September 1, 1999
Dear Dr. Bishop;
On a recent visit to Pembroke, I met with citizens who were concerned about SRB Technologies (Canada) Inc. This industry has been operating a tritium reclamation facility near this rural residential area since the early 1990's, emitting up to 970 TBq tritium in a year (maximum was apparently 1997). Tritium in local flora, around 2000 Bq per litre of water, is significantly above background, which would be expected to be below 10 Bq per litre water. The residents, I believe, have a very legitimate right to a comprehensive radiological investigation of this site and to ongoing radiation monitoring.
Some of the particular problems which stand out are the following:
SRB Management assessment of the "maximally exposed member of the general public" used a resident known to live upwind of the facility. In addition to the obvious problem of such a choice, one could make a good case for looking at the "maximally radio-sensitive member of the general public". Even when calculated properly, there is no guarantee that the maximally exposed person, often a male who works outside, will be the one experiencing radiation damage. Certainly the embryo or fetus, a fragile senior citizen or a person with serious respiratory disease may experience greater health impact.
Translation of measurements of tritium released to the environment, considering the subsequent ecological cycling, and calculating the probable body burden and dose to humans is not easy. One needs to consider the organically bound fraction, and the nocturnal release of tritium to the air in a pine forest. The rapid conversion of tritium gas to tritiated water vapour after release into air is another important factor. Theoretical dose estimates can vary by a factor of six or more. Doses received from organically bound tritium can be orders of magnitude higher than that from tritiated water.
Although tritium has often been disregarded as a pollutant, especially in Canada where the CANDU technology, considered to be the greatest tritium polluter in the world, is used, it continues to be worrisome for those persons who are concerned with the public health. The average energy of the beta particle emitted by tritium is 18.6 thousand eV. This may seem small to those physicists who must also deal with radionuclides which emit particles with energy in the million eV category. However, to the delicate
DNA of the human body which can break under an energy input of 6 to 10 eV, the 18,600 eV energy of these beta particles (which could be emitted from within the DNA molecule itself) cannot be easily dismissed as trivial.
It is my understanding that the license for this company will come for review by the AECB in December 1999. It is also my understand that the technology to significantly reduce the tritium emissions of this facility exists. Therefore, I ask that you make an intervention on behalf of the public health by withholding a licence until better control of this hazard is assured and ongoing monitoring of compliance is in place.