Bench-Scale Phytoremediation of Polycyclic Aromatic Hydrocarbon-Contaminated Marine Sediment with Tropical Plants

Abstract

ABSTRACT Elevated levels of polycyclic aromatic hydrocarbons (PAHs) were found in dredged marine sediment from Pearl Harbor. The degradation of PAHs was investigated with soil-sediment systems (washed and unwashed) and 20 plant species. Marine sediment was diluted with native soil in the first experiment. Sediment was washed with gypsum solution and water in the second and third experiments, respectively, prior to soil dilution. Soil dilution ratios were 0, 6, 16, and 37% by weight in the first experiment, 0, 37, 64, and 100% in the second and 0, 18, 64, and 100% in the third. Seven tree, nine shrub, and four grass species were grown for 12 weeks in a glasshouse. A "no plant" control was used in all the experiments. Several plant species yielded up to 90% PAH degradation in the first experiment when compared with no plant control. In the second planting, dwarf hau (Hibiscus tiliaceus) and vetiver (Vetiver zizanoides) appeared to cause the greatest PAH reduction, while paspalum (Paspalum vaginatum) and naupaka (Scaevola sericea) did not. The greatest difference between control and planted soil for both benzo[a]pyrene and total PAH occurred at the highest sediment ratios. KEY WORDS: coastal pollutionsalt toleranceremediation