Zonal features of lake acidification

Zonal features of water acidification in small lakes of European Russia are analyzed. The conditions under which the process can develop are evaluated. Studies of water chemistry variations and formulation of various criteria used to assess water acidification made it possible to prove the development of the process in the humid part of the area under study, i.e., in tundra, taiga, and forest regions. The leading natural and anthropogenic factors, whose combination governs the acidification mechanism and secondary effects are discussed. The concentrations of some metals (Al, Zn, Pb, and others) are proved to increase in waters with low pH, as well as at an increase in water color index. Critical loads of acid precipitation are evaluated and the values of their exceedance in lakes in different natural-climatic zones.