144
carbon (EC) has a chemical structure similar to impure graphite and is emitted during the combustion process as a primary particle. Oxidation processes in the gaseous phase convert reactive hydrocarbons (terpenes and aromatic compounds) into
semi-volatile organic compounds, which then bind to the aerosol’s particles, primarily in urban areas where the mentioned emission sources dominate.
5.4.1 Atmospheric Depositions of Heavy Metals
The presence of heavy metals in the soil is a consequence of natural and anthropogenic processes. There are natural pedogenetic processes by which the soil inherits
heavy metals from the parent substrate, and anthropogenic processes include urbanization, industrialization, trade, and agricultural production. In remote areas with
low anthropogenic impact on atmospheric deposition, heavy metals in soils are
mostly derived from the parent substrate, while in urban and agricultural areas, the
concentrations of heavy metals in soils are higher than concentrations in parent
substrates due to continuous input into the ecosystem. The geogenic origin of the
most ecologically interesting heavy metals, Cu, Zn, Cd, and Pb, is most often associated with sulfur minerals, which oxidize relatively quickly in the environment,
and the metal cation separates from sulfur at an early stage of mineral depletion (He
et al. 2005). In the later stages of pedogenesis, Cu, Zn, and Cd are more often in the
composition of Mn oxide, and Pb is in the composition of Fe oxide and hydroxide.
The average proportion of igneous and sedimentary rocks in the earth’s crust is
95:5, and sedimentary rocks are more common in the surface layers. Soils formed
on sandstones and acidic rocks (e.g. granite) usually contain less essential elements
and heavy metals Cu, Zn, and Co (He et al. 2005) than alkaline rock and sedimentary shale soils (may contain more than 200 mg/kg Cd). Natural geological processes on different parent rocks can result in multiple concentrations of heavy
metals compared to the soil average, affecting flora and fauna. Natural sources of
heavy metals in the soil are, in addition to parent rocks, volcanic eruptions, marine
aerosols, and forest fires (Keller et al. 2015).
Agricultural production contributes to the accumulation of heavy metals in the
surface layers of agricultural soils by applying various agrotechnical measures:
1. Fertilization with mineral fertilizers (natural minerals, individual and complex
fertilizers)
2. Fertilization with organic fertilizers (manure, compost, organic residues)
3. Soil conditioning (calcification, acidification, texture improvers)
4. Application of pesticides
5. Irrigation and fertigation
The use of various substances containing metals has significantly increased in
order to achieve stable yields, and the application of microelements such as Cu, Zn,
Fe, Mn, and B has become a common agrotechnical intervention. These elements
are regularly added to the usual formulations of complex fertilizers when fertilizing
B. Balabanova et al.
carbon (EC) has a chemical structure similar to impure graphite and is emitted during the combustion process as a primary particle. Oxidation processes in the gaseous phase convert reactive hydrocarbons (terpenes and aromatic compounds) into
semi-volatile organic compounds, which then bind to the aerosol’s particles, primarily in urban areas where the mentioned emission sources dominate.
5.4.1 Atmospheric Depositions of Heavy Metals
The presence of heavy metals in the soil is a consequence of natural and anthropogenic processes. There are natural pedogenetic processes by which the soil inherits
heavy metals from the parent substrate, and anthropogenic processes include urbanization, industrialization, trade, and agricultural production. In remote areas with
low anthropogenic impact on atmospheric deposition, heavy metals in soils are
mostly derived from the parent substrate, while in urban and agricultural areas, the
concentrations of heavy metals in soils are higher than concentrations in parent
substrates due to continuous input into the ecosystem. The geogenic origin of the
most ecologically interesting heavy metals, Cu, Zn, Cd, and Pb, is most often associated with sulfur minerals, which oxidize relatively quickly in the environment,
and the metal cation separates from sulfur at an early stage of mineral depletion (He
et al. 2005). In the later stages of pedogenesis, Cu, Zn, and Cd are more often in the
composition of Mn oxide, and Pb is in the composition of Fe oxide and hydroxide.
The average proportion of igneous and sedimentary rocks in the earth’s crust is
95:5, and sedimentary rocks are more common in the surface layers. Soils formed
on sandstones and acidic rocks (e.g. granite) usually contain less essential elements
and heavy metals Cu, Zn, and Co (He et al. 2005) than alkaline rock and sedimentary shale soils (may contain more than 200 mg/kg Cd). Natural geological processes on different parent rocks can result in multiple concentrations of heavy
metals compared to the soil average, affecting flora and fauna. Natural sources of
heavy metals in the soil are, in addition to parent rocks, volcanic eruptions, marine
aerosols, and forest fires (Keller et al. 2015).
Agricultural production contributes to the accumulation of heavy metals in the
surface layers of agricultural soils by applying various agrotechnical measures:
1. Fertilization with mineral fertilizers (natural minerals, individual and complex
fertilizers)
2. Fertilization with organic fertilizers (manure, compost, organic residues)
3. Soil conditioning (calcification, acidification, texture improvers)
4. Application of pesticides
5. Irrigation and fertigation
The use of various substances containing metals has significantly increased in
order to achieve stable yields, and the application of microelements such as Cu, Zn,
Fe, Mn, and B has become a common agrotechnical intervention. These elements
are regularly added to the usual formulations of complex fertilizers when fertilizing
B. Balabanova et al.