Recent applications of phytoremediation technologies

Abstract Although the application of microbe biotechnology has been successful with petroleum‐based constituents, microbial digestion has met with limited success for widespread residual organic and metal pollutants located above the potentiometric surface. Vegetation‐based remediation, on the other hand, shows potential for accumulating, immobilizing, and transforming low levels of persistent contamination from the subsurface. Agricultural bioremediation, called geobotany or phytoremediation, relies on the remediating abilities of contaminant‐accumulating plants to remove contamination from soil or groundwater. In natural ecosystems, plants act to filter and metabolize substances generated by nature. Phytoremediation affirmatively applies this process to help clean up contamination created by artificial means. Plants have proven effective at remediating areas contaminated with organic chemical wastes such as petroleum products, solvents, wood preservatives, pesticides, and metals. Phytoremediation is not the best technology for every site but has shown success with lead, cadmium, zinc, and radionuclides. The phytoremediation process takes much longer than conventional methods to clean a site and is dependent upon the type and degree of contamination. Concentrations must be within a narrow range of tolerable levels and the presence of the contamination must be at the appropriate depth. Nevertheless, phytoremediation offers an effective alternative to conventional, engineered remedial plans that usually involve costly activities like excavation, treatment, and disposal of soil or pump‐and‐treat technologies for groundwater. Phytoremediation also seems to be a promising new technology for the treatment of stormwater, industrial wastewater, and sewage. The relative low costs of capital for start‐up together with negligible operations and maintenance costs provide a strong incentive for further investigation and development of phytoremediation projects.