Short-term seasonal variability in 7Be wet deposition in a semiarid ecosystem of central Argentina.
The (7)Be wet deposition has been intensively investigated in a semiarid region at San Luis Province, Argentina. From November 2006 to May 2008, the (7)Be content in rainwater was determined in 58 individual rain events, randomly comprising more than 50% of all individual precipitations at the sampling period. (7)Be activity concentration in rainwater ranged from 0.7+/-0.3 Bq l(-1) to 3.2+/-0.7 Bq l(-1), with a mean value of 1.7 Bq l(-1) (sd=0.53 Bq l(-1)). No relationship was found between (7)Be content in rainwater and (a) rainfall amount, (b) precipitation intensity and (c) elapsed time between events. (7)Be ground deposition was found to be well correlated with rainfall amount (R=0.92). For the precipitation events considered, the (7)Be depositional fluxes ranged from 1.1 to 120 Bq m(-2), with a mean value of 32.7 Bq m(-2) (sd=29.9 Bq m(-2)). The annual depositional flux was estimated at 1140+/-120 Bq m(-2)y(-1). Assuming the same monthly deposition pattern and that the (7)Be content in soil decreases only through radioactive decay, the seasonal variation of (7)Be areal activity density in soil was estimated. Results of this investigation may contribute to a valuable characterization of (7)Be input in the explored semiarid ecosystem and its potential use as tracer of environmental processes.
Juri Ayub
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Grupo de Estudios Ambientales, Instituto de Matemática Aplicada San Luis, Universidad Nacional de San Luis - CONICET, Ejercito de los Andes 950, D5700HHW San Luis, Argentina.
Di Gregorio
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Velasco
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Huck
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Rizzotto
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Lohaiza
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D001118:Argentina; D001608:Beryllium / Q000032:analysis*; D017753:Ecosystem; D011834:Radiation Monitoring; D011868:Radioisotopes / Q000032:analysis*; D011891:Rain / Q000737:chemistry*; D012621:Seasons; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive; D001608:Beryllium