Earthworm-assisted bioremediation of petroleum hydrocarbon contaminated soil from mechanic workshop

The use of earthworms (Eudrilus eugenia) for vermi-assisted bioremediation of petroleum hydrocarbon contaminated mechanic workshop soils was investigated. Parameters of interest where earthworm survival, microbial count and identification, carbon and nitrogen contents of the soil and total petroleum hydrocarbon content of the soil. Earthworm survival was found to be dependent on the concentration of petroleum hydrocarbon and nature of the mechanic workshop. The survival of the worms in the as-obtained mechanic workshop soil was much lower than the survival in mechanic workshop soil diluted with petroleum hydrocarbon free soil. Earthworm inoculation also resulted in lower soil C and N contents after 35 days of vermi-assisted bioremediation. After 35 days of treatment, earthworm inoculation effected a higher drop in total petroleum hydrocarbon contents as compared to the samples without worms, indicating that earthworms may be used as biocatalysts in the bioremediation process.   Key words: Eudrilus eugeniae, total petroleum hydrocarbon, mechanic workshop soil.