Autor: |
Lasat, Mitch M., Fuhrmann, Mark, Ebbs, Stephen D., Cornish, Jay E., Kochian, Leon V. |
Zdroj: |
Journal of Environmental Quality; January 1998, Vol. 27 Issue: 1 p165-169, 5p |
Abstrakt: |
A field study was conducted to investigate the potential of three plant species for phytoremediation of a 137Cs‐contaminated site. Approximately 40‐fold more 137Cs was removed from the contaminated soil in shoots of red root pigweed (Amaranthus retroflexusL.) than in those of Indian mustard [Brassica juncea(L.) Czern] and tepary bean (Phaseolus acutifoliusA. Gray). The greater potential for 137Cs removal from the soil by A. retroflexuswas associated with both high concentration of 137Cs in shoots and high shoot biomass production. Approximately 3% of the total 137Cs was removed from the top 15 cm of the soil (which contained most of the soil radiocesium) in shoots of 3‐too‐old A. retroflexusplants. Soil leaching tests conducted with 0.1 and 0.5 MNH4NO3solutions eluted as much as 15 and 19%, respectively, of the soil 137Cs. Addition of NH4NO3to the soil, however, had no positive effect on 137Cs accumulation in shoots in any of the species investigated. It is proposed that either NH4NO3solution quickly percolated through the soil before interacting at specific 137Cs binding sites or radiocesium mobilized by NH4NO3application moved below the rhizosphere, becoming unavailable for root uptake. Further research is required to optimize the phytotransfer of the NH4NO3‐mobilized 137Cs. With two croppings of A. retroflexusper year and a sustained rate of extraction, phytoremediation of this 137Cs‐contaminated soil appears feasible in <15 yr. |
Databáze: |
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