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THE DYNAMICS OF CAESIUM-137 FROM CHERNOBYL IN UPLAND, PEAT MOORLAND ECOSYSTEMS

Objective


This study has identified retention/cycling of caesium in Scottish upland peats and retention of caesium from Greek basin peats.

The clay component of the mineral fraction of the Greek peats is probably responsible for profile retention of caesium. Plant rooting density and soil animal activity appear to be important agents of caesium cycling in Scottish peats. A competitive ion effect from ammonium through freeze/thaw and intensity of cropping (which affects root activity) may be important controls of caesium mobility.
IT IS PROPOSED TO CARRY OUT SIMILAR FIELD AND LABORATORY RESEARCH IN ABERDEEN, SCOTLAND AND THESSALONIKA, GREECE.

FIELD SITE EXPERIMENTS
SAMPLE OF VEGETATION AND CORES OF PEAT WILL BE TAKEN AT 4-MONTHLY INTERVALS OVER THE 1-YEAR PERIOD. THE MATERIAL WILL BE SEPARATED INTO VEGETATION TYPES AND THE CORE INTO INCREMENTS. RESULTING VEGETATION/PROFILE DISTRIBUTIONS OF CEASIUM WILL BE COMPARED BETWEEN SITES AND ALSO WITH TIME TO CHARACTERISE PROFILE MIGRATION. FULL SITE CHARACTERISATION WILL BE CARRIED OUT.

LABORATORY EXPERIMENTS
PARALLEL LABORATORY "PULSE" RADIO TRACER EXPERIMENTS USING INTACT PEAT/VEGETATION MICROCOSMS TO "FACTOR-OUT" THE PROPERTIES WHICH AFFECT THE MIGRATION WILL BE CARRIED OUT. THESE WILL BE SPLIT INTO BROAD AREAS.

1. THE UPTAKE OF CAESIUM BY THE DIFFERENT TYPES OF VEGETATION USED AS FOOD BY SHEEP AND GOATS WILL BE COMPARED.

2. AN ASSESSMENT OF THE INFLUENCE OF MYCORRHIZAL FUNGAL INFECTION OF THE PLANT ROOTS ON UPTAKE/TRANSLOCATION AND ABOVE GROUND ACCUMULATION OF CAESIUM WILL BE MADE.

3. THE EFFECTS OF ROOTING DENSITY AND DEPTH OF THE VEGETATION ON THE DYNAMICS OF THE PROFILE WILL BE INVESTIGATED. THIS INVESTIGATION WILL INCLUDE THE EFFECT THAT BURROWING SOIL ANIMALS, PARTICULARLY ENCHYTRAEID WORMS, HAVE ON THE DISTRIBUTION.

4. BY ARTIFICIAL CROPPING THE EFFECT OF GRAZING ON THE UPTAKE/ACCUMULATION KINETICS OF THE CAESIUM WILL BE IDENTIFIED. THIS WILL INCLUDE THE EFFECT THE RECYCLING OF CAESIUM THROUGH ANIMAL WASTE HAS ON THE DISTRIBUTION, PARTICULARLY THROUGH LOCALISED MOBILISATION AND SURFACE REDEPOSITION.

5. THE INFLUENCE COMPLEXATION-CHELATION MECHANISMS ASSOCIATED WITH ORGANIC COMPOUNDS IN THE PEAT HAVE ON THE MOBILITY AND BIOAVAILABILITY WILL BE INVESTIGATED.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

University of Aberdeen
Address
Regent Walk
AB9 1FX Aberdeen
United Kingdom