Volume 3, Issue 6 (June 2006)
Remediation Technology for Boron and Fluoride Contaminated Sediments Using Green Plants
Phytoremediation is the direct application of green plants and their associated micro-organism to stabilize or absorb contaminants from soils, sludge, sediments, surface water, or groundwater. Boron and fluoride were listed to the soil standards a few years ago in Japan; however, few researches have been reported about phytoremediation on the above elements. In this paper, the authors report the experimental results of accumulation and tolerance ability of green plants focusing on the fluoride and boron contamination. In the pot laboratory tests, the growth rate of Chinese cabbage was not affected by low fluoride concentration (<15 mg/L) or low boron concentration (<5 mg/L). In the hydroponics tests, fluoride content in both stems+leaves and roots increased 3–10 times higher than control. Fluoride is easy to be concentrated in the roots. Boron content in both stems+leaves and roots increased 1.2–1.5 times higher than control. Boron is easy to be concentrated in the upper portion. Especially, Phytolacca Americana, Ambrosia trifida L., and Commelina communis can accumulate boron with higher efficiency. The boron content in soil was 480–550 mg/kg, and the boron content in these grasses was 2–3 times higher than that in soil. These results show they can accumulate boron and fluoride, and phytoremediation can be adopted for relatively lower contamination.