A survey of environmental radioactivity measurements in the United States

A survey of selected radiochemical laboratories in the United States was conducted to estimate the relative numbers and types of analyses performed nationwide for the measurement of environmental radio-activity and to identify the regulatory requirements which affect the selection of analytical procedures and media. Information was sought from each laboratory regarding its parent facility, whether the laboratory performs its own analyses or contracts them out, and the technical and regulatory requirements for which the laboratory performed analyses.Analyses of water, air-particulate, and soil and sediment samples contribute the greatest workload. Many fewer vegetation, milk, diet, gas, or bioassay samples are processed. The most common measurements, especially for water, are for gross-α and gross-β activity. More than 50 different specific-radionuclide analyses are being performed with varying degree of regularity by the 161 laboratories surveyed. γ-spectrometry is the most frequently used method for specific-radionuclide analyses; the use of Ge (Li) detectors for γ-spectrometric measurements now exceeds that of NaI (Tl) detectors. Other radionuclides for which specific analyses are frequently performed by a large percentage (25–75%) of the laboratories include ⁹⁰Sr, ¹³¹I, ²²⁶Ra, ^238,239Pu, ^234,235,238U, and tritium in water (HTO).