Using different receptor models to determine the sources of available forms of potentially toxic elements in Rasina District-A case study

Determining the sources of potentially toxic elements (PTEs) in soil is one of the basic postulates for dealing with them properly in the future. In addition to total PTEs, it is extremely important to identify sources of available PTEs, for two reasons: 1. to determine their actual impact on the ecosystem, and 2. to establish whether sufficient levels are present in soil if they are necessary for plant development. In this study, two receptor models were used to determine sources of diethylenetriaminepentaacetic acid (DTPA)-extractable PTEs in soil in Rasina District, Serbia in 2017: Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF). Appropriate PCA was used for total forms and the accuracy of the models in determining sources was tested by comparing them. Based on the results, obtained in quite a complex geological environment, the universality and superiority of the PMF model in so-called diffusion systems, which are more prone to change, was confirmed. The PMF model took geological and anthropogenic sources, characteristic of PCA of total PTEs, into account in equal measure, as well as pedological sources, which are more characteristic of PCA of DTPA-PTEs. The accuracy of the model was also confirmed by the greater number of factors, i.e. 5 in the PMF model compared to 3 in PCA. Based on the obtained results, it is clear that the use of the PMF model is justified when determining sources of individual available PTEs in soil.