Origin, mineral speciation and geochemical baseline mapping of Ni and Cr in agricultural topsoils of Thiva Valley (central Greece)

摘要: article i nfo Lithogenic Ni and Cr enrichment in agricultural topsoils of Thiva Valley (central Greece) is the result transport weathered parent rock fragments from upslope ultramafic sources. Chemical mineralogical evolution these potentially toxic elements between trace metal bearing bedrock overlying soil horizon along two weathering profiles located an area where rocks are exposed was accomplished to unravel source mineral speciation dynamics system Valley. Within hori- zons, primarily occurs serpentine (average 0.5 wt.% NiO) secondary products like smec- tites goethite 1.1 NiO). Significant amounts this element also hosted less abundant Mn (hydr)oxides. On contrary, mainly bounded with inherited chromite 54.7 Cr2O3) a lesser extent Cr-magnetite 12.2 sili- cates enstatite 0.8 Cr2O3). As solid applied decomposition method (aqua regia digestion), geochemical anomalies within valley more pronounced respect (up 2640 mg/kg) compared 856 mg/kg). The baseline maps produced by ordinary kriging interpolation reveal strong tendency for large south- ern part warning about potential occurrence high values soils town approximate number 25,000 population. Based on residence differ- ences their bioavailability leaching groundwater anticipated.