Inter-varietal variation in caesium and strontium uptake by plants: a meta-analysis

Radiocaesium and radiostrontium enter the foodchain primarily via plant root uptake. Selecting varieties of crop that display low accumulation of these radionuclides has been suggested as an economically and socially acceptable remediation strategy for radiologically contaminated land. However, there is insufficient information available to assess the feasibility of this remediation approach. This paper presents a comprehensive literature-based evaluation of inter-varietal variation in accumulation of Cs and Sr in crop plants. Thirty-seven publications studying 27 plant species were identified as appropriate for these analyses. Inter-varietal variation was expressed at the ratio of the maximum to minimum observed concentrations for a given crop species and element and ranged from 1.0 to 6.3 and from 1.0 to 4.5 for Cs and Sr respectively. This variation suggests that exploitation of inter-varietal variation could be used in some crop species to reduce the transfer of these radionuclides to a similar extent to existing remediation strategies. Low-Sr accumulating varieties were also found to have lower concentrations of Ca, whereas low Cs-accumulating varieties were not shown to have low K accumulation. Concentrations of Cs and Sr in plants were not related, suggesting that finding varieties displaying low accumulation of both Sr and Cs may not be feasible. Varietal selection could be an effective remediation strategy, and could be used in combination with other existing methods, such as fertilisation and ploughing. However, a thorough investigation of species contributing the most to ingestion doses is recommended to fully determine the feasibility of varietal selection as a remediation strategy. The reproducibility of inter-varietal variation between sites and growing seasons should be the focus of future research.