Scholarly record

POSSIBILITIES AND LIMITATIONS RELATED TO THE APPLICATION OF NIR SPECTROSCOPY IN THE MONITORING OF SOIL CONTAMINATION

Anna Śliwińska

Abstract

Monitoring soil contamination with heavy metals is challenging because of the large areas of contaminated soil and the high cost of laboratory tests. For these reasons new measurement methods of metal concentration in soil based on the Fourier Transform Infrared Spectroscopy (FTIR) were tested. These methods include measurements made mainly in the near infrared region (NIR). Moreover the field implementation of these methods is considered. Previous results presented in the literature are not consistent and do not provide a clear answer to the question whether and to what extent infrared spectroscopy could be useful in soil monitoring. The main aim of this paper was the analysis of the possibilities and limitations of FTIR spectroscopy application in the determination of metal concentrations in soil. The NIR spectra of 100 soil samples were collected using the NIR Integrating Sphere. The calibration models of soil metal contaminations were developed with the application of the partial least squares regression (PLS) method. The rate of measurement, safety, preparation of the sample and the lack of universality of the constructed models were also analyzed in the paper. In the case of heavy metals, the FTIR spectroscopy should be regarded as a supplementary method enabling the fast and approximate control measurement of metal content. When high metal concentrations are detected, the measurements should be confirmed by other laboratory tests after the mineralization of soil samples in acids, for example Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Atomic Absorption Spectroscopy (AAS).

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