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 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 by German chemist Eugen Baumann in 1872.
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.
But we may be paying a price for PVC’s durability. 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 chemicals into the water. Esters, aldehydes, aromatic hydrocarbons and terpenoids were all found in water samples.
According to the 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 the research points to the fact that plastic pipes do not comply with this legislation, particularly when it comes to public health.
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.”
Some of the substances that end up in the water from plastic pipes are harmful. One example is 4-tert butylphenol, found in concentrations of 6.6 nanograms per liter in some water samples. This chemical disrupts hormones and lab tests show that it can cause reproductive abnormalities.
Plasticisers like phthalates, which are chemicals that are added to plastics to make them more flexible, have also 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.
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 over 60 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 (a hormone-disruptor found in plastics).
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.
Arwin 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.
But not everyone is on the same page. Wim van de Meent, of Kiwa, the institute that inspects water pipes, disagrees with Arwin’s and Soto’s position. According to him, research shows that up to 900 micrograms of 4-tert butyl phenol per liter is not harmful to health [reference needed? None noted in NL article]. As for the other substances, they occur in such low concentrations that they are negligible. That being said, the total amount of chemical residues in water should remain within the set standards of 2 milligrams per liter. Van de Meent is not convinced there is a problem, but says “It’s good that there’s a discussion about it.”
Kiwa is responsible for inspecting water pipes every year, on the basis of manufacturer specifications. According to Van de Meent, these checks are not watertight because the manufacturer information is not always correct. “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,” concludes Arvin.
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