What is Radon Toxicity?
Radon is a radioactive gas and a significant source of radiation that humans can be exposed to. It’s the leading cause of lung cancer for those who don’t smoke, and is estimated to cause about 21,000 deaths each year. The World Health Organization suggests that 3-15% of all lung cancer worldwide is due to radon exposure.
What makes radon especially dangerous is that it’s tasteless, odorless, colorless, and doesn’t show any immediate signs of exposure. It naturally occurs from the breakdown of uranium-238 and radium-226 in soil, rocks, and the ground. This gas can also be found in homes, particularly in basements, due to its long half-life of 3.5 days. This period allows the gas to spread and build up around the house, especially in areas with poor ventilation. Radon can also be found in water, further increasing the chances of exposure.
Radon is a dense, highly radioactive gas capable of damaging the lining of our lungs by emitting alpha particles. Studies have found a clear link between high radon levels and an increased risk of lung cancer. In fact, in 1988, the International Agency for Research on Cancer recognized radon and its byproducts as top-tier carcinogens.
Since radon can’t be seen, tasted, or smelled and doesn’t cause immediate symptoms, the only way to know if there’s a high exposure level is by measuring it. Reducing radon levels in the home can decrease the risk of exposure and hence, development of cancer caused by radon radiation.
What Causes Radon Toxicity?
Radon is a highly radioactive element that was first discovered in 1899 by Ernest Rutherford, a physicist in England. Radon is a natural gas found in rocks and soil and comes from the decay of uranium and radium. It’s the main source of natural ionizing radiation or radiation that can remove tightly bound electrons from the orbit of an atom, often causing it to become unstable.
Radon is an inactive gas and it’s the heaviest known gas—nine times denser than air. Being a single-atom gas, it can penetrate easily through materials like paper, leather, plastic, concrete, wood, and insulation. Radon exists in several types, but the two most common ones in the environment are radon-220 and radon-222.
Radon-220, also known as thoron, comes from the decay of thorium-232 and it only lasts for 55 seconds. On the other hand, radon-222, which comes from the decay of radium-226, lasts for 3.8 days, making it the most stable and common type of radon. Because of its longer existence, radon-222 can infiltrate homes from the environment.
Although radon-222 isn’t dangerous in itself, when it decays further into Polonium 218 and 214 and emits alpha particles, things become risky. These alpha particles can damage our DNA. The next elements in the decay chain of radon-222 are more chemically active, often called “radon daughters”. They are usually the primary source of our exposure to alpha radiation. This exposure can lead to cellular injury and DNA damage in our respiratory tract, which can trigger radon-induced lung disease, and if prolonged, lung cancer.
We primarily get exposed to radon through breathing it in and consuming it. As radon is present in groundwater, soil, rock, and enclosed spaces, like buildings and basements, we are at risk of exposure from several sources, including the ground, gas appliances, water supply, or an inward flow of air in our homes. Natural gas also contains radon; thus, when burned in furnaces, fireplaces, heaters, and stoves, radon can be released into the air. The most worrisome health risk comes from inhaling radon because it directly damages the cells lining our respiratory tract.
Risk Factors and Frequency for Radon Toxicity
Radon exposure is a global issue that affects both our environment and health. Recent studies have shown that radon has severe consequences in different parts of the world. For instance, Armenia has the highest levels of radon, contributing to around 29% to 30% of lung cancer cases. Radon is less prevalent in Japan, accounting for about 4% of lung cancers. In the United States, radon is responsible for about 9% to 13% of lung cancer cases. It used to be believed that areas with cold climates had higher radon exposure because people stayed indoors for longer, but changes in the weather and the widespread use of air conditioning have altered these patterns. High radon levels in a specific area depend on several factors, including the amount of radon in the environment, how easily it can seep into enclosed spaces or water sources, its concentration levels, and human behaviors that increase exposure.
In the United States, radon levels vary, with some states requiring a disclosure of radon levels when selling a home. North Dakota and Iowa, in particular, have notably higher levels. The United States Environmental Health Protection Agency (EPA) has created a map to show the areas of high radon levels across the nation, divided into three zones. However, regardless of the zone, the EPA advises everyone in the United States to check their homes for radon levels.
- Zone 1 includes areas with predicted radon levels greater than 4 pCi/L.
- Zone 2 includes areas with predicted radon levels between 2 to 4 pCi/L.
- Zone 3 includes areas with predicted radon levels less than 2 pCi/L.
Those in the mining and construction industries, particularly those working in confined spaces, are more at risk of radon exposure. This link between radon exposure and lung cancer was first found in the mining community. Recent studies have shown that uranium miners are at especially high risk, though appropriate ventilation can help reduce this risk.
In addition, radon exposure is the second leading cause of lung cancer in the US and the leading cause among non-smokers. You are even more at risk if you are a smoker exposed to radon, with an estimated 10 to 20 times greater risk of developing lung cancer. Children are also more at risk due to their small lung sizes and faster breathing rates which can cause higher radon inhalation.
In the 1930s and 1940s, a contrast agent called thorium dioxide, popularly known as thorotrast, was used and considered safe. This agent was key to performing angiographies due to its high radiodensity. However, it was found to decay into thorium-232 and then radium-228, leading to the release of alpha particles throughout a key system in our body. This lifetime exposure to radiation eventually led to the development of various cancers, causing thorotrast to be pulled off the market.
Signs and Symptoms of Radon Toxicity
Lung cancer can be caused by several risk factors, such as being exposed to radon, having relatives with lung cancer, smoking cigarettes, or being around secondhand smoke. To evaluate a person’s risk of getting lung cancer from radon exposure, it’s important to get an accurate account of their experiences, which might include:
- Their job, especially if they’ve ever worked somewhere with limited ventilation or where they could have been exposed to radon (like miners, builders, excavation workers)
- The year their home was built and its age
- Their family’s health history, focusing on cases of lung cancer
- Being around smoke either at home or at work
- Their home appliances that use gas
- Any measurements of radon in their home
- The amount of time they spend in enclosed spaces like basements
- The ventilation system in their home
Prior health issues can also help in forming a diagnosis. It’s important to note if they’ve had lung diseases before, because radon directly affects the lungs. It’s challenging to recognize radon exposure because it doesn’t really cause distinct symptoms. Since being exposed to high radon levels can lead to lung cancer, the physical checkup should mainly focus on signs of lung cancer. Although these signs are not specific to radon exposure, these can guide a health professional in making a diagnosis.
These signs may include:
- Shortness of breath
- Wheezing
- Coughing up blood
- Coughing
- Chest pain
- Weight loss
There could also be some signs related to lung cancer, such as swollen lymph nodes in the upper chest and lower neck area, unusual nail shape (clubbing), or repeated episodes of pneumonia. Based on the symptoms and the person’s history, the health professional will decide the next steps for evaluation, which may involve more tests or consultations with specialists.
Testing for Radon Toxicity
Exposure to radon gas over a long period of time can lead to lung cancer. Every year, around 21,000 deaths are thought to occur from lung cancer that’s caused by radon. In fact, radon is believed to be responsible for between 3-15% of all lung cancers across the world.
What makes radon particularly dangerous is that you usually don’t notice any symptoms or warning signs from being exposed to it. Therefore, it’s important for doctors to check for radon toxicity in patients, particularly if their medical history or physical examination suggests that they could have been exposed to radon.
The National Comprehensive Cancer Network suggests that people who are over 50, who have a history of heavy smoking (a minimum of 20 packs a year), and who have been exposed to radon should have a low-dose CT (computed tomography) scan. A CT scan is a type of X-ray that gives detailed images of the inside of the body.
However, the American Academy of Family Physicians has stated that they’re not sure whether using low-dose CT scans to check for lung cancer in people who are high risk is a good idea or not. Likewise, the United States Preventive Services Task Force, another medical organization, hasn’t found any clear benefits from using screenings to catch lung cancer early in people who don’t show symptoms.
There’s still a lot we don’t know, and more studies are needed to figure out the best way to check for lung cancer in people exposed to high levels of radon. In the meantime, doctors can use a combination of physical examinations, medical history reviews, chest X-rays, CT scans, and evaluating samples of mucus that’s coughed up from the lungs (known as sputum cytology) to help them make a diagnosis.
Treatment Options for Radon Toxicity
Radon is a harmful gas that can cause severe health problems. It’s invisible and odorless, so the only way to know if it’s in your home is by testing. The key is preventing exposure to radon as its harmful effects can’t be seen or felt immediately.
Radon levels are usually measured in units called “picocuries per liter of air”, or pCi/L. On average, outdoor air has about 0.4 pCi/L of radon, and it’s recommended that the levels indoors should never be higher than this. However, as radon gases can build up inside houses, it’s crucial to test regularly to make sure the levels are not too high.
Thankfully, checking your home for radon is an easy and affordable process. A small kit called a caracole canister can be used to measure radon levels. If these levels reach or exceed 4 pCi/L, the Environmental Protection Agency (EPA) advises on lowering them as soon as possible.
There are several methods to reduce radon levels in your home. The EPA suggests hiring a trained professional to help assess and manage radon levels. Some techniques are designed to prevent radon from entering the home in the first place, while others can lower levels even if radon is already present. A common approach is soil suction, where radon is pulled out from under the house and vented into the outside air where it dissipates.
Different types of soil suction methods are suitable depending on the structure and construction of your house. Homes with basements or built on concrete slabs can benefit from methods like sub-slab suction, drain tile suction, sump hole suction, or block wall suction.
For instance, in sub-slab suction, suction pipes are installed under the floor or from outside the house, below the concrete slab. A fan attached to the pipe then sucks radon from under the house and releases it into the air. This technique can reduce radon levels by up to 99%.
Properties with a crawlspace typically use a method known as submembrane suction. This involves covering the floor with a plastic sheet, then using a pipe and fan to pull radon from underneath the sheet and vent it outside.
Besides soil suction, other methods can also help reduce radon levels. These include sealing cracks, increasing pressure inside the house or basement to prevent radon from entering, installing a heat recovery ventilator to improve ventilation, and natural ventilation by opening windows and doors periodically. However, these methods should be seen as supplementary as they may not significantly lower radon levels alone and the effect is often temporary.
It’s important that all homes are regularly tested for radon levels. If you’re building a new house, consider incorporating radon-resistant features during construction, and have it tested before moving in to ensure radon levels fall below the recommended 4 pCi/L.
What else can Radon Toxicity be?
When doctors are making a diagnosis, they need to consider all possible health conditions that could be causing the symptoms. This process is called differential diagnosis. Here, they would need to rule out:
- Lung cancer (including types like small cell carcinoma, adenocarcinoma, large cell carcinoma, and squamous cell carcinoma)
- Pneumonia
- Bronchitis
- Leukemia
They have to carefully examine the patient and conduct any necessary tests to make the correct diagnosis.
What to expect with Radon Toxicity
Radon, often referred to as a “silent killer,” causes approximately 21,000 deaths each year in the United States. The tricky part about radon exposure is that symptoms typically don’t appear until years later when signs of cancer start to show. For this reason, it’s usually hard to predict the outcome of radon exposure.
However, research estimates that if the radon levels could be reduced below 4 pCi/L (that’s a measure of radioactivity), it could potentially reduce the death rate from lung cancer by 2 to 4%.
Possible Complications When Diagnosed with Radon Toxicity
Exposure to radon has been linked with several health problems, including the following:
- Lung cancer
- Frequent infections
- Emphysema
- Pulmonary fibrosis, which is a disease that causes scarring in the lungs
- Increased risk of Alzheimer’s disease
- Pleural effusion, which is a condition where excess fluid builds up in the lung
- Metastasis, this is when cancer spreads from where it began to other parts of the body
- In severe cases, radon exposure can lead to death
These effects as noted, can result from long-term exposure to radon.
Preventing Radon Toxicity
The US Environmental Protection Agency (EPA) advises everyone selling or buying a home to check the level of radon inside their homes. Radon is a type of gas that you can’t see, taste, or smell, and it can be harmful if its levels are too high. Areas with high radon levels sometimes even have a law that makes these checks mandatory. In fact, it’s interesting to know that 34 states have specific rules about radon and its harmful effects. About 29 states insist that people must talk about the radon levels and most recent checks when they are selling a house.
There are 9 states that demand that every new house built must be designed to resist radon. Do you know that around 1986, the EPA decided on a certain level above which immediate action should be taken to reduce the radon level inside homes? That level is 4 pCi/L.
The best way to deal with the harmful effects of radon is by making everyone aware and working towards preventing high radon levels. So, if you’re buying a new home, don’t forget to ask about the latest radon checks, especially if you are in a state known for having high radon levels. If you already own a house and are worried about the levels of radon inside, you should get a contractor to check the levels for you. It’s a simple process but you’ll find a lot of peace in knowing your house is safe. The EPA’s website has lots of helpful resources where you can learn more about radon and get help for homeowners.
