An Ecological and Geochemical Characterization of Water Extracts from Ashes of Shiveluch Volcano (the Eruption of April 11–13, 2023)

This paper reports the results of laboratory experiments in the interaction of meteoric water and distilled water with the Shiveluch ash discharged during the eruption of April 11–13, 2023. The water extracts obtained using a variety of methods made it possible to simulate naturally occurring situations in which ash falls in a water environment and is washed by atmospheric precipitation. It has been found that the salt complex of Shiveluch Volcano contains a well-soluble component, viz, sodium chloride, magnesium salts, and a poorly soluble component consisting of calcium sulfate. The water extracts of fresh ashes contain high (relative to the concentration in the rocks of Shiveluch edifice) concentrations of volatiles (boron and selenium), as well as calcium, copper, and rare earth elements. The level of rock relationships was observed in some alkaline (Li, Na, K, Sr), high-charge (Y, Pb), and transitional (Zn, Ni, Co, Mn) elements. The transfer ratios for the other elements are very low, including rock-forming ones (Fe, Al, Si, Ti). Water extracts having ash–water ratios of ∼1 : 10 contain higher concentrations of fluoride ions reaching 3 MAC (maximum allowable content) and of sulfate ions reaching 2 MAC relative to the maximum allowable concentrations in objects of household-drinking and cultural water use. Ash that is washed by atmospheric precipitation loses its toxic potential during a few months. Stagnant water bodies favor accumulation of soluble components of volcanic origin, because water extracts show exceedance of safe parameter values in several heavy metals, the water–ash system is a dynamic one. The highest exceedance of maximum allowable content have been found for aluminum, manganese, copper, and cadmium. Also, volcanic ash can be a source of prolonged supply to drinking water of mixtures that are subject to regulations because they affect the quality of potable water.