JURI AYUB Jimena
Assessment of 7Be content in precipitations in a South American semi-arid environment
JURI AYUB, J.; LOHAIZA, F.; VELASCO, R. H.; RIZZOTTO, M.; DI GREGORIO, D.E.; HUCK, H.
SCIENCE OF THE TOTAL ENVIRONMENT
ELSEVIER SCIENCE BV
Lugar: Amsterdam; Año: 2012 p. 111 - 116
There are two naturally occurring radiogenic isotopes of beryllium,7Be and 10Be. These are produced when cosmic radiation interacts with oxygen and nitrogen in the atmosphere. After production, these radionuclides are input to ecosystems through wet and dry deposition. In recent years 7Be and 10Be have proved a powerful tool to study dynamic processes that occur on the surface of the earth. We measured the 7Be content in precipitation at a semiarid location in central Argentina. From November 2006 to March 2009, 68 precipitation events were collected. Measured 7Be content ranged from 0.7 ± 0.4 Bq/L to 3.2 ± 0.7 Bq/L, with a mean of 1.7 Bq/L +/- 0.6 Bq/L. Beryllium-7 content of rainfall did not show clear relationships with amount of rainfall (mm), mean intensity (mm/h) or duration (1/h), or elapsed time between events (days). The general results indicate that for the typical range of precipitation there was no atmospheric washout and that the reload of the atmosphere is not a relevant factor, but when the amount of precipitation is very high washout may be expected. On the other hand, when the 7Be content throughout a single rain event is evaluated, a high content of this radionuclide is associated to a very low rainfall intensity (≈ 3 mm/h), this suggests that rain intensity could affect the 7Be content. Using all data, a good linear relationship between 7Be deposition and rain magnitude was obtained (r2 = 0.82, p