Sediments quality must be considered when evaluating freshwater aquatic environments used for recreational activities

L. CHÁVEZ DÍAZ; D. GUTIÉRREZ CACCIABUE; H. R. POMA; V. B. RAJAL

INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH

ELSEVIER GMBH

Año: 2020 vol. 223 p. 159 - 170

1438-4639

Although water quality from freshwater recreational aquatic environments (RAEs) has been long analyzed worldwide, little information is available about their sediments. The aim of this work was to study the physicochemical and microbiological quality of water and sediments under different seasonal events. For that, Wierna River (WR) and General Belgrano reservoir (GB) were used as freshwater RAEs models. A total of 33 water and 33 sediments samples (15 from WR and 18 from GB from each phase) were collected and analyzed. Physicochemical variables in water (pH, turbidity, dissolved oxygen, temperature, conductivity, alkalinity, hardness) and sediments (organic matter, humidity, ash, and conductivity) were measured. For the microbiological characterization, total aerobic mesophiles, total and thermotolerant coliforms, E. coli, enteroccocci, Salmonella spp., and Pseudomonas aeruginosa were evaluated using culture-based methods. Universal and human Bacteroides were also quantified by real-time PCR. Univariate (Kruskall-Wallis, Spearman correlation) and multivariate (cluster analysis, principal component analysis) statistical techniques were applied for data analysis. All bacterial indicators were almost two-logs higher in sediments than in water, for both RAEs. Also, due to rainfall events and recreational activities, sediments were resuspended in surface water exceeding in most cases, the limits established. Significant correlation was observed between culturable bacteria and turbidity (p