UN Report: Natural Radiation Exposure in Mamuju Reaches 9 Times Global Average

Jakarta – The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2024 report, announced on 12 February 2026, states that Mamuju, West Sulawesi, receives natural radiation exposure nearly nine times higher than the global average.

Indonesia’s representative to UNSCEAR and Senior Research Fellow at the National Research and Innovation Agency’s (BRIN) Centre for Research on Nuclear Safety Technology, Metrology, and Quality (PRTKMMN), Nur Rahmah Hidayati, said Mamuju has been classified as a High Natural Background Radiation Areas (HNBRA) or area with high background radiation in the report.

The estimated annual effective dose from natural radiation sources in the region reaches approximately 27 millisieverts (mSv) per year. By comparison, the global average annual effective dose from natural radiation is estimated at around 3.0 mSv per year.

“When compared, the exposure received by Mamuju residents is nearly nine times greater than the world average,” said Nur Rahmah during a statement in Jakarta on Monday.

The concentration of Uranium-238 and Thorium-232 at several locations in Mamuju was reported to be in the range of hundreds to more than 1,000 Becquerel/kilogramme (Bq/kg), whilst the global averages are approximately 33 Bq/kg for Uranium-238 and 45 Bq/kg for Thorium-232.

Furthermore, the concentration of radon outdoors in Mamuju ranges between 22 and 760 Becquerel/cubic metre (Bq/m³), with an average of approximately 290 Bq/m³.

“This figure is considered very high and contributes significantly to the radiation dose received by the local community,” she stated.

Nevertheless, Nur Rahmah disclosed that the building style and lifestyle habits of the local community help prevent higher radon accumulation inside homes. Natural ventilation factors and traditional building structures are among the explanations for why indoor radon concentration does not increase dramatically compared with the external environment.

“The presence of areas with high natural radiation like Mamuju is scientifically important as it can serve as a research location to understand the long-term health impacts of low-level radiation exposure on human health,” said Nur Rahmah Hidayati.