Geochemical background in soils: a linear process domain? An example from Istria (Croatia)

Abstract

Definition of geochemical background in exploration and environmental geochemistry has always been regarded as contingent upon scale and investigated locality but mostly under assumption that hosts of processes that produce the data more or less conform individually to Gaussian law of ''central tendencies''. Recently, understanding of pedogenesis as synergetic process being characterized by non-linear dynamics renders thermodynamic approach directly applicable in assessment of geochemical thresholds, with concepts of linearity and normality set alongside in solving the problems of soil geochemistry. Seen from this perspective the work is an attempt to relate conceptual fundamentals of non-linear dynamical theory to basic statistical methods in order to elucidate the nature and origins of element subpopulations hidden in the original geochemical data from the soils of Istrian Peninsula (western Croatia). To this purpose the two major groups of soils were selected for analysis depending on the type of bedrock as one of the main soil-forming factors. Geochemical data were subjected to the trimming procedure by which the outliers were removed from the total data collective and attributed to non-linear causes precluding simple cause-and-effect relationships as the sine qua non of Gaussian distribution. Geochemical background is then defined as the normal range of data of the remaining (trimmed) dataset indicating the ''thermodynamic branch'' of the specific soil processes as opposed to outliers being described as dissipative structures.

Geochemistry of Croatian superhigh-organic-sulphur Raša coal, imported low-S coal and bottom ash: their Se and trace metal fingerprints in seawater, clover, foliage and mushroom specimens

“…Regarding the geological, hydrological and hydrographical setting, more details can be found elsewhere (Durn et al, 1999;Peh et al, 2010;Halamić et al, 2012;Frančišković-Bilinski et al, 2014). Briefly, the most prominent geological characteristic of the study area is the karst topography and carbonate bedrock.…”

Geochemical distribution and threshold values determination of heavy metals in stream water in the sub-basins of Vermelho and Sororó rivers, Itacaiúnas River watershed, Eastern Amazon, Brazil

“…Particularly for toxic heavy metals, the determination of background values or threshold limits of elements is highly relevant to distinguish between natural and anthropogenically-influenced metal concentrations (Urresti-Estala et al 2013, Arpine & Gayane 2016. The imprecise use of the terms background and threshold and the statistical methods for their determination have been discussed (Ander et al 2013, Cembranel et al 2017, Gałuszka & Migaszewski 2012, Gałuszka 2007, Matschullat et al 2000, Nakić et al 2007, 2010, Peh et al 2009, Rodrigues et al 2013, Teng et al 2009, Urresti-Estala et al 2013, Zgłobicki et al 2011. Geochemical background and threshold values are generally used as a reference to distinguish between natural concentrations of a certain element from the concentrations affected by anthropogenic activities, considering temporal and spatial variables of the area under investigation (Gałuszka 2007.…”

“…Geochemical background and threshold values are generally used as a reference to distinguish between natural concentrations of a certain element from the concentrations affected by anthropogenic activities, considering temporal and spatial variables of the area under investigation (Gałuszka 2007. Moreover, statistical methods for the determination of threshold values are a current discussion on literature , Cembranel et al 2017, Ander et al 2013, Rodrigues et al 2013, Nakić et al 2007, 2010, Peh et al 2009, Teng et al 2009, Gałuszka 2007, Matschullat et al 2000.…”

Application of stable isotopes (δ34S-SO4, δ18O-SO4, δ15N-NO3, δ18O-NO3) to determine natural background and contamination sources in the Guadalhorce River Basin (southern Spain)

“…These techniques are more powerful and realistic tools for this specific task (Apitz et al, 2009;Masetti et al, 2009;Peh et al, 2010). One of the first approaches in determining the NBLs based on statistical criteria was carried out with probability plots and the upper limits of the obtained ranges (Sinclair, 1974;Stanley and Sinclair, 1989;Tobias and Bech, 1997).…”