soluble calcium-strontium fraction, which is known to be actively absorbed by living plants. The marked difference between the percentage of the calcium-strontium fraction found in the plants from Engebi and that found in the soils. indicates that the plants absorbed moreof this fraction than any of the other radioactive materials present in the soil. 4.6.5 Conclusions Analysis of the data obtained from counts made of 57 samples of land plants collected after Mike detonation shows a correlation between distance of collection area from Ground Zero and amcunt of radioactivity in the samples. On the basis of these data no clear-cut differences can be pointed out ag to the relative activity between species or between organs of a plant. The problems presented by surface contamination make further interpretations unreli- able. eu Table 4.15-—-RADIOCHEMICAL ANALYSES OF SOILS AND PLANTS, POSTSHOT* Fission product Ld 25.0 21.2 24.5 16.0 31.2 13.5 24.6 24.6 25.7 24.2 20.8 20.8 4.0 3.2 24.5 19.3 6.5 3.6 25.5 19.3 3.6 iL 19.8 $1.5 13.7 16.6 4.5 16.8 12.9 22.0 4.0 11.3 0 0 0 0 0 32.2 18.5 rare earths strontium mab Runit Rojoa Zirconium Ruthenium Barium Calcium and Cesium and Engebi plants — A ~ Triumfetia Sedge — Engebi Rigili Cerium Trivalent Soil —~. 3.0 rubidium was * Measured as the percentage of the total recovered activity. 4.7 LAND VERTEBRATES 4.7.1 Collecting Methods Attempts were madeto collect rodents and birds at each of the principal collecting sta- tions, although they were not always successful. Rats, Rattus exulans, were collected by setting live traps in the runways near the openings of the rat burrows. The traps were left overnight since these rats are, for the most part, nocturnal in their feeding habits. Openings to the burrows are found under and around clumps of wees grass or under beach magnolia bushes, Scaevola frutescens. These rats do not inhabit areas containing no plants. Rats were found on Engebi, Biijiri, and Rojoa prior to Mike detonation, .After the shot they were taken on Biijiri only and were ill and lethargic. There is little probability that any rats survived on Engebi because it was denuded by the heat and shock wave, then partly inundated by water waves from the blast, and had a radiation reading of 11 r/hr 2 in. from ground level for beta-gamma seven daysafter the detonation. That there was little chance of animals surviving is illustrated by the fact that the sole bird found on Engebi postshot had been blown to pieces by the shock wave. 49 ee pw UNCLASSIFIED - ~~ oe es 4 eo @