Assessment of natural background radiation in one of the highest regions of Ecuador

摘要

Natural background radiation was measured in the province of Chimborazo (Ecuador) with the following reference coordinates 1 40'00 '' S 78*39'00 '' W, where the furthest point to the center of the planet is located. Natural background radiation measurements were performed at 130 randomly selected sites using a Geiger Miiller GCA-07W portable detector; these measurements were run at 6 m away from buildings or walls and 1 m above the ground. The global average natural background radiation established by UNSCEAR is 2.4 mSv y(-1). In the study area measurements ranged from 0.57 mSv y(-1) to 3.09 mSv y(-1) with a mean value of 1.57 mSv y(-1), the maximum value was recorded in the north of the study area at 5073 metres above sea level (m.a.s.l.), and the minimum value was recorded in the southwestern area at 297 m.a.s.l. An isodose map was plotted to represent the equivalent dose rate due to natural background radiation. An analysis of variance (ANOVA) between the data of the high and low regions of the study area showed a significant difference (p alpha), in addition a linear correlation coefficient of 0.92 was obtained, supporting the hypothesis that in high altitude zones extraterrestrial radiation contributes significantly to natural background radiation.