Uptake, Selectivity, and Inhibition of Hydroponic Treatment of Contaminants

It is estimated that the Departments of Defense, Energy, and Agriculture will spend up to 300 billion federal dollars on environmental remediation during the next century. Phytoremediation, the use of vegetation for the remediation of contaminated sediments, soils, and ground water, is an emerging technology for treating several categories of persistent, toxic contaminants. Although effective, phytoremediation is still in a developmental stage and therefore is not a widely accepted technology by regulatory agencies and public groups. Research is currently being conducted to validate the process effectiveness as well as increase regulatory and community acceptance. This research will focus on the ability of plants to hydroponically treat water contaminated with cadmium, chromium, nickel, radionuclides (cesium and strontium), and∕or phthalates. Specifically, the effectiveness of dwarf sunflowers (Helianthus annuus) and two strains of mustard seed (Brassica juncea) were investigated. The selectivity, on a mass basis, for the sunflowers and Indian mustard was Cd > Ni > Cr and Cr > Ni > Cd, respectively. This selectivity order did not change when cesium was present. For the individual phthalate treatment, the selectivity was dibutyl phthalate > benzylbutyl phthalate > dioctyl phthalate. When metals were present, the uptake of phthalates was severely limited.