CL-36 AND I-129 IN TEETH AND BONES

Measurements of Cl-36 and I-129 in inert biological matrices such as t eeth and bone have the potential to provide a record of exposure to hi gh neutron fluxes and direct exposure to these isotopes in air and foo d. In fossil specimens, measurements of Cl-36 and I-129 atom ratios in bone and teeth may provide a methodology to determine the age of samp les that cover a range of ages from similar to 100 k to similar to 200 k and 15 M to 75 M years before present, respectively. To demonstrate the feasibility of exploiting these potential records, we have develo ped and tested a pyrolytic technique to extract the isotopes and stabl e analogs without introducing contamination. Concentrations of stable chlorine and iodine measured in teeth and bone range from 100 to 3000 ppm and 20 to 700 ppb, respectively and provided sufficient sample for measurement by AMS. Cl-36 and I-129 concentrations measured in sample s of teeth and bone that were exposed to elevated concentrations of th ese two isotopes during weapons testing have elevated concentrations o f the isotopes within the expected range of concentrations.