Abstract
Soil and water contamination with volatile organic compounds (VOCs) is a global environmental problem, including developing countries with semi-arid climates. One particular VOC, 1,4-dioxane, is a suspected carcinogen and difficult to remove from contaminated sites. Phytoremediation of 1,4-dioxane is expected to be an inexpensive, effective, and widely applicable method, even at sites with low soil moisture. Some species of willows were used for forestation in semi-arid areas because of their relative drought tolerance. This study aims to assess the potential of willows (Salix) for phytoremediation of 1,4-dioxane (volatilization, metabolization, and accumulation), and to clarify differences between three willow species in 1,4-dioxane phytoremediation features. This investigation tests the removal efficiencies of 1,4-dioxane from solution by the species KKD clone which shows extreme fast-growing, FXM clone which shows relatively strong drought tolerance, and SEN which shows relatively strong insect resistance. In hydroponic tests, 1,4-dioxane was removed by 32.8%±12.4% for KKD, 15.0%±6.4% for SEN, and 12.0%±8.5% for FXM, of the initial amount of 4000 µg. Mechanistically, volatilization, metabolization, and accumulation accounted for 68.7%, 18.5%, and 2.4%, respectively, of 1,4-dioxane removal in KKD.
