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Superfund Radiation Risk Assessment: a Community Toolkit

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Superfund Radiation Risk Assessment: a Community Toolkit United States Office of Superfund Directive 9230.1-48 Environmental Protection Agency Remediation and EPA -540-R-012-015 Technology Innovation May 2014 Superfund Radiation Risk Assessment: A Community Toolkit - 0 - Introduction This toolkit was developed by the U.S. Environmental Protection Agency (EPA) to help the public understand more about the risk assessment process used at Superfund sites with radioactive contamination. The toolkit is made up of a collection of 22 fact sheets that provide information that may be important to the risk assessment process for Superfund sites with radioactive contamination. Not all of these fact sheets will be useful at all sites. It is recommended EPA staff working on a site provide only the fact sheets that are useful for the public at that specific site. The fact sheets will also be available on the Internet for any interested members of the public. The fact sheets in this toolkit are: 1. Superfund Radiation Fact Sheet (10 pages) 2. Superfund Radiation Risk Assessment Fact Sheet (8 pages) Attachment A: Compendium of Information on the Preliminary Remediation Goal (PRG) and Dose Compliance Concentration (DCC) Calculators 3. Primer on EPA PRG and DCC Calculators (1 page) 4. Preliminary Remediation Goals (PRG) Calculator (1 page) 5. Dose Compliance Concentration (DCC) Calculator (1 page) 6. Building Preliminary Remediation Goals (BPRG) Calculator (1 page) 7. Building Dose Compliance Concentration (BDCC) Calculator (1 page) 8. Surface Preliminary Remediation Goals (SPRG) Calculator (1 page) 9. Surface Dose Compliance Concentration (SDCC) Calculator (1 page) Attachment B: Compendium of Information on Radionuclides Commonly Found at Superfund Sites 10. Primer on Radionuclides Commonly Found at Superfund Sites (2 pages) 11. Americium-241(2 pages) 12. Cesium-137 (2 pages) 13. Cobalt-60 (2 pages) 14. Iodine (2 pages) 15. Plutonium (2 pages) - 1 - 16. Radium (3 pages) 17. Radon (3 pages) 18. Strontium-90 (2 pages) 19. Technecium-99 (2 pages) 20. Thorium (3 pages) 21. Tritium (2 pages) 22. Uranium (2 pages) - 2 - Superfund Radiation Fact Sheet What is Superfund? The Superfund program is administered by U.S. Environmental Protection Agency (EPA) in cooperation with state and tribal governments. It allows EPA to clean up hazardous waste sites and to force responsible parties to perform cleanups or reimburse the government for cleanups led by EPA. For a variety of reasons, hazardous commercial and industrial wastes were mismanaged and may pose unacceptable risks to human health and the environment. This waste was dumped on the ground or in waterways, left out in Superfund is the informal name for the the open, or otherwise improperly Comprehensive Environmental Response, managed. As a result, thousands of Compensation, and Liability Act (CERCLA). hazardous waste sites were created In 1980, Congress enacted CERCLA in throughout the United States. These response to growing concerns over the hazardous waste sites commonly include health and environmental risks posed by manufacturing facilities, processing hazardous waste sites. This law was plants, landfills, and mining sites. enacted in the wake of the discovery of chemically contaminated toxic waste Superfund was established in 1980 by an dumps such as Love Canal and Valley of act of Congress, giving EPA the funds and the Drums in the 1970s. authority to clean up polluted sites Some Superfund sites contain radioactive Goals of Superfund: contamination. This document was Protect human health and the developed by EPA to answer questions environment by cleaning up polluted sites about radiation hazards and how EPA Involve communities in the assesses health risks from potential Superfund process exposure to radioactive contamination at Make responsible parties pay for Superfund sites. work performed at Superfund sites - 1 - What are atoms? An element is a specific type of atom. All atoms of an element have the same To understand radiation and number of protons. For example, all radioactivity, it is important to atoms of oxygen have eight protons, understand atoms. while all uranium atoms have 92 protons. Atoms are the very small particles that It is possible for atoms of the same make up our bodies and everything element to have different numbers of around us. Atoms consist of a central neutrons. These various forms are called nucleus made up of protons and isotopes. For example, while all atoms of neutrons. Protons are positively charged, oxygen have eight protons, isotopes of while neutrons have no charge. Electrons oxygen can have from four to 16 have a negative charge and orbit (or go neutrons. around) the nucleus. Most atoms are What is Radiation? neutral, which means they have the same number of protons and electrons. Atoms Radiation is energy that travels in the that are not neutral are called ions. form of waves or high-speed particles. There are two types of radiation: Atomic Structure Non-ionizing radiation is low energy. Neutron It includes radio waves, microwaves, and visible light. Non-ionizing radiation can generate heat, but it does not have enough energy to remove electrons from atoms. Ionizing radiation is high energy. It can remove tightly bound electrons Proton from an atom. Ionizing radiation can Electron be harmful to humans by damaging An atom consists of a central nucleus (made living tissue and increasing cancer risk. of protons and neutrons) orbited by X-rays are a familiar form of ionizing electrons radiation. - 2 - blocked by a piece of paper or by skin. Common Types of Radiation However, radionuclides that give off alpha particles can be very harmful if they enter your body in other ways such as through the air, food, or water because your internal organs are not protected by skin. Beta particles are light weight, relatively fast moving particles. They can be blocked by a thin piece of metal or wood. Beta particles can penetrate (pass through) the outer layer of skin and cause radiation burns. Like alpha particles, beta particles can damage your health if In this fact sheet, the term “radiation” they enter your body. will mean ionizing radiation. Gamma rays are waves of pure energy What is Radioactivity? that often accompany beta and alpha particles. Gamma rays can pass Some isotopes of certain atoms are through the body and damage internal unstable. When these unstable atoms organs. A thick wall of metal or release ionizing radiation in the form of concrete is needed to absorb gamma waves or particles, it is called radiation. radioactivity. A radioactive atom is called a radionuclide. When a radionuclide Radiation Penetrating Power emits (gives off) radiation, it is said to decay. There are three main types of radiation given off when a radionuclide Alpha decays: Beta Alpha particles are heavy, relatively Gamma slow moving, particles. They can be Paper Wood Concrete - 3 - Ionizing Radiation Found at Superfund Sites Alpha Particles Beta Particles Gamma Rays Two protons and two Made up of an electron Pure energy traveling neutrons bound together ejected from nucleus at the speed of light into a single particle Fast moving, low mass Often accompanies Description Heaviest and slowest particle the emission of alpha moving type of ionizing Negatively charged or beta particles radiation Has no rest mass and Positively charged no charge HIGH MODERATE LOW Interacts strongly with Interact less strongly Since they have no Ionizing surrounding material than alpha particles but mass and no charge, Very energetic more strongly than gamma rays interact Power gamma rays with with matter less than surrounding material alpha and beta particles LOW MODERATE HIGH Travels no more than a Able to travel several Able to travel few centimeters in air meters through air hundreds of meters Penetrating Can be stopped by a sheet Can be stopped by a through air Power of paper thin layer of metal or Can be stopped by a Unable to penetrate skin plastic thick concrete wall Can penetrate outer Able to pass through layers of skin the human body No health effects from Can cause skin burns Can cause harm from external exposure since from external exposure external exposure they are unable to Harmful if taken into Can pass into the Human penetrate skin the body (though not body and cause Health Very harmful if alpha- usually as harmful as internal radiation Effects emitting radionuclide is alpha particles) exposure taken into the body by ingestion,r breathing, or through an open wound - 4 - What happens to radionuclides as they decay? As radionuclides decay, they become new elements called daughter products, which are also known as decay products. These daughter products may or may not be radioactive themselves. If a daughter product is also radioactive, it in turn will decay to form a different daughter product. This process will continue until a measure activity. One curie is 37 billion stable, nonradioactive product is formed. decays per second. This unit is too large The radioactive decay of a radionuclide and all of its daughters is known as a to use at most Superfund sites to assess radiation risk, so EPA usually uses a unit decay chain. called a picocurie. One picocurie is equal What is half-life? to one trillionth of a curie, or about 2.2 radionuclide decays per minute. The rate a radionuclide decays is its half- life. Half-life is defined as the amount of EPA measures radioactive contamination time it takes for half of the amount of a by the number of picocuries measured in substance to emit radiation and change a specific amount of contaminated to a different substance. Radionuclide material. Soil contamination, for half-lives can be very long or very short. example, is measured in picocuries per For example, uranium-238 has a half-life gram. of 4.5 billion years, while carbon-11 has a Why are radionuclides harmful to half-life of only a few minutes.
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