When it became apparent that lead pipes contaminate water with toxic heavy metal residues, governments began replacing them with plastic pipes, believing these were safer. But studies have uncovered that plastic pipes also leach harmful chemicals like bisphenol A into the water.
PVC (polyvinyl chloride) is one of the most widely used plastics worldwide. We produce 40 million tons of it every year. It was first discovered in 1838 by French inventor Henri Victor Regnault, then rediscovered in 1872 by German chemist Eugen Baumann. [ref:, and]. But nothing was done with this new material until 1933, when the B.F. Goodrich Company developed a method to plasticize PVC and make it more flexible. From then on it began being used for all sorts of commercial uses, from construction to consumer products.
Because PVC is cheap, durable, and chemically resistant to acids, alcohols and solvents, it is used in many industries. Since the 1960s, it has been the preferred material for water pipes, replacing those made of lead, concrete and cast iron. Unfortunately, we pay a price for this durability. PVC leeches chemicals into the environment, including our water supplies.
Materials that are in contact with water usually end up transferring some of their components into the water (for example when pipes are made of lead or copper, a small amount of the metals end up in the water). That is the case with pipes made of PVC: they release polyvinyl chloride into the water. But that’s not all.
A Danish study published in the journal Water Research shows that pipes made of PVC and other polyethylene plastics like PEX (cross-linked polyethylene) and HDPE (high-density polyethylene) release esters, aldehydes, aromatic hydrocarbons and terpenoids into the water. Other studies show that PVC pipes release bisphenol A (BPA) and phthalates into the water.
The chemicals that contaminate the water from PVC pipes are hormone-disrupting and cancer-causing. Let’s take a closer look at what science says.
One of the phenols in PVC is 4-tert butylphenol. Lab tests show that it can cause reproductive abnormalities.
Phthalates, which are chemicals that are added to plastics to make them more flexible, have come under fire for their negative effects. A review of studies published in the International Journal of Environmental Responsibility and Public Health finds that phthalates are linked to fertility disorders in men and women (such as lower sperm production and a higher risk of miscarriage), puberty abnormalities, and cancer.
Bisphenol A is also considered an endocrine disruptor and scientific studies have pointed to a link between exposure to bisphenol A and cancer, infertility, diabetes and obesity.
Hormones are vital for health – they are messenger chemicals that regulate many of the body’s vital functions (for example insulin, which tells the body to absorb and use glucose; or melatonin, which regulates your sleep-wake cycles, or sex hormones like testosterone and oestrogen, which can influence aspects of physical and mental health beyond reproduction). When hormones are disrupted, disease is not far behind. That’s why a group of almost 90 scientists from around the world have called for a boycott on the production and use of endocrine disruptors.
Their calls are being answered. Recently the European Food Safety Authority proposed a 100,000-fold cut in bisphenol A. They set a new temporary tolerable daily intake (TDI) of 4 micrograms per kilogram of body weight per day, a considerable reduction from the earlier TDI of 50 micrograms per kilogram of body weight per day. The EFSA based this recommendation on studies showing that Bisphenol A has a negative impact on “T-helper” cells (white blood cells that have a key role in the immune system).
In an article entitled ‘Danger from the Tap’ by Algemeen Dagblad, Ana Soto, professor of cell biology at Tufts University in Boston, states “We have been outlining the dangers of endocrine disruptors for 15 years, but nothing has changed. Now it appears that these substances can end up in drinking water. I wonder how long governments will wait before taking action.” .
The longer the water is in contact with plastic pipes, the more chemicals leach into the water. Researcher Erik Arvin left water in plastic pipes for seven days to assess the impact. “We found more than 20 chemicals that had leached into the water. Most of them were alkyl phenols, such as 4-tert butylphenol, and phthalates.” According to Arvin, this happens mostly in and around the home. That’s because water in outdoor pipes (the main water network) is continuously on the move, whereas indoors it is often at a standstill for hours, or even days, waiting for a tap to be opened. The temperature is also often higher inside. These conditions make it more likely for the plastic chemicals to end up in the water. What’s more, the smaller the diameter of the pipe, the more contact there is between the water and the pipe, and this results in a higher degree of chemical leaching.
Arvin points out that only 10% of the chemicals have been identified. The other 90% remain a mystery – he doesn’t know what they are, nor whether they are harmful to health. Another thing that isn’t yet clear is whether these substances can enter the body via the skin, for example when showering. According to Ana Soto, this may be the case. “We know that Bisphenol A diglycidyl ester can penetrate the skin. We don’t yet know about other phenols, but it is likely that phenols of a similar size can also enter the body through the skin,” she says.
There has been some debate over whether these chemicals are a problem for human health.
Wim van de Meent, of Kiwa, the institute that inspects water pipes in The Netherlands, disagrees with Arvin’s and Soto’s position. According to him, research shows that up to 900 micrograms of 4-tert butylphenol per liter is not harmful to health. As for the other substances, they occur in such low concentrations that they are negligible. Van de Meent is not convinced there is a problem, but says “It’s good that there’s a discussion about it.”
Despite the debates, it is impossible to ignore the studies linking plastic by-products with health issues. According to a study published in the journal Environmental Toxicology and Pharmacology, polyvinyl chloride “is the most toxic polymer type”.
The latest Guidelines for Drinking Water Quality published by the World Health Organisation sets limits for some of the chemicals related to PVC, but not all.
The European Drinking Water Directive goes further on some of the chemicals, while being more relaxed on others:
According to the Dutch Water Supply Decree, the materials used for transporting water should adhere to strict rules. Article 17g reads:
“The owner ensures that the materials and chemicals used in the extraction, preparation, treatment, storage, transport or distribution of tap water and the way in which they are used do not lead to materials and chemicals:
a. remaining in the tap water in a higher concentration than is necessary for the use of those materials or chemicals; and
b. having adverse consequences for public health.”
This might, at first glance, appear to offer some protection, but some research points to the fact that plastic pipes do not comply with this legislation, particularly when it comes to public health.
Around 54% of the Dutch water pipe network (64420 kilometers) is now made of PVC , while 25% of homes in the Netherlands have water pipes made of PVC or PE (polyethylene).
And this number is growing. PVC is cheap and durable, making it the preferred material for water pipes.
Since the 60’s, PVC has been the preferred material for water pipes, replacing those made of lead, concrete and cast iron. Around 47% of France’s public water network (416 800 kilometers) is now made from PVC. Many houses in France, especially those built in the last 30 years, also have PVC or PE (polyethylene) water pipes.
In Italy, 25% of the public water network was laid over 50 years ago and is in urgent need of being updated. According to the National Statistic Institute, over 40% of the water transported by these pipes leaks during transit. In some cities, as much as 70% of the water is lost this way. The worst affected zones are Chieti, Sicily, and Basilicata.
The public water network is managed at a regional level, which makes the task of updating the pipes enormous and very slow. For this same reason, it is hard to know exactly which materials have been used for water pipes. The most common are cast iron, brass, copper and PVC. If you live in a house built in the last 30 years, there’s a high probability that your water pipes are in PVC or PE.
The public water supply network in Germany is 530,000 kilometers long. Polyethylene (PE) has been used as a water pipe material since the 60’s. Evaluations from 2015 show that around 20% of the network consists of pipes made of PE. “From the estimated average age of the pipes – 35 years – we can conclude that polyethylene has become the standard pipe material in water supply. In 2015, 73% of the 16 million house connection lines were made of PE. When re-laying pipes, this plastic is the most chosen material,” says Dr. Elmar Löckenhoff, former managing director of the German plastic pipe association e. V. (KRV).
“If you have plastic pipes in your house, I strongly recommend that you let the water run for a while in the morning to get rid of water with a high concentration of chemicals,” Erik Arwin
Whether you have plastic pipes in your home or not, the chances are that your tap water has been through some of the PVC pipes in the public water distribution network. That means that it is likely to contain some of the chemicals mentioned in this article.
Several methods have been tested to eliminate BPA and other chemicals from water. These include reverse osmosis, carbon filtration, and biofilm reactors. The easiest way is to use a filter that’s proven to remove harmful chemicals from tap water.
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