Drug residues in drinking water

Drug residues put a strain on drinking water in Berlin
Drinking water in Berlin is burdened with a relatively high concentration of drug residues. The researchers came to the conclusion when investigating the water on remnants of magnetic resonance imaging or magnetic resonance tomography (MRI) contrast agent gadolinium. The values ​​determined are considered as an indicator of the total load of drinking water with residues of medicines.

Drug residues enter the drinking waterr
Professor Michael Bau from Jacobs University Bremen and doctoral student Serkan Kulaksiz have investigated the residues of the MRI contrast agent gadolinium in a comprehensive study, the drinking water in Berlin, and then mapped their results. The measured gadolinium concentration serves as an indicator for the general load of the drinking water with residues of medication. As such, the MRI contrast agent is particularly well suited because the toxicant is wrapped with a non-toxic chemical compound before use or incorporated into sheath molecules to prevent absorption (uptake by the organism). Thus, the human body excretes the altered, so-called anthropogenic gadolinium (Gd) a short time after intravenous administration or injection again completely. The anthropogenic gadolinium passes through the toilet into the wastewater, but can not be degraded or removed there because it is virtually immune to chemical reactions due to the mantle molecules. Thus, the MRI contrast medium with the purified sewage water reaches the Teltow Canal as well as the Spree and Havel. From there, gadolinium makes its way via groundwater to Berlin's over 800 drinking water wells and back into tap water.

Gadolinium concentration as an indicator of drug residues
Since many drugs and drugs take the same route, the gadolinium concentration in the eyes of scientists is only an expression of the general burden of drinking water with drug residues. „Because numerous drugs and their degradation products behave similarly to the gadolinium-containing contrast agents, high levels of contrast agent gadolinium are a clear indication of increased levels of drug residues in drinking water“, the Bremen researchers explained the approach of their report. And they added that „in contrast to non-toxic gadolinium from contrast media according to the current state of knowledge, however, such drug residues may be hazardous to health.“ This raises the question of what burdens and health risks citizens of Berlin face every day due to the concentration of drugs in drinking water.

Downtown area and West Berlin most affected
As an approach to spatial differentiation, Professor Michael Bau and Serkan Kulaksiz have mapped the gadolinium concentration. It turns out that the load of drinking water in the different parts of Berlin turns out to be very different. Generally more affected is the inner city area and the west. The Reichstag Reichstag measured 17.62 ng / kg of Berlin's highest concentration of gadolinium, closely followed by the Zoologischer Garten and the Kurfürstendamm. In Friedrichshain and the old town of Spandau, on the other hand, only values ​​of 0.15 ng / kg were determined, which was below the respective natural gadolinium concentration (0.33 and 0.42 ng / kg). Throughout East Berlin, only the district of Mitte was affected by an increased concentration.

Health risk can not be excluded by other medicines
The gadolinium concentrations were not high enough at any of the measurement points to be hazardous to health, emphasized Professor Michael Bau and Serkan Kulaksiz in their study. However, against the background that the residues of the MRI contrast agent are only an indication of the general drug load of the drinking water, a health risk from other drug residues can not be ruled out. Therefore, the next step should be targeted to search for drugs that can be harmful even in minimal concentration, the scientists said. For example, they are thinking of female sex hormones from oral contraceptives and certain antidepressants because the effects on the sex development of fish have already been scientifically proven for the corresponding hormones. What effects these have on humans and whether they can be cause for infertility here, too, is not yet clear. Nevertheless, caution seems necessary in view of the sometimes greatly increased values, and everyone should be aware that taking medicines can also be associated with stress on drinking water. (fp, 08.10.2010)

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Picture credits: Rainer Sturm