The U.S. Geological Survey established a sampling program on Amchitka Island in 1967 in cooperation with the U.S . Atomic Energy Commission. Water samples are analyzed routinely for tritium, gross alpha, and gross beta/gamma content, Frequency of sampling was semiannually prior to Cannikin and has been bimonthly since the Cannikin event (November 6, 1971). The sampling frequency will be quarterly for the remainder of the first year (through November 1972). Sampling frequency will be changed to an annual basis approximately 1 1/2 years after the event.
The techniques and procedures used for sample collection, identification, and analysis are described in Beetem, Washington, Janzer, and Schroder (1971) and in Schroder (1971), Radiochemical data obtained from samples analyzed by the U.S. Geological Survey through November 1970 are reported in Beetem, Washington, Janzer, and Schroder (1971), Radiochemical data obtained from samples analyzed by the U.S. Geological Survey from September 1971 through December 1971 and January 13 through April 5, 1972, are reported in Schroder and Ballance (1972a,b). This report presents the radiochemical data from samples collected during July 1972,