ESOP collects quarterly dairy milk samples to determine if radionuclides have been ingested by dairy cows. Exposure to radionuclides could be the result of atmospheric releases depositing chemicals on pastures, pastures being irrigated with contaminated groundwater, or plants growing in soil contaminated with radioactive materials.

Fresh milk samples are provided by multiple dairy farms located within a 50-mile radius of the SRS’s center (Dairy Milk Monitoring locations). Milk samples are analyzed for tritium, selected gamma-emitting radionuclides, and strontium. Strontium is of concern due to its ability to act as a chemical analog to calcium in the human body. By being an analog to calcium, it will act similarly and will be stored in bone tissue.