Weniger häufig vorkommende Elemente mit potentieller Bedeutung für die Umwelt

Trace elements assessment in agricultural and desert soils of Aswan area, south Egypt: Geochemical characteristics and environmental impacts

“…This indicates that these elements could be adsorbed or coprecipitated by Al-, Fe-and Mn-oxides, hydroxides and oxyhydroxides, and clay minerals, as well as, they could be formed complexation with organic matter in soil (Bhumbla and Keefer, 1994;Tessier et al, 1996;Edwards et al, 1999;Soltan et al, 2000;Alam et al, 2003;Yanes et al, 2006). Thus, soil properties, particularly the organic matter content, were found to be important factors in the distribution and composition of metals (Zhao et al, 2014).…”

“…Where, Cd and Mo are mainly derived from agricultural activities and agronomic practices, like pesticides and chemical fertilizers, manure and sewage sludge that are widely used by farmers to secure higher yields (Alloway, 1995;Alloway and Ayres, 1997;Wong et al, 2002;Nicholson et al, 2003;Qu et al, 2011;Agca and Özdel, 2014). Regarding to Y, Sc, Li are most probably due to lithogenic sources; where, they could be associated with fine heavy mineral fractions (van Westrenen et al, 1999; Abd El-Naby and Dawood, 2014), fine grained phyllo-silicates (clays, mica) and carbonate minerals (Hirst, 1962;Mason, 1987;Edwards et al, 1999). Cluster 3 contains the association of P, Zn and Mn that could be contributed to agricultural soil during farming practices as a result of the intensive use of composted materials, agrochemical products, such as phosphate-and Zn-based fertilizers, animal manure and cattle slurry (Lin, 2002;Nicholson et al, 2003;Gowd et al, 2010;Guo and He, 2013).…”

“…Cluster 1 is related to F1, F2 and F3 of factor analysis and includes the association of Mo, Ni, Li, Cu and Co. These elements are possibly associated with lithogenic particulates because of they have a strong affinity to fine grained minerals and phyllosilicates (clays and mica) by selective adsorption, ion exchange processes, or combined structurally in the lattices of clay minerals that are acting as scavengers and considered as the main phases that trap migrating elements in the supergene environment (Hirst, 1962;Edwards et al, 1999). The pollution level caused by Mo is most probably due to atmospheric deposition of vehicular and industrial emissions or weathering products of agricultural soil.…”