Nickel in drinking water: causes, risks and what you can do about it

Nickel is mainly known for causing allergic skin reactions for many people on external contact. However, oral ingestion of the heavy metal, for example through nickel in drinking water, can also have harmful effects and should therefore not be underestimated.

In this Guidebook we have summarized for you...

• ... what nickel is and how it gets into Tapwater in the first place,
• ... which limit values for nickel are safe,
• ... the consequences of exceeding these limits,
• ... and what you can do yourself against nickel in drinking water.

Heavy metals such as copper, lead and nickel in drinking water: regulations and legal situation

Drinking water should naturally be free of pollutants and impurities and is therefore strictly controlled in Germany. The water must be tested regularly to ensure that it does not exceed the concentrations of pollutants specified in the Drinking Water ^Ordinance1. However, even if the water meets these controls , small amounts of heavy metals such as copper, lead and nickel can still be present in drinking water.

What is nickel?

Many people are mainly familiar with nickel as a trigger for dermatitis - the heavy metal causes one of the most common contact allergies worldwide. According to a study by the European Foundation for Allergy Research, which evaluated more than 100,000 patient data between 2005 and 2014, 15.5% of adults in Germany were already affected by nickel sensitization at that time³. This means that around one in seven Germans react to the heavy metal, with sensitization occurring more frequently in women.

Due to the correspondingly frequent allergic reactions to the metal, the use of nickel for articles of daily use that are in prolonged contact with the skin has been prohibited since 1994 by the EU Nickel Directive ⁴ and most recently by the EU-wide REACH Regulation ⁵_. However, it is not only various articles of daily use that can contain the heavy metal , but also our drinking water.

Although nickel is not soluble in water in its pure form, the metal is mostly used in the form of nickel-based alloys. As nickel alloys have proven to be resistant to corrosion and high temperatures, they are used in a wide variety of industries, as well as in everyday appliances. Particles of the metal can get into drinking water through such alloys. The following section explains exactly how nickel gets into our drinking water.

Nickel in drinking water: causes and transport routes

There is not just one single cause of nickel in drinking water, as the metal can enter via several different transport routes. The causes of nickel in drinking water, especially in groundwater, include, for example

• agricultural areas on which fertilizers containing nickel are used,
• untreated wastewater from industrial companies,
• as well as nickel-containing waste gases from waste incineration plants or industrial companies that seep into the groundwater after precipitation.

However, the metal can also get into the water through household items. Some saucepans or kitchen utensils, such as knives and chopping boards made of stainless steel, for example, can release very small amounts of nickel. This means that the metal can not only get directly into the food, but also into the wastewater when rinsing.

This should not actually be a problem, as our Tapwater is treated in waterworks before it reaches the end consumer. This ensures that the water meets the limits set by the drinking water supply before it reaches the end consumer.

Of course, in some cases limits may be exceeded - for example due to malfunctions at the waterworks ⁶. Unfortunately, however, the last mile of the water supply is often particularly problematic.

THE LAST MILE

The so-called last mile is the proverbial last mile, the last few meters that our water travels before it comes out of the tap⁷. This refers to the path of our drinking water from the house connection to the tap.

The last mile usually causes the greatest stress. This is because fittings, taps and water pipes may contain nickel or have nickel-containing coatings to protect the metal from corrosion⁸. If the water flows through these or stagnates in them, nickel can be released.

But is even a small amount enough to pose a risk to health? In the following, we clarify for you which limit value means too much nickel in drinking water.

When is there too much nickel in drinking water?

Waterworks monitor the nickel level in drinking water to ensure that it complies with the legal requirements of the Drinking Water Ordinance. In Germany (as in all other EU countries), the limit value for nickel in drinking water is 0.02 milligrams per liter. At the waterworks, the water is regularly checked for the concentration of pollutants such as nickel and treated.

Drinking Water Ordinance 2023

The amendment to the Drinking Water Ordinance approved in March does not provide for a reduction in the limit value for nickel in drinking water². Accordingly, the 0.02 mg per liter will continue to apply as soon as it comes into force.

Anything above 0.02 mg per liter is therefore too much nickel in drinking water. If the limit value is exceeded, the waterworks immediately take measures to reduce the pollutant content in the water. But how toxic is nickel really?

Is drinking water with nickel toxic?

The same applies to nickel as to many other harmful substances: The dose makes the poison. This is because nickel is poorly absorbed by the body - very small amounts are usually excreted unprocessed ⁹. Larger quantities, on the other hand, are problematic - if ingested, nickel can become toxic to the body.

IS NICKEL CARCINOGENIC?

Nickel and its alloys are all classified as carcinogenic. In this respect, the heavy metal is particularly dangerous if it is ingested in the form of fine dust via the respiratory tract ¹⁰. This poses a health risk, especially for people who come into contact with a lot of nickel dust in the course of their work.

However, a carcinogenic effect of the heavy metal due to oral ingestion has not yet been confirmed.

Too much nickel in drinking water: symptoms

According to a detailed report by the EFSA (European Food Safety Authority), there is an upper limit for the tolerable daily intake of nickel¹¹. This was set at 1.3 mg per kg body weight for adults and should not be exceeded. This is because, despite its relatively low toxicity when ingested orally compared to intake via the respiratory tract, exceeding the tolerable daily dose of nickel can have an impact on health. Nickel is therefore toxic, but only in very large quantities.

Excessive doses can be accompanied by stressful symptoms such as nausea or vomiting, although the long-term effects of constantly ingesting too much nickel are not yet fully understood. However, it is assumed that children in particular may be exposed to an increased risk of chronic effects as a result¹².

According to the EFSA report cited above, previous rodent studies also indicate other negative consequences of long-term exposure to high doses of nickel, such as organ damage or neurological deficits¹¹. However, there is not yet sufficient evidence for the same effect of the heavy metal on humans. Further negative effects on humans therefore still need to be researched.

Although it is unlikely that such symptoms are only triggered by nickel in drinking water, a certain group of people still need to take particular care when ingesting it: Allergy sufferers in particular suffer in some cases from nickel in drinking water.

The effect of nickel in drinking water on allergy sufferers

The effect of nickel in drinking water on people who suffer from a nickel allergy should not be underestimated, as the increased intake of the heavy metal could in some cases intensify allergic reactions.

There is reason to believe that oral ingestion of nickel may in some cases influence the frequency and severity of nickel contact dermatitis. The following symptoms can occur as part of an oral nickel allergy ¹³:

• Skin reactions such as pustules or eczema,
• gastrointestinal reactions such as nausea and abdominal pain,
• Fever,
• etc.

According to a statement by the Federal Environment Agency, an allergic reaction to the oral ingestion of nickel only occurs at relatively high doses¹⁴. However, it should not be forgotten that Tapwater isnot the only source of nickel in everyday life and the level contained in it must therefore be kept particularly low:

Many foods also contain nickel, which drives up people's daily nickel intake¹⁵. Additional nickel intake via drinking water should therefore be avoided as far as possible. A food-related low-nickel diet is only recommended for allergy sufferers on medical advice, as this involves major dietary changes due to the many foods containing nickel. Purifying water containing nickel, on the other hand, is an uncomplicated option to at least somewhat limit intake.

It is therefore particularly worthwhile for people with an intolerance to pay attention to their nickel intake through Tapwater . But what can you do to find out if nickel is present in Tapwater and what can you do about it?

Too much nickel in drinking water: what to do?

Do you suspect that your Tapwater may contain nickel? In this case, it usually makes sense to test the water quality. This way you can find out what condition your Tapwater is really in - you will find out how much nickel is in your drinking water and what you can do about it.

You can also use a professional test to determine whether other harmful contaminants such as heavy metals or germs and bacteria are also present. You can use the professional findings to plan further steps.

Once you have confirmation, you need to take action. The following measures can help against an excessively high nickel content in Tapwater :

• Allow the water to run briefly before use to avoid ingesting stagnant water, which is particularly susceptible to impurities such as nickel.
• Check whether your fittings and pipes are chrome-plated. If possible, replace them with nickel-free versions.
• Install a water filter that can filter out nickel.

A water filter is a particularly good option if the main cause is the pipes and fittings, which would require complicated building work to replace.

Water filter against nickel in drinking water

The heavy metal nickel may only be harmful to the body at relatively high doses. Nevertheless, its effects should not be underestimated. People who suffer from a nickel allergy in particular should pay attention to their daily nickel intake, depending on the status of their allergy.

Reducing the amount of nickel in drinking water is an uncomplicated option to reduce daily intake. By using a water filter, you can efficiently reduce the nickel content of your water - so you can be sure that your Tapwater is really clean.

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