Lysimeter gneissic residual soil constructed and instrumented in situ to evaluation of biodegradation of benzene and toluene

摘要

Accidents related to the production, storage and transportation of oil can lead to environmental contamination by hydrocarbons. The aromatics hydrocarbons (BTEX) present in the gasoline in contact with the soil water to partially dissolve contaminants being the first to reach the water table. Research indicates biological degradation as the main mechanism for minimizing the toxic characteristics of these pollutants. Given the paucity of studies in situ residual soils to evaluate the behavior of BTEX, this study aimed at developing a methodology for the construction, instrumentation and monitoring of a large rectangular block of undisturbed gneissic residual soil, for application of contaminant flow to assess the biodegradation of compounds of the BTEX group. Based on the satisfactory operation of the experiment, applicated it the horizontal flow of a contaminant solution composed of water, benzene and toluene, to evaluate the biodegradation of these compounds, along the time. The experiment was monitored for a period of 85 days and the determination of the concentration of benzene and toluene in the samples of solution collected from pre-established monitoring points in the block was made by the technique of gas chromatography. In the results of this analysis observed a decay in the concentrations of the compounds over time. The results indicate the occurrence of biodegradation of compounds benzene and toluene. This experiment can be proposed to evaluate the biodegradation of compounds in this soil type.