LM3 (antagonist) were tested in vitro to demonstrate equal properties regarding distribution coefficients and cell uptake into SST receptor-positive AR42J tumor cells. The radiopeptides were further investigated in AR42J tumor-bearing nude mice using the method of dual-isotope (terbium-161/lutetium-177) SPECT/CT imaging to enable the visualization of their distribution profiles in the same animal. Equal pharmacokinetic profiles were demonstrated for either of the two peptides, irrespective of whether it was labeled with terbium-161 or lutetium-177. Moreover, the visualization of the sub-organ distribution confirmed similar behavior of 161Tb- and 177Lu-labeled SST analogues. The data were verified in quantitative biodistribution studies using either type of peptide labeled with terbium-161 or lutetium-177. While the radionuclide did not have an impact on the organ distribution, this study confirmed previous data of a considerably higher tumor uptake of radiolabeled DOTA-LM3 as compared to the radiolabeled DOTATOC.

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