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Asbestos in drinking water, the norm in Quebec!

We know that water is a source of life, but can it also be a source of asbestos fiber? Asbestos is a fibrous mineral that has been widely used in the past for its many applications, particularly in the construction industry. Quebec used to be a major producer and exporter of chrysotile asbestos. Although asbestos is now subject to a relatively strict framework, there is no standard in Quebec on the presence of asbestos in drinking water. This situation is starting to raise public interest since the spring.

Indeed, asbestos can be found in the water we consume. Of course, there is some naturally occurring in the Quebec subsoil, but it is mainly the contribution of fibrocement pipes that is of concern. Degradation of these pipes over time can release fibers into the drinking water distribution system and be consumed by humans.

Health risks

The effects of exposure to inhaled asbestos are very well known. Lung cancer, mesothelioma, asbestosis, asbestos remains the most frequent cause of occupational death in our country. However, the effects of asbestos ingestion, rather than inhalation, remain poorly understood. It is known that in some cases, which could be described as extreme, ingested asbestos is linked to a higher incidence of gastrointestinal cancers. The epidemiological link remains to be confirmed, but we suspect that a continuous ingestion of fibers could cause an increase in these cancers (e.g. stomach, rectal, spleen, colon, pancreas, etc.).

The U.S. Environmental Protection Agency, like some other countries in the world, has a standard on the presence of fibers in drinking water. It is from this limit of 7 million fibres per liter of water that Quebec could presumably draw inspiration.

This may seem enormous, but it must be remembered that these fibers are extremely fine and that the erosion of the pipes separates the bundles of asbestos fibers that are usually observed under the optical microscope into extremely fine fibrils of the order of about twenty nanometers on a side (0.00002 mm). The use of an electron transmission microscope is therefore necessary for this analysis.

Standard in Quebec

In order to compare with the standard on respirable fibres (1 fibre/ml for chrysotile), we must first refer to the same volume.

Water standard
7 million fibers/liter = 7000 fibers/ml of water
Air standard
1 fiber/ml of air

Then, a “respirable fiber”, or rather “respirable fiber bundle”, is by definition up to 3 µm wide or 0.003 mm. If we consider that a single asbestos fiber measures 0.02 µm (0.00002mm), each bundle of respirable fibers would actually contain 60,000 single fibers perfectly packed together.

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Water standard
7,000 fibers/ml of water = Approximately 0.00012 fiber bundle/ml
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Air standard
1 fiber/ml of air

This comparison is strongly biased by the fact that we have chosen the largest bundles of respirable fibers allowed by the definition and the smallest fibrils described, but it still shows that the standard is not as permissive as it seems and could logically fit in a regulation aiming at reducing the exposure of the population to asbestos fibers. In short, we need tighter control over the water we consume, for the health and safety of Quebecers!

LAB’EAU-AIR-SOl offers training on safe management of asbestos

À propos de notre expert

Christian Lebeau-Jacob, Microbiologiste

Directeur et microbiologiste chez LAB’EAU-AIR-SOL depuis plus de sept ans, Christian possède une maîtrise en microbiologie de l’Université de Sherbrooke et un baccalauréat en science de la biologie médicale. Son implication auprès de l’Association des microbiologistes du Québec, à titre de président, ainsi plusieurs autres groupes d’experts font de lui un professionnel reconnu et à l’affût des avancées dans son domaine. Il est spécialisé en bactériologie, identification de moisissure et amiante ainsi qu’en détection de légionnelle.

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