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Biotic, temporal and spatial variability of tritium concentrations in transpirate samples collected in the vicinity of a near-surface low-level nuclear waste disposal site and nearby research reactor.
Twining, J R; Hughes, C E; Harrison, J J; Hankin, S; Crawford, J; Johansen, M; Dyer, L.
Afiliación
  • Twining JR; Institute for Environmental Research, ANSTO, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia. jrt@ansto.gov.au
J Environ Radioact ; 102(6): 551-8, 2011 Jun.
Article en En | MEDLINE | ID: mdl-21397999
The results of a 21 month sampling program measuring tritium in tree transpirate with respect to local sources are reported. The aim was to assess the potential of tree transpirate to indicate the presence of sub-surface seepage plumes. Transpirate gathered from trees near low-level nuclear waste disposal trenches contained activity concentrations of (3)H that were significantly higher (up to ∼700 Bq L(-1)) than local background levels (0-10 Bq L(-1)). The effects of the waste source declined rapidly with distance to be at background levels within 10s of metres. A research reactor 1.6 km south of the site contributed significant (p < 0.01) local fallout (3)H but its influence did not reach as far as the disposal trenches. The elevated (3)H levels in transpirate were, however, substantially lower than groundwater concentrations measured across the site (ranging from 0 to 91% with a median of 2%). Temporal patterns of tree transpirate (3)H, together with local meteorological observations, indicate that soil water within the active root zones comprised a mixture of seepage and rainfall infiltration. The degree of mixing was variable given that the soil water activity concentrations were heterogeneous at a scale equivalent to the effective rooting volume of the trees. In addition, water taken up by roots was not well mixed within the trees. Based on correlation modelling, net rainfall less evaporation (a surrogate for infiltration) over a period of from 2 to 3 weeks prior to sampling seems to be the optimum predictor of transpirate (3)H variability for any sampled tree at this site. The results demonstrate successful use of (3)H in transpirate from trees to indicate the presence and general extent of sub-surface contamination at a low-level nuclear waste site.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Contexto en salud: 12_ODS3_hazardous_contamination / 2_ODS3 Problema de salud: 12_water_sanitation_hygiene / 2_enfermedades_transmissibles / 2_quimicos_contaminacion Asunto principal: Contaminantes Radiactivos del Suelo / Árboles / Tritio / Contaminantes Radiactivos del Agua / Monitoreo del Ambiente Tipo de estudio: Prognostic_studies País/Región como asunto: Oceania Idioma: En Revista: J Environ Radioact Asunto de la revista: SAUDE AMBIENTAL Año: 2011 Tipo del documento: Article País de afiliación: Australia

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Contexto en salud: 12_ODS3_hazardous_contamination / 2_ODS3 Problema de salud: 12_water_sanitation_hygiene / 2_enfermedades_transmissibles / 2_quimicos_contaminacion Asunto principal: Contaminantes Radiactivos del Suelo / Árboles / Tritio / Contaminantes Radiactivos del Agua / Monitoreo del Ambiente Tipo de estudio: Prognostic_studies País/Región como asunto: Oceania Idioma: En Revista: J Environ Radioact Asunto de la revista: SAUDE AMBIENTAL Año: 2011 Tipo del documento: Article País de afiliación: Australia
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