OPERATION CENIZA-ARENA: THE RETENTION OF FALLOUT PARTICLES FROM VOLCAN IRAZU (COSTA RICA) BY PLANTS AND PEOPLE. PART ONE.
STANFORD RESEARCH INST MENLO PARK CALIF
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The report summarizes data on the retention of fallout particles ejected by Volcan Irazu Costa Rica by the foliage of vegetables and native plants that were obtained from field experiments in April and May 1964. The data show that the foliage of plants retain, initially, all sizes of falling particles, and when the relative humidity is greater than about 90 percent, the foliage retains about twice the weight of particles that is retained under drier conditions. Meteorological data were obtained, and the influence of these on the data is discussed. A few data on personnel contamination were obtained. The mass median particle diameter of the volcanic debris termed ceniza-areana that deposited at the various collecting stations generally was between 50 and 100 microns. In general, it was found that the foliage retained more of the depositing particles than reported for nuclear weapon fallout in the desert regions of the United States and Australia this difference was attributed mainly to differences in meteorological factors although sampling times and procedures also were contributing factors. Author
- Geology, Geochemistry and Mineralogy