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Bill C-14

CanTox Executive Summary


CanTox assessment of risks associated with drinking water consumption with respect to drinking water materials (additives, devices and components)

The objective of the Drinking Water Materials Safety Act, Bill C-14, is to provide legislation for the regulation (via certification and registration) of drinking water materials in Canada. Drinking water materials (DWM) include devices, additives and system components which come into contact with drinking water. Bill C-14 would also provide for the establishment of national drinking water quality guidelines and for the conduct of research to maintain and improve the quality of drinking water in Canada.

CanTox's Mandate and Methodology
  1. Assess the potential health risks associated with drinking water, and the possible relationship of these health risks to the use of DWM (additives, devices and components); two approaches were used:
  2. assessment of the future health implications of current concentrations of chemicals in Canadian drinking water, based on provincial monitoring data in comparison to drinking water guidelines; and
  3. assessment of current health effects attributed to drinking water or DWM (additives, devices and components) based on the toxicological literature, in order to identify actual sources of risk, and to quantify and classify these actual risks as to their origin (i.e., from sources unrelated to DWM, or from sources within DWM).
  4. Develop hypothetical options for mitigation of the identified actual sources of risks, with consideration of the efficacy of the proposed legislation in ameliorating such risks.
  5. Review the report submitted to Health Canada regarding the health issues related to DWM (additives, devices and components) (Brun del Re, 1996).

Results and Discussion:

Assessment of future health implications of current concentrations of chemicals in Canadian drinking water.

The provincial monitoring data of priority chemical and microbiological agents indicate that adverse health effects would not be expected in Canadian consumers, because:
 
  • The quality of drinking water in Canada is very high; and
  • There are only occasional or minimal exceedences of health-based drinking water guidelines, which would not be expected to result in adverse health effects because the guidelines are highly conservative, and are protective of human health for life-long exposures.

Assessment of current health effects attributed to drinking water or DWM (additives, devices and components) based on the toxicological literature.

(i) Microbial Issues

The predominant sources of actual microbial risk to consumers were found to be:
  • the microbiological quality of the raw water sources;
  • inadequacy of water treatment disinfection processes at municipal facilities; and
  • opportunity for colonization and regrowth, dependent on adequate disinfection, maintenance of a chlorine residual, optimal distribution system design, and proper maintenance of distribution and treatment systems.
Conclusions regarding the role of DWM (components and devices) in microbial issues:
  • role of components and devices is limited to potentially providing sites for regrowth;
  • the literature suggests that this regrowth is mainly of heterotrophic bacteria, and that it has not been associated with increased adverse health effects;
  • mitigation of this regrowth in DWM (components and devices) would require proper application of devices (e.g., complying with manufacturers= recommendations regarding use) and adequate maintenance of components (e.g., carbon filters, etc.);
  • Bill C-14 would not be expected to provide mitigation of risks associated with biological agents.

(ii) Chemical Issues
 
  • The predominant sources of actual chemical risk to consumers were found to be:
    • contamination of source waters by chemicals of natural or anthropogenic origins;
    • contamination of water following collection (e.g., by-products of disinfection, additives or impurities therein, leaching from components and/or corrosion of components).
  • Many of the sources of potential risks from chemical agents introduced into drinking water by DWM (additives, devices and components) are not considered to pose actual risk of adverse health effects, as indicated by routine compliance of finished water and tapwater with Canadian drinking water guidelines.
  • Several issues were identified as being of concern with regard to chemical contamination of drinking water:

The chemical by-products of disinfection may pose theoretical risk of adverse health effects to consumers, however:
  • the significant health-related benefits of disinfection in mitigation of risks of waterborne disease are considered to far out-weigh these potential risks;
  • the high quality of disinfectants used in treatment is assured by industry standards;
  • the mitigation of these risks depends on following the proper treatment protocol and using the best-available technology, rather than cessation of disinfection.

Leaching of lead from previously-installed DWM (components, specifically pipes, solders and fixture fittings) may pose risk of adverse health effects, as indicated by standing and purged line water containing lead levels exceeding guidelines, however:
  • mitigation of exceedences noted for purged line water would involve replacement of lead pipes and lead-containing components in residences and distribution systems; and
  • mitigation of elevated concentrations in standing water would involve purging the line prior to use (i.e., running the water for 1 minute).

Current practices include the use of Alead-free@ solders (up to 0.2% lead) and, while fixture fittings may contain up to 8% lead, DWM (devices and components) are required to meet industry standards for lead leaching (ANSI/NSF 61); therefore, current practices would not be expected to pose risk of adverse health effects to consumers via leaching of lead.
 
  • In conclusion, because:
    • the quality of DWM (devices, additives and components) in Canada is high, and industry standards are already in place to assure this quality;
    • the practices used in Canada represent the best available technology; and,
    • for certain processes, the health benefits of employing these technologies far out-weigh potential risks, therefore attempted mitigation of potential risks may be counterproductive, because it would require cessation of beneficial practices;

the impact of legislation under Bill C-14 on the chemical quality of drinking water in Canada would be minimal, and it would not increase compliance with Canadian drinking water quality guidelines.

Review of the report submitted to Health Canada

In the course of the above assessment, the document regarding health issues related to drinking water materials (Brun del Re, 1996) was reviewed. In general, this document provides a comprehensive summary of the potential sources of risk associated with DWM, but does not attempt to quantify these risks, nor to identify which of the potential sources of risk are actual sources of risk. In the review conducted by CanTox, the potential risks were put into perspective through consideration of improper application or maintenance of DWM, the risks posed by sources independent of DWM, a cost/benefit analysis of employment of certain practices, and Canadian drinking water monitoring data.

Conclusions

In conclusion, the predominant predictors of drinking water quality are the quality of the source waters and the proper application of best-available technology in treatment of raw waters for drinking water. Many of the DWM (additives, devices and components) issues raised as potential sources of risk to consumers are not considered to pose actual health risks, based on the expectation of very low levels of contamination. The routine compliance of Canadian drinking water with health-based guidelines supports this conclusion. Mitigation of issues identified as actual risks does not require the elimination or improvement of certain current DWM, rather, it requires the proper employment and application of current DWM (additives and devices), and in certain cases, the replacement of previously-installed materials by current DWM (components), whose quality is assured by industry standards already in effect.