scholarly journals A consistent model for estimating the partitioning of Am, Pu and Se in agricultural soils

2021 ◽  
Author(s):  
Volker Hormann
Keyword(s):  
Soil Solution ◽  
Agricultural Soils ◽  
Additive Model ◽  
Distribution Coefficients ◽  
Single Parameter ◽  
Batch Experiments ◽  
Consistent Model ◽  
Parameter Variations ◽  
Experimental Values ◽  
Solution Parameters

AbstractThe component additive model UNiSeCs II for simulating the physicochemical behaviour of the radionuclides americium, plutonium and selenium in agricultural soils is presented. The model is validated by estimating the distribution coefficients (Kd) of these elements measured in batch experiments from the literature. For all three elements, the resulting average relative deviations from the experimental values are smaller than a factor of 2.5. This indicates that the model has the potential to significantly improve the predictions of radioecological models that normally use tabulated Kd values from the IAEA which are known to have large uncertainties. Using UNiSeCs II, the soil solution parameters most important for the partitioning of Am, Pu and Se are identified by single parameter variations.

scholarly journals An Additive Model to Predict the Rheological and Mechanical Properties of Polypropylene Blends Made by Virgin and Reprocessed Components

Recycling ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Francesco Paolo La Mantia ◽  
Maria Chiara Mistretta ◽  
Vincenzo Titone
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Additive Model ◽  
Industrial Process ◽  
Theoretical Predictions ◽  
Experimental Values ◽  
Polypropylene Blends ◽  
Polypropylene Sample

In this work, an additive model for the prediction of the rheological and mechanical properties of monopolymer blends made by virgin and reprocessed components is proposed. A polypropylene sample has been reprocessed more times in an extruder and monopolymer blends have been prepared by simulating an industrial process. The scraps are exposed to regrinding and are melt reprocessed before mixing with the virgin polymer. The reprocessed polymer is, then, subjected to some thermomechanical degradation. Rheological and mechanical experimental data have been compared with the theoretical predictions. The results obtained showed that the values of this simple additive model are a very good fit for the experimental values of both rheological and mechanical properties.

scholarly journals Sorption and leaching characteristics of pesticides in volcanic ash soils of Jeju Island, Korea

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Won-Pyo Park ◽  
Kong-Man Chang ◽  
Hae-Nam Hyun ◽  
Kyung-Hwan Boo ◽  
Bon-Jun Koo
Keyword(s):  
Volcanic Ash ◽  
Agricultural Soils ◽  
Distribution Coefficients ◽  
The Other ◽  
Jeju Island ◽  
European Standard ◽  
Leaching Behavior ◽  
Mobility Assessment ◽  
Leaching Characteristics ◽  
Volcanic Ash Soils

Abstract It is important to evaluate leaching behavior in agricultural soils to prevent the pollution of groundwater by pesticides. We identified the distribution coefficients (Kd) of ten pesticides with different physicochemical properties and compared their leaching characteristics using wick lysimeters from three distinct soil types on Jeju Island. The Kd values varied by pesticide and soil, but were within the range of 1.2 to 4231 L kg−1. Based on the European standard (Kd < 10 L kg−1), six pesticides (alachlor, ethoprophos, carbofuran, napropamide, tebuconazole, and etridiazole) were mobile in at least one tested soil, and their soil organic carbon affinity was ≤ 5.811. This value differed greatly from the other pesticides (16.533 and higher). The solubility of the six mobile pesticides was ≥ 32 mg L−1, which substantially differed from the other pesticides (≤ 0.71 mg L−1). Thus, we conclude that our mobility assessment, which is based on Kd values, can be used to predict the leaching of pesticides in the volcanic ash soils of Jeju Island. The use of pesticides should be strictly controlled to reduce the possibility of groundwater contamination.

Influence of Nitrilotriacetate on the Elimination of Metal Ions by Coprecipitation with Ferric Hydroxide

1987 ◽  
Vol 19 (5-6) ◽  
pp. 1013-1019 ◽  
Author(s):  
F. H. Frimmel ◽  
J. Geywitz
Keyword(s):  
Conditional Distribution ◽  
Ferric Hydroxide ◽  
Distribution Coefficients ◽  
Metal Species ◽  
Batch Experiments ◽  
Reaction Conditions ◽  
Low Concentrations ◽  
Zinc Cadmium ◽  
Copper Zinc ◽  
Cadmium And Lead

The elimination of dissolved copper, zinc, cadmium and lead by coprecipitation with iron(III) hydroxide was investigated. The reaction conditions of the batch experiments were adopted from water treatment. Conditional distribution coefficients show the order Cd &lt; Zn &lt; Cu &lt; Pb for increasing interaction of the metals with the ferric hydroxide. The presence of nitrilotriacetate (NTA) decreases the efficiency of the metal elimination. NTA is also able to remobilize metals from the metal enriched precipitation. There is a significant effect, even at low concentrations of a few µmol/l. Remobilization of Cu, Zn and Cd increases, remobilization of Pb decreases with reaction time. The “ageing” of the precipitation plays an important role for the yield of the reactions. From a broad application of NTA in detergents an increase of the concentration of dissolved metal species has to be expected.

scholarly journals Zinc speciation in soil solution of selected Poland’s agricultural soils

2014 ◽  
Vol 101 (2) ◽  
pp. 147-152
Author(s):  
Beata Rutkowska ◽  
Wiesław Szulc ◽  
Jan Łabętowicz
Keyword(s):  
Soil Solution ◽  
Agricultural Soils ◽  
Zinc Speciation

scholarly journals A Single Incident of Soil P Leaching in a Mature Forest Corresponds to 10 Years of Average Leaching

2018 ◽  
Author(s):  
Ann-Mari Fransson
Keyword(s):  
Soil Solution ◽  
Heavy Rainfall ◽  
Continuous Monitoring ◽  
Agricultural Soils ◽  
Mineral Soil ◽  
Point Sources ◽  
Spruce Forest ◽  
Soil P ◽  
Second Year ◽  
P Leaching

Incidental P losses from non-point sources may contribute to eutrophication and to decreased soil fertility. These incidents have been related to heavy rainfall on freshly fertilized agricultural soils and little is known about such incidents on more natural soils or in forests. The aim of this work is to determine if incidents of high P leaching also occur in spruce forests, and if such incidents are of significance in P cycling. We found a peak in the mineral soil solution showing that single events of high P leaching occur. The orthophosphate concentration in the Bf-horizon of the 80-year old spruce forest peaked in the autumn of the second year of a continuous monitoring. The concentration increased by more than 85 times compared to the highest concentration obtained earlier during the sampling. The amount leached during this 6 months peak is 10 times higher than the average annual leaching. This P leaching might be due to a combination of high P deposition/through-fall and a high anion exchange with dissolved-organic-carbon and Cl-. We suggest that single events of high sub-surface P leaching may contribute to the overall P leaching, and might increase with the global warming as more DOC is expected to be released to the soil solution.

scholarly journals Evaluation of radioactivity of cereals and legumes using a nuclear impact detector CN-85

2018 ◽  
Vol 16 (38) ◽  
pp. 139-146
Author(s):  
Asmaa Ahmad Aziz
Keyword(s):  
Soil Solution ◽  
International Atomic Energy Agency ◽  
Uranium Concentration ◽  
Agricultural Soils ◽  
Plant Roots ◽  
Human Consumption ◽  
Energy Agency ◽  
Yellow Corn ◽  
Nuclear Effects ◽  
Impact Detector

The research aims to evaluate the radioactivity in elected samples of cereals and legume which are wide human consumption in Iraq using Nuclear Track Detectors (NTDs) model CN-85.The samples were prepared scientifically according to references in this field. After 150 days of exposure, the detector were collected and chemically treated according to scientific sources (etching chemical), nuclear effects have been calculated using the optical microscope.Radon (222Rn) concentration and uranium (238U) were calculated in unit Bq/m3 and (ppm), the results indicate that the highest concentration of radon and uranium was in yellow corn where the concentration of radon was 137.17×102 Bq/m3 and uranium concentration 2.63 (ppm). The lowest concentration of radon and uranium was in Oats, where the concentration of radon was 24.27×102 Bq/m3, and uranium concentration 0.466 (ppm), concentrations of other cereals and legumes varied between these two values. These different in radon and uranium concentrations due to different in geological nature of the different agricultural soils, and the different absorption of plant roots for certain elements present in the soil solution. These values for the concentration of radon and uranium for cereals and legumes are within the permitted globally and as issued by the International Atomic Energy Agency (IAEA).

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