Online Volumes of the Journal of Hydrology and Hydromechanics


J. Hydrol. Hydromech., Vol. 70, No. 4 - Early View, 2022, p. 1 - 11, doi: 10.2478/johh-2022-0024
Scientific Paper, English

Hana Fajković, Maja Ivanić, Ivan Nemet, Sanda Rončević, Štefica Kampić, Dana Leontić Vazdar: Heat–induced changes in soil properties: fires as cause for remobilization of chemical elements

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  • Exposure of soil constituents to elevated temperatures during wildfire can significantly affect their properties and consequently, increase the mobility of the bound contaminants. To estimate the potential of wildfires to influence metal remobilization from the burned soil due to the changes in cation exchange capacity (CEC) after organic matter combustion and mineral alteration and degradation, changes in soil properties after exposure to different temperatures was investigated. This was accomplished through analysis of geochemical, mineralogical and surface physicochemical properties of a soil sample exposed to different temperatures in a laboratory. Heating the soil sample at 200 °C, 500 °C and 850 °C resulted in an increase in pH (from 5.9 to 12.3), decrease in cation exchange capacity (from 47.2 to 7.3 cmol+kg–1) and changes in the specific surface area (observed only at 500 °C), that are associated with structural modifications of clay minerals and ferromagnetic minerals. Extraction analysis showed the increase in the concentration of almost all analysed elements (Al, Cd, Co, Cr, Fe, Mn and Zn) in soil eluates. The observed increase, following high– temperature heating (500 °C and 850 °C), was as much as 15 times higher (e.g., Al), compared to the native soil sample (25 °C). This strongly indicates that wildfire can act as a trigger for remobilization of heavy metals.

    KEY WORDS: Heating; Soil; Trace metals; Physicochemical properties.

    Address:
    - Hana Fajković, Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia.
    - Maja Ivanić, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička c. 54, 10 000 Zagreb, Croatia. (Corresponding author. Tel.:+385 1 456 1176 Fax.: Email: mivanic@irb.hr)
    - Ivan Nemet, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia.
    - Sanda Rončević, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia.
    - Štefica Kampić, Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia.
    - Dana Leontić Vazdar, Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10 000 Zagreb, Croatia.

     




J. Hydrol. Hydromech., Vol. 70, No. 4 - Early View, 2022, p. 1 - 9, doi: 10.2478/johh-2022-0025
Scientific Paper, English

Irena Atanassova, Milena Harizanova, Maya Benkova, Stefan H. Doerr: Changes in organic molecular marker signatures in soils amended with biochar during a three-year experiment with maize on a Fluvisol

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  • Biochar is widely used as a soil amendment to improve soil properties and as a tool to absorb net carbon from the atmosphere. In this study we determined the signatures of organic molecular markers in soil following the incorporation of 5 and 10 t/ha biochar in a Fluvisol, cultivated with maize at the experimental field of the ISSAPP “N. Poushkarov” institute in Bulgaria. The n-alkane distribution in the biochar treated soils was uni- or bimodal maximizing at n-C17 alkane, n-C18 or C18 branched alkanes, i.e. there was an imprint of biomass burning, e.g. from the biochar due to predominance of short chain (< C20) homologues and increased microbial activity (presence of branched alkanes). This is also confirmed by the values for the average chain length (ACL) of n-alkanes which indicated prevalence of homologues of shorter chain (20–21 C atoms) in the variants of longer biochar residence time. There was evidence of trans-13-docosenamide, which originated from biochar. Fatty acids and fatty alcohols distributions also implicate microbial contribution to soil organic matter (SOM), supporting the suggestion that biochar addition can improve soil microbiological status.

    KEY WORDS: Biochar; Organic molecular markers; Fluvisol.

    Address:
    - Irena Atanassova, Institute of Soil Science, Agrotechnologies and Plant Protection, Department of Agrochemistry, Agroecology and Soil Tillage, 7 Shosse Bankya Str., Sofia 1331, Bulgaria. (Corresponding author. Tel.: Fax.: Email: i.d.atanassova@abv.bg)
    - Milena Harizanova, Institute of Soil Science, Agrotechnologies and Plant Protection, Department of Agrochemistry, Agroecology and Soil Tillage, 7 Shosse Bankya Str., Sofia 1331, Bulgaria.
    - Maya Benkova, Institute of Soil Science, Agrotechnologies and Plant Protection, Department of Agrochemistry, Agroecology and Soil Tillage, 7 Shosse Bankya Str., Sofia 1331, Bulgaria.
    - Stefan H. Doerr, Department of Geography, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, UK.

     




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