and were immediately stored in a deep freeze unit where they remained until time for processing. Algae and plants that were to be used for autoradiographs or as herbarium specimens were dried and pressed in the field. All plankton samples, as well as fish and algal specimens, that were to be used for identification were preserved in 4 percent formalin. 3.2 Ashing The samples were ashed and plated in much the same manner as previously described (AECD- 3446). was as follows: (1) Fish, Briefly the procedure invertebrates, birds, rats and lend plants were dissected and approximately one-gram samples of various tissues were placed upon weighed 13-inch stainless steel plates. Wet sample weights depended upon the amount of tissue available and the activity of the sample as determined by survey meter at the time of dissection. The mean sample . weight of 145 randomly selected samples was 1.17 2.074 grams.* (2) he plates with the wet samples were placed in a drying oven at 97°-99°9C for 12 to 24 hours. (3) They were then cooled in 8 desiccator and dry weights determined. (4) The plates were next moved to the muffle furnace for about 12 hours, during which time the temperature was gradually raised to 300°C then more rapidly to a maximum of 550°C, except for *In this report the value following the mean is the standard error. -U- :