Petroleum hydrocarbons reduction by selected tropical grass species in oil-based drill cuttings contaminated soil

The potential of phytoremediation of oil-based drill cuttings (OBDCs) contaminated soils was assessed by the measuring level of petroleum hydrocarbons reduction. The contamination experiment was simulated in a randomized complete block design by factorial of 6 x 3 x 2 x 2 for grass species (Pennisitum purpureum, Panicum maximum, Andropogon gayanus, Heteropogon contortus, Axonopus compressus, and Chloris virgata), drill cuttings treatments (0%, 25%, and 50% OBDCs contamination), time (0 day of planting and 105 days of harvesting), and growth stage (young and mature). The parameters assessed were total petroleum hydrocarbons (TPHs) in soils, roots, and shoots; bioconcentration factor in roots and shoots; and translocation factor. The TPH reductions achieved in 25% treatment level were young A. compressus (58.01%), mature P. purpureum, young A. gayanus and C. virgata (44.24%), young P. purpureum (27.67%), mature A. compressus (25.29%), mature H. contortus (2.56%), mature P. maximum (4.01%), and unplanted soils (2.10%). Thus young A. compressus, A. gayanus, C. virgata, and mature P. purpureum are recommended for TPH reduction in 25% OBDCs contaminated soils. Young P. purpureum and mature A. compressus can be used to achieve 25% - 27% TPH reduction. Novelty statement Reduction of petroleum hydrocarbon in oil-based drill cuttings (OBDCs) contaminated soils using grass species without addition of fertilizers Addition of Axonopus compressus and Chloris virgata as grass species with potential to reduce petroleum hydrocarbon in OBDCs contaminated soils Growth stage of grass species is an important consideration for phytoremediation of OBDCs contaminated soil Determination of phytoremediation mechanism in OBDCs contaminated soil