Reference levels of natural radioactivity for the beach sands in a Brazilian southeastern coastal region

Abstract Gamma dose rates of ten beaches in Ilha Grande, an island of Brazilian southeastern cost, were measured in situ using an environmental radiation detector. The values ranged from 62 nGy h - 1 at Dois Rios Beach to 126 nGy h - 1 at Preta Beach. The activity concentrations of radionuclides 232 Th series, 238 U series and 40 K in three different sand profiles (0–10, 10–20 and 20–30 cm) were measured using gamma ray spectrometry and the result is shown in Bq kg - 1 . In most of the cases, eight out of ten beaches, 40 K was the main contributor to the calculated local gamma dose rate. The annual effective doses were 0.15 ± 0.03 mSv yr - 1 for Preta and 0.10 ± 0.02 mSv yr - 1 for Caxadaco beaches, while in the others beaches the mean value of annual effective doses was 0.08 mSv yr - 1 . None of the beaches analysed were considered a radiological risk.

[1]  M. P. Rajan,et al.  Distribution of natural and anthropogenic radionuclides in soil and beach sand samples of Kalpakkam (India) using hyper pure germanium (HPGe) gamma ray spectrometry. , 2002, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.

[2]  Nations United.  sources and effects of ionizing radiation , 2000 .

[3]  A. T. Ramli.  Environmental terrestrial gamma radiation dose and its relationship with soil type and underlying geological formations in Pontian District, Malaysia , 1997 .

[4]  Debashish Sengupta,et al.  Natural radioactivity in the newly discovered high background radiation area on the eastern coast of Orissa, India , 2004 .

[5]  V. Meenakshisundaram,et al.  Natural radionuclide distribution in soils of Gudalore, India. , 2000, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.

[6]  M. Eisenbud,et al.  STATUS OF INVESTIGATIONS IN THE BRAZILIAN AREAS OF HIGH NATURAL RADIOACTIVITY. , 1965, Health physics.

[7]  岩崎 民子.  SOURCES AND EFFECTS OF IONIZING RADIATION : United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR 2000 Report to the General Assembly, with Scientific Annexes , 2002 .

[8]  A. C. Freitas,et al.  Gamma dose rates and distribution of natural radionuclides in sand beaches--Ilha Grande, Southeastern Brazil. , 2004, Journal of environmental radioactivity.

[9]  K. Siddappa,et al.  A new natural background radiation area on the southwest coast of India. , 1993, Health physics.

[10]  A. Malanca,et al.  Distribution of 226Ra, 232Th, and 40K in soils of Rio Grande do Norte (Brazil) , 1996 .

[11]  A. Navas,et al.  238U 226Ra 210Pb, 232Th and 40K activities in soil profiles of the Flysch sector (Central Spanish Pyrenees). , 2002, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.