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

  • Various US federal and state agencies are responsible for routine monitoring of drinking water and certain foods, including milk, for the presence of various contaminants including radionuclides.
    • Which agency has jurisdiction depends on whether food, water, or milk is being monitored for contamination.
    • Enhanced monitoring may be done if radiation or other kinds of hazardous incidents occur.
    • Agencies also establish policies for intervening if certain levels are identified.
    • Federal and state entities (and other countries) may have different monitoring and intervention policies.
  • What is measured?
    • Level of radiation in food or water, in Bq/kg or Bq/liter; or pCi/kg or pCi/liter
  • How is the measured level of contamination used?
    • The goal is to detect levels of radioactive contaminants, which, if ingested, could lead to individuals or populations receiving a predetermined radiation dose (in units of rem or mSv) which should be avoided.
    • That predetermined dose to be avoided is known as the Protective Action Guides (PAG).
    • Various national and international organizations have studied risks from radiation, and their data have been used to establish PAGs.
  • Protective Action Guides (PAGs)
  • 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).
    • May include
      • Interdiction of foods, milk, and water
      • Shelter-in-place
      • Evacuation
      • Medical countermeasures, like potassium iodide
  • Note especially that
    • Different units are used to express
      • Levels of contaminants (in units of Bq/kg or Bq/liter; pCi/kg or pCi/liter)
      • Doses to people used in PAGs (in units of rem or mSv)
    • Various agencies and countries may have different
      • Allowable levels of contamination for specific isotopes in water, or milk, or food
      • Protective Action Guides (PAGs)
      • Methods of implementing Protective Actions
  • Derived Intervention Levels (DILs): set by the Food and Drug Administration (FDA)
  • Maximum Contamination Levels (MCLs): set by the Environmental Protection Agency (EPA)
  • 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
      • U.S. Environmental Protection Agency is no longer 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.