Avaliação do potencial detoxificação de associações do lodo de esgoto e solo por meio de bioensaios com Allium cepa

Abstract

Ensuring an environmentally appropriate disposal of the LE is of paramount importance, considering that although it is made up of organic matter and nutrients, pathogenic microorganisms and toxic metals are found in its composition. Through the bioremediation technique, it is possible to minimize the toxicity of a compound using a biostimulant agent and the microorganisms present in the medium. Tests with Allium cepa seeds have proven to be an efficient bioassay, as they are excellent indicators of cytogenotoxic agents. The objective of this work was to study the LE detoxification process, using agricultural soil and soil in natura as bioremediating agents, evaluating the toxicity potential of the combinations of LE + soil in the proportions (1:1) and (1:3) in the periods (T0) before treatment and (T1) post-bioremediation through bioassays with onion seeds (Allium cepa). Chemical and microbiological analyzes and toxicity tests were carried out through macroscopic analysis of the seeds. Chemical analyzes required a greater reduction of organic matter for LE and at least one macronutrient from each sample, in comparison there was an increase in micronutrients, with emphasis on agricultural soil that presented greater availability of nutrients compared to soil in natura. Microbiological analyzes show a high concentration of Colony Forming Units (CFUs) of bacteria in the initial period (T0) and predominance of CFUs of fungi in (T2). The results of the toxicity tests show a reduction in the toxicity of the experimental units in the period (T1), as the association with the agricultural soil showed the best detoxification results. With the work it was concluded that the bioremediation process using the soil as a biostimulant agent is promising.