Phytoremediation of a Radiocesium‐Contaminated Soil: Evaluation of Cesium‐137 Bioaccumulation in the Shoots of Three Plant Species

Abstract

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 retroflexus L.) than in those of Indian mustard [Brassica juncea (L.) Czern] and tepary bean (Phaseolus acutifolius A. Gray). The greater potential for 137Cs removal from the soil by A. retroflexus was 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. retroflexus plants. Soil leaching tests conducted with 0.1 and 0.5 M NH4NO3 solutions eluted as much as 15 and 19%, respectively, of the soil 137Cs. Addition of NH4NO3 to the soil, however, had no positive effect on 137Cs accumulation in shoots in any of the species investigated. It is proposed that either NH4NO3 solution quickly percolated through the soil before interacting at specific 137Cs binding sites or radiocesium mobilized by NH4NO3 application 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. retroflexus per year and a sustained rate of extraction, phytoremediation of this 137Cs‐contaminated soil appears feasible in <15 yr.

The biology of Canadian weeds. 130. Amaranthus retroflexus L., A. powellii S. Watson and A. hybridus L.

“…Amaranthus retroflexus was shown to have a high rate of accumulation of sulphadimethoxine, an antimicrobial drug given to livestock and present in sludge spread on farmland (Migliore et al 1997). It also proved to be superior to Indian mustard (Brassica juncea L.) in removing the radionuclides cesium-137 and strontium-90 from contaminated soil, largely because of its higher rate of biomass accumulation (Lasast et al 1998;Fuhrmann et al 2002).…”

Mapping Cadmium distribution in roots of Salicaceae through scanning electron microscopy with x-ray microanalysis

“…Total Cd content showed higher ability of poplar clones to remove metal from the solu tion than willow clones (see also Zacchini et al 2009), which could imply a substantial capability for more advantageous transloca tion of metal to the aboveground plant struc tures. The integrity of root system involved in Cd uptake, coupled with the capacity of translocation to shoots, represents an impor tant factor in screening clones for phytore mediation (Lasat et al 1997, Shen et al 1997, Lasat et al 1998.…”

Phytoremediation: A novel green technology to restore soil health

“…The roots of established plants absorb metal elements from the soil and translocate them to the aboveground shoots, where they accumulate. If metal availability in the soil is not adequate for sufficient plant uptake, chelates or acidifying agents may be used to liberate them into the soil solution (Huang et al, 1997;Lasat et al, 1998). After sufficient plant growth and metal accumulation, the aboveground portions of the plant are harvested and removed, resulting in the permanent removal of metals from the site.…”