oete . : arte tae tes bee ete Re alk is tah atte es tee Ba hake ee Loo thdayeBaeees re -7- RESULTS of ‘3 also ally me of etona- hey Plan of presentation For each of the ten primary subjects of investigation (survey meter readings, soil, water, plankton, algae, land plants, invertebrates, fish, birds, and rats), the trends or declines are shown graphically, and in some cases also in tabular form. For all subjects the regressions along with relevant data are brought together in Table 1. Where available the pre-Nectar level appears near the left edge of the decline graph as either a short horizontal bar or wedge. For the straight lines depicting the declines where linearity appears to prevail, the time span involved is stipulated in Table 1 as well as being shown by the abscissal range of the lines in the graphs. For conversion between microcuries and disintegrations per minute the following relationship was employed: luc = 2.2 x 10° d/m. The log-log regression line is determined by its slope and y-intercept on day number 1, according to the relationship: Y= at? where Y is the amount of radioactivity at time t in days after assumed detonation day, and a is the y-intercept expressed in units of radioactivity of the regression line of slope b on day number 1. For example, the second entry in Table 1, survey meter readings at Belle, graphed in Figure 3, involved observa- tions on 16 days over the period 5-540 days after Nectar. regression was - The Y= 2.5 x 103 t7l-)4 opr, with a correlation of -.971, which is far beyond the 1% level of P. Along with decline data, available decays for as nearly Simultaneous periods as possible are presented for comparison. Decays start later than declines because declines were corrected back to date of collection, while decays are for the actual . dates of counting. On the decay graphs the ordinate represents gross beta plus the negligible alpha and gamma activity that would be detected. Decay curves even on the same graph sare not comparable to one another as to absolute levels, because of vertical shifting to obtain compact presentation, but may be compared as to slope. gp ARCH ee 1 ow