Dose assessment for marine biota and humans from discharge of 131I to the marine environment and uptake by algae in Sydney, Australia

Abstract

Iodine-131 reaches the marine environment through its excretion to the sewer by nuclear medicine patients followed by discharge through coastal and deepwater out falls. 131I has been detected in macroalgae,which bio-accumulate iodine, growing near the coastal out fall of Cronulla sewage treatment plant (STP) since 1995. During this study, (131)I levels in liquid effluent and sludge from three Sydney STP's as well as in macroalgae (Ulva sp. and Ecklonia radiata) growing near their shoreline out falls were measured. Concentration factors of 176 for Ulva sp. and 526 for E. radiata were derived. Radiation dose rates to marine biota from (131)I discharged to coastal waters calculated using the ERICA dose assessment tool were below the ERICA screening level of 10 μGy/hr. Radiation dose rates to humans from immersion in seawater or consumption of Ulva sp. containing (131)I were three and two orders of magnitude below the IAEA screening level of 10 μSv/year, respectively.

The effect of climate change on sources of radionuclides to the marine environment

“…Additionally, unintended releases of naturally occurring radionuclides to the marine environment can occur during the transport and handling of mineral ores, coal, and other raw materials intended for various industrial uses [42][43][44] . Operational releases of man-made radionuclides from non-nuclear industries also occur from the production of radiochemicals and radiopharmaceuticals and the use of typically short-lived isotopes for therapy and diagnostic purposes in hospitals 37,45,46 .…”

More surprises in the global greenhouse: Human health impacts from recent toxic marine aerosol formations, due to centennial alterations of world-wide coastal food webs

“…There had also been relatively small releases of local Australian medical, short-lived iodine radio-wastes in sewage outfalls of Sydney (Carolan et al, 2011). But, given the long halflife of 129 I, two more likely options are: prior British nuclear bomb tests at the Montebello Islands, Emu Field, and Marilinga in Australia; and French nuclear bomb tests at Moruroa Atoll in French Polynesia.…”

Global searches for microalgae and aquatic plants that can eliminate radioactive cesium, iodine and strontium from the radio-polluted aquatic environment: a bioremediation strategy

“…On the other hand, iodine is an essential element for higher animals but has negative effects at high concentrations. Some organisms such as brown macrophytes accumulate high concentrations of iodine in the algal body (Carolan et al 2011; Chowdhury and Blust 2011; Gall et al 2004; Iwamoto and Shiraiwa 2012; Küpper et al 1998; Martinelango et al 2006; Marzano et al 2000; Rowan and Rasmussen 1994). When organisms ingest drinking water or foods with heavy radiopollution or breathe polluted air, it would increase the risk of suffering radiation problems (Escher and Hermens 2004; Golikov et al 2004).…”