Radiation And Pollution: Is There A Link?

Radiation pollution, also known as nuclear pollution, is a significant environmental issue that has emerged with increasing industrialization. It refers to the release of high-energy particles into the air, water, or surfaces, causing serious health risks to humans, animals, and ecosystems. This pollution is caused by human activities that add to the natural radiation background, such as nuclear power plants, nuclear weapons testing, nuclear accidents, and improper handling of radioactive waste. When radioactive material contaminates the environment, it can enter the bodies of humans and animals through ingestion, inhalation, or absorption, leading to radiation poisoning and genetic mutations. The effects of radiation pollution can be long-lasting, leaving soil infertile and air dangerous to breathe for decades. To minimize the risks and protect public health, it is crucial to understand the sources, impacts, and solutions for radiation pollution.

Nuclear explosions and detonations

The fireball from a nuclear explosion reaches its maximum size in around 10 seconds, releasing vast amounts of energy in the form of blast, heat, and radiation. An enormous shockwave is produced, reaching speeds of several hundred kilometres per hour, causing lung injuries, ear damage, and internal bleeding. People may also sustain injuries from collapsing buildings and flying objects.

Nuclear explosions release radioactive particles into the atmosphere, which can spread over vast distances, depending on weather conditions. The most dangerous concentrations of fallout particles occur within 10 to 20 miles downwind of the explosion, where they can cause fatal external exposure to those outdoors. These fallout particles are often visible as they fall, resembling fine sand or table salt, and can create visible dust and debris, serving as an indicator of a direct radiation hazard. However, fallout may not be easily noticeable on rough or dirty surfaces after accumulating on the ground.

The radiation levels from nuclear detonations subside rapidly over the first few days, but residual radiation from long half-life fission products, such as 90Sr, 106Ru, 137Cs, 147Pm, and 155Eu, can persist and contribute significantly to exposure, even after about 10 years. The primary radiation hazard from nuclear fallout arises from external exposure to penetrating radiation released by decaying radioactive particles. While internal contamination from breathing or ingesting radioactive material is possible, external radiation exposure poses the greatest preventable injury risk after a nuclear detonation.

Nuclear power plants

While living near a nuclear power plant is generally considered safe, accidents at these plants can have severe consequences. If the cooling system fails, for example, nuclear waste can be released, causing radiation leaks that impact the surrounding environment and potentially lead to radiation sickness or radiation poisoning. Major accidents have occurred at the Fukushima I Nuclear Power Plant in Japan, the Chernobyl Nuclear Power Plant in Ukraine, and the Three Mile Island plant in the US. These accidents resulted in radiation leaks, evacuations, and in some cases, deaths.

Nuclear accidents

One of the most well-known nuclear accidents is the Chernobyl disaster, which occurred in 1986 in Ukraine. A sudden power surge during a reactor systems test resulted in an explosion and fire, releasing massive amounts of radiation that spread across Europe. The accident directly killed 30 people, damaged $7 billion worth of property, and led to the relocation of approximately 220,000 people. The radiation fallout contaminated areas of Belarus, Ukraine, and Russia, and is estimated to potentially cause up to 4,000 additional cancer deaths among those exposed to high radiation levels.

Another notable nuclear accident is the Fukushima Daiichi nuclear disaster in 2011, caused by an earthquake and tsunami that struck eastern Japan. The natural disasters cut off external power to the reactors and disabled backup diesel generators, crippling the reactor cooling systems. This led to hydrogen explosions and reactor core damage, resulting in radiation releases that contaminated a wide area and forced the evacuation of nearly half a million residents.

To prevent future nuclear accidents, technical measures have been implemented to reduce the risk of accidents and minimize radioactivity releases. However, human error remains a concern, and the complexity of nuclear power plants means that accidents can be relatively expensive. Additionally, the vulnerability of nuclear plants to deliberate attacks, such as the Battle of Enerhodar in 2022, which damaged the Zaporizhzhia Nuclear Power Plant, underscores the ongoing risks associated with nuclear energy.

Nuclear waste handling and disposal

Nuclear waste can be categorised into three types based on its level of radioactivity and the duration of its hazardous nature: low-level waste (LLW), intermediate-level waste (ILW), and high-level waste (HLW). LLW typically includes items such as rags, papers, filters, protective clothing, and construction debris, while HLW includes spent nuclear fuel. The disposal methods for each type of waste vary accordingly.

LLW and most ILW disposal is a well-established practice, with permanent disposal occurring in dedicated facilities. In contrast, HLW is often stored safely in specialised facilities until its radioactivity decreases to non-hazardous levels. This process can take a long time, and the waste must be isolated from living nature during this period. One method of isolating HLW is by deep geological disposal in repositories surrounded by protective barriers.

The management and disposal of nuclear waste are highly regulated to ensure safety and environmental protection. In the United States, the Environmental Protection Agency (EPA) sets standards for radioactive waste management through legislation such as the Nuclear Waste Policy Act and the Uranium Mill Tailings Radiation Control Act. The Department of Energy (DOE) is responsible for managing much of the nation's radioactive waste, including providing repositories for HLW and operating facilities for defence-related transuranic waste.

Additionally, organisations like the Nuclear Energy Agency (NEA) support member countries in developing safe, sustainable, and socially acceptable strategies for radioactive waste management. The NEA emphasises the importance of optimising waste management plans by considering environmental, economic, and societal aspects and coordinating with all stakeholders. Furthermore, the Nevada National Security Site (NNSS) in the United States plays a crucial role in the permanent disposal of low-level and mixed-level radioactive waste, adhering to stringent regulations and criteria to safeguard the public, workers, and the environment.

Natural radiation background

The biggest source of natural background radiation is radon, a radioactive gas that emanates from the ground. Radon is a decay product of uranium, which is found in the Earth's crust and in ore-bearing rocks. It seeps into the atmosphere, groundwater, or buildings, and can be inhaled, posing significant health risks in certain areas. Radon levels can be influenced by factors such as weather and building construction, with poorly sealed dwellings or poor basement ventilation contributing to higher concentrations.

In addition to radon, other natural sources of background radiation include radionuclides present in rocks, soil, water, and air. These radionuclides, such as uranium and thorium, undergo radioactive decay, releasing radiation and forming other radionuclides like radium and radon. The radiation levels from these sources can vary depending on location and time, with factors such as elevation and ecosystem interactions influencing their distribution.

The worldwide average natural dose of background radiation to humans is about 2.4 mSv (240 mrem) per year, exceeding the average artificial radiation exposure. However, in some developed countries like the US and Japan, artificial exposure from medical imaging can surpass natural exposure. Nevertheless, natural radiation sources still contribute over half of the annual radiation exposure for an average person in the United States.

Some notable locations with exceptionally high natural background radiation levels include Ramsar in Iran, Guarapari in Brazil, Karunagappalli in India, Arkaroola in Australia, and Yangjiang in China. These areas may present potential health hazards due to elevated radiation levels.

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