Heavy metals in water: filtering copper, lead and co. out of drinking water

Some heavy metals are important for various functions of the human organism. Others, however, damage our bodies even in small quantities and therefore have no place in our drinking water.

But this is easier said than done. Due to a variety of circumstances, German drinking water still contains some worryingly high concentrations of certain heavy metals, most notably lead - even though its harmful effects have been confirmed many times over.

In this Guidebook , you will learn...

... what heavy metals actually are,
... which heavy metals are dangerous for our bodies and which are not,
... which heavy metals are found in German drinking water
... and how you can filter heavy metals, especially lead, from drinking water.

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Updated on: 08.03.2022

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What are heavy metals anyway?

The term heavy metals refers to a group of metals that are compiled based on different factors depending on the definition. The most common criterion is a high density of more than 4.5 or 5 g/cm3.

They occur naturally as a component of various rock strata and enter the water cycle through leaching or industrial processes.

Well-known examples of heavy metals are

Gold
silver
Platinum
Mercury
Iron

Copper
Lead
Zinc
Chrome
Uranium

Heavy metals and the human body

Our body needs some heavy metals - at least in certain quantities. These metals, known as trace elements, include copper and zinc, for example. However, our body cannot utilize many heavy metals, meaning that they are harmful if the concentration is too high (e.g. lead, cadmium, mercury or chromium)

Good to know

Heavy metals always become dangerous for us humans when they can no longer be excreted via the kidneys and intestines. This is because these substances then pass through our blood into various other organs, our bones or teeth, where they can accumulate and cause damage.

High concentrations of heavy metals, especially lead, are particularly problematic in infants. This is due to the fact that the central nervous system only develops over time and is therefore still very sensitive to various influencing factors, especially in infants. Numerous studies confirm that some heavy metals have a toxic effect on the child's nervous system. Evidence includes intelligence deficits, developmental disorders and poor concentration. ^{[1], [2], [3]}

Heavy metals in German drinking water

In principle, the German Drinking Water Ordinance ensures that our Tapwater does not exceed limits for certain pollutants, including numerous heavy metals^[4]. However, this is no guarantee that there are no heavy metals in the drinking water.

The biggest problem is the in-house pipes and fittings. Pipes made of lead or copper, for example, continuously release heavy metal particles into the water.^[5]

The best-known heavy metals in German drinking water include

Table header 0	Table header 1
Copper	Copper is a trace element that the human body needs to live. There are virtually no natural copper deposits in German soils and waters. Copper is used in agriculture as a fertilizer and feed additive. The metal enters the soil and groundwater with liquid manure. Water pipes are often made of copper. The drinking water ordinance limit is 2.0 mg per liter. Copper is only dangerous in very high concentrations. It can cause stomach and intestinal problems, colic and liver damage, among other things.
Lead	Lead is a natural component of the earth's crust. Lead pipes were used for drinking water installations until the 1970s. Especially if the water stands in lead pipes for a longer period of time, it can have a higher lead content. The limit value of the Drinking Water Ordinance is 0.010mg per liter. Lead remains in our bodies and can no longer be excreted for the most part. In adults, it can lead to kidney diseases and disorders in blood formation. Lead is particularly dangerous for infants and small children, as it can cause lasting damage to mental development.
Iron	Iron is an important trace element and is essential for blood formation. It is one of the most common metals in the earth's crust. The drinking water ordinance limit is 0.200 mg per liter. In principle, iron is not harmful to health. It only causes a metallic taste and turbidity in the water.
Nickel	Nickel is not soluble in water in its pure form, but nickel alloys are. It enters drinking water completely unnoticed through chrome-plated fittings with a nickel coating. The limit value of the Drinking Water Ordinance is 0.020 mg per liter. Nickel is only dangerous in very high concentrations. It is more likely to cause allergic skin reactions than other health problems. Excessive concentrations can lead to stomach and intestinal problems under certain circumstances.
Cadmium	Cadmium is a by-product of zinc, lead and copper extraction. Cadmium is also found in fertilizers and pesticides. It is not required for metabolism and is therefore completely undesirable in water. The limit value of the Drinking Water Ordinance is 0.0030 mg per liter. Cadmium can damage the kidneys, liver and bones in particular at high concentrations.
Chrome	Chromium mainly enters the environment through industrial wastewater. It has different properties depending on the oxidation state. Elemental chromium is often used as a coating for fittings. The limit value of the Drinking Water Ordinance is 0.050 mg per liter.

Lead in drinking water

Lead is one of the greatest dangers to German drinking water. For this reason, we take a closer look at this heavy metal here.

Good to know

The most common cause of high lead concentrations in drinking water is outdated lead pipes. These gradually release lead into our drinking water, usually without us noticing. Depending on how long the water has been in the pipe, sometimes alarmingly high lead concentrations can be detected in drinking water.

Legal situation

This is despite the fact that the legal situation in this regard is actually very clear: the installation of lead pipes has been banned in Germany since 1973, as they pollute drinking water too much. In 2013, the limit values for lead in drinking water were also tightened.

Since then, a limit of 0.010 mg lead per liter of water may no longer be exceeded. As this limit can only be adhered to if the drinking water does not flow through lead pipes, a large proportion of outdated lead pipes have been replaced as a result.

However, lead water pipes that have not been renovated can still pose a problem, particularly in old buildings. ^[6]

Lead wires can be recognized by bulging solder joints

How to recognize lead pipes?

If you live in old buildings from before 1973 and are not sure whether lead pipes are still being used in the building installation, you should ask the building owner, property manager or janitor about this. You can also call in a specialist, have the lead content of your water tested by an approved testing body by taking a sample or check the visible pipes for lead yourself.

How to identify lead pipes:

If you tap on lead pipes, you will not hear a metallic sound but rather a muffled noise.

Lead lines can be recognized by their sound

Lead wires are soft and can be scratched with
a coin.

Lead pipes are not magnetic.

Lead pipes are sometimes laid in curved lines as they are very flexible.

Lead pipes are flexible and often laid in curves

Lead pipes are silver-grey unless they have been painted.

Lead pipes do not have screwed connections but bulging soldered joints and often have an irregular diameter.

Filtering lead from drinking water: With what?

In principle, three different water filters are suitable for lead filtration. However, all of them have both advantages and disadvantages.

Ion exchange filter

With ion exchange filters, the lead ions in the water are exchanged for harmless sodium ions. However, such filters only have a limited exchange capacity and must be cleaned and regenerated when they are completely saturated. The biggest problem here is that the ion exchangers do not indicate when their maximum capacity has been reached. This means that saturation can quickly go unnoticed.

Reverse osmosis filter

Reverse osmosis filters purify the water using an extremely fine membrane. Lead compounds cannot penetrate this membrane and are therefore filtered out of the drinking water. However, this also leaves behind some minerals, which means that the drinking water has to be remineralized after filtering. Reverse osmosis filters also require a relatively large amount of water and energy, as the membrane has to be flushed regularly.

Activated carbon filter

Activated carbon filters make use of the adsorption capacity of activated carbon by using it specifically to filter pollutants out of the water. However, the type of activated carbon is very important here. Poured activated carbon, as used in table-top can filters, is strongly discouraged as it carries a relatively high risk of contamination. risk of contamination risk of contamination.

Good to know

So-called activated carbon block filters are better, as they have a much higher adsorption capacity and pose fewer risks. With activated carbon block filters , however, it is also important to ensure that the cartridges are replaced regularly, otherwise the filter will lose its effectiveness.

Water filter as protection against heavy metals in drinking water

Despite the Drinking Water Ordinance and corresponding laws to reduce heavy metals in drinking water, German water contains high concentrations of heavy metals, at least in some cases.

To protect yourself from unwanted metals, it is advisable to purify the water with a suitable filter process before drinking. The quality of the drinking water filter is of paramount importance here, as this is decisive for the success or failure of the filtering process. It is also essential to check your pipes and have them replaced, especially in the case of lead pipes.

FAQs

How do heavy metals get into the water?

Heavy metals get into the groundwater and then into our drinking water due to emissions and contaminated sites from factories, particulate matter and overfertilization in agriculture via rainwater and seepage water. In addition, certain pipelines release heavy metal particles into the Tapwater .

Are heavy metals harmful?

There is no one-size-fits-all answer to this question. On the one hand, there are some heavy metals that are essential for our body, at least in certain quantities. These include iron, zinc and copper, for example. On the other hand, other heavy metals such as lead, cadmium or mercury are harmful to the human organism.

Can lead be filtered out of the water?

Yes, you can filter lead out of your drinking water with a suitable water filter. However, for a permanent solution, it would be advisable to replace any old lead pipes and thus reduce the risk of lead in drinking water many times over.