By: Joe Cotruvo
Health Canada, the department of the Government of Canada responsible for national health policy, recently published a notice of public consultation to consider establishing an “Objective” for total PFAS in drinking water. In 2018, Health Canada established drinking water guidelines for perfluorooctane sulfonic acid (PFOS, 600 ppt) and perfluorooctanoic acid (PFOA, 200 ppt). Health Canada also produced screening values for 9 other PFAS including perfluorobutanate (PFBA), perfluoropentanoate (PFPeA) perfluorohexanoate (PFHxA), perfuoroheptanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS) and 2 perfluorotelomers.
In Canada, the national government produces drinking water guidelines and other advice that provinces may adopt at their discretion. Health Canada is proposing to adopt a new group-based approach by producing a single Objective target value of 30 ppt aggregating measurable PFAS using reliable analytical techniques. Their approach considered the potential number of PFAS that might be found in some drinking waters (as analytical methods continue to achieve lower reporting limits), the mixed and limited toxicology data, potential exposure to multiple PFAS, and differences between worldwide numerical recommendations. The proposed 30 ppt Objective is technology based and does not consider the widely differing health-based values for the many PFAS.
The suggested Canadian Objective value is not a standard, or guideline, but a recommendation. It is based on estimated technical and economic feasibility. It has some analogies with the UK and WHO recommendations of 100 and 500 ppt for total PFAS, respectively, as practical guidance. Health Canada produced the proposed Objective considering the following:
- Published treatment data and efficacy;
- Treatment of PFAS by Granular Activated Carbon, Reverse Osmosis, and Anion Exchange technologies under conditions found in Canadian drinking waters;
- Reporting levels for PFAS using validated analytical methods;
- Canadian monitoring data;
- Lowest concentrations technically achievable.
Canada has concluded that this proposed Objective concept is the most appropriate approach for reducing multiple PFAS in drinking water while formal guidelines are being revised.
Internationally, there are numerous diverse recommended values for individual PFAS chemicals and for total PFAS in drinking water and diet. For example, the current Australian guidance for PFOA is 560 ppt, and 70 ppt for PFOS. The United Kingdom, the World Health Organization and the European Union have suggested 100 ppt each for PFOA and PFOS, and 500 ppt for total PFAS as practical guidance. The European Food Safety Agency recommends a total diet value below 4.4 ng/kg/week, which would compute to approximately 44 ng/day from all sources, with drinking water being a relatively small contributor. The U.S. EPA in 2016 had issued Health Advisories of 70 ppt each and combined for PFOA and PFOS. In 2022 the EPA revised them to 0.004 ppt and 0.020 ppt interim values while it is developing drinking water standards.
A public access webinar is scheduled in English on March 1, and in French on March 7. The release of the proposal is available on the Health Canada website.