


Asbestos: Dangerous and still present
Water pipes made of asbestos concrete - a real danger?
Deaths after more than 40 years and serious occupational illnesses: Asbestos, a material that was once praised, has been banned for years and yet has lost none of its horror. It can still be found in the environment. And old drinking water pipes made of asbestos cement are still making the headlines. One of the main problems is the disposal of old pipes, which can only be carried out by specialists. But what about pipes that have been in operation for decades and are still in use?
What is asbestos?
Asbestos is a collective term. The heat- and acid-resistant mineral comprises six different fibrous silicate minerals that occur naturally in rocks. They were used by humans for building materials, including asbestos cement. Typical of this substance are the tiny fibers, which can remain in the human body for a very long time.
The high danger of asbestos has been known since the last century, but the substance has only been banned since 2005. It must be disposed of under strict health and safety regulations. Asbestos is to be completely eliminated in the EU by 2035.

Unprofessional disposal of asbestos
Why is asbestos dangerous?
Pulmonary asbestosis, a fatal hardening of the lungs, was discovered as early as 1900. This is caused by the inhalation of fine branch asbestos fibers that remain in the lungs for years. The irritation of the lung tissue leads to its hardening and endangers lung function. Asbestos also causes cancer. Certain asbestos fibers, such as crocidolite, are even considered extremely carcinogenic. They therefore pose an enormous health risk.

Asbestos fibers on closer inspection
Four diseases caused by asbestos are recognized occupational diseases: Pulmonary asbestosis, pleural asbestosis, lung cancer and so-called mesotheliomas. These are tumors in the pleura and peritoneum that can develop even after brief exposure to asbestos and offer little chance of survival. Asbestos is also suspected of causing other types of cancer. For this reason, it is being discussed whether the ingestion of asbestos fibers through drinking or eating can possibly cause cancer. This question has not been clearly clarified.1
How and where was asbestos used in water pipes?
In the 1950s and 1960s in particular, asbestos cement was used to lay drinking water pipes. An estimated 30,000 km of asbestos drinking water pipes were used, mainly in Schleswig-Holstein. Today, this material may no longer be used.
What are the potential dangers?
The question of whether drinking water pipes made of asbestos cement pose a current health risk is a subject of constant debate. The fact that cement can be dissolved by mechanical contact with water and by dissolved salts and acids in soft water speaks in favor of a hazard.
This could result in large quantities of asbestos fibers contaminating the drinking water. This assumption is based on a drinking water study conducted by the Fraunhofer Institute in 1983, which found up to 1.57 million freely dissolved asbestos fibers per liter in drinking water (umweltanalytic.com).
In fact, the study had consequences: The German Federal Health Office developed a method for avoiding asbestos fibers in drinking water, which was proposed as a "best available technique" by the top environmental authority in the USA. 2

Asbestos can settle in the respiratory tract, but is also not harmless if swallowed
Nevertheless, doubts remain. It is still unclear whether orally ingested asbestos fibers are just as dangerous as inhaled ones. It is disputed whether the asbestos fibers are excreted from the gastrointestinal tract or whether they migrate in the body. 3
In any case, the laying of new asbestos cement pipes has been prohibited since January 1, 1995. Older pipes may continue to be used. 4
To this day, the WHO and the Federal Health Office are of the opinion that the operation of asbestos cement pipes poses no risk if the "transported water complies with the Drinking Water Ordinance". Water must therefore not be too "soft".
The Drinking Water Ordinance requires the pH value of the water at the waterworks outlet to be greater than 7.7. The highest possible pH value is intended to keep the lime solubility (calcite dissolving capacity) as low as possible. This is believed to minimize the risk of asbestos fibres being released. 4
In contrast to Germany, the US Environmental Protection Agency (EPA) has set limits for asbestos in water in order to protect public health.
Danger when showering
If there is indeed a concentration of asbestos fibers in the water, there could also be a risk from inhaling asbestos fibers: The U.S. Environmental Protection Agency (EPA) classifies showering with asbestos-contaminated water as severely harmful to health. Asbestos fibers could be suspended in the air (source: umweltanalytic.com).
Be careful with blocked drains!
It can become critical if pipes made of asbestos cement have been used in the home. If damage occurs here, for example due to a blocked drainage pipe, a specialist company must be commissioned. They will be familiar with the strict health and safety regulations for asbestos removal in the event that pipes need to be cut. 6
Where can I find help?
The local water supplier can provide information on the presence of water pipes made of asbestos cement. If property owners or businesses want to find out more about how to deal with the hazardous substance asbestos cement in drinking water pipes, they can get help from the German Technical and Scientific Association for Gas and Water (dvgw), which has compiled recommendations on dealing with drinking water pipes made of asbestos cement in a 2011 leaflet.
What protects against asbestos?
Asbestos fibers in drinking water can be retained by nanofiltration. Activated carbon filters also protect against possible asbestos fibers in the water. In areas where there are older drinking water pipes made of asbestos cement, the use of an activated carbon filter may therefore be advisable. Reverse osmosis can also be used to remove asbestos fibers.
Conclusion
Asbestos in cement pipes is considered largely harmless as long as the pipes are intact and are not decomposed by mechanical influences or lime-dissolving water. Opinions differ on the danger of asbestos fibers in water. Filtration, for example using activated carbon filters, can remove asbestos fibers from the water.

Sintered activated carbon with high porosity is a high quality feature.
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References
- Final report on the research project Dealing with asbestos cement pipes, IKT Institute for Underground Infrastructure, https://www.ikt.de/website/down/f0078langbericht.pdf
- German Bundestag, printed matter https://dipbt.bundestag.de/doc/btd/11/056/1105604.pdf
- Der Spiegel, 1989, https://www.spiegel.de/spiegel/print/d-13495344.html
- lfu Bavaria, https://www.lfu.bayern.de/wasser/merkblattsammlung/teil1_grundwasserwirtschaft/doc/nr_187.pdf
- Deutsche Welle, https://www.dw.com/de/asbest-krebsgefahr-kann-in-jeder-wand-lauern/a-45484320