ABSTRACT
This chapter describes an approach that utilizes the biotransformation activities of aquatic microphytes intrinsic to the Selenium (Se)-laden agricultural evaporation basins for “natural” remediation. It also describes the laboratory studies which involved fractionating the commonly occurring microphyte species from the basin waters, establishing monocultures of these species, measuring their Se volatilization kinetics, and characterizing the biotransformation products of Se. Medium water, the trap, and biomass samples were digested using a microdigestion method described previously, which substantially simplified the procedure and reduced sample requirement compared with reported macrodigestion methods. The relationship between Se depletion from the medium and rates of Se volatilization as a function of selenite concentrations by the filamentous cyanophyte culture was also investigated. Selenium contamination and accumulation in the agricultural drainage evaporation basins of the San Joaquin Valley has been a major concern for California’s multi-billion dollar agriculture.
