Niveles de radioactividad en tres regiones de Costa Rica

Abstract

The establishment of the first radioactivity levels of natural radiation was carried out during the period 1991 to 1994 in three different regions of Costa Rica. The radionuclides studied belong to different soil types related to each selected region. Utilizing low level counting techniques the specific activity of the natural radioactive chains ²³⁸U daughters, ²³²Th and the element ⁴⁰K were measured for a total of 120 samples during this period. The amount of ¹³⁷Cs, as fall out radionuclide, was also studied.  The average national values in Bqkg^-1 measured for ²³⁸U were 11.66 for ²¹⁴Bi, 34.42 for ²²⁶Ra and 10.73 for ²¹⁴Pb, for ²³²Th daughters were 4.08 for ²⁰⁸Tl, 9.65 for ²¹²Bi and 7.62 for ²²⁸Ac. The specific activity values for ⁴⁰K 95.14 Bqkg^-1 and for ¹³⁷Cs was 2.38 Bqkg^-1. It is found that Costa Rica is not highly natural radioactive country and that the values for ¹³⁷Cs are well below international reported values.