2002 IRISH SCIENTIST YEAR BOOK

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QUEEN’S UNIVERSITY BELFAST [1] , DEPARTMENT OF AGRICULTURE AND RURAL DEVELOPMENT (NI)[2] & RADIOLOGICAL PROTECTION INSTITUTE OF IRELAND, DUBLIN [3]
JACK PEARCE [1,2], TONY JOHNSON [2] , HUGH SYNOTT 3 & JOHN CUNNINGHAM [3]
The effects of ‘Prussian Blue’ on plant growth and soil microbiological processes in upland pasture

Hill sheep on upland pasture.

Following the Chernobyl accident in April 1986, in which radioactive fallout was deposited over much of Europe, food products from many semi-natural areas of Europe contained relatively high levels of radiocaesium. This resulted in a renewed interest in countermeasures that are effective in reducing the transfer of radioactivity to food products. One such countermeasure is ‘Prussian Blue’. This is a group of similar compounds, and interest has focused on ammonium-ferric-hexacyanoferrate (AFCF), which is extremely effective against radiocaesium. AFCF administered to animals prevents any radiocaesium ingested in the diet from being absorbed and transferred to milk and meat. The resulting AFCF-Caesium complex is excreted by the animal via faeces to the environment.

 Very little information exists concerning the fate of AFCF in the environment, whether applied directly to pasture or excreted by animals via faeces. Information on any ecological effects is clearly required to evaluate fully the use of AFCF as an overall agricultural countermeasure strategy.

 This project investigated the effects (in field investigations and controlled greenhouse studies) of AFCF on plant growth, plant bio-diversity, biomass, soil microbiological activity, invertebrate fauna, and its stability in upland pasture in Counties Antrim (NI) and Cavan (RoI).

 The results obtained showed:
  1. Four/five months after AFCF applications to upland pasture it had little or no effect on plant growth, both in field trials and a controlled greenhouse study.
  2. There were no effects of AFCF on plant bio-diversity, vegetation biomass and soil microbial processes.
  3. AFCF had no effect on 137 Cs levels in the various species studied in upland field trials. However, it reduced 137 Cs uptake by Eriophorum vaginatum, an upland species, in a controlled greenhouse study.
  4. Most of the AFCF at the time of sampling (4/5 months after application) remained in the upper peat soil layers (litter/moss and root matt). There was some indication that the AFCF chemical structure was degraded, as indicated by the presence of the cyanide moiety especially in the litter/moss layer and root matt. However, any free cyanide in the soil is likely to be metabolised to harmless compounds by soil bacteria.
  5. AFCF had no effects on invertebrate fauna as reflected in the range of carabid beetle species and their numbers in upland pasture treated with AFCF.
  6. The results suggested that AFCF may be safely used as a radio-caesium countermeasure within peatland ecosystems without any significant impact on the key environmental factors of plant growth, plant bio-diversity, biomass, soil microbial activity or carabid beetles.
Contact: Professor Jack Pearce, Food Science Division,
Department of Agriculture & Rural Development, Newforge
Lane, Belfast BT9 5PX; Tel: +44 (028) 90255349;
Fax: +44 (028) 90255006; E-mail: [email protected]