Determination of the trace elements distribution of polluted soils in Hungary by X-ray methods

摘要

The pollution of soils is a source of danger to the health of people, even to those living in cities. The anthropogenic pollution caused by heavy industries enters plants then goes through the food chain and ultimately endangers human health. In addition, the top layer of the soil can be easily resuspended by wind as dust particles and can be inhaled. This is important because it is well known that the toxic elements tend to accumulate in the smallest particle size fractions of soils. In our experiments we selected three representative soils and spiked them with toxic elements, namely Ph, Cr and Cd. These elements were added as nitrate salts depending on the physical properties of the soil. The soil samples were separated into eight particles size fractions and their mineral phases were characterized by X-ray diffractometry. Determination of the total organic carbon, which plays an important role in governing the distribution of toxic elements in soil, was carried out by TOC analysis. The main constituents of soil, the elements originally present and spiked toxic elements were determined by X-ray fluorescence spectrometry. The instruments were as follows: X-ray diffractometer PHILIPS PW 1710 and PHILIPS PW 2404 X-ray fluorescence spectrometer. We established that toxic elements accumulated in the finest particle size fraction of the soil irrespective of the type of the soil, in which they are adsorbed primarily by clay minerals and soil organic matter. If particle size distribution is taken into account, it can be concluded that the amount of trace elements and toxic elements is determined by particle size distribution. That is the maximum of the particle size distribution corresponds to that of the concentration distribution of toxic elements. Another point is that pollution can also modify the original distribution of trace elements which in turn affects plant uptake. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 5]