Accumulation of Cs-137 and Sr-90 from contaminated soil by three grass species inoculated with mycorrhizal fungi

The use of plants to accumulate low level radioactive waste from soil, foll owed by incineration of plant material to concentrate radionuclides may pro ve to be a viable and economical method of remediating contaminated areas. We tested the influence of arbuscular mycorrhizae on Cs-137 and Sr-90 uptak e by bahia grass (Paspalum notatum), johnson grass (Sorghum halpense) and s witchgrass (Panicum virginatum) for the effectiveness on three different co ntaminated soil types. Exposure to Cs-137 Or Sr-90 over the course of the e xperiment did not affect above ground biomass of the three grasses. The abo ve ground biomass of bahia, johnson and switchgrass plants accumulated from 26.3 to 71.7% of the total amount of the Cs-137 and from 23.8 to 88.7% of the total amount of the Sr-90 added to the soil after three harvests. In ea ch of the three grass species tested, plants inoculated with Glomus mosseae or Glomus intraradices had greater aboveground plant biomass, higher conce ntrations of Cs-137 or Sr-90 in plant tissue, % accumulation of Cs-137 or S r-90 from soil and plant bioconcentration ratios at each harvest than those that did not receive mycorrhizal inoculation. Johnson grass had greater ab oveground plant biomass, greater accumulation of Cs-137 or Sr-90 from soil and plant higher bioconcentration ratios with arbuscular mycorrhizal fungi than bahia grass and switchgrass. The greatest accumulation of Cs-137 and S r-90 was observed in johnson grass inoculated with G. mosseae. Grasses can grow in wide geographical ranges that include a broad variety of edaphic co nditions. The highly efficient removal of these radionuclides by these gras s species after inoculation with arbuscular mycorrhizae supports the concep t that remediation of radionuclide contaminated soils using mycorrhizal pla nts may present a viable strategy to remediate and reclaim sites contaminat ed with radionuclides. (C) 1999 Published by Elsevier Science Ltd. All righ ts reserved.