Avaliação dos impactos gerados pela vinhaça bruta e após ajuste de pH, em representantes da fauna edáfica
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2018-09-28
Autores
Moreira-de-Sousa, Cristina
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Universidade Estadual Paulista (Unesp)
Resumo
A cana-de-açúcar é uma das principais culturas mundialmente difundida e a alta produtividade resulta na geração de inúmeros resíduos. A vinhaça, resíduo da produção do etanol tem chamado a atenção devido suas características e propriedades, quando empregada na fertirrigação das culturas de cana-de-açúcar. Diversos benefícios foram descritos, ganhos na fertilização e enriquecimento do solo, bem como aumentos na produtividade. Entretanto, a vinhaça também apresenta substâncias que podem ser nocivas, afetando negativamente a fauna existente nos locais de aplicação do resíduo. Frente a essa problemática, diversos estudos foram desenvolvidos com o intuito de melhor compreender os impactos da vinhaça no meio ambiente e, mesmo diante dos benefícios que a fertirrigação com a vinhaça implica economicamente ainda há a necessidade de maiores cuidados com a utilização do resíduo no campo. Nesse contexto, o objetivo deste trabalho foi propor um tratamento para a vinhaça, ajustando seu pH em 7,0 (neutro) utilizando cal (CaO), com a intenção de amenizar sua toxicidade para posterior uso no solo, visto que, um dos grandes problemas apresentados pela vinhaça é o pH ácido. O uso de cal foi escolhido por ser este produto utilizado em campo para correção do solo. Foi associado o uso de diversos biomarcadores à bioindicadores de solo, além de testes ecotoxicológicos para avaliar o efeito da vinhaça bruta em comparação à vinhaça tratada. Diplópodos da espécie Rhinocricus padbergi foram expostos à vinhaça em sua forma bruta e tratada com CaO, na concentração estabelecida pela Norma da CETESB, e ao dobro desta mesma concentração, simulando uma situação de super dosagem. A análise do intestino médio destes animais por meio das ferramentas ultraestruturais, imunohistoquímica e marcação de morte celular revelou que a vinhaça bruta pode ocasionar danos nos tecidos dos animais expostos e que o tratamento desta vinhaça surtiu efeito na diminuição desses danos. Testes ecotoxicológicos de fuga e reprodução, padronizados mundialmente pela Organização Internacional de Normalização (ISO), foram realizados com as espécies Eisenia andrei, Enchytraeus crypticus e Folsomia candida; de um modo geral, observou-se que as espécies E. crypticus e F. candida não tiveram seus comportamentos influenciados pela vinhaça bruta e nem pela vinhaça tratada, mas a espécie E. andrei apresentou-se mais sensível a presença da vinhaça no solo demonstrando comportamento de fuga em concentrações mais elevadas de vinhaça bruta e tratada, e, no teste de reprodução, respondeu a exposição à vinhaça tratada, com aumento no número de juvenis em relação a vinhaça bruta. Logo, o emprego da vinhaça na fertirrigação ainda requer cuidados, uma vez que seus efeitos nocivos são notórios, e nesse sentido, a alternativa de neutralizar seu pH pode representar uma medida de emprego desse resíduo com menos impacto.
Sugarcane is one of the main crops worldwide and the high productivity results in the generation of many wastes. Vinasse, the residue of ethanol production, has attracted attention because of its characteristics and properties, when used in the fertirrigation of sugarcane crops. Several benefits have been described, gains in fertilization and soil enrichment, as well as increases in productivity. However, the vinasse also presents substances that can be harmful, negatively affecting the fauna existing in the places of application of the residue. Faced with this problem, several studies were developed with the purpose of better understanding the impacts of vinasse in the environment and, even in view of the benefits that fertirrigation with vinasse implies economically, there is still a need for greater care with the use of the residue in the field. In this context, the objective of this work was to propose a treatment for vinasse, adjusting its pH to 7.0 (neutral) using lime (CaO), with the intention of mitigating its toxicity for later use in the soil, since one of the great problems presented by vinasse is acid pH. The use of lime was chosen because this product is used in field for soil correction. It was associated the use of several biomarkers to soil bioindicators, as well as ecotoxicological tests to evaluate the effect of raw vinasse in comparison to the treated vinasse. Diplopods of the species Rhinocricus padbergi were exposed to vinasse in their raw form and treated with CaO, at the concentration established by the CETESB Standard, and at twice the same concentration, simulating a super dosage situation. The analysis of the midgut of these animals using ultrastructural tools, immunohistochemistry and cell death marking revealed that raw vinasse can cause damage to the tissues of the exposed animals and that the treatment of this vinasse had an effect in reducing these damages. Ecotoxicological tests of the avoidance and reproduction tests, standardized worldwide by the International Organization for Standardization (ISO), were carried out with the species Eisenia andrei, Enchytraeus crypticus and Folsomia candida; in general, E. crypticus and F. candida were not influenced by raw vinasse or treated vinasse, but the E. andrei species was more sensitive to the presence of vinasse in the soil, demonstrating in the higher concentrations of raw and treated vinasse, and in the reproduction test, the exposure to treated vinasse responded, with an increase in the number of juveniles in relation to raw vinasse. Therefore, the use of vinasse in fertigation still requires care, since its harmful effects are notorious, and in this sense, the alternative of neutralizing its pH can represent a measure of the use of this residue with less impact.
Sugarcane is one of the main crops worldwide and the high productivity results in the generation of many wastes. Vinasse, the residue of ethanol production, has attracted attention because of its characteristics and properties, when used in the fertirrigation of sugarcane crops. Several benefits have been described, gains in fertilization and soil enrichment, as well as increases in productivity. However, the vinasse also presents substances that can be harmful, negatively affecting the fauna existing in the places of application of the residue. Faced with this problem, several studies were developed with the purpose of better understanding the impacts of vinasse in the environment and, even in view of the benefits that fertirrigation with vinasse implies economically, there is still a need for greater care with the use of the residue in the field. In this context, the objective of this work was to propose a treatment for vinasse, adjusting its pH to 7.0 (neutral) using lime (CaO), with the intention of mitigating its toxicity for later use in the soil, since one of the great problems presented by vinasse is acid pH. The use of lime was chosen because this product is used in field for soil correction. It was associated the use of several biomarkers to soil bioindicators, as well as ecotoxicological tests to evaluate the effect of raw vinasse in comparison to the treated vinasse. Diplopods of the species Rhinocricus padbergi were exposed to vinasse in their raw form and treated with CaO, at the concentration established by the CETESB Standard, and at twice the same concentration, simulating a super dosage situation. The analysis of the midgut of these animals using ultrastructural tools, immunohistochemistry and cell death marking revealed that raw vinasse can cause damage to the tissues of the exposed animals and that the treatment of this vinasse had an effect in reducing these damages. Ecotoxicological tests of the avoidance and reproduction tests, standardized worldwide by the International Organization for Standardization (ISO), were carried out with the species Eisenia andrei, Enchytraeus crypticus and Folsomia candida; in general, E. crypticus and F. candida were not influenced by raw vinasse or treated vinasse, but the E. andrei species was more sensitive to the presence of vinasse in the soil, demonstrating in the higher concentrations of raw and treated vinasse, and in the reproduction test, the exposure to treated vinasse responded, with an increase in the number of juveniles in relation to raw vinasse. Therefore, the use of vinasse in fertigation still requires care, since its harmful effects are notorious, and in this sense, the alternative of neutralizing its pH can represent a measure of the use of this residue with less impact.
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Palavras-chave
Bioindicadores de solo, Testes ecotoxicológicos, Ultraestrutura, Imunohistoquímica, Morte celular, Soil bioindicators, Ecotoxicological tests, Ultrastructure, Immunohistochemistry, Cell death