Ecological strategy for the recovery of an agricultural soil polluted by gasoline

Abstract

A soil contaminated by 10,000 ppm of gasoline (GAS), is a concentration higher than the limit of 4,400 ppm established by the Mexican standard NOM-138-SEMARNAT/SSA1-2003. In the soil, it inhibits the mineralization of organic matter causing loss of fertility. Therefore, the aims of this research a) biostimulation of a soil impacted by 10,000 ppm of GAS, and b) phytoremediation through Zea mays enhanced with Azotobacter vinelandii to decrease the GAS to a value lower than the maximum of the NOM-138-SEMARNAT/SSA1- 2003. In that sense an agricultural soil was impacted by 10,000 ppm of GAS was biostimulated applying a crude fungal extract (CFE)/2 months and vermicompost (VC)/1 month, later it was phytoremediated with Z. mays enhanced by A. vinelandii/2 months; with the response variables phenology and seedling biomass and flowering: The experimental data were validated by ANOVA/Tukey HSDP<0.05%. Results: showed that the biostimulation of the soil impacted by 10,000 ppm of GAS with 60,000 ppm of CV was sufficient to reduce the concentration of GAS, followed by phytoremediation with Z. mays/A. vinelandii at flowering, where 5.79 g of aerial dry weight (ADW) and 2.59 g of root dry weight (RDW) were recorded, numerical values with statistical difference with the 4.49 g ADW and the 2.07 g RDW of Z. mays grown in uncontaminated soil by GAS fed with a mineral solution or relative control, with which soil biorecovery was achieved by decreasing GAS from 10,000 to 500 ppm, a value lower than the maximum allowed by NOM-138-SEMARNAT/SSA1-2003. The biorestoration of a soil impacted by GAS through biostimulation and phytoremediation is slow compared with strong oxidizing chemical agents but is ecological and allowed to reuse soil for agricultural production. It’s concluded that it is possible to biorecover soil contaminated by GAS due ecological and simple strategy.