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

This paper reports on the recovery of desert plant communities after 20 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 and can potentially 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 and recorded 42 plant species, with Haloxylon salicornicum (Moq.) Bunge ex Boiss., Cyperus conglomeratus Rottb., and Rhanterium epapposum Oliv. as the dominant species. Analysis of plant tissues indicated plant uptake and accumulation of some polycyclic aromatic hydrocarbons (PAHs), depending on plant species and specific PAH compounds. Total PAHs in plant tissues in the most contaminated sites were over 200 μg kg⁻¹. H. salicornicum could develop in both oil-contaminated soil and uncontaminated soil although their biomass was about 16.7% smaller than usual. However, the plants appeared green and healthy in both sites, and showed no overt stress. The results suggest that some desert plant communities can recover 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 support to other ecosystem services through improving soil quality and biodiversity.