▁networks ▁declared ▁increased ▁radio activity ▁levels ▁in ▁Europe , ▁coming ▁from ▁Eastern ▁Europe , ▁in ▁the ▁first ▁days ▁of ▁October : ▁ ▁the ▁Swiss ▁Federal ▁Office ▁of ▁Public ▁Health ▁( F OP H ) ▁reported ▁increase ▁of ▁radio active ▁particles ▁of ▁r uth enium - 1 0 6 ▁since ▁ 2 5 ▁September ▁ ▁The ▁Institute ▁of ▁Rad iop rote ction ▁and ▁N uc lear ▁Saf ety ▁of ▁France , ▁indicated ▁that ▁the ▁relatively ▁high ▁levels ▁in ▁the ▁beginning ▁of ▁October ▁have ▁stead ily ▁decre ased ▁from ▁ 6 ▁October , ▁while ▁no ▁radio active ▁element ▁was ▁detected ▁after ▁ 1 3 ▁October . ▁ ▁An ▁assess ment ▁of ▁the ▁French ▁nuclear ▁safety ▁inst itute ▁I RS N ▁indicated ▁that ▁while ▁there ▁was ▁no ▁health ▁risk ▁for ▁the ▁vast ▁majority ▁of ▁people ▁in ▁Europe , ▁the ▁radio active ▁quantity ▁released ▁was ▁significant , ▁estimated ▁from ▁ 1 0 0 ▁to ▁ 3 0 0 ▁ter ab ec quer els , ▁which ▁would ▁require ▁an ▁ev acu ation ▁of ▁people ▁from ▁a ▁radius ▁of ▁several ▁kilom eters ▁from ▁the ▁source , ▁as ▁yet ▁then ▁un ident ified . ▁ ▁The ▁source ▁of ▁the ▁a for ement ioned ▁ 1 0 0 – 3 0 0 ▁T B q ▁activity ▁corresponds ▁approximately ▁to ▁ 1 – 3 ▁gr ams ▁of ▁the ▁r uth enium - 1 0 6 ▁is ot ope . ▁ ▁Possible ▁source ▁▁ ▁While ▁the ▁release ▁of ▁the ▁g ase ous ▁noble ▁gas ▁element ▁K rypt on - 8 5 ▁is ▁routine