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Descripción
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| Antimony trioxide (Sb2O3) is a widely used chemical that can be emitted to soil. The fate and toxicity of this poorly soluble compound in soil is insufficiently known. A silt-loam soil (pH 7.0, background 0.005 mmol Sb kg-1) was amended with Sb2O3 at various concentrations. More than 70% of Sb in soil solution was present as Sb(V) (antimonate) within 2 days. The soil solution Sb concentrations gradually increased between 2 and 35 days after Sb2O3 amendment but were always below that of soils amended with the more soluble SbCl3 at the lower Sb concentrations. The soil solution Sb concentrations infreshlyamendedSbCl3 soils(7daysequilibration)wereequivalent to those in Sb2O3-amended soils equilibrated for 5 years at equivalent total soil Sb. Our data indicate that the Sb solubility in this soil was controlled by a combination of sorption on the soil surface, Sb precipitation at the higher doses, and slow dissolution of Sb2O3, the latter being modeled with a half-life ranging between 50 and 250 days. Toxicity of Sb to plant growth (root elongation of barley, shoot biomass of lettuce) or to nitrification was found in soil equilibrated with Sb2O3 (up to 82 mmol Sb kg-1) for 31 weeks with 10% inhibition values at soil solution Sb concentrations of 110 ìM Sb or above. These concentrations are equivalent to 4.2 mmol Sb per kg soil (510 mg Sb kg-1) at complete dissolution of Sb2O3 in this soil. No toxicity to plant growth or nitrification was evident in toxicity tests starting one week after soil amendment with Sb2O3, whereas clear toxicity was found in a similar test using SbCl3. However, these effects were confounded by a decrease in pH and an increase in salinity. It is concluded that the Sb(V) toxicity thresholdsareover100-foldlargerthanbackgroundconcentrations in soil and that care must be taken to interpret toxicity data of soluble Sb(III) forms due to confounding factors. | |
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Internacional
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JCR del ISI
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Título de la revista
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ENVIRONMENTAL SCIENCE & TECHNOLOGY |
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ISSN
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0013-936X |
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Factor de impacto JCR
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4,363 |
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Información de impacto
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Volumen
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42 |
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DOI
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Número de revista
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0 |
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