Water Quality

Yes, not only Berliner Wasserbetriebe says that, but also the German Environment Agency (Umweltbundesamt). It recently certified that especially the drinking water from larger water supplies is of “excellent quality” (press information dated 12/2/2015, http://www.umweltbundesamt.de/presse/presseinformationen/deutsches-trinkwasser-erhaelt-wieder-die-note-sehr). And: Berlin’s tap water is drinking water. This is not only a name, but rather says that our water is subject to the requirements of the Drinking Water Ordinance (Trinkwasserverordnung) – the strictest food regulations in Germany.

Trace substances are chemical compounds that occur in water in very low concentrations  – that is, within a range of one microgram (μg) per litre or less. The organic trace substances in surface water, groundwater or drinking water include, for example, pharmaceutical substances, industrial chemicals and artificial sweeteners. By way of explanation: One microgram is one millionth of a gram.

In Berlin there is a natural water cycle: Berlin’s drinking water – as in most other areas of Germany – is abstracted from groundwater and bank filtrate. Our waterworks draw water from the soil through deep wells, which has previously infiltrated and percolated there – through precipitation and from surface waters (which is the bank filtrate). The water reaches the citizens through the pipe network and after they have used it, it is returned through the sewer system to the wastewater treatment plants. There it is treated and then discharged into waters such as the Tegeler See lake, the River Spree or the Teltow Canal. The cycle starts all over again.

Organic trace substances enter the water cycle in different ways: air, wastewater treatment plants, rainwater gullies, sewage sludge - or waste disposal or contaminated sites. Human medicinal products primarily get into wastewater via the toilet, pass through the wastewater treatment plant and from there they get into the water cycle. It is therefore important that expired or no longer needed medicines are never disposed of down the toilet, but are handed in to the hazardous substance collection points of the waste management company, BSR (www.bsr.de).

Berliner Wasserbetriebe analyses its water for a range of trace substances and publishes the analysis values on the internet (www.bwb.de/wasser). All these substances exist in concentrations in the order of micrograms (μg) per litre – some with far smaller concentrations. One μg is one millionth of a gram. Two examples clearly illustrate what this quantity means: 1 μg/L is as if you were to dissolve a sugar cube in as much water as can be carried by 100 road tankers. Or in other words: A tablet contains 400 milligrams of active ingredients (that is 400,000 micrograms, i.e. four million times as much as in one litre of drinking water.) To ingest this dose through drinking water, you would have to drink two litres of it a day – for more than 2,000 years.

A note on measuring: Measurement methods and instruments are becoming increasingly finer – but this does not mean that what is measured can always be assessed. Science – and we too – has this problem with numerous trace substances that we find in the water cycle. An example of the fineness of today’s measuring instruments: If, after ingesting an X-ray contrast medium, you went to the toilet and the contents of the toiler flowed untreated into the Tegeler See lake (which naturally does not happen), we could then measure this X-ray contrast medium. (The calculation behind this: Assumption - 26g X-ray contrast medium in 26 million cubic metres of water.) However, at present it is not yet known how harmful it is for the animals in the lake and later for the water cycle and the drinking water. There are therefore so-called indicative health values (GOW - Gesundheitlicher Orientierungswert).

A GOW is not a limit value, but merely a precautionary value for substances that cannot yet be conclusively assessed. They are very conservative values. Their short to medium-term exceedance (up to ten years) by three to ten times the limit “does not give any cause for health concern” according to the German Environment Agency (UBA). In simpler terms: GOW are values with built-in safety margins, in order to exclude a health hazard. (Source: German Environment Agency (UBA), The German Federal Institute for Risk Assessment (Bundesamt für Risikobewertung - BfR).

If, thanks to our modern measurement methods, we find new substances in the drinking water, we report them to the Berlin State Office for Health and Social Affairs (Landesamt für Gesundheit and Soziales - LAGeSo) and the UBA as the competent authorities and apply for a GOW. If a GOW is exceeded, water suppliers must consult the health authorities and agree short and medium-term measures to be taken to minimise this value. We do this (see Question 8).

Limit values (limits) are maximum concentrations for natural constituents, active ingredient residues and environmental pollutants in food, commodities and also in water and the air. These values are specified in laws and ordinances. If they are exceeded, the responsible establishments – this can be water companies, as well as industrial companies or pharmaceutical producers – must take immediate steps to reduce the values and to prevent hazards. The German Drinking Water Ordinance defines a range of limits for lead, cadmium, sodium and uranium, for example. Berlin's drinking water achieves values that are far below these limits. You can also find information on water quality, the constituents and the Drinking Water Ordinance here: www.bwb.de/wasser.

For Berliner Wasserbetriebe, safeguard the high drinking water quality is its highest priority,which is why we monitor our drinking water at more than 3,300 monitoring wells, for example, at the groundwater wells, in the waterworks and in the pipe network.

In addition, Berlin Wasserbetriebe together with the competent authorities, LAGeSo and UBA, as well as the scientific institutions test further steps that lead to permanent reduction of the trace substance concentration in the entire Berlin water cycle. These steps include the use of ozone, flocculation filtration and activated carbon for further wastewater treatment in Schönerlinde wastewater treatment plant and the implementation of a further 4 treatment steps in our other four wastewater treatment plants.

In addition, we sample and analyse the collected raw water and the drinking water in the waterworks continuously, two to three times a week. The some 650 wells and quality monitoring wells within the catchment area of the waterworks are additionally sampled and analysed at least once a year. This monitoring extends beyond the legal scope specified in the Drinking Water Ordinance.

Moreover, for years Berliner Wasserbetriebe have actively participated in numerous research projects concerning the detection, assessment and reduction of trace substances in the water cycle. For example, the ASKURIS research project (askuris.tu-berlin.de), which is concerned with finding, assessing and removing trace substances in the water cycle and has supplied us with valuable information on wastewater treatment. In other projects, together with partners in science, we examine trace substances in Berlin’s surface waters and rainwater outlets/gullies and test how to integrate the removal of trace substances into the further treatment stage of wastewater treatment plants. Further information about research and development at the Berliner Wasserbetriebe is available at http://www.bwb.de/forschung.

Every single one of us can do their bit to reduce  trace substances, for example, by targeted and sparing taking of medicines. Ask your doctor whether they know anything about the environmental integrity of the prescribed medication and whether there is an equally effective alternative that is less harmful for the environment and the water cycle. Because there are medicines that are completely degraded in the wastewater treatment plant or on the way into the groundwater at the latest. It is also important that you never throw away unused or expired medicines in the toilet but instead dispose of them in an environmentally compatible way through the hazardous substances collection points of the BSR (www.bsr.de). Cleaning agents and other chemicals should be used sparingly and never thrown away in the toilet. The same applies to paints and varnishes, because they also otherwise get into the water cycle.

On www.bwb.de/wasser you will not only find information about trace substances but also about the constituents in water in general. The precise analysis values of our waterworks are published there. The ASKURIS research project (Anthropogenic Trace Substances and Pathogens in the Urban Water Cycle: assessment, barriers and risk communication) also has an internet site on which lots of information on the topic is published: www.askuris.de. Further information is also available, for example, on the internet sites of the German Environment Agency www.uba.de, the Berlin Centre of Competence for Water, www.kompetenz-wasser.de, the Micropollutants Competence Centre Baden-Württemberg, www.koms-bw.de, the German Association for Water, Wastewater and Waste (DWA) www.dwa.de and the RWTH Aachen university, www.spurenstoffe.net.