Toxicity of two effluents from agricultural activity: Comparing the genotoxicity of sugar cane and orange vinasse.

Vinasse, produced by several countries as a by-product of agricultural activity, has different alternatives for its reuse, mainly fertirrigation. Several monocultures, such as sugar cane and orange crops, produce this effluent. Sugar cane vinasse is already widely used in fertirrigation and orange vinasse has potential for this intention. However, its use as a fertilizer has caused great concern. Thus, ecotoxicological evaluation is extremely important in order to assess the possible effects on the environment. Therefore, the aim of this study was to evaluate the potential toxicity of vinasse of two different crops: sugar cane and orange. For this purpose, bioassays with Allium cepa as a test organism were performed with two vinasse dilutions (2.5% and 5%) to detect chromosomal aberrations and micronucleus induction. The results showed that both types of vinasse are able to induce chromosomal aberrations in meristematic cells, mainly nuclear and anaphasic bridges, suggesting genotoxic potential. The induction of micronuclei in cells of the F1 region suggests that the two residues have mutagenic potential. Thus, caution is advised when applying these effluents in the environment.

Comet assay and micronucleus tests on Oreochromis niloticus (Perciforme: Cichlidae) exposed to raw sugarcane vinasse and to phisicochemical treated vinasse by pH adjustment with lime (CaO).

In Brazil vinasse, a main sugarcane distillery residue, stands out because every liter of alcohol generates 10-15 L of vinasse as waste. An alternative for the disposal of this waste is the fertirrigation of the sugarcane culture itself. However, the high amount released can saturate the soil and through leaching/percolation contaminate water resources. The aim of this study is verifying the toxic potential of vinasse in tilapias and effectiveness of the physicalchemical treatment of this waste with pH adjustment with lime (CaO). The comet assay and the micronucleus test were applied on animals exposed to dilutions of raw vinasse and vinasse adjusted to neutral pH. Bioassays with raw vinasse dilutions indicated a toxic and genotoxic potential; fish exposed to the highest concentration died less than 48 h after the exposure; the incidence of micronucleus was significantly higher when compared to negative control for all dilutions. For the comet assay, the scores of damage were statistically higher for all dilutions, with the exception of the 1% dillution. However, in the bioassay with the chemically treated vinasse (neutral pH), most fish in the 10% dilution survived and there was no significant difference when compared to the control. Damage scores in the comet assay were similar to the results of the untreated vinasse. The chemical treatment of vinasse with lime to neutralize the pH proved to be an effective alternative for the toxicity reduction of this residue, since it reduced the mortality of fish at higher concentrations and the incidence of damage to DNA.

Allium cepa and Tradescantia pallida bioassays to evaluate effects of the insecticide imidacloprid.

The indiscriminate use of pesticides has become a serious environmental concern. Of them, imidacloprid (IMI) is one of the most widely used worldwide. In 2010 in Brazil, 1.934 tonnes of IMI were sold and mainly used for sugarcane crops. Several studies have examined the toxicity of IMI as well as its possible ecological effects. However, few studies have examined its toxicity at the genetic level. This is one of the biggest challenges for the scientific community, which is concerned about the impacts of these contaminants on the environment and human health. In this study, we evaluated the effects of IMI above the genetic material in Allium cepa and Tradescantia pallida following exposure to different concentrations of this insecticide. The results demonstrated that the concentrations tested induced chromosomal alterations and increased the frequency of micronuclei. Therefore, IMI in these concentrations was genotoxic to the tested organisms. These factors should be taken into account when applying this pesticide.