Germination and development of Mimosa pilulifera in petroleum-contaminated soil and bioremediated soil

In 2000 there was an oil spill at the Getúlio Vargas Refinery (REPAR/PETROBRÁS) in Paraná, Brazil. Nearly five years after contamination and the use of bioremediation, a study was carried out to identify the effects of the contaminated soil and the bioremediated soil on the germination and initial growth of Mimosa pilulifera seedlings. The experiment consisted of three treatments: petroleum-contaminated soil, bioremediated soil and uncontaminated soil, with five repetitions each. The following measurements were taken after 30, 60 and 90 days of planting: the percentage of germination, biomass and leaf area of the eophylls, biomass and length of the shoot and the roots in addition to the shoot/root ratio. The percentage of germination and the root biomass were not affected by the contaminated soil or by the bioremediated soil. On both the contaminated soil and the bioremediated soil biomass and leaf area of the eophyll were reduced. Plant length and shoot biomass were lower in the contaminated soil. Furthermore, the effect of the contaminated soil and the bioremediated soil was greater in the shoot than in the root system, since the bioremediation reduced the toxicity of the petroleum-contaminated soil.