STUDY OF THE USE FEATURES OF THE X-RAY FLUORESCENCE ANALYSIS FOR THE HEAVY METALS DETERMINATION IN SOIL

Abstract

Under conditions of intense anthropogenic impact on ecosystems, due to the ingress of heavy metals into the environment, the ecosystems' protective properties have significantly decreased. Now the search for accurate, simple and affordable methods for heavy metals determining in soil is an urgent task, since reducing the time to accurately determine the content of these toxic elements will facilitate the rapid application of effective methods to improve the soils' condition. The work purpose is to study the features of the heavy metals determination in soil by the X-ray fluorescence (XRF) method and to develop recommendations for conducting an accurate soil analysis for the heavy metals content. As test pollutants, salts of transition and post-transition metals were used: FeSO4·7H2O, Ni(CH3COO)2·4H2O, CuSO4·5H2O, ZnSO4, SrCl2, PbCl2, CoCl2. To determine the elements' concentrations, a Sprut-K energy dispersive spectrometer (Ukrrentgen JSC, Kharkov) with an X-123 SDD detector from Amptek (USA) was used. It was found that the lower concentration of most heavy metals, which must be determined, reaches 0.01 mg/L. During the XRD method' sensitivity study, the results as pulses' number for each of the studied metals were obtained. It was found that even at a higher concentration, the pulses number is much smaller in the presence of adhesive tape on top, which indicates that it is not completely transparent, and it is desirable to produce samples for analysis open to the sensor. In addition, it was found that the heavy metals' pulses number during heat treatment of the soil decreases. The concentration dependences' study showed that the dependence of the concentration of the metal is not linear, but can be very well described by the quadratic binomial for all the studied metals. The study originality lies in the development of recommendations for the samples preparation for the heavy metals determination in soil. The practical value lies in the development of recommendations for the determination of heavy metals in soil by the XRD method, which can be successfully applied in real conditions.