DETERMINATION OF THE RATIO OF TOTAL TRANSURANICS TO AMERICIUM IN THE CAPE MIXAN AREA, ISLAND SALLY DOE/ERSP TECH NOTE NO. 2.21 DATED: June 1978 AUTHOR: M. Barnes, DRI There were two distinct ratios of total transuranics (TRU) to americium in the Cape Mixan area on the western tip of Sally. Most of the area had a ratio from the same population as in the Yuma ground zero region. However, one small area had americium concentrations much higher than the remainder of Cape Mixan, and this small area was therefore soil-sampled intensively, The TRU to americium ratio in these soil samples was also much higher than for the rest of Cape Mixan. Figure B-2-5 is a map of Cape Mixan which shows the location of the anomalous area. Some of the soil samples in the anomalous area were composites of six subsamples each, taken at three depths, 0, 10, and 20 em. The locations and ratios for these samples are in Table B-2-5. The rest of the soil samples were single samples, not composites, and were surface only. These ratios and locations are in Table B-2-6. All of these ratios were included in computing a mean ratio and associated error for the small anomalous area, using the methods and assumptions referenced in Tech Note 2.2-A, The remainder of Cape Mixan had uniformly lower americium concentrations and soil samples taken at location 17-N-7 showed a TRU to americium ratio very similar to the Yuma ground zero area, Therefore, the ratio and error computed for Yuma was used to calculate TRU in the remainder of Cape Mixan. Table B-2-7 contains the locations and ratios from which the Yuma area value was computed, The ratio computed for the small anomalous area was 9.58, with error 0.66*, The ratio for Yuma ground zero area, and for the remainder of Cape Mixan, was 5.31 with error 0.90*, These ratios were used in estimating average concentrations of total transuranics and upper bounds on the estimates. *Due to programming error, the standard deviation reported here is overestimated. B-2-23