Surface Water under Growing Anthropogenic Loads: from Global Loads to Regional Consequences: A Review

Abstract

The paper presents a review of currently available evaluations of the effects of continuously increasing anthropogenic loads on water resources. The increase in the fluxes of elements and compounds into the environment, such as the emission of greenhouse gases and dispersion of nutrients (nitrogen and phosphorus), acidifying gases, and toxic elements and compounds that adversely affect the water quality are considered. The significance of fresh waters as a life support factor of the human populations is demonstrated. Examples are presented to illustrate how key anthropogenic induced processes develop in land waters under the effect of anthropogenic loads, as exemplified by the Russian Kola regions. Climate warming and the increasing dispersion of elements are demonstrated to result in the eutrophication of surface waters even in areas remote from anthropogenic impacted regions. Although the emissions of acidifying gases diminish, the waters are still acidified in acid-vulnerable areas, and the chemical compositions of the waters have been significantly modified over the past decades, which indicates that the changes in the chemical composition of the waters are of irreversible. A new feature of the waters is distinguished: the toxicity of the habitats for aquatic organisms. Arguments are presented for establishing a theoretical approach for evaluating critical loads.