Chemical leaching studies were carried out on transuranic (TRU) waste contaminated (=882 pCi/gm) soil samples that were collected near the 903 Pad at tile Rocky Flats Plant, Colorado. The studies were conducted in the research facilities of the Department of Metallurgical and Material ,Engineering, Colorado School of Mines.The solvents studied were hydrochloric, sulfuric, and nitric acids in the concenl_ration range of 10.2 to 1.0 molar. Solid to liquid ratios were 1:2 and 1:8. The soil size range was 75 to 150 _tm.Agitation-leach experiments having a 4 hour duration produced TRU extractions in the 65 to 85% range. TRU extraction by percolation leaching for 48 hours was about 75%. Soil losses were less than 5% when percolation leaching was used and appeared to be primarily the organic component of the soil. No significant differences were observed among the acids used.
Background and aimsThe Brazilian Atlantic forest has been affected by the deposition of Ni and Zn, among other heavy metals adsorbed from atmospheric particles, which can be incorporated into the soil. If available in the soil, they can be absorbed by plant roots. The study aimed at testing experimentally the hypotheses: 1) Ni and Zn depositions increase their bioavailable fractions in the soil; 2) pioneer tree species demonstrate a greater potential to absorb Ni and Zn from the soil and less growth changes than non-pioneer species.MethodsThe experiment was carried out with six pioneer and non-pioneer species native to the Atlantic Forest, grown for 90 days in soil from an urban fragment of the Atlantic Forest, according to the treatments: soil with balanced fertilization (control) and soil enriched with Ni, Zn and Ni+Zn. At the end, the concentrations of Ni and Zn were determined in four soil fractions (F1: soluble; F2: linked oxides/hydroxides; F3: organic matter: F4: residual metals) and in leaves, stems/branches and roots. Mobility factors in soil, concentration ratios between treatments and respective controls, translocation index and relative growth rate in height, leaf number and total biomass were also calculated.ResultsThe results showed that Ni and Zn concentrations increased significantly in the bioavailable soil fractions (F1, F2). The absolute content of Ni and Zn in the plants directly reflected the soil level in the available forms.ConclusionsThe metal accumulation in the species occurred regardless of the successional group to which they belonged. Non-pioneer species showed greater susceptibility to the metals.
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