A comparison of methods of analysis of heavy metals in soil samples of Mitrovica environment, Republic of Kosovo

Abstract

In this work, the distribution of heavy metals in surface soil samples (0-5 cm) from the MitrovicaRegion, was studied. The investigated region (301.5 km2) is covered by a sampling grid of 1.4×1.4 km. Intotal 156 soil samples from 149 locations were collected. Digestion methods, including Aqua RegiaDigestion (mixture of HNO3 and HCl and water at 95ºC - the 1DX1 method) and acid digestion: use ofconcentrated acids such as hydrofluoric acid (HF), hydrochloric acid (HCl), nitric acid (HNO3) andperchloric acid (HClO4) (ISO 14869- 1:2001(E) method), are used to prepare samples for spectroscopicanalysis. High-sensitivity spectroscopy techniques such as inductively coupled plasma emissionspectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) were applied tomeasure the concentration of Ni and Co in soil samples. Data analysis and construction of the map wereperformed using the Statistica (ver. 9), AutoDesk Map (ver. 2008) and Surfer (ver. 9) software. It was foundthat the average content of Ni and Co in the surface soil for the entire study area is 96 mg/kg (with a rangeof 7.6-2600 mg/kg) and 22 mg/kg (with a range of 2.7-1600 mg/kg), respectively. The obtained averageand median values obtained by ICP-MS are very similar to those obtained by ICP-AES. Namely, thecorrelation factor for Co and Ni between the results from both methods are 0.92 (for normal distribution),0.93 (for logarithmic) and 0.94 (for rank), and 0.86 (for normal distribution), 0.94 (for logarithmic) and0.96 (for rank), respectively. The obtained results show that the high concentrations of Ni and Co in thesurface soil samples may originate from similar sources and their distribution follows the lithology of thestudy area.