|Terry, Norman - UC BERKELEY|
|Zayed, A - UC BERKELEY|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 15, 1996
Publication Date: N/A
Interpretive Summary: Elevated levels of selenium (Se) found in soils in the western US, i.e., central California, are potentially toxic for the agricultural ecosystem. The management of the movement of Se from the soil to agricultural effluent and its biotransfer became a primary objective by State and Federal Agencies in California after waterfowl deformities were observed at the Kesterson Reservoir wetlands in California. As an alternative strategy, the Water Management Research Laboratory demonstrated that phytoremediation can manage selenium levels in the soil. In this approach certain plant species that accumulate, tolerate, and volatilize high levels of Se are planted in Se-laden soils. Plants containing high concentrations of Se can be harvested and removed from the soil. As a result of plant volatilization and absorption of Se, phytoremediation in conjunction with water management reduces the amount of soluble Se from entering the ecosystem via agricultural effluent.
Technical Abstract: Solubilization of natural-occurring Se deposits resulted in high Se concentrations in many agricultural soils on the westside of central California. Other areas in the western US with irrigation drainage projects on natural-occurring Se soils are concerned about the potential problems caused to the ecosystem with soluble soil Se. As part of the irrigation/drainage strategy developed by Water Management Research Laboratory (WMRL) and UC Berkeley to manage high levels of Se in the soil, two major areas of study; accumulation and volatilization, were conducted under Se-contaminated conditions using phytoremediation. Results showed 1) reduction of soil Se under greenhouse and field conditions by planting Brassica juncea, Hibiscus cannibinus, Festuca arundinacea; and 2) volatilization of Se by different Brassica spp. The above studies demonstrated that Brassica spp. effectively lower soil Se (up to 40%) by both uptake and volatilization of Se. The results suggest that planting selected crops in conjuncation to practicing irrigation/drainage management is a viable strategy to reduce the amount of Se entering the ecosystem and accumulating to potentially toxic levels.