Systematics of radon at the Wairakei geothermal region, New Zealand.
J Environ Radioact
; 92(1): 16-29, 2007.
Article
em En
| MEDLINE
| ID: mdl-17056160
ABSTRACT
222Rn and 220Rn in geothermal steam at Wairakei, NZ, range from 11 to 19, 500 Bq kg-1, and 25 to 16, 700 Bq kg-1, respectively, but do not cause toxic concentrations in air. The wide ranges are mainly due to differences in different physical conditions underground (e.g. thin silica diffusion barriers), not geochemical differences. Groundwater Rn from outside the area probably plays only a minor role. 210Po was found present in non-toxic levels in the steam. Historical records showed little change in Rn concentration over several decades, therefore potentially hazardous concentrations might be predicted from early exploration. 220Rn concentrations at Wairakei should decrease as the field becomes steam-dominated. Rock surfaces were variably leached or enriched with U, Th, Ra and 210Pb, providing a possible model for deposition in cooler regions near the field. Estimates of 222Rn permeability ranged from 2 to 77% of the maximum possible, with a median of 13%.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Monitoramento Ambiental
/
Radônio
/
Fontes Termais
Tipo de estudo:
Prognostic_studies
País/Região como assunto:
Oceania
Idioma:
En
Revista:
J Environ Radioact
Assunto da revista:
SAUDE AMBIENTAL
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Nova Zelândia