Table 3. Levels and decay rates of beta radioactivity of Rongelap- Ailinginae plankton, 1954-1957 Plankton net Number Meshes Mate- eter Date of desigper rial of net collect__ nation inch inches ing P late No. Atoll Island 8201 8202 8303 8239 8240 19005 Rongelap " " " " " Labaredj " " Kabelle " " 19006 " "W 19019 19020 19024 " " " Labaredj " Rongelap 19026 19027 19028 " " " 19030 19031 19067 19068 " " " " 19070 19071 " Ailinginae 19025 19029 19069 " t " Diam - 12 " " 6 20 6 or 20 tt 125 " " 74 173 -- -- ? ? ? Silk " ? ? ? 20 20 " 20 "1 tt Dateof first counting 3-26-54 " " 7-16-54 " 12-8-54 rt First count in uc/kg* Ash Wet basis basis 5-11-54 83 " 2330 " 4000 8-11-54 68 " 46 . 1-3-55 tt 168 168 Decay slope from date of first counting to October 30, 1957 -140 2.1 2.7 - 6.2 - 1.75 10.4 - 1.08 1.32 1.27 1.32 1.33 1, 35 ** 6 20 6 74 173 74 " " " " " " 12-18-54 " 1-26-55 " " 2-22-55 104 32 25 5.0 3.9 54 - 1.72 - 1,73 - 1,68 Labaredj " Kabelle 6 20 6 74 173 74 " " " " " " 1-28-55 " 1-29-55 " " " 27 12 58 .93 41 1.8 - 1.56 - 1.55 - 1.61 - 1. 61 Lukuen " Kabelle " 6 20 1 2 74 173 74 157 1.5 4.4 20 . 18 - 1.70 1.70 1.76 1.72 2 157 1 74 "1 't Rongelap " MojiriEnibuk 20 20 1 173 173 74 tt ft " " Nylon " it Ht " " " " " " " " " " "I " " " 1-30-55 " " " .10-21-55 11-26-55 " " 10-22-55 " 10-23-55 " " " 24 93 37 95 6.4 6.9 2.1 2.0 4.5 95 5. 8 .044 . 047 . 70 _ - lL. 72 .73*** - 1.38 - 1.58 1 rr & '