Factor analysis applied to distinguish influences of parent material, mining industry and agriculture on the groundwater in the Strumica valley, Macedonia

Abstract

Determination of the groundwater chemistry in Strumica valley was essential since the widespread use of it in the irrigation of agricultural production.  For this purpose were collected 224 water samples from boreholes. The groundwater chemical composition was determinated on the selected analytes: As, Sr, Mn, Ni, Cu, Zn, Mo, Ba, Pb, Na, Mg, Al, K, Ca, Ti, Li, Cr, Fe, U, CaCO3, Cl-, NO3-, NH4+, SO42- and PO43-. The source and internal correlations of the analytes were set out by performing multivariate statistical analyses (factor analyses). Factor analyses yielded 7 factors and the geochemical maps of the obtained factors were generated using kriging method. The groundwater chemistry was predominantly controlled by geologic background and some anthropogenic influence due to agriculture and mining to the concentrations and spatial distribution of arsenic, phosphates, sulphates, nitrates and some metals (copper, iron, chromium, lead, nickel, zinc). Mining of copper/gold (molybdenum) in area of Ilovica increased concentration of analytes Al, Cu, Pb, Cr, NO3-, Ni, Zn, Na, K, Li and PO43-  in groundwater but only at a local level.

Keywords

• groundwater, chemistry, factor analyses, Strumica, Macedonia