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Monitoring Radionuclides in Drinking Water and Food: Routinely and After a Release

General Information


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What are Protective Action Guides and Protective Actions?

  • Protective Action Guides (PAGs)
    • PAGs (specific dose levels) and contamination limits and are used together as guides which help officials in emergency conditions recommend Protective Actions that will avoid or minimize accumulation of a projected radiation dose either
      • Over a lifetime of chronic intake or
      • From a single acute exposure
    • May refer to a projected dose absorbed by
      • The whole body, or,
      • A specific organ, like the thyroid
    • May vary by age group, and are usually lower for children and infants
    • The PAGs are intended to
      • Prevent short-term health effects
      • Balance protection with other important factors that may arise during an emergency (ensuring the actions result in more benefit than harm)
      • Reduce the potential for absorbed doses (mSv) to result in long term health effects, i.e. pulmonary fibrosis.
  • Protective Actions
    • Are formal prevention or mitigation strategies recommended by officials to reduce or avoid the chance of individuals or populations reaching a PAG (dose level).
    • Methods of implementing Protective Actions may include
      • Interdiction of foods, milk, and water
      • Shelter-in-place
      • Evacuation
  • Prophylactic use of a Medical countermeasures to block uptake in, for example, the thyroid, by use of potassium iodide (KI)
  • Implementation of regulations and guidance
    • Various public and private agencies, government entities and countries may have different
      • Allowable levels of contamination for specific isotopes in water, or milk, or food
      • Assigned radionuclide limits in their specific Protective Action Guides (PAGs)
    • See EPA PAG Manual 2017 about how implementation is planned.

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The 2017 EPA PAG Manual Includes Drinking Water Guidance

  • PAG Manual: Protective Actions Guides and Planning Guidance for Radiological Incidents, EPA-400/R-17/001 (PDF - 1.48 MB) (EPA January 2017)
    • This 2017 PAG Manual includes new drinking water guidance entitled “Protective Actions for Food and Drinking Water
      • See Chapter 4, Section 4.6, pages 53-62
      • Chapter 4 discusses Intermediate Phase of Protection Actions
      • See page 53-54 of the PAG manual for discussion of FDA role in food surveillance, EPA role in water surveillance and how they 2 jurisdictions work together.
  • Federal Register announcement about the new drinking water guidance.
  • Selected concepts from the drinking water section of the PAG (see page 53)
    • EPA developed a new drinking water PAG as non-regulatory guidance to protect the public in the event of a radiological incident that affects drinking water supplies.
    • The drinking water PAG will help federal, state, local and public water system officials make decisions about use of water during radiological emergencies.
    • The PAGs are not legally binding regulations or standards and do not supersede any environmental laws.
    • The purpose of the protective action for the drinking water exposure pathway is to
      • Restrict the use of contaminated water for drinking
      • Provide recommendations for local communities to consider in providing alternative drinking water for the affected community during a nationally significant radiological incident, such as a disaster at a nuclear power plant, an RDD or an IND.
  • The drinking water PAG is for use only during an emergency
    • It is not a substitute for compliance with EPA’s National Primary Drinking Water Regulations (NPDWRs) for Radionuclides.
    • The drinking water PAG is not binding and does not in any way affect regulatory requirements or enforcement of the Safe Drinking Water Act (SDWA), including maximum contaminant limits (MCLs) for radionuclides established by regulation under the SDWA. See also EPA PAG Manual 2017, page 63
    • The drinking water PAG is guidance only and is intended for use by federal, state and local emergency management officials in the unlikely event of significant radiological contamination incidents, such as a disaster at a nuclear power plant, a radiological dispersal device or an improvised nuclear device, and for a duration which may last for weeks to months but not longer than one year.
  • EPA expects that any drinking water system adversely impacted during a radiation incident will take action to return to compliance as soon as possible.
  • The drinking water PAGs apply during the intermediate phase of an incident, which may last for weeks to months but not longer than one year.
  • This guidance only provides recommendations and does not confer any legal rights or impose any legally binding requirements upon any member of the public, states, or any other federal agency.
  • The PAG includes both EPA guidance and other standards as wells as guidance about how to interpret and apply the PAG guidance
  • Key details from the EPA PAG document
    • EPA recommends a two-tier drinking water PAG for use during the intermediate phase of an incident following a nationally significant radiation incident: see page 53 of 2017 PAG document
      • 500 mrem (5 mSv or 0.5 rem) projected dose for the general population (defined as anyone over age 15, excluding pregnant women and nursing women)
      • 100 mrem (1 mSv or 0.1 rem) projected dose for pregnant women, nursing women and children age 15 and under
    • Intermediate phase doses can be projected using a 1-year duration and compared to the PAG so that actions can be taken to avoid the cumulative exposure.
    • PAG levels were calculated based on a maximum 1-year exposure and provide a level of protection roughly equivalent to applicable National Primary Drinking Water Regulations (NPDWRs for radiation), which are based on 70 years of exposure ("a life span").
  • Key EPA Information about radionuclides and drinking water for specific audiences
  • Key regulatory concepts
    • Safe Drinking Water Act (SDWA)
    • Maximum Contaminant Levels (MCLs): set by the Environmental Protection Agency (EPA)
      • Maximum Contaminant Level (MCL): An enforceable standard established to protect the public against consumption of drinking water contaminants that present a risk to human health.
      • A MCL is the maximum allowable amount of a contaminant in drinking water that is delivered to the consumer. Is the "maximum permissible" level of a specific contaminant, including specific radionuclides, in water delivered to any user of a public system
    • Derived Intervention Levels (DILs): set by the Food and Drug Administration (FDA)
      • Derived Intervention Level (DIL): A set level (concentration) at which a required intervention is considered or introduced as protective measures.
      • When FDA tests food for radioactive contamination, it measures how much radiation is emitted by radioactive materials that are not naturally occuring (expectant).
      • Unit of measure is typically Bq/kg.
      • FDA uses DILS, a calculated value, to enhance food safety.
        • It is not an arbitrary level that distinguishes between safe and unsafe food.
        • It is one way to estimate the potential for increased risk (of cancer) if enough of a contaminated food is eaten over time (a cumulative exposure) to reach the established PAG.
        • Even if someone were to consume a food contaminated to the level of a DIL for a whole year, they would not likely receive the PAG dose because of the conservatism built into the calculation of the DIL.
        • DIL is one factor FDA uses to help decide whether intervention may be recommended.
      • Published DILs are specific for each radionuclide.
      • The criteria used to set DILs include the
        • Percentage of potentially contaminated foods in a person's diet
        • Amount of food typically eaten
        • Length of time that a person may be expected to eat contaminated food
        • Potential exposure to contaminated foods of different members of the population, including infants and children.
      • In general, DILs apply to all foods.
        • FDA does not have different DILs for different types of food, though DILs may be adjusted based on, for example, whether a food must be rehydrated before being ready to eat.
    • Monitoring of milk
      • FDA's Food Sampling Programs
        • The FDA's Office of Regulatory Affairs collects and analyzes food, including milk, for radionuclides under two programs:
          • Total Diet Study (TDS) or "Market-Basket Survey"
            • Four types of milk (whole, skim, low-fat, and chocolate), as well as other dairy products, are analyzed at least once a year for radionuclides.
            • Food samples from grocery stores and restaurants are collected in cities throughout the country.
            • More information on FDA's TDS.
          • Toxic Elements in Food and Foodware, and Radionuclides in Food Program
        • The extent of FDA's milk sample collection and analysis during an emergency would depend on the nature and scale of the event. The FDA's Office of Crisis Management (OCM) serves as the agency's focal point for coordinating emergency and crisis response activities involving FDA regulated products.
      • EPA no long samples milk for radionuclides
        • EPA stopped sampling milk as part of the radiological monitoring network, RadNet, as of November 3, 2014.
        • EPA completed its final quarterly milk sample collection in April 2014, and the results from analyzing those samples, along with historical milk sampling results, will continue to be available on Envirofacts.
        • EPA is stopping milk sampling because it is redundant of U.S. Food & Drug Administration programs, and FDA has the authority/responsibility for food safety, including monitoring radiation in milk.