Synergy of the Tropical Earthworm Pontoscolex corethrurus and Oil Palm Bagasse in the Removal of Heavy Crude Oil.

The tropical endogeic earthworm Pontoscolex corethrurus, a non-standard species used in ecotoxicity, has been found in crude oil-contaminated habitats. We estimated the removal of total hydrocarbons from heavy crude "Maya" oil on an artificially contaminated soil with a median lethal concentration of P. corethrurus and an addition of oil palm bagasse. P. corethrurus had a high survival rate, and the addition of oil palm bagasse led to a greater growth and an increase in abundance of bacteria and fungi. The activity of P. corethrurus and the nutritional quality of oil palm bagasse had a significant impact on the removal of a larger amount of petroleum hydrocarbons from contaminated soil. We concluded that the endogeic earthworm P. corethrurus and oil palm bagasse acted synergistically to achieve a more effective removal of total petroleum hydrocarbons from soil. These results show the potential for using P. corethrurus to remove, either directly or indirectly, crude oil from soil.