Ecotoxicity of vinasse for fish tetra-serpae (Hyphessobrycon eques) and macrophyte duckweed (Lemna minor)

Abstract

The aim of this study was to evaluate the possibility of using the tetra-serpae fish (Hyphessobrycon eques) and the macrophyte duckweed (Lemna minor) as biomarkers of toxicity of vinasse, estimating the LC50 and mortality percentages of the test organisms in the period of the crop of sugarcane. The concentrations tested were: 0.5; 1.0; 1.5; 2.0; 2.5; 3.0; 3.5; 4.0; 4.5; 5.0; 7.5 and 10% vinasse, with three fish per repetition and three repetitions, and the macrophytes were exposed to: 1.0; 3.0; 5.0 and 7.0% of vinasse, with 12 fronds per repetition and three repetitions, both with a completely randomized design in tests (CRD). The LC50 values for fish ranged from 0.75 to 7.72% and for macrophyte, 1.30 to 4.27%. The biomarkers H. eques (fish tetra serpae) and L. minor (macrophyte duckweed) can be used in ecotoxicological effluent vinasse ratings, which is very toxic to fish during the months of August and September and toxic for fish and for macrophyte duckweed in the remaining months of trial.