Seafood dose parameters: Updating 210Po retention factors for cooking, decay loss and mariculture

Abstract

²¹⁰Po has been identified as one of the main contributors to ingestion doses to humans, particularly from the consumption of seafood. The amount of ²¹⁰Po activity concentration data for various types of seafood has increased greatly in recent times. However, to provide realistic seafood dose assessments, most ²¹⁰Po data requires correction to account for losses that can occur before the seafood is actually consumed. Here we develop generic correction factors for the main processes associated with reduction of ²¹⁰Po in seafood - leaching during cooking, radioactive decay between harvest and consumption, and sourcing from mariculture versus wild-caught. When seafood is cooked, the overall mean fraction of ²¹⁰Po retained is 0.74 for all cooking and seafood types, with the means for various seafood types and cooking categories ranging from 0.56 to 1.03. When considering radioactive decay during the period between harvest and consumption, the overall mean fraction remaining is 0.81 across all seafood preservation/packaging types, with estimates ranging from 0.50 (canned seafood) to 0.98 (fresh seafood). Regarding mariculture influence, the available limited data suggest marine fish and crustaceans raised with processed feed have about one order of magnitude lower (×0.10) ²¹⁰Po muscle content than wild-caught seafood of the same or similar species, although this ratio varies. Overall, this study concludes that ²¹⁰Po activity concentrations in seafood at the time of ingestion may be reduced to only about 55% compared to when it was harvested. Therefore, correction factors must be applied to any data derived from environmental monitoring in order to achieve realistic dose estimates. The data also suggest lower ²¹⁰Po ingestion doses for consumers who routinely favour cooked, long shelf-life and farmed fish/crustaceans. However, more data is needed in some categories, especially for cooking of molluscs and seaweed, and for the ²¹⁰Po content in all farmed seafood.

Keywords: Aquaculture; Farmed seafood; Ingestion dose; Loss of (210)Po; Marine monitoring; Polonium.