Assessment of the biological contribution to monitored natural recovery of anthropized freshwater sediments

MADUEÑO, LAURA; STAREVICH, VIVIANA AYELEN; B.M. COPPOTELLI; AGNELLO ANA, C.; M.T. DEL PANNO; VIDAL, NURIA; ONETTO, MARIA ELENA; IRMA S. MORELLI

Nueva Orleans

Conferencia; ternational Conference on Remediation and Management of Contaminated Sediments; 2019

Aquatic ecosystems are suffering from different anthropogenic pressures due to contaminants released by discharges from domestic and industrial wastewaters. Among the organic pollutants, petroleum hydrocarbons are of major concern because of their wide persistence and toxicity. Monitored natural recovery (MNR) of historically contaminated sediments is a viable and cost-effective remediation strategy that relies on natural physical, chemical, and biological processes to isolate, degrade or reduce the toxicity of contaminants. For a proper implementation of MNR the characterization of the ability of autochthonous microbial communities to biodegrade petroleum hydrocarbons is necessary.The studied sediments come from two sites of a freshwater course with a history of oil pollution and whose recovery began 20 years ago.Four sediments cores were extracted of each site using a hammer piston tool. In a previous study, water samples were analysed, showing significant difference in the dissolved oxygen between the two sites, while hydrocarbons were not detected. Likewise, surface sediment horizons showed the lowest or non-detectable hydrocarbon concentrations. By contrast, deeper horizons were contaminated with aliphaticand aromatic hydrocarbons. At cultivable level, the counts of anaerobic heterotrophic bacteria were one to two orders of magnitude higher than aerobic heterotrophic bacteria.The aim of the present work was to assess the hydrocarbon degrading capacity of autochthonous microbial communities through the prediction of relative abundance of functional genes encoding enzymes for hydrocarbon degradation pathways by an in silicometagenomics approach.