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Submitted to: Biofactors
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/7/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Selenium toxicity can occur in arid and semi-arid regions of the world with alkaline, seleniferous soils derived from marine sediments. Once present in soils and waters at high concentrations, Se is very complicated and highly expensive to remove with conventional physical and chemical techniques. Approaches to prevent movement of soluble Se from irrigated areas with seleniferous soils were needed. One such strategy proposed for managing naturally-occurring Se is phytoremediation. Phytoremediation uses plants in conjunction with microbial activity to extract, accumulate, and volatilize Se. Any one of these plant responses result in lower concentrations of Se in the soil and thus lower amounts of Se available to concentrate in sensitive areas. An overview of recent greenhouse and field studies conducted by the WMRL is presented on the phytoremediation program used for managing Se in central California soils. Technical Abstract: Phytoremediation is the use of plants to remediate soils and water that are contaminated with organic and/or inorganic pollutants, e.g., Se. Both greenhouse and field studies were initiated to identify potential plant species that accumulate Se under both controlled and field conditions. Greenhouse studies demonstrated that Brassica species as the primary candidates for Se phytoremediation, accumulate up to 1000 mg Se/kg DM, and that their protein content was significantly correlated with both shoot Se level concentration and leaf surface area. Moreover, selenomethionine, an easily absorbable free selenoamino acid was found up to 958 ng/g DM. Under field conditions, crop rotations with Brassica species were able to lower total Se levels up to 60 percent between 0 to 60 cm soil depth after 4 years and up to 25 percent in another field study. Efficiency of field phpytoremediation of Se will differ from site to site. Field phytoremediation of Se requires a long-term commitment to effectively manage Se levels in the soil. Disposal posibilities for Se-laden plant material are presently being evaluated for use in animal and human nutrition, because Se is an essential micronutrient for biological systems. |
