ay atinn As noted in the e& eynacoresr from natural sources 1 COS omrem per year. About half of this , sfeeng). exm 1 5 e | due to rttye ate manter cosmic rays plus rad: earth's crust. i The vt the ve curring elements taker inta +, bn, natural radiation exo guideline fcr con’r:s' ar org + v aty UP traathe wp a t te Federa’ ra eratian made wee BYDC On a Pacrfee see Thic res ta naturally occurriss “Jatitude, }tw ele.a° in the soi? resuli iv ou Northern Marsha: ! earth's crust ard tre: Soe uer radioactive mater.a rf per year in the Morsn. ano) + Measurements o ‘. ragsdante indicate that the nat. mort pf Pray tac the internal exposure, occurring radiation co’ 22 vrar ale a ]00 mrem per year fer Ae mos 4 nm i yhorall., t- about 53 mrem per yea U.S. As with Tolalt.r, in the soil of laic ar: the atmosphere. ac73" source for doth iiter’: a tpi ge nF in| tams- aor aon Faint tacting In addt+innal op thy