Evaluación de la eficiencia de tres procesos de biorremediación en suelos contaminados con petróleo, mediante la determinación de la concentración letal 50 (CL50) en la lombriz californiana, Eisenia Foetida (lombricidae)

Abstract

This project consisted of the application of three bioremediation techniques (biostimulation – bioboosting – natural attenuation), its application was ex-situ and was carried out in the laboratories of the University of Santo Tomas, simulating the oil spill with a concentration of 2,498 mg/kg and suitable soil conditions for assembly, being monitored for 60 days, in which the experimental units were aerated every 3 days and a maintenance of applied doses and humidity every 10 days, maintaining the latter parameter at 21-9% in order to have the desired conditions during the process. To verify the efficiency of the methods, a bioassay was performed based on the OECD methodology, Test No. 222: reproduction test of earthworms with the Eisenia foetida earthworm, this bioassay was applied before starting the bioremediation techniques and at the end 60 days of the same, in order to compare the levels of lethal concentration 50. When evaluating the efficiency of the applied techniques, 100% mortality was found in biostimulation treatments with triple commercial product 15, in bioaugmentation with the commercial product Biodyne 101 26% mortality and finally 2,5% mortality for natural attenuation treatments. With analyses of soil physicochemical characteristics and mortality presented in the bioassay, it was identified that natural attenuation was the best treatment for soil bioremediation, cost-benefit was more effective than others being friendly with the organisms present and helping the soil return to its pre-spill conditions with hydrocarbons.