Hot seafood

2019-03-08 03:06:13

By Rob Edwards FLOUNDER, sole and mussels in Britain’s largest estuary are contaminated with levels of radioactive tritium hundreds of times higher than expected. Tritium is discharged into the Severn Estuary by a factory in Cardiff run by Nycomed Amersham to make isotopes for the pharmaceuticals industry. Scientists working for the British government had assumed, based on advice from the UN International Atomic Energy Agency in Vienna, that the concentrations of tritium per kilogram of fish in the area would be roughly the same as those in each litre of seawater. But scientists at the Ministry of Agriculture, Fisheries and Food (MAFF) have found that this assumption was mistaken. Although levels of tritium in the seawater are less than 100 becquerels per litre, those in flounder, sole and mussels were hundreds of times higher. Flounder contained 37 800 becquerels per kilogram earlier this year. “Obviously these results called into question the previous assumptions made regarding tritium in the marine environment,” says Mike Segal, MAFF’s head of radiological safety. Recent surveys by the Environment Agency have also found high levels of tritium in sediment and molluscs at the bottom of the Severn Estuary. Although the reasons for the high levels of contamination are still under investigation, MAFF and Environment Agency scientists suspect that the precise chemical composition of some of the 700 tritium compounds manufactured at the Cardiff plant somehow made it more likely that fish would eat them. MAFF was alerted to the problem last year by Barry Lambert, a radiobiologist at St Bartholomew’s medical school in London who has been studying tritium emissions. He says that people eating large quantities of fish from the Severn Estuary could receive a quarter or more of internationally accepted dose limits from this source alone. But Nycomed Amersham insists that even people who eat large quantities of contaminated fish will not be exposed to dangerous radiation levels. And Graham Guilford, director of site services in Cardiff,