Question

During the Three Mile Island incident, people in central Pennsylvania were concerned that strontium-90 (a beta emitter) released from the reactor could become a health threat (it did not). Where would this isotope collect in the body? If so, what types of problems could it cause?

Short answer

Strontium-90 collects in the bones and can cause bone cancer or leukemia by damaging bone marrow.

Step-by-step solution

Understanding Strontium-90

Strontium-90 ( ^90Sr) is a radioactive isotope that is a beta emitter. It is similar to calcium in its chemical properties, which means it can interact with and replace calcium in the human body.

Relation to Human Body

Because of its similarity to calcium, Strontium-90 is likely to be absorbed into the body's bone structure. The body uses it as if it were calcium, incorporating it into the bones and teeth.

Potential Health Risks

Once inside the bones, Strontium-90 continues to emit beta radiation. This can damage bone marrow and potentially lead to serious health issues such as bone cancer and leukemia, as the bone marrow is responsible for blood cell production.

Key concepts

Radioactive Isotopes

Radioactive isotopes, also known as radionuclides, are atoms with unstable nuclei that lose energy by emitting radiation. This emission occurs as the isotopes attempt to reach a more stable state. There are three primary types of radiation these isotopes can emit: alpha, beta, and gamma radiation.
Strontium-90 is a classic example of a radioactive isotope. It has 38 protons and 52 neutrons, leading to an atomic mass of 90. Because its nucleus is unstable, it goes through decay, emitting radiation in the process. It's crucial to understand these isotopes because they are often byproducts of nuclear reactions, such as those occurring in power plants. These byproducts can have various applications in medicine and industry, but they can also pose significant risks to health if not properly managed.

Beta Radiation

Beta radiation consists of high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei, such as Strontium-90. Compared to alpha particles, beta particles are lighter and can penetrate materials more deeply.

• Beta particles can travel further than alpha particles but not as far as gamma rays.
• They can be stopped by materials like plastic, glass, or a few millimeters of aluminum.

Understanding beta radiation is important because, while it is less harmful externally compared to other radiation types, it can be very damaging internally. If an organism absorbs a beta-emitting isotope, the particles can cause damage to the cells and tissue where they accumulate, leading to potential health risks.

Human Health Risks

The absorption of radioactive isotopes like Strontium-90 poses significant health risks. When these isotopes enter the body, they can deposit in tissues and continue to emit radiation, causing cellular damage over time. This is particularly dangerous when the isotopes are mistaken by the body for necessary nutrients.
Common health effects associated with radioactive exposure include:

• Tissue and organ damage due to prolonged exposure to radiation.
• Increased risk of cancer, specifically bone cancer and leukemia, due to radiation's effect on living cells.
• Potential for acute radiation sickness if exposed to extremely high radiation levels in a short time.

Mitigating these risks involves minimizing contact or ingestion of radioactive materials, implementing clean-up measures after incidents, and monitoring radiation levels consistently.

Bone Marrow

Bone marrow is a crucial tissue found within bones, responsible for producing blood cells, including red blood cells, white blood cells, and platelets. It plays a vital role in maintaining healthy immunity and oxygen transportation in the body.
When radioactive materials like Strontium-90 are absorbed, they can become incorporated into the bone structure. The constant emission of beta radiation from such isotopes can damage the bone marrow. This leads to:

• Impairment in blood cell production.
• Suppression of the immune system, reducing the body's ability to fight infections.
• Increased risk of blood-related cancers due to the ongoing radiation damage to vital bone marrow cells.

Protecting bone marrow from radiation exposure is essential for overall health, emphasizing the need for stringent safety protocols in environments where radioactive materials are present.

Calcium

Calcium is a vital element for many biological processes, playing a key role in building strong bones and teeth, muscle function, nerve signaling, and blood clotting. It is predominantly stored in the bones.
Given Strontium-90's similarity to calcium, the body can misidentify it and incorporate it into the bone structure just like calcium. This substitution results in continuous exposure of the bone to radiation from the isotope. Since the bones act as a reservoir for calcium, any disruption in the balance or composition of this mineral can have profound health effects.
To protect against this, ensuring adequate calcium intake can help reduce the absorption of radioactive strontium. This is because the body is less likely to absorb strontium if it already has sufficient amounts of calcium to meet its needs.