Management practices and phytoremediation by native grasses

Using native species for phytoremediation may be more ecologically beneficial and cost-effective than monoculture planting approaches. This study evaluated the effect of various soil amendments and management on the potential of Midwestern prairie grasses to remediate field soil contaminated with polycyclic aromatic hydrocarbons (PAHs) and other pollutants. A greenhouse investigation was conducted using six different grass species native to Ohio. Plants were grown in buckets containing topsoil and a layer of field-collected contaminated soil. Buckets were amended with commercial compost, fertilizer, or a combination of both. Replicates were watered every fourth day (frequently) or every sixth day (infrequently). Chlorophyll content were measured monthly for five months during the growing season. After five months, cores were sampled from each treatment and the total petroleum hydrocarbon (TPH) and PAH concentration of the soil determined. Native Ohio grasses reduced TPH contamination at least 87% with frequent irrigation and 90% with infrequent irrigation from buckets containing both compost and fertilizer. PAHs were dissipated to concentrations below detection limit of 1 ppm except for benzo (123) perylene and indeno (123-cd) pyrene. Results of this study suggest that it may be effective to allow contaminated sites to re-vegetate with native grasses.