Characterization of soils around a former chemical plant in Braila, SE Romania, using high performance atomic techniques (EDXRF, AAS, ICP-MS)

Abstract

This paper presents the problem of soil pollution in the vicinity of a former chemical plant, given that production activity was stopped for more than thirty years ago. The old chemical plant was located in the southern part of Braila town, SE Romania, just a few kilometers from the left bank of the Danube River. Prior to 1990, there was a significant production of industrial chemical goods, such as sulfuric acid, carbon dioxide for synthetic fibers, chlorine gas and hydrochloric acid obtained by electrolysis processes with mercury electrodes and heavy metal catalysts (Cd, Ni, Zn), sodium sulfide and sulphate, etc. For the good development of the experimental program, a number of 10 soil samples were collected from the north, northwest, west, southwest and south of the former chemical plant. The multi-element analysis method used to determine the trace elements in the soil samples was energy-dispersive X-ray fluorescence spectrometry (EDXRF), using a Genius XRF portable spectrometer manufactured by Skyray Instruments Inc., equipped with a large surface Si with a Be window and a 40 kV/100 µA miniature X-ray tube excitation source with Ag target. The spectrometric system has an energy resolution up to 139 eV, and the detection limits of the order of ppm. A total of 21 chemical elements were identified in the target soil samples, such as: K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Hg, Rb, Sr, Y, Zr, Nb, Mo, Sn, Sb, Pb. The compositional analyses of contaminated industrial soils were completed by using the AAS and ICP-MS high performance and selectivity techniques.