| dc.description.abstract | Apatite was added to a soil highly contaminated with As and Pb to enhance As uptake by the hyperaccumulating fern, Pteris cretica. Arsenic and lead co-contamination is common in smelter soils and can be a major source of environmental harm. In situ chemical stabilization of contaminants can be an acceptable remediation option, but simultaneous immobilization of Pb and As faces serious obstacles. The two contaminants have antagonistic immobilization chemistries: the effective use of P to immobilize Pb greatly mobilizes As. However, this effect can be exploited if the mobilized As is assimilated by As hyperaccumulating plants, such as members of the Pteris species. Apatite is an effective source of phosphorus when used with Pteris arsenic hyperaccumulators but the effect of particle size has not been studied. Changes in soil and plant chemistry were studied for two concentrations of total soil As (750 mg/kg and 1,500 mg As /kg soil); three particle sizes of added apatite (500 μm-250 µm, 250 μm-105 µm, <105 µm); and three molar ratios of P:As (1:1, 1:2, 1:5). The treatments were found to have a significant impact on both the arsenic concentrations in the plants and plant biomass. In addition, IVBA analysis of the soil showed a reduction in the amount of arsenic found to be bioaccessible. Plant phosphorus concentrations and plant arsenic concentrations were correlated with indications that phosphorus is promoting arsenic uptake and plant growth. | en |
