Radioactive pollution occurs when radioactive materials are present or deposited in the atmosphere or environment, especially when their presence is unintentional and poses a risk to the environment due to radioactive decay. While there are several man-made sources of radiation pollution, natural sources such as the cosmic rays, terrestrial rays, and the radiation found internally in every human can also cause radioactivity. This article will explain to you about Natural Sources of Radioactive Pollution which will be helpful in preparing the Environment Syllabus for the UPSC Civil Service exam.

Natural Sources of Radioactive Pollution

Radioactive Pollution

What is Radioactive Pollution?

• Radioactive pollution is the term for the dangerous level of radiation emitted by radioactive elements.
• The radioactive materials cause destruction by emitting hazardous ionizing radiation (radioactive decay) such as beta or alpha particles, gamma rays, or neurons into the environment where they exist.
• Human activities are considered to be responsible for around 20% of the radiation we are exposed to.
• Activities involving radioactive materials, such as mining, handling and processing radioactive materials, handling and storage of radioactive waste, and the use of radioactive reactions to generate energy (nuclear power plants), as well as the use of radiation in medicine (e.g. X-rays) and research, are all examples of human activities that can release radiation.

Natural Sources of Radioactive Pollution

Exposure from Cosmic Radiation

• Cosmic radiation is constantly bombarding the earth's outer atmosphere.
• Cosmic radiation is made up of fast-moving particles that exist in space and can come from a variety of places, including the sun and other celestial occurrences.
• Protons make up the majority of cosmic rays, although they can also be other particles or wave energy.
• Natural radiation exposure occurs when ionizing radiation enters the earth's atmosphere and is absorbed by humans.
• Natural radiation exposures vary based on where you live and what you do. Higher-altitude areas are subjected to more cosmic radiation.

Terrestrial Radiation

• Terrestrial radiation is produced by the Earth itself. Natural radioactive materials can be found in soil and rock.
• Natural reserves of uranium, potassium, and thorium, which produce modest amounts of ionizing radiation during natural decay, are the principal sources.
• Uranium and thorium are "ubiquitous," which means they can be found almost wherever.
• Because traces of these minerals can be present in building materials, natural radiation can be absorbed both indoors and out.

Radiation Through Inhalation

• Inhalation of radioactive gases created by radioactive materials found in soil and bedrock accounts for the majority of variations in natural radiation exposure.
• The decay of uranium-238 produces radon, an odorless and colorless radioactive gas.
• It is an inert gas, which means it does not react with the matter around it.
• Radon can easily migrate up through the ground and into the sky since it does not react. Thoron is a thorium-derived radioactive gas.
• The amount of radon and thoron in the air varies greatly depending on the soil and bedrock makeup.
• These gases generally dilute to harmless levels in the atmosphere if released into the air, but they can become trapped and accumulate inside buildings, where they are ingested by residents.
• If radon gas is allowed to build up in a home, it poses a health concern not only to uranium miners but also to homeowners. It is the most common source of natural radiation exposure.

Exposure Through Ingestion

• Radioactive minerals are naturally present in trace concentrations in food and drinking water.
• Vegetables, for example, are commonly grown on soil and groundwater contaminated with radioactive elements.
• These minerals cause internal exposure to natural radiation once consumed.
• Potassium-40 and carbon-14, for example, are naturally occurring radioactive isotopes with the same chemical and biological properties as their non-radioactive counterparts.
• These radioactive and non-radioactive elements are necessary for the construction and maintenance of human bodies.
• Natural radioisotopes expose humans to radiation on a regular basis. The table below shows how much radioactivity from potassium-40 is present in 500 grams of various food products.
• A becquerel is a radioactivity unit that equals one decay (transformation) per second.

Internal Radiation

• Aside from cosmic and terrestrial sources, everyone is born with radioactive potassium-40, carbon14, lead-210, and other isotopes inside their bodies.
• The variation in dose from cosmic and terrestrial sources is not as big as the range in exposure from one person to another.
• Internal radioactive material exposes a person to a dose of roughly 40 millirems per year on average.

Conclusion

We usually have limited control or reduction over ionizing radiation emitted by natural sources such as the sun, earth, or rocks. While there is never a completely risk-free situation, this type of exposure is usually relatively low. Natural sources of radioactivity, such as radon gas in the home, may, however, be too high in some situations and need to be decreased.

FAQs

MCQs

1. Which of the following is a major contributor to natural radioactive pollution?

A) Chlorofluorocarbons
B) Radon gas
C) Carbon dioxide
D) Methane

2. Which of the following is an effect of prolonged exposure to cosmic radiation?

A) Increase in lung diseases
B) Skin irritation
C) Increased cancer risk
D) Decreased heart rate

3. How can radon gas enter buildings?

A) Through windows
B) Through cracks in the foundation
C) Through ventilation systems
D) Through open doors

4. What is the primary source of potassium-40, a naturally occurring radioactive element?

A) Water bodies
B) Soil and rocks
C) Living organisms
D) Air

5. Which of the following is NOT a natural source of radioactive pollution?

A) Uranium
B) Radon
C) Thorium
D) Carbon monoxide

GS Mains Questions and Model Answers

Q1: Discuss the natural sources of radioactive pollution and their impact on the environment and human health.

Answer: Natural sources of radioactive pollution include radon gas, cosmic radiation, uranium, thorium, and potassium-40. Radon, which emanates from the decay of uranium and thorium in soil and rocks, poses a health risk when it accumulates in enclosed spaces, leading to increased lung cancer rates. Cosmic radiation, while mostly absorbed by the atmosphere, still contributes to radiation exposure, particularly at higher altitudes. Uranium and thorium, found in trace amounts in the Earth's crust, decay over time, releasing radiation into the environment. Potassium-40 is present in soil and living organisms and contributes to low-level radiation. While natural radioactive pollution levels are generally low, their cumulative long-term exposure can have significant environmental and health impacts, particularly for populations living in radon-prone areas or at higher altitudes.

Q2: What measures can be implemented to mitigate the health risks associated with natural radioactive pollution?

Answer: Mitigation measures for natural radioactive pollution include the installation of radon mitigation systems in homes, especially in high-risk areas, to prevent radon accumulation. Regular monitoring of radon levels in buildings and soil can help identify areas where mitigation is needed. Educating the public about the dangers of radon and the importance of testing their homes can reduce health risks. Additionally, government regulation of radon levels in drinking water and air quality standards can help limit exposure. For cosmic radiation, reducing exposure in high-altitude areas, such as limiting the number of flights for passengers and crew, can be considered. Promoting research on natural radioactive pollution and its effects on health will further support public health and safety.

Q3: Analyze the impact of natural radioactive sources on biodiversity and ecosystems.

Answer: Natural radioactive sources can impact biodiversity and ecosystems through long-term exposure to low levels of radiation. For example, uranium and thorium in soil can accumulate in plants, affecting their growth and potentially entering the food chain. Radon can contaminate groundwater, impacting aquatic ecosystems and biodiversity. While natural radiation is typically low, over time, its effects on genetic mutations in plants, animals, and microbes can result in biodiversity loss. Ecosystems exposed to higher natural radiation may experience reduced species diversity, as some species may be more sensitive to radiation than others. Additionally, radiation can affect the reproductive systems of organisms, leading to changes in population dynamics and ecosystem health.

Previous Year Questions on Natural Radioactive Pollution

1. UPSC CSE Prelims 2020:

Question: Which of the following is a naturally occurring radioactive element found in the Earth’s crust?

A) Radon
B) Nitrogen
C) Oxygen
D) Carbon

Answer: (A)

Explanation: Radon is a naturally occurring radioactive gas emitted from the decay of uranium and thorium in the Earth’s crust.

2. UPSC CSE Mains 2019 (GS Paper 3):

Question: How do natural sources of radioactive pollution affect human health, and what steps can be taken to mitigate these effects?

Answer: Natural sources of radioactive pollution, such as radon gas and cosmic radiation, pose significant health risks, particularly in areas with high concentrations of radon. Long-term exposure to radon increases the risk of lung cancer, while cosmic radiation can contribute to cancer risk, especially at high altitudes. Mitigation measures include installing radon mitigation systems in buildings, conducting regular radon testing, and educating the public about the risks. Monitoring cosmic radiation levels and minimizing exposure for airline crews and passengers is also essential. These steps will help reduce the impact of natural radioactive pollution on human health.