Some may remember my posts about iodine- 131 in dulse in the Bay of Fundy. Four points: 1. It can and probably has happened here in NB. 2. The “half-life” is the time (8days) it takes to lose half its radioactivity. BUT it takes another 8 days to lose half of the remaining half and so on and so on. 3. The danger comes from the initial level (concentration) that is taken up by the seaweed. 4. Most radionuclides become deadly when ingested, particularly i-131 which concentrates in the thyroid.