Variability of the I131Concentrations in the Milk Distribution System of Large City

Late in 1962, when dairy products in New York City were contaminated with I131from U.S.S.R. nuclear tests then in progress, studies were made of the variability of the I131content of the milk from twenty-one of the milk processing plants in New York City. These measurements, which were made on 4 separate days, indicate that the variations from dairy to dairy were random in nature and that at the end of an extended period of sampling, such as 1 month, the mean concentrations of the milk from the various dairies would not have been significantly different from each other. It is concluded that during the period when the studies were conducted, the practice of analyzing single daily random samples of the milk of New York City provided a satisfactory estimate for the milk supply as a whole.