Substantiation of threshold values of hydrochemical characteristics of the Pivdennyi Buh river water quality according to the EU water framework directive - V. V. Shkapenko; L. O. Buzhuk; O. O. Zholudenko; Yu. V. Lytvynenko; T. V. Fomina; N. M. Vashchenko; O. D. Zheliak (Geochemistry of technogenesis, 2020)