engleski

Comparison of metal content determination methods in real agricultural soil samples - case study Podravina, Croatia

Since 1991, agroecosystem monitoring (soil and plant) in surrounding of Central Gas Station (CGS), Molve, located in Northern part of Croatia as a part of Croatian Gas Energetic System Podravina, has been conducted by the University of Zagreb Faculty of Agriculture, on the carefully selected representative locations, different soil types and water regimes. Synergy of agriculture and energy production in this part of Croatia is very important issue. In this paper, measured soil concentrations of Pb, Zn, Ca, Sr, Cd and Hg, sampled in Spring and Autumn 2019 at 6 different locations and soil types in surface and subsurface soil layers (0-3 cm and 3-8 cm) will be discussed (n=28). Two different methods of soil metals determination will be compared: real totals (RT) with pXRF (G2-VCR, Olympus, ISO 13196) and aqua regia (AR) digestion (in 1:20 w/v) and ICP-OES determination (ICPE 9000, Shimadzu, ISO 11466). Results shows that both methods are valid for determination of Pb, Zn, Ca and Sr in soil samples. For Cd and Hg, ICP-OES method was appropriate while pXRF was not (soil concentrations < LOD). Correlation between methods for Pb and Zn determination were complete (r=0.933 and 0.990, respectively), very strong for Ca (0.814) and very weak for Sr (r=0.1077). No significant difference between mean values were observed just for Pb (p=0.088). Quality control analysis shows that accuracy (rel. error) in accordance to referent samples were up to 19 % depending on the element and method.

aqua regia, Central Gas Station Molve, ICP-OES, pXRF, real totals

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