Geochemical baseline for chemical elements in top- and subsoil of Idrija

Abstract

This study is a continuation of our previous study (Bavec et al., 2015), where the geochemical baseline levels of potentially harmful elements (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb and Zn) in Idrija top-and subsoil (0-10 cm and 10-20 cm) at 45 locations were reported. Here we summarise our previous work and present baseline levels of additional 33 elements (Ag, Al, Ba, Be, Bi, Ca, Ce, Cs, Fe, Ga, Hf, In, K, La, Li, Mg, Mn, Nb, P, Rb, S, Sb, Sc, Se, Sn, Sr, Th, Ti, Tl, U, V, Y and Zr) in order to round off the first systematic geochemical survey of soil in Idrija town and establish a data set of soil elements, which will serve as a baseline for monitoring future changes in the soil chemical composition of the studied area.The baseline levels were determined after aqua regia digestion, their statistical distribution was examined and the medians were compared to the recently established European grazing land and Maribor urban soil medians. To investigate relationships between elements, a correlation-matrix-based hierarchical clustering method was performed and the spatial distribution of their highest levels was examined. The results showed that in general, the median levels of elements in Idrija soil are mostly similar or slightly higher than in European and Maribor soil, with exception of Hg. Elements Al, Bi, Ca, Ce, Co, Cr, Cs, Fe, Ga, Hf, La, Li, Mg, Mn, Nb, Ni, Rb, S, Sc, Th, Ti, Tl, V, Y and Zr are enriched in the rural surroundings, while elements Ag, Ba, Cu, Hg, P, Pb, Se, Sb, Sn and Zn are enriched only partly in the rural surroundings, but mostly in the urban part of the study area. It is assumed that elements, which are enriched only in the rural surroundings, are of natural origin, while elements, which are enriched also in the urban area, are to a certain extent influenced by anthropogenic activities. IzvlečekPredstavljena študija je nadaljevanje preteklih raziskav (Bavec et al., 2015), kjer smo obravnavali vrednosti geokemičnega ozadja potencialno škodljivih elementov (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb in Zn) v zgornjem in spodnjem (0-10 cm in 10-20 cm) sloju tal Idrije na 45. lokacijah. V članku povzemamo prejšnje preiskave in obravnavamo geokemična ozadja dodatnih 33 elementov (Ag, Al, Ba, Be, Bi, Ca, Ce, Cs, Fe, Ga, Hf, In, K, La, Li, Mg, Mn, Nb, P, Rb, S, Sb, Sc, Se, Sn, Sr, Th, Ti, Tl, U, V, Y in Zr) z namenom, da bi zaokrožili prve sistematične geokemične raziskave tal v mestu Idrija, ter da bi vzpostavili nabor podatkov o elementih v tleh, ki bodo služili kot osnova za spremljanje prihodnjih sprememb v kemijski sestavi tal na preiskovanem območju.Vrednosti ozadja smo določili po razklopu z zlatotopko, preiskali njihovo statistično porazdelitev in primerjali ugotovljene mediane z medianami elementov v evropskih pašniških in mariborskih mestnih tleh, ki so bile vzpostavljene nedavno. Z namenom, da bi prepoznali povezave med elementi, smo uporabili metodo hierarhičnega razvrščanja na podlagi korelacijske matrike in ugotavljali prostorsko porazdelitev najvišjih vrednosti elementov. Rezultati...