title: Modelling the risk of mortality of Corbicula fluminea (Müller, 1774) (Bivalvia: Corbiculidae) exposed to different turbidity conditions.
abstract: The provision of sediment in rivers, due to erosion processes that occur in the environment, consists of a major source of pollution and alteration of the physicochemical conditions of water resources. In addition, the increase in water turbidity may cause siltation, dramatically impacting aquatic communities. Specifically considering the bivalve Corbicula fluminea (Müller, 1774), the aim of this study was to analyse the effect of exposure to different turbidity conditions of sediments, as a risk factor for the animals. For this purpose, a docking device was designed to ensure water circulation in a closed system and to maintain the desired levels of turbidity. Although C. fluminea can generally tolerate environmental changes in aquatic systems, an intolerance to high turbidity levels was experimentally observed, expressed by the mortality rate of the animals when exposed to conditions above 150 nephelometric turbidity units (NTU). This value was similar to the one recorded at study sites in the rivers Pardo (Serrana-SP-Brazil) and Mogi Guaçu (Porto Ferreira-SP-Brazil) during the rainy season. Using a logistic regression model, the experimental results were analysed and the observed mortality rates indicate that the exposure of the animals to turbidity levels above 150 nephelometric turbidity units (NTU), for periods longer than 120 hours, may be considered a probable cause of mortality for the species.
authors.affiliation: Department of Biology, Faculty of Philosophy, Sciences and Languages of Ribeirão Preto ? FFCLRP, University of São Paulo ? USP, Ribeirão Preto, SP, Brazil.
authors.forename: W E P
authors.initials: WE
authors.lastname: Avelar
authors.affiliation: Department of Biology, Faculty of Philosophy, Sciences and Languages of Ribeirão Preto ? FFCLRP, University of São Paulo ? USP, Ribeirão Preto, SP, Brazil.
authors.forename: F F
authors.initials: FF
authors.lastname: Neves
authors.affiliation: Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto ? FCFRP, University of São Paulo ? USP, Ribeirão Preto, SP, Brazil.
authors.forename: M A S
authors.initials: MA
authors.lastname: Lavrador
mesh_terms: D000818:Animals; D049874:Corbicula; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000032:analysis*; D009026:Mortality; D009391:Nephelometry and Turbidimetry; D012307:Risk Factors; D012621:Seasons