Mean 40% concentration TOL 2oO O — 5 7 | . A 137, - entire fish B 3 v 1.0bR © 2 0.5- c 0.3 —— i= eviscerated whole fis E 207, ; e a h | fi a h 7 2 a ec = o 2 7: = viscera 7 6 “oO 155 Eu D 207, - viscera 5 £ - IS5ey - eviscerated whole fish Cc 2 ~ J Column legend =a bs OF FIL 7 hr r ry m7 I pa | a ry ba z © 0.05g jd =~ 0.03 - hs = = 4 { 0.0) LUAIBICHOLE] TARsichodel tafetctcte)Ags tcpfeh Pap atcfope) AgegCJOFE] AB POVEY Av etcporey BELLE RENE JANET URSULA YVONNE DAVID FRED HENRY PAL FIFE LERCY Collection site Fig. 160, Average 13Tog levels (av 15 pCi/g). and 207; concentration in convict surgeon from but 25 pe, 1972. The 40k value is the mean for 9 No 69 Go, 207 Bi, or 155.) were observed, 9055, 155 Enewetak Atoll, October to December, all convict surgeon samples, 800 and 2075; data for the two collection 137 a5 and 239, 240 by were found in some periods, The effective half-life of 2.7 yr for 8005 {radioactive decay half-life or all of the samples, usually at levels 5.24 yr) and 5.1 yr for 207 Bi {radioactive comparable to the lower values found at decay half-life 30 yr) implies an effective Enewetak. half-life in the ecosystem for both isotopes As. with the plankton, comparison of of about 5-6 yr. data obtained from this survey with similar Of the marine invertebrates present at data from samples taken in 1964 indicates Enewetak, tridacna clams, Sea cucum- that, for some nuclides at least, there are bers, spiny lobster, and top snails were processes operating to reduce concentra- collected and analyzed, tions in the lagoon faster than is expected 806 was the most abundant radioisotope from radioactive decay alone, found, and it was present in higher Table 220, In the tridacna, amounts in the kidney than in the viscera, for example, presents a comparison of I-24