Background radiation higher in Kerala, but no risk: study

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Last Updated21/03/2023

A pan-India study conducted by the scientists at the Bhabha Atomic Research Centre (BARC) has revealed that in a few areas of Kerala, background radiation levels emitted from natural sources including rocks, sand or mountains, are about three times higher than what has been assumed.
However, the higher rate of radiation does not translate to an elevated health risk.

Radiations are emitted due to the disintegrating nucleus of an unstable element.
Gamma rays are extremely energetic types of radiation that can pass unobstructed through matter.
Gamma radiations are harmless unless present in large concentrated doses.
Gamma radiation levels are to be monitored and assessed, especially around nuclear plants along with the average quantity of radiation that plant workers are exposed to.

The International Atomic Energy Agency (IAEA) has specified the maximum radiation exposure levels which have also been adopted by India’s atomic energy institutions.
As per the specifications, public exposure levels must not cross 1 milli-Sievert every year and those workers of the plants should not be exposed to over 30 milli-Sievert every year.

The recent study conducted indicated that the average natural background levels of gamma radiation in India were 94 nGy/hr (nano Gray/hour) (close to 0.8 milli sievert/year).
Gray/hour refers to radiation emitted whereas sievert/year indicates biological exposure.
The last such study, conducted in 1986 had measured the highest radiation exposure at Chavara, Kerala at 3,002 nGy/year whereas the recent study found that the levels in the Kollam district were 9,562 nGy/hr.
The high radiation levels in the Kollam district are mainly due to the monazite sands that are high in thorium.