Venera Tsolovaa, Martin Banovb, Viktor Kolchakovb and Plamen Tomovb
a Agricultural Academy, 1373, Sofia, Bulgaria
b Agricultural Academy, Institute of Soil Science, Agrotechnologies and Plant Protection “N. Poushkarov”, 1331 Sofia, Bulgaria
Tsolova, V., Banov, M., Kolchakov, V. & Tomov, P. (2024). Pyrogenic carbon in soils dominated in mine-energy regions of Bulgaria. Bulg. J. Agric. Sci., 30(6), 982–993
Pyrogenic carbon (PyC) is a temperature forcing agent, air pollutant and dangerous to human health, but its functions in soils are still under discussion. There is a huge knowledge gap in Bulgaria on PyC distribution in soils especially in those located in mine-energy regions where the PyC major source are concentrated. Therefore, the present study aims to propose a method for determination of PyC content and to present its 3D-distribution in soils located in the oldest mine-energy regions of Bulgaria.
The method described in this article is a modification of the method developed by Lim and Cachier and uses a dichromate mixture for isolation of PyC fraction. It is experimented with Vertisols which are considered PyC-containing soils. The method is also applicable to soils strongly enriched with coal fragments that are usually located in mine-energy regions of Bulgaria.
According to the results obtained a strong variation of PyC content was established in studied soils from Maritsa-iztok and Pernik mine-energy regions (0.10% – 19.07%). A higher content (max 19.07%, average 4.30%) was registered in the region of Pernik, where weakly transformed organic artefacts (soot and coal) increased weather-resistant pyromorphic carbon forms.
According to the developed evaluative scale, the medium content of PyC prevails in Bulgarian soils – from 0.29% to 0.51%. The factors influencing this distribution are: paleo- and present fires, the content of coal impurities, and deposition of PyC-enriched aerosols emitted from coal operating thermal-electric power plants, domestic heating with coal, coal mining and transport.