Abstract Isotopes of iodine play significant environmental roles, including a limiting micronutrient, an acute radiotoxinand a geochemical tracer. But the cycling of iodine through terrestrial ecosystems is poorly understood, due to its complex environmental chemistry and low natural abundance. To better understand iodine transport and fate in a terrestrial ecosystem, we traced fallout 131iodine throughout a small temperate catchment following contamination by the 11 March 2011 failure of the Fukushima Daiichi nuclear complex. We find that atmospheric iodine deposition is efficiently scavenged by surface soils, and subsequently redistributed via fluvial processes in a manner analogous to that of the particle-reactive tracer beryllium-7. These processes of surficial redistribution create radioiodine hotspots in the terrestrial environment where fine, particulate organic matter accumulates, and likely regulate the delivery of iodine nutrients and toxins alike from small catchments to larger river systems, lakes and estuaries.
Landis, J.D., Hamm, N.T, Renshaw, C.E., Dade, W.B ., Magilligan, F.J., Gartner, J.D., Surficial redistribution of fallout 131-iodine in a small temperate catchment, Proceedings of the National Academy of Sciences, in press, 2012.