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Geochemical Studies and Elemental Contaminants in the Bay of the City of Asuncion

Journal of Chemistry and Chemical Engineering 2013年第11期7卷 1060-1067页

作者： juan f. facetti-masulli franklin flores Peter Kump National University of Asunci6n-Hydroconsult Asunci6n 980 Paraguay Jozef Stefan Institute Ljubljana I000 Slovenia

Minor and trace elements composition of bottom sediments from the bay of Asunci6n on the Paraguay River have been investigated by XRf （X-ray fluorescence） techniques to determine their correlation as well as provenance. The analysis of complex spectra was performed by the AXIL software and the quantitative analysis by the QAES （quantitative analysis of environmental samples ） software. Analyzed trace elements were the refractory elements Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Pr, Nd, Zr, Th and others with high field stabilization energy as Cr, Ni, Cu, together with Zn, As, Cd, Pb. Minor elements were Ti, Mn, fe which are often to the above refractories related. According to their normalized spidergrams, two sets of sediments can be differentiated. Those that show LREE （light rare earth elements） enrichment, negative Nb and Ti anomalies and no spike at Zr and those that have spidergrams very alike, with strong negative anomalies at Nb, Nd and Ti whereas a of fe versus the refractory elements except fe-Zr in which correlation seem to be low. positive spike at Zr. In both set, there are strong correlations is negative. Potential hazards of toxic elements in sediments

关键词： Bottom sediments Asuncion Bay XRf LREE Paraguay River.

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Secchi Disc and Lago de la Repubfica, Eastern Paraguay

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Journal of Earth Science and Engineering 2015年第8期5卷 482-486页

作者： John A. fitzpatrick juan f. facetti-masulli Hyclroconsult Charles de Gaulle 980 Asuncidn Paraguay National University of Asuncion San Lorenzo Paraguay

The Secchi disc is used to obtain the water transparency D and a value for the attenuation coefficient Kt according to Kt = Cx.D1 where C is a factor estimated supposedly as a constant. Lago de la Republica, a small reservoir seated on basaltic residual soil laterites rich in secondary sesquioxides of fe, AI, etc of the Alto Parana formation, after rainfalls incorporates significant amount of sediments rich in iron compounds easily hydrolyzed to produce colloidal hydrated ferric oxides. After some heavy rainfalls, advantage was taken to look for the effect of such compounds onto transparency and light attenuation coefficient of the lake water and their relationship.

关键词： Transparency light attenuation coefficient sediments Lago de la Republica.

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Pre Impoundment Studies in Monday River, Eastern Paraguay I: Soils and Submerged Soils

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Journal of Chemistry and Chemical Engineering 2019年第2期13卷 82-92页

作者： juan f facetti-masulli Carmelo López Amado González Hydroconsult SRL-Laboratory Asunción Z12 – Paraguay

Monday River, at Eastern Paraguay is located south of the Itaipu Dam, and discharges into the Paraná River. At the point of discharge it has been projected to build a Hydroelectric power Plant and the reservoir will extend upstream the Monday. As a result of the impoundment of a river, the flooded soil can provide a certain amount of nutrients into the aqueous medium setting new conditions for aquatic life and affecting to a greater or lesser degree the ecosystems. The aim of this work is the assessment of the impact on the water quality of the incorporation of major nutrients into the water body after damming Monday River. Samples from soil profiles were taken at selected sites on both banks of the river;the amount of phosphorus, nitrogen, potassium, calcium and magnesium as well as other parameters as pH, organic matter, exchangeable bases were determined using standard procedures. Granulometric analysis was also performed. Phosphorus availability was determined by isotopic exchange. In addition the samples were submitted to submersion/incubation experiments along 60 days, and the concentration of elements incorporated into the water analyzed. Results show that flooded soils are low in phosphorus and nitrogen which is scarce in some cases;so does other nutrients. Submersion experiments also indicate generally limited incorporation of such nutrients into the water body. Significant negative impact of these soils on the water quality of the reservoir cannot be expected.

关键词： Alto Paraná Dpt Monday River Soils E-value Incubation experiments

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Selected Mineral Contents in Wheat from Paraguay by X-ray fluorescence

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Journal of Chemistry and Chemical Engineering 2012年第12期6卷 1114-1120页

作者： V. Romero de González A. De Lorenzil P. Kump J. f. facetti masulli Universidad Nacional de Asunción Charles de Gaulle 980 Paraguay Jozef Stefan Institute Ljubljana Jamova 39 Slovenia

The two fold purpose of this paper is to determine the composition of selected elements in Paraguayan wheat and flour as well as to analyse the implications of the bromine/bromate content on bakery products： the use （malpractice） of KBrO3 as an additive in the bakery dough to improve the whiteness and other characteristics of bread is well known. Accordingly, selected minor and trace elements in eight varieties of wheat from the center and south areas of Eastern Paraguay as well as commercial flour samples and bakery products were analyzed by XRf （X-ray fluorescence） techniques. The examined elements were K, Ca, Ti, Mn, fe, Cu, Zn, Br, Rb, Sr. The results on wheat and commercial flour were consistent with those found elsewhere. With regard to the bakery products, in about 35% of the samples, the bromine/bromate content exceeded the normal Br values of Paraguayan flour showing bromate malpractice. from dietary point of view, it should be emphasized that KBrO3 is a complete carcinogen and its use as food additive has been banned. The employment of XRf to analyze bromine is easy, simple and reliable.

关键词： Trace elements wheat of Paraguay bromine in flour potassium bromate bakery products XRf.

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