CHEMICAL STATE OF TRITIUM IN THE ATMOSPHERE AND SOURCES OF TRITIATED METHANE A. HAINES and B. MUSGRAVE University of Arkansas, Fayetteville, Arkansas ABSTRACT The T/H ratios in atmospheric hydrogen and methane are discussed in relation to some of the available information on the amounts of tritium released by the nuclear industry. The increase in the T/H ratio in atmospheric hydrogen prior to 1952 can be attributed to this source. From the rate of tritium release, an estimate of the production of tritiated methane can be made. Such an estimate gives reasonable agreement with the observed T/H values. INTRODUCTION The presence of tritium (7H or T) in at least three different chemical forms in the atmosphere is well known. A number of studies have been made which have resulted in a reasonably good understanding of the general nature of this distribution. Lack of detailed information about the sources of the tritium, however, has prevented a complete explanation of the variations with time of the T/H ratio in hydrogen and methane. The data!~’ for T/H ratios in northern- and southern-hemisphere methane and northern-hemisphere hydrogen from 1948 to 1955 are shown in Fig. 1. Bishop and Taylor® have suggested that the T/H ratio in hydrogen was increasing exponentially prior to the 1952 Operation Ivy nuclear test series and is continuing to increase in this manner. More recently Bainbridge et al.! have proposed that the natural level was high and that no increaSe occurred prior to 1954; however, the 144

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