Ecotoxicological assessment of BTEX to soil organisms using a terrestrial microcosm: multispecies soil system (MS-3)

This study aimed to investigate the toxicity of BTEX (benzene, toluene, xylene and ethylbenzene) on a microcosm scale using the MS-3 multispecies system. The multispecies system (MS-3) was employed to investigate the BTEX diluted in water and ethanol. The columns for the test were prepared in PVC tubes, open at the top and the bottom was covered by a mesh. In each system were added soil macro-decomposers (earthworm and woodlice) and plant species (mustard and lettuce). The soil used in the column was dried beforehand and sieved. It was placed in MS-3 system up to 20 cm height of soil and approximately 6 kg of soil. During the 14 days of experiment, five applications of BTEX were performed and, at the end of the period, the growth and survival of organisms and enzymatic activity in the soil were analyzed. After the exposure time, it observed the decrease in the weight of the woodlice and a reduction in lettuce and mustard seed germination in BTEX water system, while there was no statistically significant difference between the BTEX + ethanol system and their respective control. There were no changes of mortality in macro-invertebrates, length of seedlings or alterations of the soil microbial activity. With our data, we conclude that the implementation of this model to evaluate the quality of the soil constitutes a promising alternative in ecotoxicological investigations and that the BTEX can affect soil organisms in different ways.