20 March 2023.
Background radiation refers to the radiation emitted from natural sources such as rocks or mountains. A recent study conducted by scientists at the Bhabha Atomic Research Centre (BARC) found that certain areas in Kerala are experiencing nearly three times more background radiation than previously assumed. The study is significant, as it sheds light on the natural radiation levels in India, which has important implications for the country’s nuclear energy plans.
Monazite sands and high levels of thorium
The higher radiation levels in Kollam, a district in Kerala, are attributed to the presence of monazite sands that are high in thorium, a natural radioactive element. Thorium is a common radioactive element that is found in small amounts in soil, rocks, and water. Monazite sands are one of the most important sources of thorium, and India has been using these sands as a source of nuclear fuel for many years. Southern India, which is home to granite and basaltic volcanic rock, has higher levels of radiation from uranium deposits.
The study conducted by BARC scientists measured radiation levels from nearly 100,000 locations across India. The study found that the average natural background levels of gamma radiation in India were 94 nGy/hr. However, in Kollam district, the levels were found to be 9,562 nGy/hr, which is about three times more than the assumed levels. The 1986 survey conducted previously had mapped only 214 locations.
No elevated health risk
Although the higher radiation levels in Kollam district might seem concerning, the study’s authors note that there is no elevated health risk associated with these higher radiation levels. The human body is accustomed to higher doses of radiation, and there is no evidence to suggest that the higher levels of radiation in Kollam district are causing any adverse health effects.
IAEA safety standards
The International Atomic Energy Agency (IAEA) specifies maximum radiation exposure levels, which have also been adopted by India’s atomic energy establishment. The IAEA recommends that public exposure to radiation should not exceed 1 milli-Sievert every year, and those who work in nuclear plants or are exposed to radiation by virtue of their occupation should not be exposed to over 30 milli-Sievert every year.