Effect of geo-pedological conditions on the distribution and chemical speciation of selected trace elements in forest soils of western Alborz, Iran

Geochemical hunting of lithogenic and anthropogenic impacts on polymetallic distribution (Bregalnica river basin, Republic of Macedonia)

“…Soil-forming processes greatly influence the trace element distribution within the soil profile. [12] Significant variations were not detected in the contents of the other elements in traces in the sediment and in the fluvisol soils, as well as in relation to the Dutch standards for these elements. Considering the rest of the elements, the overview of the contents of microelements and elements in traces by zones is provided in Table 4.…”

“…[8] The addition of Ca-salts usually results in a higher release of exchangeable metals in the soil solution compared to the addition of Na-salts, which are less competitive for sorption. [12] The sediments are characterized with median value of Ca contents of 1.9% and 1.8% in fluvisol vs. 1.6% and 1.7% for Na contents respectively (Table 3). Aluminum is present in the highest concentration in the sediment (6.6%) of the fourth zone of the Bregalnica river course, with almost insignificant variations to 5.5% in the alluvium of the river Lakavica.…”

“…[4,10,11] Only a small portion of free metal ions, however, stay dissolved in water. [12] Thus, the distribution of trace metals in sediment adjacent to populated areas (includes industries, mining exploitation in particular) can give us the evidence of anthropogenic influence on aquatic system and convenience in assessing the potential risks associated with human waste discharge. [13] For example, in the Republic of Macedonia there are several significant pollution sources of potentially toxic elements/metals that continuously introduce tailings and waste into river waters.…”

Impact of parent rock and topography aspect on the distribution of soil trace metals in natural ecosystems

“…The natural vegetation is characterized by forest trees consisting mainly of Alnus subcordata, Zelkova carpinifolia, Carpinus betulus, and Mespilus germanica. Geologically, the area is characterized by Precambrian and Paleozoic metamorphic and mafic rocks as well as Cretaceous shale and limestone (Darvishzadeh 2002;Nael et al 2009). …”

“…Although there is great diversity in the pedogenic processes contributing to the trend of trace metals, they can be generalized as (1) the physical and chemical processes of weathering (dissolution, hydration, hydrolysis, oxidation, reduction, and carbonatization) and (2) sorption, desorption, and the formation of various species of elements which are controlled by leaching, eluviation, podzolization, alkalization, aluminization, laterization, salization, and hydromorphic processes (Kabata-Pendias and Mukherjee 2007;Nael et al 2009). Koons et al (1980) and Rezapour and Samadi (2011) found that clay minerals, iron oxides, organic mater, and calcium carbonate, caused by weathering and pedological processes, are important significantly in the translocation and accumulation of trace metals.…”