No abstract

No abstract

The soil is a very complex and dynamic system and its contamination has become one of the main environmental concerns. Sugar-ethanol mills, for example, have a high hazard potential, mainly soil contamination, due to the production of different residues. The use of vinasse, a by-product of ethanol production, as fertilizer is a technically and economically feasible alternative. However, excessive quantities have been used, causing adverse changes in the soil. The present study was aimed at evaluating the toxic potential of vinasse in the Tradescantia pallida test system using the micronucleus test (Trad-MCN). Ten plants were exposed to ultrapure water as the negative control (NC), in MMS as the positive control (PC), raw vinasse (RV), and vinasse diluted to 50% (C1), vinasse diluted to 25% (C2), vinasse diluted to 12.5% (C3). The medium buds of each plant were used to assess the mutagenic effects based on the presence of micronuclei in tetrads. The results revealed that RV and C1 had a mutagenic potential compared to that of NC. The alterations observed suggest damage to the DNA of the test organism, which may not be reintegrated to the cell nucleus. The findings suggest caution in the application of this product to the soil despite this being an economically viable practice.

Residues like sewage sludge and vinasse have been reused as agricultural fertilizers, but they also present a potential to contaminate soils. Diplopods have been considered excellent bioindicators of soil contamination. In the present study, Rhinocricus padbergi were used to assess toxicity in samples of sewage sludge, biosolids, and sugarcane vinasse. The behavioral analysis, mortality rate, and histological, histochemical, and ultrastructural analyses of the midgut of diplopods were the parameters evaluated. Behaviorally, some diplopods avoided burying themselves after 30 days in soil with biosolid or vinasse. Besides, certain residue combinations were able to cause death of all individuals between 60 and 90 days of exposure. The main tissue responses were significant brush border thickening, induction of epithelial renovation, clustering of hemocytes, accumulation of cytoplasmic granules in hepatic cells, hepatic cells with heteropycnotic nuclei, and cytoplasmic degradation. Alterations were observed at various levels among treatments with different samples and exposure times. Ultrastructural analysis revealed elongation of microvilli coated with a layer of an amorphous substance, resulting in a thicker brush border as observed in the histological analysis. After 30 days of exposure, animals showed an accumulation of spherocrystals in hepatic cells and high absorption of substances, based on the elongation of microvilli. Results obtained in the chemical analysis and the behaviors observed in diplopods suggest that animals processed the residues. Therefore, caution should be exercised in the disposal of these residues in agriculture.

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 Allium cepa organism test. A. cepa 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, * Corresponding author. J. Pedro-Escher et al. 603suggesting that one should be very careful in the use of this waste that has been used sometimes indiscriminately in soils.