R01025: Transfers of radionuclides deposited onto the external surface of plants, particularly fruits, to internal compartments

Study Duration: April 1999 to February 2003

Contractor: ADAS

The Food Standards Agency needs information to support its assessment of the dose received by consumers of crops following a release of radioactive material into the atmosphere. This study was carried out on the transfer of material from leaves to other parts of the crops.

The leaves of three species of crops (apple, dwarf French bean and cabbage) were artificially dosed with stable isotopes of caesium, strontium and lead to simulate the wet deposition of radioisotopes from the atmosphere onto the leaves. In addition, different types of co-contaminants likely to be found with the isotopes in leaf deposits were applied with the three isotopes.

The leaves of three species of crops (apple, dwarf French bean and cabbage) were artificially dosed with stable isotopes of caesium, strontium and lead to simulate the wet deposition of radioisotopes from the atmosphere onto the leaves. In addition, different types of co-contaminants likely to be found with the isotopes in leaf deposits were applied with the three isotopes. These contaminants were represented by simulated acid rain, acid rain plus basic cations, clay particles, and carbon. A control or blank solution was also used, giving five solutions in total. The solutions had concentrations of contaminants comparable with those reported from atmospheric measurements and were applied to the plants (in amounts of 125µl per plant or 25-50µl per leaf, depending on its size) using a micro-pipette. The outcome of the experiments was that, generally, the dosed leaves of apples and beans retained a high proportion of the applied isotopes at harvest. A lower amount transferred to fruit and bean pods that are consumed.

The solutions containing the contaminants were applied to the crops either six weeks or three days before harvest. The crops were divided into various components (apples: dosed leaf, un-dosed leaf, fruit, core and stem; beans: dosed leaf, un-dosed leaf, pod and stem and for the cabbages dosed leaf, un-dosed leaf and heart). The components of the crops were then dried and the concentrations of the applied contaminants measured using inductively coupled plasma mass spectroscopy. The measured concentrations were then used to derive rate coefficients for the transfer of the contaminants from the external leaf surfaces to the other compartments of the crops. These rate coefficients are directly applicable to models used by the Agency for assessing the transfer of radioactive material into food crops.

The final report is available from the FSA Library and Information centre.
To obtain a copy, please contact the Enquiry Desk, Dr Elsie Widdowson Library and Information Services, Food Standards Agency (tel: 020 7276 8181/8182 or email: library&info@foodstandards.gsi.gov.uk)

Contact: For any enquiries concerning this research project, please contact the relevant Programme contact or email science@foodstandards.gsi.gov.uk