Experimental system to displace radioisotopes from upper to deeper soil layers: chemical research.
BACKGROUND
Radioisotopes are introduced into the environment following nuclear power plant accidents or nuclear weapons tests. The immobility of these radioactive elements in uppermost soil layers represents a problem for human health, since they can easily be incorporated in the food chain. Preventing their assimilation by plants may be a first step towards the total recovery of contaminated areas.


METHODS
The possibility of displacing radionuclides from the most superficial soil layers and their subsequent stabilisation at lower levels were investigated in laboratory trials. An experimental system reproducing the environmental conditions of contaminated areas was designed in plastic columns. A radiopolluted soil sample was treated with solutions containing ions normally used in fertilisation (NO3-, NH4+, PO4--- and K+).


RESULTS
Contaminated soils treated with an acid solution of ions NO3-, PO4--- and K+, undergo a reduction of radioactivity up to 35%, after a series of washes which simulate one year's rainfall. The capacity of the deepest soil layers to immobilize the radionuclides percolated from the superficial layers was also confirmed.


CONCLUSIONS
The migration of radionuclides towards deeper soil layers, following chemical treatments, and their subsequent stabilization reduces bioavailability in the uppermost soil horizon, preventing at the same time their transfer into the water-bearing stratum.
Cazzola
Pietro
P
Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta and C.Re.A.A. - Via Bologna 148 I-10154 Torino, Italy. pietroluigi.cazzola@izsto.it
Cena
Agostino
A
Ghignone
Stefano
S
Abete
Maria C
MC
Andruetto
Sergio
S
D000059:Accidents; D015258:Acid Rain / Q000032:analysis / Q000633:toxicity; D001673:Biodegradation, Environmental; D003666:Decontamination / Q000379:methods*; D005308:Fertilizers; D020387:Food Chain; D019015:Geologic Sediments; D006801:Humans; D009689:Nuclear Warfare; D011210:Power Plants; D011847:Radioactive Fallout; D011851:Radioactivity; D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive / Q000032:analysis / Q000037:antagonists & inhibitors*; D013051:Spectrometry, Gamma
D015258:Acid Rain; D005308:Fertilizers; D011847:Radioactive Fallout; D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive