Plant communities and potential native phytoremediator species in petroleum hydrocarbon-polluted desert systems

This paper reported the recovery of desert plant communities after twenty years of oil-derived hydrocarbon contamination in desert habitats of Kuwait, caused by the First Gulf War (1990 – 1991). The hypothesis that certain native desert plant species can tolerate weathered oil-polluted soils with oil breakdown products (i.e., polycyclic aromatic hydrocarbons ( PAHs)) and have the potential to function as bioindicators and phytoremediator species for oil-polluted soil was tested. A field survey of 200 quadrat sampling plots at seven hydrocarbon-contaminated and unpolluted desert areas in Kuwait was performed that recorded 42 plant species, with Haloxylon salicornicum, Cyperus conglomeratus and Rhanterium epapposum as the most dominant species. Analysis of plant tissues indicated plant uptake and accumulation of some PAHs. H. salicornicum was used as a representative species in a controlled field study that included growth of plants in hydrocarbon-polluted and unpolluted soils in two separate desert areas under similar growth conditions. Results showed a significant decrease in plant biomass in oil-contaminated soil compared to those from the uncontaminated site. However, the plants appeared green and healthy in both sites, and showed no overt stress. The results suggest that some desert plant communities exhibit signs of recovery after severe oil pollution, and that H. salicornicum may serve as a phytoremediator of oil-contaminated desert soils. Our results also demonstrated that some desert plant communities could be cultivated in oil fields to reduce hydrocarbon contamination and provide guide to other ecosystem services through improving soil quality and biodiversity.