Concentration of 226Ra in soil and sugar cane after application of calcareous, gypsum or phosphogypsum / ConcentraÃÃo de 226Ra em solo e em cana-de-aÃÃcar apÃs aplicaÃÃo de CalcÃrio, Fosfogesso ou Gipsita

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

All kinds of soil possess 226Ra, and its absorption by the plants, depends on the specific characteristics of each region and of the cultivated species. In different parts of the world, radioecological studies are currently developed to evaluate the transferences of 226Ra in the soil-plant system and the presence of this radioelement in human nutrition. In recent years, the amount of 226Ra in the soil has been increased by the use of correctors and fertilizers. In Pernambuco, the sugar cane (Saccharum officinarum) consumes large amounts of fertilizers and corrective. Comparative tests have been processed between phosphogypsum and gypsum for the correction of aluminium in depths, in sugar cane cultivated soils. Phosphogypsum possesses considerable amounts of 226Ra. This dissertation studied the transference of 226Ra in sugar cane cultivated in soils previously corrected with dolomitic lime, natural gypsum and phosphogypsum. Soil samples in different depths and sugar samples two varieties cultivated cane from in a mill in Pernambuco âZona da Mataâ were analyzed. The 226Ra was determined, in the soil, by the technique of the gamma spectrometry, and, in the sugar cane, by the method of emanation of 222Rn. The samples of lime, gypsum and phosphogypsum presented average concentrations of 226Ra of 3, 5 and 119 Bq.kg-1, respectively. The concentrations of 226Ra in the soil samples corrected with lime, gypsum and phosphogypsum varied from 19 to 33, 18 to 26 and 20 to 30 Bq.kg-1, respectively. The concentrations of 226Ra that resulted from use of lime, gypsum and phosphogypsum in the variety of sugar cane 1011, ranged from 274 to 384, 202 to 561 and 198 to 347 mBq.kg-1, respectively, and those of the sugar cane variety 3250, from 198 to 376, 188 to 382 and 188 to 252 mBq.kg-1, respectively. No significant differences in the availability of 226Ra were found among soils corrected with lime, gypsum and phosphogypsum neither among the two sugarcane varieties. Even though the levels of 226Ra in the phosphogypsum were relatively high, compared to lime and gypsum, the accumulation of this radionuclide in the soil was incipient. Therefore, the use of phosphogypsum as a soil ammendment is environmentaly safe, at least regarding the accumulation of 226Ra in the soil

ASSUNTO(S)

corrective sugar cane phosphogypsum radioecologia nuclear energy energia nuclear cana-de-aÃÃcar fosfogesso engenharia nuclear corretivo radioecology

ACESSO AO ARTIGO

Documentos Relacionados