6 Mar (NucNet): The incidence of cancer in communities near a plant in Canada processing radium and uranium ores is similar to that in the general population with “no statistically significant increases” in most cases, a study has concluded.
The ecological study is of cancer incidence near the Cameco-owned plant in Port Hope, Ontario. The plant supplies uranium dioxide (UO2) for Canadian-made Candu nuclear reactors.*
The study, published in the Journal of Radiological Protection, covers the period from 1992 to 2007 and says cancer incidence in the community for all cancers combined was similar to the Ontario population, health regions with similar socio-economic characteristics in Ontario and in Canada, and the Canadian population.
It says no statistically significant differences in childhood cancer, leukaemia or other radiosensitive cancer incidence were observed, with the exception of statistically significant elevated lung cancer incidence among women.
“However, the statistical significance was reduced or disappeared when the comparison was made to populations with similar socio-economic characteristics,” the study says.
These findings are consistent with previous ecological, case-control and cohort studies conducted in Port Hope, and also with environmental assessments, and epidemiological studies conducted elsewhere on populations living around similar facilities or exposed to similar environmental contaminants, the study concludes.
Although the current study covered an extended period, the power to detect risk at the sub-regional level of analysis was limited since at 16,500 the Port Hope population is small, the authors of the study said. The study nevertheless indicated that “large differences in cancer incidence are not occurring in Port Hope” compared to other similar communities and the general population.
A plant processing radium and uranium ores has been operating in the town of Port Hope since 1932. The authors said the study was carried out because of “ongoing public health concerns”.
The study was carried out by Jing Chen and Deborah Moir of Canada’s Radiation Protection Bureau, and Rachel Lane and Patsy Thompson of the Canadian Nuclear Safety Commission, the country’s nuclear regulator.
The Port Hope Conversion Facility (PHCF) was established in Port Hope, Ontario in 1932. The facility was initially extracting radium from high-grade pitchblende ores. In 1942, the focus shifted to processing uranium for nuclear reactors. After 1966, only purified feed material (yellow cake) was processed at the PHCF.
The study says that beginning in 1983 operational changes were implemented which resulted in “lower overall atmospheric emissions of radionuclides”. Since the mid-1980s, emissions have primarily been natural uranium.
PHCF is the only uranium conversion facility in Canada and one of only four in the western world. According to Cameco, facilities include uranium dioxide (UO2) and uranium hexafluoride (UF6) processing plants and technology development laboratories. The plant is the only supplier of UO2 for Canadian-made Candu nuclear reactors.
The study is online:
http://iopscience.iop.org/0952-4746/33/1/227
* Candu stands for “Canada Deuterium Uranium”. The Candu reactor is a Canadian-designed pressurised heavy water reactor (PHWR) that uses heavy water (deuterium oxide) for moderator and coolant, and natural uranium for fuel. Candu reactors are in operation in Canada, Argentina, Romania, South Korea and China. Pakistan and India operate “Candu derivatives” that were developed from the Candu design. All seven countries are members of the Candu Owners Group (www.candu.org).
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