Physicochemical and mineral characteristics of soil materials developed naturally on two ∼ 50 years old coal combustion residue disposal sites in Croatia

Petrović, Marija; Ivanić, Maja; Vdović, Neda; Dolenec, Matej; Čermelj, Branko; Šket, Primož; Medunić, Gordana; Fiket, Željka (2023) Physicochemical and mineral characteristics of soil materials developed naturally on two ∼ 50 years old coal combustion residue disposal sites in Croatia. CATENA, 231 . ISSN 0341-8162

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Abstract

Coal combustion has been one of the most dominant sources of energy for the last two centuries, generating tonnes of coal combustion residue (CCR). Rapid soil formation has been observed at old CCR disposal sites, altering the physiochemical and mineral properties of CCR, affecting contaminant release mechanisms and nutrient availability. Although ubiquitous, pedological properties of weathered CCR have been studied at only a small number of disposal sites. This study characterized two CCR landfills of similar age (~50 years) using a range of parameters, including pH, total nitrogen and organic carbon content, major oxides (Al2O3, CaO, and SiO2), and macronutrients (Ca, K, Mg, P, and S), as well as textural and mineralogical data. In addition, specific surface area and cation exchange capacity were determined to assess particle properties, and 13C and 29Si NMR spectra were examined to characterize the organic matter and degree of polymerization of the coal ash glassy phase. Such comprehensive approach aimed to determine indicators of soil formation and to characterize the capacity of such landfills to retain water, nutrients, and contaminants. Both landfills displayed evidence of pedogenesis reflected in the pH decrease, formation of secondary minerals (such as ettringite, hydrotalcite, gypsum, and calcite), and changes in the C:N ratio. The Plaški landfill seems to have a better capacity to hold water, nutrients, and contaminants evident by higher clay content, CEC, and SSA values, possibly explaining why it developed more rapidly than Štrmac despite their similar age. The presence of montmorillonite in Plaški could be one of the main factors accelerating pedogenesis. 13C NMR spectra point to the unburned coal particles as the main origin of organic matter and 29Si NMR spectra showed higher depolymerization of a non-crystalline fraction in bare ash samples than in vegetated ash samples.

Item Type:	Article
Uncontrolled Keywords:	coal ash; slag; CCR; Technosols; weathered; aged
Subjects:	NATURAL SCIENCES > Geology NATURAL SCIENCES > Interdisciplinary Natural Sciences > Environmental Science
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Transport, sudbina i toksičnost metal(oid)a otpuštenih iz ležišta industrijskog otpada-FORtIS Željka Fiket; Antonela Ninčević Grassino; Jelena Loborec; Sanja Kapelj; Matej Dolenec; Uroš Herlec; Gordana Medunić IP-2019-04-9354 HRZZ
Depositing User:	Marija Petrović
Date Deposited:	15 Jan 2025 09:25
URI:	http://fulir.irb.hr/id/eprint/9453
DOI:	10.1016/j.catena.2023.107338

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