Bioremediation and Accelerated Phytoremediation of a Soil Impacted by a Hydrocarbons Mixture

Waste motor oil (WMO), without adequate final confinement, is spill in agricultural soil, there, it easily exceeds 4400 ppm according to the Mexican standard NOM-138-SEMARNAT/SSA1-2012; a concentration that causes loss of fertility. The aims of this research were: i) biostimulation of agricultural soil impacted by 39,000 ppm of WMO with Triton X-100/Tween 80 at 0.5% and mineral solution: ii) phytoremediation by Phaseolus vulgaris enhanced with Methylobacterium symbioticum and Xanthobacter autotrophicus to reduce WMO at lower concentration than the maximum accepted by NOM-138-SEMARNAT/SSA1-2021. The response variables were: a) the initial and final concentration of WMO by Soxhlet, and b) P. vulgaris: germination percentage; phenology and biomass at seedling and pre-flowering stages. The experimental data were analyzed by ANOVA/Tukey 0.05%, with the program Statgraphics Centurion XVI. II.

The results showed that biostimulation of soil impacted by 39,000 ppm of WMO with Triton X-100/Tween 80 at 50%, and a mineral solution, decreased to 26,990 ppm in 25 days. Subsequently, phytoremediation by sowing P. vulgaris with M. symbioticum and X. autotrophicus, at pre-flowering reduced WMO to 1233 ppm in 50 days, a concentration lower than the maximum, accepted by NOM-138-SEMARNAT/SSA1-2012. This supports that is possible to accelerate biostimulation and phytoremediation reduced WMO in the agriculture soil to recover its productive capacity.