Immobilization of Radioactive Strontium in Contaminated Soils by Phosphate Treatment

Abstract

The feasibility of in situ phosphate- and metal- (calcium, aluminum, and iron) solution treatment for 90Sr immobilization was investigated. Batch and column experiments were performed to find optimum conditions for coprecipitation of 90Sr with Ca-, Al-, and Fe-phosphate compounds in contaminated soils. Separate columns were packed with artificially 85Sr-contaminated acid soil as well as 90Sr-contaminated soil from the Oak Ridge Reservation. After metal-phosphate treatment, the columns were then leached successively with either tapwater or 0.001 M CaCl2 solution. Most of the 85Sr coprecipitated with the metal phosphate compounds. Immobilization of 85Sr and 90Sr was affected by such factors as solution pH, metal and phosphate concentration, metal-to-phosphate ratio, and soil characteristics. Equilibration time after treatments also affected 85Sr immobilization. Many technology aspects still need to be investigated before field applications are feasible, but these experiments indicate that phosphate-based in situ immobilization should prevent groundwater contamination and will be useful as a treatment technology for 90Sr-contaminated sites.

Ecological Effects of Heavy Metal Pollution on Soil Microbial Community Structure and Diversity on Both Sides of a River around a Mining Area

“…The abandoned land and the paddy fields on both sides of the river were acidic, probably because the acid ore water flowing down the mine flows into the river, causing the residents to use the river water when irrigating the farmland, thus having a certain impact on the pH of the soil. On the other hand, paddy fields have long been flooded by acid-containing mine wastewater, which seriously affects the soil properties and makes the soil pH weakly acidic [ 40 ].…”

Phosphorus–cadmium interactions in paddy soils

“…The only metal(loid)s undergo volatilisation losses are As, Hg, and Se as they tend to form gaseous compounds (Bolan et al, 2013a;Mahimairaja et al, 2005). In paddy soils, the most important process which affects the soil chemistry is water-logging, which under continuous cultivation, can shift soil pH to neutrality and increase organic C and soluble P (Kim et al, 1991). However, pH is not the sole factor in paddy soils that controls movement of metallic ions within the soil.…”

Gas treatment of Cr(VI)-contaminated sediment samples from the North 60`s pits of the chemical waste landfill

“…Solid treatment agents, for example, have been used to remediate relatively small sites consisting of metal or radionuclide-contaminated soils on or near the ground surface (Czupyrna et al 1989, Kim et al 1990, and Browman and Spalding 1984). Injection of aqueous solutions of dithionite into an aquifer to reduce structural Fe in sediment clay minerals has also been proposed and a single-well field demonstration has been canied out ; Fruchter et al 1996).…”