Mobilization of aluminum by the acid percolates within unsaturated zone of sandstones

0392115 - GLÚ 2014 RIV NL eng J - Článek v odborném periodiku
Navrátil, Tomáš - Vařilová, Z. - Rohovec, Jan
Mobilization of aluminum by the acid percolates within unsaturated zone of sandstones.
Environmental Monitoring and Assessment. Roč. 2013, č. 9 (2013), s. 7115-7131. ISSN 0167-6369. E-ISSN 1573-2959
Institucionální podpora: RVO:67985831
Klíčová slova: acidification * drip water * chemical weathering * salt efflorescence * Black Triangle * Bohemian Switzerland National Park, Czech Republic
Kód oboru RIV: DD - Geochemie
Impakt faktor: 1.679, rok: 2013

The area of the Black Triangle has been exposed to extreme levels of acid deposition in the twentieth century. The chemical weathering of sandstones found within the Black Triangle became well-known phenomenon. Infiltration of acid rain solutions into the sandstone represents the main input of salt components into the sandstone. The infiltrated solutions–sandstone percolates–react with sandstone matrix and previously deposited materials such as salt efflorescence. Acidic sandstone percolates pH 3.2–4.8 found at ten sites within the National Park Bohemian Switzerland contained high Al-tot (0.8–10 mg L⁻¹) concentrations and high concentrations of anions SO₄ (5–66 mg L⁻¹) and NO₃ (2–42 mg L⁻¹). A high proportion (50–98 %) of Al-tot concentration in acid percolates was represented by toxic reactive Alⁿ⁺. Chemical equilibrium modeling indicated as the most abundant Al species A^l3+, AlSO₄ ⁺, and AlF²⁺. The remaining 2–50 % of Al-tot concentration was present in the form of complexes with dissolved organic matter Al-org. Mobilization and transport of Al from the upper zones of sandstone causes chemical weathering and sandstone structure deterioration. The most acidic percolates contained the highest concentrations of dissolved organic material (estimated up to 42 mg L⁻¹) suggesting the contribution of vegetation on sandstone weathering processes. Very low concentrations of Al-tot in springs at BSNP suggest that Al mobilized in unsaturated zone is transported deeper into the sandstone. This process of mobilization could represent a threat for the water quality small-perched aquifers.
Trvalý link: http://hdl.handle.net/11104/0222754