Effect of Natural Ionizing Radiation on Health Indicators in Region with Monazite Sand in Brazil

Objective  This article compares the occurrence of cancer and germinal damage in the city of Guarapari-Espírito Santo (ES), an area with high natural ionizing radiation, with other coastal cities. Material and Methods  The evaluated cities were: Guarapari (ES), Campos (Rio de Janeiro), Rio Grande (Rio Grande do Sul), and Ilhéus (Bahia); the following factors were considered: mortality rate % from tumors (2007-2017), mortality rate % from tumors up to 15 years of age (2007-2017), hospital morbidity rate % from tumors up to 15 years of age (2008-2018), and hospital morbidity rate % from congenital malformation and chromosomal anomalies (2008-2018). Radiometric surveys were conducted by the Applied Physics Group at Universidade Federal do Espírito Santo. Results  The natural radiation levels recorded in Guarapari resulted in accumulated dose between 3.65 and 10.95 mSv/year, and 1 mSv in the other cities. The highest average cancer mortality rates were: Rio Grande = 22.4%; Guarapari = 17.6%; Campos = 16.7%; and Ilhéus = 11.8%. The proportional hospital mortality and morbidity rates for cancer up to 15 years of age are as follows: Ilhéus = 3.36 and 5.87%; Rio Grande = 0.79 and 7.38%; Guarapari = 0.64 and 7.25%; and Campos = 0.39 and 9.13%. The hospital morbidity rate due to congenital malformations and chromosomal anomalies was 0.72% for Campos, 0.63% for Rio Grande, 0.62% for Guarapari, and 0.43% for Ilhéus. Conclusion  There was no increase in cases of cancer or germ damage in Guarapari. These results indicated a dose threshold in the induction of these damages, contradicting the current linear no-threshold theory.