The article discusses a pan-India study conducted by scientists at the Bhabha Atomic Research Centre (BARC) that discovered background radiation levels in parts of Kerala are nearly three times higher than previously thought.
What exactly is background radiation?
- Background radiation is a measurement of the amount of ionising radiation present in the environment at a specific location that is not the result of the intentional introduction of radiation sources.
- Background radiation comes from a variety of natural and man-made sources.
How is it calculated?
- The International Atomic Energy Agency (IAEA) specifies maximum radiation exposure levels, which India’s atomic energy establishment has also adopted.
- Public exposure should not exceed one millisievert per year, and those who work in plants or are exposed by their occupation should not be exposed to more than 30 millisieverts per year.
- It is usually measured in nanogray per second. A (nGy/s) is a decimal fraction of the SI-derived unit of absorbed dose rate from ionising radiation.
Natural sources-
- Cosmic radiation
- Environmental radioactivity from naturally occurring radioactive materials (such as radon and radium)
Man-made sources-
- Medical X-rays,
- Fallout from nuclear weapons testing and nuclear accidents.
Factors that influence such radiation
- There is natural background radiation all around us.
- The amount of naturally occurring radioactive elements in soil, water, and air varies from location to location and over time.
- Weather conditions also have an impact on radiation levels because snow can shield these elements and radioactive particulates can wash out of the air during rainstorms.
- Cosmic radiation from the sun, our galaxy, and beyond surrounds us all the time and contributes to natural background radiation.
- The level of background radiation at any given location can also be influenced by altitude and latitude.
How dangerous is it?
- All rocks and soils contain some natural radioactivity, which can be ingested or inhaled if disturbed.
- Radon is a gas that, along with its decay products, can accumulate indoors and be inhaled.
- Radioactivity can also be ingested through the food and water we consume.
- The annual dose of background radiation received by you and your family is determined by a number of factors.
- Gamma rays, for example, are a type of radiation that can pass through matter unimpeded and are harmless in small doses but can be dangerous in concentrated bursts.
Results of the BARC Study
- The average natural background level of gamma radiation in India was 94 nGy/hr (nano Gray per hour) (or about 0.8 millisievert/year), according to the study.
- The most recent study, completed in 1986, calculated such radiation to be 89 nGy/hr.
- The study discovered that the levels in Kollam district, Kerala, were 9,562 nGy/hr, or roughly three times higher than expected.
- This amounts to about 70 milliGray per year, or slightly more than what a nuclear plant worker is exposed to.
- This does not necessarily imply that residents of Kollam are being exposed to dangerous levels of radiation, as previous studies have found no increased rates of cancer or mortality.
Reasons for Kerala’s Higher Radiation Levels
- The higher radiation levels in Kollam are attributed to thorium-rich monazite sands, which are part of India’s long-term plan to produce nuclear fuel sustainably.
- Southern India has higher levels of radiation due to the presence of uranium deposits in granite and basaltic volcanic rock.
Source: https://pubmed.ncbi.nlm.nih.gov/19066487/