This page has been archived on the Web

Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please contact us to request a format other than those available.

Summary of Public Comments on N-Nitrosodimethylamine (NDMA)

(PDF Version - 67 KB)

Environment-related Sections

Comments on the environment-related sections of theCEPA PSL Draft Assessment Report on NDMA were provided by:

  1. Ontario Ministry of the Environment, Toronto, Ontario
  2. Canadian Water and Wastewater Association, Ottawa, Ontario

Comments and responses are summarized below by Environment Canada.

Comments and responses
CommentResponse
Identification of typographical and editorial errors in report (1).The changes suggested will be incorporated into the final assessment report.
While the CWWA agrees that the potential exposure from sewage sludge should be examined, its significance, however, must be carefully evaluated as the bioconcentration factor is not applicable as biota can generally biotransform NDMA. Due to cost issues, CWWA recommends that any requirements to monitor sewage sludge include provision to establish site-specific sampling frequencies, ranging from an annual sample to a maximum quarterly sampling frequency. This should be based on the results of establishing a baseline level for NDMA in sludge in a given community(2).This comment will be forwarded to risk managers for their information.

Health-related Sections

Comments on the health-related sections of the CEPA PSL Assessment Report on NDMA were received from:

  1. Canadian Water and Wastewater Association
  2. Federal-Provincial Subcommittee on Drinking Water
  3. Drinking Water Quality Program of Health Canada
  4. Chemical Manufacturers Association
  5. SNF-Floerger in Saint-Etienne, France

All comments related to the statement within the Synopsis and section on Consideration for Follow-up of the NDMA PSL Assessment Report that "Optimization of drinking water treatment to minimize formation of NDMA is also recommended. In particular, the suitability of the use of the specific preblended polyamine/alum water treatment coagulant identified to be contributing to levels of NDMA in drinking water in Ontario should be considered."

Comment

CommentResponse
It was suggested that it was inappropriate for theCEPAPSL assessment report to include such a statement, since NDMA (in drinking water) is not considered a national priority for evaluation by the Federal-Provincial Subcommittee on Drinking Water, and that it is only this Sub-committee that should develop recommendations concerning methods for the disinfection of drinking water supplies in Canada.The Priority Substances were selected following recommendations to the Ministers by an expert multistakeholder Advisory Panel based on potential for both exposure and effect in Canada. In the assessments, these substances are considered from the perspective of exposure in all media, including drinking water. Hence, it is anticipated that recommendations from this program would be considered by the Sub-committee on Drinking Water in its priority setting exercises.
It was suggested that the inclusion of any statement concerning the "Optimization of drinking treatment to minimize formation of NDMA…" also include a statement to the effect that the implementation of any change to the processes for the disinfection of drinking water supplies (to reduce levels of NDMA), must never compromise human health protection.The statement in the PSL report was changed toOptimization of drinking water treatment to minimize formation of NDMA is also recommended, though such measures must not compromise human health protection".
Data were submitted as a basis for the contention that polyamines and polyamine/alum blends are not likely to represent a significant source of NDMA in drinking water supplies. However, it was also noted by another commentor that it would be useful for manufacturers providing products to the drinking water sector to provide some assurance that their products do not contain NDMA above specified levels, and will not result in NDMA formation following chlorination.The data and the suggestion have been passed to the risk managers for consideration, in collaboration with relevant authorities (i.e., the Sub-committee on Drinking Water) in the subsequent risk management phase.
Date modified: