Determination and assessment of contamination of toxic chemical elements in soils – Review

This work reviews the main topics in determining and evaluating the contamination of the toxic chemical elements antimony, arsenic, cadmium, lead, and mercury in soils. Initially, the sampling and storage steps are discussed. Next, the advantages and limitations of drying methods using oven heating, freeze-drying, air drying, and infrared radiation are presented. Subsequently, the importance of particle size in soil analysis is addressed. In addition, sample preparation procedures involving microwave-assisted radiation and the acids and their mixtures used for digestion of soil matrices are commented. Subsequently, the spectrometric analytical methods used to quantify chemical elements, such as inductively coupled plasma optical emission spectrometry (ICP OES), inductively coupled plasma mass spectrometry (ICP-MS), atomic fluorescence spectrometry (AFS), atomic absorption spectrometry with electrothermal atomization (ET AAS) and the direct mercury analyzer (DMA) are compared. Finally, the single and integrated indices used to evaluate the contamination of soils with toxic chemical elements in are briefly reported.