Multidisciplinary approach to assess the water self-depuration characteristics of Suquía River (Córdoba, Argentina)

TLDR: In this article, the authors analyzed the water self-depuration capacity along a polluted river (Suquia River) in Argentina: abundance of microbial metabolic groups, cover and type of vegetation, and type and concentration of soil and sediment humic substances.

Abstract: We analyzed the following characteristics of water self-depuration capacity along a polluted river (Suquia River) in Argentina: (a) abundance of microbial metabolic groups, (b) cover and type of vegetation, and (c) type and concentration of soil and sediment humic substances. The objective was to establish the modifications of water self-depuration characteristics of the polluted sites in comparison to a reference site in order to provide basic data for ecological restoration programs. Five samples of riparian soil, water, and sediments were collected at a reference site and five polluted sites during low- and high-flow water periods. In each site the vegetation type and soil cover were recorded. In all samples the abundance of ammonifiers, nitrate reducers, sulfate reducers, cellulolytic microorganisms, aerobic heterotrophs, and fermenters was measured. Besides, soil and sediment organic matter and humic and fulvic acids content were analyzed. Our results showed that all sites differed in their water self-depuration characteristics with respect to the reference site and that these variations are due to a combination of natural and anthropic factors. The Suquia River presents a great heterogeneity of water self-depuration characteristics but it does not achieve a mitigation of the anthropogenic impact produced by Cordoba city. We concluded that restoration actions in lotic ecosystems should be adapted for each river sector.