-18- SUMMARY 1. Surveys were made in 1954 to 1958 to determine the geographical limits of the radioactive contamination from the tests in the central Pacific Ocean. 2. Collections of biological samples and soils were made at one test site island 3. (Bikini) and ten "off-site" islands. The gross beta radioactivity decreased with distance from the test site; in 1956 and 1958 islands within a 130- mile radius contained at least ten times as much radioac- tivity as the other islands. 4. The levels of radioactivity also were related to direc- tion from the test site. In 1955 the islands to the east contained high levels of radioactivity. Tarawa, In 1956 and 1958 800 miles southeast of the test site, low levels whereas Kapingamarangi, distance to the southwest, amounts of radioactivity. contained very approximately the same contained significantly higher DOE ARCHIVES radioisotopes present in the majority of the samples. F