Sugarcane Vinasse, a Residue of Ethanol Industry: Toxic, Cytotoxic and Genotoxic Potential Using the <i>Allium cepa</i> Test

Abstract

The search for fuels to replace petroleum consumption has caused an increase in the production of biofuels worldwide. The ethanol, which comes from sugarcane, is an energy resource with low polluting potential, but its production generates other environmental problems. On average, 10 to 15 liters of vinasse are generated while preparing each liter of ethanol. Vinasse is the final by-product of the biomass distillation, mainly for the production of ethanol, from different cultures such as sugarcane. Because excessive quantities of vinasse are produced, alternatives have been required for use, for example as fertilizer, in a process known as fertigation. These excessive amounts of vinasse applied in soils have generated adverse effects on soil properties and to the organisms. This study carried out the toxic, cytotoxic and genotoxic potential of sugarcane vinasse obtained from two different harvests (Samples I and II), using the <i>Allium cepa</i> organism test. <i>A. cepa</i> seeds were exposed to raw vinasse (RV) and diluted in different concentrations: control soil + raw vinasse (SV); vinasse diluted in water at 50% + control soil (V 50%); vinasse diluted in water at 25% + control soil (V 25%); vinasse diluted in water at 12.5% + control soil (V 12.5%). The chemical characterization of vinasse samples showed a low pH and high concentration of potassium. The results demonstrate that the two RV samples tested are toxic, since no seeds germination was observed. The cytotoxic potential was observed in the sample II of SV and V (50%). All groups evaluated in samples I and II, induced chromosomal alterations, statistically significant compared with negative control. An increase in frequency of micronuclei in meristematic cells was observed in the SV (Sample I) and all groups evaluated in samples II. Based on the results it is concluded that the genetic material of the test-system was damaged when exposed to sugarcane vinasse, suggesting that one should be very careful in the use of this waste that has been used sometimes indiscriminately in soils.