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Submitted to: Yearbook of Science and Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/1/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Selenium functions as an essential element or as a toxic compound to humans, livestock, waterfowl, and certain bacteria. Evidence of selenium poisoning was observed in waterfowl frequenting Kesterson Reservoir in central California, while at the same time, selenium deficiencies have been observed in many of the western United States. As a result of Se toxicity and deficiencies, multi-disciplinary researcher have searched for strategies to augment Se in deficient soils, as well as sought methods to reduce selenium entry in the ecosystem. The WMRL has developed a technology for lowering levels of Se in the environment, called Phytoremediation, which uses plants to absorb, accumulate, and volatilize Se. Plants are grown in Se-laden soils, harvested, removed from site and used as a Se-enriched animal feed additive. This paper generally illustrates how different plant species lower soil Se levels, and dhow these harvested plants are successfully used as supplemental feed for sheep and cows. Technical Abstract: The basic idea that plants can be used for environmental remediation has been developed into an alternative technology termed "phytoremediation". Utilizing information about Se-accumulating plants, the WMRL evaluated different plant species for their ability to accumulate Se and contribute to an overall lowering of Se levels in the soil. Among the tested plants, Brassica napus (canola), was the best performer. Not only did the species accumulate more se than the other species, but other processes, i.e., volatilization, contributed to the loss of Se in the soil. Recognizing that Se is an essential element in biological diets, the WMRL harvested the Se-rich canola and carefully used it as a animal feedstuff for sheep and cows. Various tissues, blood, milk, and excreta were analyzed for their Se content in both types of animals during and at the end of the study. Results how that levels in Se increased in the various tissues of animals fed Se-enriched canola. Plants used in the phytoremediation of Se may help sheep and cows meet their nutritional need for Se, when carefully incorporated into their diet. |
