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- Author or Editor: C. Appoloni x
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Abstract
The aim of the present review is to evaluate, on the basis of published papers, the real potential of XRF technique for environmental analysis. Special attention is given for the determination of heavy metal pollution in water. Results of numerous papers for various samples are presented. Some details of the technique and preconcentration methods employed are also discussed.
Summary
Cereal flours are the major component of the Brazilian diet and are also important exportation products. Radioactivity concentrations of 232 Th, 226Ra, 40K and 137Cs were determined in commercial samples of South-Brazilian cereal flours (soy, wheat, corn, manioc, rye and oat flour) to verify the radiological security of these foodstuffs. The measurements were carried out by gamma-ray spectrometry using a 66% relative efficiency HPGe detector. The 40K flour activities, at 95% of confidence level were in: soy 474±3 Bq . kg-1; corn 30.0±0.3 Bq . kg-1; rye 94±1 Bq . kg-1; manioc 67±1 Bq . kg-1; oat 76±1 Bq . kg-1 and wheat 36.2±0.4 Bq . kg-1. The lower limit of detection for 40K ranged from 0.54 to 1.43 Bq . kg-1. The 137Cs activities in flour samples were: soy £0.07 Bq . kg-1, corn £0.01 Bq . kg-1, oat £0.03 Bq . kg-1 and in wheat, manioc and rye £0.02 Bq . kg-1. The highest concentrations levels of 232 Th and 226Ra were 0.69±0.04 Bq . kg-1 and 0.44±0.03 Bq . kg-1, respectively, in soy flour.
Summary
Cesium-137 methodology has been successfully used to assess soil erosion. Seven erosion plots were sampled to determine the 137Cs profile and to assess the erosion rates. Cesium-137 profile for native pasture plot showed an exponential decline below 5 cm depth, with little 137Cs activity in the superficial layer (0-5 cm). Cesium-137 profile for wheat-soybean rotation plot in conventional tillage showed a uniform distribution with depth. For this plot, the soil loss occurs more in middle than upper and lower level. Cesium-137 profile for wheat-soybean rotation and wheat-maize rotation plots in no-tillage showed a similar result to the native pasture, with a minimum soil loss in the superficial layer. Cesium-137 profile for bare soil and cultivated pasture plots are similar, with a soil erosion rate of 229 t ha-1 year -1 . In the plots with a conventional tillage a greater soil loss occur in middle than upper and lower level. In no-tillage cultivation plots occurs soil loss in lower level, but no sign of soil loss neither gain in the upper level is observed. Cesium-137 methodology is a good tool to assess soil erosion and the 137Cs profile gives possibility to understand the soil erosion behavior in erosion plots.
Summary
This paper presents the first measurement of the elemental composition of the suspended particulate matter in the atmosphere of Londrina city (Paraná State, Brazil). The sampling was accomplished in the summer of 2003 and in the winter of 2002, with a stacker filter holder, collecting simultaneously the fine particulates (PM2.5) and the coarse particulates (PM10). The concentration of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb associated with particulate matter was determined by energy dispersive X-ray fluorescence. The results of the grouping analysis suggested that the elements in the aerosol particles came from two sources: soil re-suspension and industrial or anthropogenic activities.
Summary
Energy dispersion X-ray fluorescence technique (EDXRF) was employed to study the effects of the fumagina disease through the elementary chemical composition of leaves. The experimental setup consisted of a Mo X-ray tube (Kµ=17.44 keV) with Zr filter and a Si(Li) detector. The measurements were performed with infected and healthy leaves of citric plants. The elements Ti, Mn, Fe, Cu and Zn were quantified. For all the elements of interest the measured detection limit was at the order of mg . g-1.
