Spatial distribution and associated spatial uncertainty of potential toxic elements: the Lake Kalimanci case study (Republic of Macedonia)

Abstract

Pollution from mining activities is a significant problem in various regions of the Republic of Macedonia. A geochemical survey of the surface deposits of Lake Kalimanci in the easterly region of the Republic of Macedonia was carried out before (2001) and later (2007) the dam failure and thus allowing the measurement of the tailings’ material from Sasa Pb-Zn Mine-Osogovo Mountains (Eastern Macedonia). The concentrations of potentially toxic elements (PTE): Ag, Au, Cd, Co, Cu, Pb, Sb, Th, S, U and Zn were obtained by ICP Mass Spectrometry (ACME Laboratories in Vancouver, Canada). Data analysis, through Principal Component Analysis (PCA), was performed in order reduce the space of analyses by the construction of synthesis variables (Principal Factors). Geostatistical modeling was used, throughout conventional variography and the Sequential Gaussian Simulation algorithm (SGS), to model the new factors' spatial distribution. A hundred simulations, differing in their initial random-number seed, were performed and a Mean Image (MI) obtained. Spatial uncertainty evaluation (simulation’s Standard Deviation) allowed the definition of future monitoring and sampling strategies as well as the measurement of remediation possibilities.