Asbestos cement pipe and its impact on drinking water

Throughout the 1950s and 1960s, the United Kingdom installed thousands of kilometres of asbestos cement pipe on the country’s water network. Fifty years on and the world is all too aware of the dangers posed by asbestos, which begs the question – what impact is it having on our water?

We will get to that. First though, it helps to understand why asbestos cement was so commonly used, not just in the UK but around the world for the transportation of drinking water.

Cement was considered one of the best types of material for pipework during the mid-20th century because of its high corrosion resistance. It did however lack tensile strength.

Adding asbestos to cement was a way to improve the mechanical properties of cement, including increasing its tensile strength to levels which allowed it to operate effectively on water networks.

Approximately one fifth of the population of England and Wales drink water that has passed through asbestos cement pipework. That figure may seem startling, but it is actually quite low compared to other countries.

Take the United States for example. According to the World Health Organisation (WHO), most of the population of the US consumes drinking water contaminated with asbestos, although the WHO believes in concentrations so low that it does not pose a risk to health.

Believes of course is the key word there, because nobody can really say for sure. Whilst we know plenty about the dangers of inhaling asbestos, less is known about what happens when it is ingested through drinking water, other than some very basic facts.

One of those facts is that asbestos fibres do not dissolve in water. That means that once they enter pipes, they are carried directly into homes and businesses.

This has been going on for the best part of 70 years and there is no obvious data to suggest that people have suffered health complications because of it.

Another fact borne out by research is that asbestos fibres which are less than 1 µm in length – a millionth of a metre – are considered to pose little to no risk. Studies conducted across Europe, the US and Canada found that nearly all asbestos fibres found in drinking water were sized below 1 µm.

And what if fibres are sized above this so-called safe limit? That is where things become murky. The problem that the world now faces is that we could well find out as much of the world’s asbestos cement pipe reaches the end of its lifespan.

The 37,000km of asbestos cement pipework installed across the UK was expected to last 50 to 70 years. Failures in these lines are now becoming more common, and it is an accepted fact that the release of large fibres into water occurs when breakages happen.

As the UK’s asbestos cement pipes come to the end of their life in the next decade, it is fair to assume that higher levels of potentially dangerous sized asbestos will enter the water network as the frequency of leaks and bursts increases.

The WHO remains of the opinion that this is not a problem. The organisation re-examined its position in 2014 and considered asbestos ingested via drinking water to be a low priority. Scientists outside of the WHO remain less convinced.

In the UK, there are no guidelines as to when asbestos fibre levels in water are considered a health risk – and with no guidelines, there is no way of ensuring or enforcing safe levels. Britain does not even routinely test its water for asbestos.

The last time the issue was investigated by the British government was in 1988. A report by the Environment Department concluded there was no need to remove asbestos cement pipes, even through the same report concluded that degraded pipes leached more fibres into the network. That mirrored the WHO’s stance.

Further concern to those in the UK comes from the WHO’s research being based upon the presence of chrysotile (white asbestos) in asbestos cement pipes. The majority of Britain’s network is made up of pipes with crocidolite, so-called blue asbestos.

Of the two, blue asbestos is known to be more harmful than white because of its pointed fibres. These pose a bigger threat because they can more easily enter the tissue of organs such as the stomach or colon.

Blue asbestos was the first type to be outlawed by Britain for use in the construction industry in 1985. It would be another 14 years before white asbestos was deemed equally unsafe and made illegal.

The village of Cranleigh in Surrey is served by an unusually high proportion of asbestos cement pipes. On average in south east England, two percent of drinking water supply pipes are made from the material. In Cranleigh, that figure is 29 percent.

In 2017, their network began suffering from an obvious increase in bursts and failures, prompting serious concerns amongst the population when they realised what material was being used to transport the drinking water.

The Cranleigh Civic Society (CCS) called a public meeting after it was discovered that the village had such a high proportion of asbestos cement pipes. The society subsequently contacted both the Drinking Water Inspectorate (DWI) and their water supplier with their concerns.

A spokesman for the CCS told Surrey Live: “We have asked the DWI three times if there is any risk from ingesting asbestos fibres from the old pipes, and each time they have prevaricated and refused to answer the question with a simple yes or a no.”

“They keep saying that there is no evidence to show that there is a problem but that is our point. There is no evidence to say ingesting it is safe. There is no evidence either way and that is why we approached the DWI and asked them to carry out a study to see if Cranleigh residents are at risk.”

The water supplier cited the WHO’s study in asbestos cement pipes as saying that the residents of Cranleigh had no cause for concern. Asbestos cement pipe repairs continued to be made, rather than the replacement which locals felt were needed to keep them safe.

Cranleigh is not the only village to be concerned about the use of asbestos cement in their water supply network. Temuka, a small town on New Zealand’s south island began suffering from low water pressure and water filters clogged up with a grey substance.

This turned out to be asbestos, released into the network by a 9 kilometre asbestos cement pipe running to the town from a local reservoir that had been installed 54 years earlier in 1964.

Although the local authorities attempted to reassure the residents that there was no danger posed by the asbestos cement pipe, the people of Temuka remained unconvinced and a replacement polyethylene pipe was ultimately installed.

The cost of replacing all asbestos cement pipes on New Zealand’s water network has been put at an estimated $1.6 billion. Australia meanwhile has committed to replacement of their network at a cost of nearly $6 billion.

There are no plans for the UK to follow suit. In response to the concerns of the residents of Cranleigh, the principal inspector of the DWI Sue Pennison wrote: “We have sought views from Public Health England and the World Health Organisation who have the knowledge, expertise and processes in place to review relevant evidence and conclude upon the risks to health presented by a wide range of chemicals.”

“On current evidence, the World Health Organisation has concluded that there is no requirement to set a health based guideline value for asbestos in drinking water.”

“We have also stated that should further evidence become available by way of peer reviewed science or advice from recognised health bodies or toxicologists and relates to ingestion of asbestos [not inhalation] which contradicts this we will review this position.”