It is known as the ‘new asbestos’ and is increasingly in the news: chromium-6, a toxic metal that is dangerous to health, is present in our drinking water. “Chromium-6 may be present in our water pipe network,” says René Nuij, operational safety expert at Waternet.
The fact that chromium-6 is harmful to health became apparent in Brabant between 2004 and 2011, when maintenance work was being carried out in Tilburg for railway company NedTrain. During the grinding work, chromium-6 was released. As a result, some of the 33 workers suffered health damage. The case went to court, and NedTrain was found liable for the damage suffered by the victims. According to the court, NedTrain should have known that the workers would be exposed to very dangerous substances.
Chromium is a metal that is found in the air and in the soil. The most common forms of chromium are chromium-0, chromium-3 and chromium-6 (also known as hexavalent chromium). Not all forms of chromium are toxic. Chromium-3 is present in certain foods, and does not harm health. In fact, not getting enough chromium-3 can even increase the risk of diabetes. Chromium-0 and chromium-6 are produced by industrial processes. The metal chromium (the chromium-0 form) is used for making steel. Chromium-3 and chromium-6 are used for chrome plating, dyes and pigments, leather tanning, and wood preserving.
Chromium-6 is formed and released when materials containing chromium-0 or chromium-3 are processed with heat, for example during the grinding work in Tilburg, or during sanding, welding or combustion work. Inhaling chromium-6 can cause nasal irritation and nose bleeds. It can also cause long-term health problems, such as DNA mutation, respiratory issues, kidney and liver damage, weakened immunity, and many cancers.
The chrome-containing paint used on the trains in Tilburg has now been banned. Nevertheless, the metal is still regularly released into the environment because this type of paint is still present in many old buildings. During renovation or maintenance works, chromium-6 can end up in the air, soil and possibly in surface water: our drinking water source. The water solubility of each chromium-6 compound differs, up to 1667 grams per litre [this information needs to be checked – is there a reference available from NL writer?]. And that is important, because the extent to which chromium-6 dissolves in surface water affects drinking water.
Various chromium compounds can be present in water. The quality requirements for drinking water are dictated by the Drinking Water Decree, which is based on the European Drinking Water Directive and advice from the World Health Organisation (WHO). The maximum amount of total chromium in drinking water and natural mineral water is 50 micrograms per litre. As yet, there is no set standard for chromium-6 alone. When the total chromium limit in drinking water is exceeded, a drinking water company is obliged to stop supplying consumers.
Drinking water companies must also sample and test chromium at the tap via a Random Day Time (RDT) test. This sample is representative of the amount of metal that a consumer ingests weekly from drinking water. Measurements taken between 2004 and 2006 showed that chromium-content sporadically exceeded the standard. In 2019, the National Institute for Public Health and the Environment (RIVM) issued a reassuring statement: “There is no health concern due to exposure to chromium-6 through food or drinking water.” According to the RIVM’s report, concentrations of chromium-6 in drinking water in the Netherlands are “very low”, but in urban areas the concentration in the air is higher.
In areas such as in IJmuiden, the smoke plumes from steel giant Tata Steel contain chromium-6. The company produces questionable amounts every year. “According to the 2016 annual report, the emissions amounted to 7,79929052 kilograms per year. In the 2017 annual report: exactly the same number. In 2018 and 2019: ditto. How credible is that?” says Jacob de Boer, professor of environmental chemistry and toxicology at VU University Amsterdam.
Despite a ban on chromium-6, the metal has not completely disappeared from our society. In fact, you can find it in all kinds of products, such as cosmetics, plastics, dyes, preserved wood, cement, leather and tattoo ink.
Partly for this reason, the Belgian newspaper De Morgen has placed chromium-6 in the top 10 substances that threaten our soil and waterways where we extract our drinking water. “We had known for some time that chromium-6 was present in the soil, but recently we also learned that buildings and waterways are contaminated with it,” says Jan De Vos, environmental engineer and soil expert. “We were already aware of the dangers of lead paint and asbestos, but chromium-6 also appears to be a serious problem that must be taken into account during demolition work. The EU has already drastically curtailed their use, but historical pollution also needs to be addressed.”
In the United States, the problem became known to the general public thanks to the film Erin Brockovich, which is based on a true story. Lead actress Julia Roberts plays a lawyer who helps the victims of contaminated groundwater. It remains to be seen whether such a disaster can also be expected in the Netherlands. Nevertheless, the attention is growing. René Nuij of Waternet issues a warning in his ‘Security Heroes’ campaign of the Ministry of Social Affairs and Employment. “We have recently also been dealing with chromium-6. We have piping in which chromium-6 may be present. I think it’s my role to warn.”
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1963 – WHO guideline: 50 micrograms of total chromium per litre of drinking water.
1998 – RIVM study: in 17 drinking water sources and 2 intake points chromium-6 concentrations are found in surface water.
2000 – American film Erin Brockovich premieres about chromium-6 drinking water drama in California (US).
2011 – Drinking Water Decree: guideline of 50 micrograms of total chromium per litre remains enforced.
2014 – Parliamentary debate after news that the Department of Defence already knew that in 1987 maintenance personnel were not adequately protected against chromium-6.
2016 – Independent committee: NS and the municipality of Tilburg guilty of exposing hundreds of employed Tilburgers to chromium-6.
2021 – Public Prosecution Service to criminalise NS; the municipality of Tilburg prosecutes.
