In continuing studies to characterize and identify fission product activities formed in the piles and appearing in plant dissolver solutions work was done to determine whether or not long-lived isotopes of certain elements were present. Two of the elements in this category were iodine and arsenic. The iodine isotope of particular interest was I{sup 129}. Its tellurium parent has been identified but no daughter activity attributable to iodine has been observed. The arsenic activities of interest were the long-lived isotopes (16 days and 90 days) which have been produced artificially by several different nuclear reactions.