GEOCHEMICAL FEATURES OF NATURAL WATER OF BUILDING STONE QUARRIES IN PITKÄRANTA AREA (KARELIA)

Abstract

The relevance of the research is related to the need for a regional assessment of the impact of the building stone deposits development on the natural waters of the Northern Ladoga region. The study area is part of the Ladoga Lake catchment basin, the preservation of the superior water quality is a crucial issue. Currently, the lake resources are used in household and industrial water supply, as well as in fish farms and agriculture. The main aim of the research is to investigate the chemical composition and identify the main features of the behavior of chemical elements in the natural waters of building stone quarries. Objects: natural waters and rocks of building stone quarries in the Pitkäranta area of the Republic of Karelia. Methods. Water chemistry analyzed by means for a set of methods: potentiometric titration, ion chromatography, atomic emission spectroscopy and mass spectrometry. The mineral composition of the rocks was determined using an electron microscopy and powder X-ray diffraction. The mobility of chemical elements was assessed by coefficients of water migration (Kx) according to A.I. Perelman. The speciation of chemical elements in natural waters were calculated using the HCh software package. Results. The considered waters are fresh neutral or slightly alkaline with HCO3 Ca, SO4-HCO3 Na-Ca or HCO3 Na-Ca types. An analysis of a wide range of chemical elements made it possible to determine that S, Ca, Mg, As, Mo, U, Re have the highest mobility in the studied waters. The sources of easily mobile and mobile metals are sulfide minerals and feldspars. According to the thermodynamic calculations dominating species for Zn, Cd, Ni, Co, Sr, Rb, Ba, and Cs are ionic species, for Cu are carbonate species, and for Pb are carbonate and hydroxyl species. The main species of U are carbonate complexes. The water of Ladoga Lake differs in lower salinity and pH value from quarry waters, lower metal contents, which are more typical of being in ionic species. The coefficients of water migration are similar in the studied samples. However, the Kx elements curve of Ladoga Lake is different from the quarry ones. It causes due to the overlap of a number of factors and processes that form the water chemistry of such a large lake. Quarry waters are characterized by enrichment with some trace elements, especially U, Li, Mo, Re, as interaction time and the rock-water ratio increase.

Keywords

• water migration
• water chemistry
• uranium
• rare earth elements
• aqueous species
• pollution
• granite
• technogenic impact
• stone quarrying
• ladoga lake