Background radiation and Effects

The Bhabha Atomic Research Centre (BARC) has published a study, which has found that ‘background radiation’levels are nearly three times more than what’s been assumed in the State of Kerala.

Findings of the report:

• Background radiation levels that emitted from natural sources such as rocks, sand or mountains, are nearly three times more than what’s been assumed in Kerala.
• The average natural background levels of gamma radiation in India were 94 nGy/hr (nanoGray per hour) (or roughly 0.8 millisievert/year).  
• The last such study, conducted in 1986, computed such radiation to be 89 nGy/hr.  

About the Background Radiation:

• Background radiation levels are emitted from natural sources such as rocks, sand or mountains.
• All rocks and soils contain some trace amount of natural radioactivity and can sometimes be ingested or inhaled if disturbed.

• Radiation results from the disintegrating nucleus of an unstable element and these can be from anywhere, including from inside our bodies to the constituents of matter.
• Gamma rays are a kind of radiation that can pass unobstructed through matter. Though extremely energetic, they are harmless unless present in large concentrated doses. 
• Standard Limit:
  • Public exposure shouldn’t exceed 1 milli-Sievert every year; those who work in plants or are by virtue of their occupation shouldn’t be exposed to over 30 milli-Sievert every year.

Source of background radiations:

Natural Source: Natural sources, such as the earth, air, building materials, and food, provide the majority of background radiation. Cosmic rays from outer space also contain radiation.

• Cosmic Rays- Radiations that reach us from outer space
• Animals- All Animals emit a natural level of radiation.
• Rocks- Some rocks give off radioactive radon gas.
• Soil and plants- Radioactive material from the rock is absorbed by the soil and passed to plants.

Artificial Source: Human activity, on the other hand, has increased background radiation by building and employing artificial radiation sources.

• X-Rays- When going through security or having an X-ray in the hospital, we are exposed to this type of radiation.
• Nuclear missile- Man has exploded bombs in the environment, producing radioactivity.
• Nuclear Power- Radiation has been emitted into the atmosphere by nuclear power plants.

Factors affecting Background radiation:

• Background radiation varies from place to place and over time, depending on the amount of naturally-occurring radioactive elements in soil, water and air.
• Weather conditions also affect radiation levels, as snow cover may shield these elements, and radioactive particulates can wash out of the air during rain storms.
• Cosmic radiation from the sun, our galaxy, and beyond is constantly around us and contributes to natural background radiation.
• Altitude and latitude can also influence the level of background radiation at any one site.