Concerns about Rössing’s radiation levels

AN international nuclear watchdog on Wednesday voiced concern over radiation levels it had detected near Rössing, saying ‘indications are there might be a problem’.

Nuclear physics engineer Bruno Chareyron was hesitant to blame the mine, saying that the interpretation of the results of 38 samples of top soil, surface sediments, as well as underground and tap water taken in the vicinity of Rössing last year ‘will require additional work’.’One has to be extremely cautious not to say this is Rössing’s fault and not to say it isn’t,’ he said.Chareyron is the director of the laboratory of the Commission for Independent Research and Information about Radiation (CRIIRAD). He and his team joined Earthlife Namibia in September and October last year to monitor radiation near uranium mines in the country. The solid samples they collected were analysed by laboratories in France, whose accuracy in radiation monitoring is acknowledged by the French Nuclear Safety Authority.CRIIRAD measured the radiation dose rate in the parking lot of the Rössing mine. It was about six times above the natural background value, Chareyron said. In video footage shown at a press conference, he described the reading taken in the parking lot as ‘really crazy’.’This radiation is probably due to the use of radioactive tailings from [the] Rössing mill,’ he said. Chareyron said the analysis of top soil showed that radium 226 and uranium 238 activity was ’19 times above the natural concentrations measured in soil samples collected in Swakopmund or Etango areas’.CRIIRAD is also concerned about Rössing’s management of its waste rock dumps, and said it needed to be improved.’Some waste rocks are dumped on the banks of the Khan River (at the intersection with Dome Gorge) without fencing and confinement. The radiological impact of this activity has to be studied in detail but preliminary measurements show various impacts on the environment,’ Chareyron said.He said the finest fraction of radioactive rocks is washed down by rain water and contaminates the sediments of the Khan River. The values of uranium 238 and radium 226 activity in the samples were ten times above those of sediments in the Khan River upstream of Rössing. He further said gamma irradiation from the waste rock dump was detected further than 150 metres away.’CRIIRAD calculated that people spending only 30 minutes to 35 hours at a distance below 25 metres from the waste rock dump would receive an external irradiation dose above the trivial dose value of ten microSieverts per year,’ he said.In addition, preliminary monitoring of radon gas activity in the air near the waste rocks showed ‘high readings’. Chareyron said it was ’48 times above typical mean natural radon activity in the open air’.’Radon inhalation is acknowledged by the World Health Organisation (WHO) as the second cause of lung cancer after smoking,’ he said.Chareyron also said the high uranium concentration in underground water collected downstream of Rössing in the Khan River and Swakop River alluvium ‘raises the question of the origin of this uranium’.CRIIRAD wants a detailed study on the impact of leakages occurring below the tailings dam. Chareyron said the uranium concentration in underground samples downstream the tailings dam was high.’Rössing has a network of ‘dewatering wells’ and trenches designed to allow pumping back these contaminated waters to the tailings dam. But the question is the efficiency of this system and its durability in the future has to be studied,’ he said.CRIIRAD has already submitted its report to Rössing. The mine’s spokesman, Jerome Mutumba, on Wednesday confirmed this. Mutumba said Rössing will only be able to comment once its experts have finished studying the report.CRIIRAD and Earthlife Namibia will meet with uranium mines, local radiation experts and the Namibia Uranium Institute in Swakopmund next week.