¹²⁹I from the nuclear reprocessing facilities traced in precipitation and runoff in Northern Europe

A huge amount of radioactive ¹²⁹I has been released into the environment from the nuclear energy industry, atomic weapon tests, and nuclear accidents. In this study, we present weekly and seasonal data on ¹²⁹I measured in precipitation and runoff of northern Europe during 1998 and 1999. The ¹²⁹I concentration is at 10⁸-10⁹ atoms/L in precipitation and (2-5) × 10⁸ atoms/L in runoff water, and it is 3-4 orders of magnitude higher than in the prenuclear era. Snow shows lower ¹²⁹I concentration than rain, and there is apparently a positive correlation between surface air temperature and ¹²⁹I. Precipitation chemistry, expressed as the content of Cl, SO₄, and NO₃ and atmospheric ozone, exhibits weak negative correlation with ¹²⁹I values. Our ¹²⁹I data on precipitation suggest significant influence of the northern European atmosphere by the discharges from the nuclear reprocessing facilities at Sellafield and La Hague.