The migration of 32 elements from natural zeolitized tuffs from the Beli Plast and Golobradovo deposits (Bulgaria) was determined in ultrapure, tap, mineral, and coal mine waters in order to evaluate their desorption and adsorption properties. The tuffs are Ca-K-Na and contain clinoptilolite (90 and 78wt.%, respectively), plagioclase, sanidine, opal-CT, mica, quartz, montmorillonite, goethite, calcite, ankerite, apatite, and monazite. The desorption properties are best revealed during the treatment of ultrapure, tap, and mineral water, whereas the adsorption properties are best manifested in coal mine water treatment. The concentrations of Al, Si, Fe, Na, Mn, F, K, Pb, and U increase in the treated ultrapure, tap, and mineral water, while the content of K, Be, Pb, and F increase in the treated mine water. The tuffs show selective partial or complete adsorption of Na, Mg, Sr, Li, Be, Mn, Fe, Co, Ni, Cu, Zn, Al, Pb, U, and SO₄²⁻. They demonstrate the ability to neutralize acidic and alkaline pH. Sources of F are presumed to be clinoptilolite and montmorillonite. The usage of zeolitized tuffs for at-home drinking water treatment has to be performed with caution due to the migration of potentially toxic and toxic elements.

In this work we report data from LA-ICP-MS analyses of 7 bentonite samples from the Eastern Rhodopes as three of the samples come from two bentonite deposits – Zlatna Livada and Propast-Dobrovolets. The obtained results show no significant accumulation of trace elements in the studied samples. Their overall chemical composition is strongly influenced by the volcanic glass chemistry, the presence and abundance of magmatic minerals and lithic clasts and to lesser extent by secondary authigenic mineral associations. Respectively, their trace element signature is similar to that of the unaltered extension-related orogenic volcanic rocks in the Eastern Rhodopes. No correlation between any of the trace elements measured and the relative montmorillonite abundance (in samples A-ZL and I-PD) have been established. Nevertheless, these data complete the knowledge of bentonite clays from the Eastern Rhodopes; they can shed more light on the connection between volcanic precursors and alteration products and can provide deeper insight into the process of glass transformation.