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Influence of the Iron-Reducing Bacteria on the Release of Heavy Metals in Anaerobic River Sediment

Gounou, Catherine, Bousserrhine, Noureddine, Varrault, Gilles, Mouchel, Jean-Marie
Water, air, and soil pollution 2010 v.212 no.1-4 pp. 123-139
acetates, bacteria, butyrates, carbon, glucose, heavy metals, iron, iron oxides, microbial growth, mineralization, monitoring, organic acids and salts, pH, rivers, sediments, toxicity
The impact of autochthonous anaerobic bacteria on the release of metals in river sediment was studied. The sediments were characterized and bacterial activity was monitored in a batch reactor, where the sediments were incubated with a synthetic substrate solution containing glucose as carbon source. The results showed that metal release was correlated to the bacterial growth (carbon mineralization). In particular, a relationship between iron reduction and metal release was observed indicating that iron-reducing bacteria had a strong influence. By reductive dissolution of iron oxides, bacteria also released their associated toxic elements into the liquid phase. While organic analysis showed acetate and butyrate production leading to a decrease in pH and indicating a Clostridium fermentative bacteria activity, the results did not indicate any direct role of organic acids in the dissolution of iron and their associated metals.