Do you also drink your coffee with Viagra?

Into a fresh glass of water from the tap, this can be a wonderful experience, especially on hot summer days. You feel fresh again, well chilled – and as a man, possibly even pleasantly aroused.

Because Dutch researchers have now discovered considerable traces of the active ingredient Sildenafil - better known under the brand name 비아그라 - in the wastewater. And that's just one of many medications that can get into our bodies in the morning through a cup of coffee.

A research team led by Bastiaan Venhuis from the National Institute for Public Health and the Environment analyzed 비아그라 구매 residues in the sewage of Amsterdam, Eindhoven, and Utrecht and compared the readings obtained with the number of prescriptions issued for the drug in the selected cities.

It turned out that the drug residues in the water were 60 percent higher than they should have been according to the prescriptions. "There is obviously a lot of sildenafil in circulation from the black market in the Netherlands," concludes Venhuis. And its residues end up in the water cycle just like their properly traded counterparts.

The researchers have not investigated what concrete consequences these drug residues have in nature. So whether, for example, frogs and fish or even people have changed their sexual behavior as a result.

But one should not underestimate this risk. At the beginning of 2013, a study presented at the annual meeting of the American Association of Scientists caused a sensation, according to which the residue of a popular tranquilizer in the water can turn even an otherwise shy bass into an adventurous daredevil.

The Swedish research team led by Tomas Brodin from Umeå University examined oxazepam concentrations in a sewage treatment plant and a neighboring river in Uppsala, and in the muscle tissue of perch caught there. Measurements using liquid chromatography and mass spectrometry revealed that the anxiolytic substance in the animals was six times more concentrated relative to the water in which they were swimming. And, as the researchers were able to demonstrate in experiments, this does not remain without an effect on the behavior of the fish.

On the one hand, he becomes more active and curious, but on the other hand, he becomes more antisocial and gluttonous. "Normally, perch are shy and hunt in schools, which is part of their survival strategy," explains Brodin.

"But under the influence of oxazepam, they become significantly braver and more solitary." It is worrying that the levels of a drug found in the environment could have such an effect.

Hundreds of tons in the German water cycle

And what causes concern in Sweden is even more true for pill-loving Germany. For here alone, those with statutory health insurance are prescribed nine pharmaceutical packs with 520 defined daily doses per capita and year.

In every seventh household, many medicines are not even swallowed, but disposed of through the toilet flush; and those that are ingested cannot be fully absorbed by the body, and it excretes up to two-thirds of them.

That adds up to several hundred tons, and they enter the water cycle almost unaffected. Because if humans cannot completely absorb a substance, neither can a sewage treatment plant that focuses on biological degradation.

Washed down antibiotics make bacteria resistant

It is, therefore, no wonder that more than a hundred medicinal substances have already been found in German waters - from antibiotics to painkillers to X-ray contrast media. How all this affects nature has so far been little researched. But we now know that antibiotics inhibit the growth of algae in the water and that the hormone residues of the birth control pill can cause entire fish populations to die out.

The painkiller diclofenac can damage the gills and kidneys of fish. At the Leibniz Institute for Freshwater Ecology and Inland Fisheries in Berlin, they were surprised when, of all things, the thyroid gland of frogs atrophied under the influence of progestin, a female sex hormone - they had expected an effect on reproduction. But a drug can have a completely different effect in the water of a river than in the body of a human, who also reacts very differently from that of an amphibian.

After all, the two-legged friend does not necessarily have to fear that he will die out due to the hormone residues in his coffee, because the water has come such a long way to his cup that drug residues are only present in the nanogram level. Nevertheless, the intake of medicated water has an effect on him as well.

Because the medicinal traces are combined hundreds of times in the drinking water, the consequences of this mixture can hardly be estimated. In addition, the funds often have an indirect effect on people through the back door. If, for example, antibiotics are released into nature, they promote the development of resistance in bacteria, which the patient will feel at the latest when his infection no longer reacts to antibiotic therapies.

Disposal system for old medicines

Reasons enough, not only for ecological reasons but also for self-protection, to bring the drug residues in the water under control. Some sewage treatment plants are already experimenting with activated carbon and ozone, but the hopes placed in them have not yet been fulfilled. Dresden physicists and engineers are therefore working on irradiating water with highly active UV light in order to destroy the structures of the pollutants.

Although the EU directives take into account the environmental problems of medicinal products, only newly approved preparations have to undergo appropriate compatibility tests. Classics such as the painkiller diclofenac and the antiepileptic carbamazepine, on the other hand, are exempt from this, although they have been repeatedly detected in the water cycle. A few years ago, the carbamazepine used to treat delusions even flowed out of the taps of the Reichstag in Berlin.

It would therefore be important that at least the unused medicines are not simply flushed down the toilet. For this, as Jürgen Resch from the German Environmental Aid warns, a “uniform and binding collection system for old medicines” is needed.

There has been a corresponding EU directive for ten years, but it has not yet been implemented in Germany. Therefore, only a few of the more than 20,000 pharmacies in Germany welcome their customers with open arms when they want to dispose of their medicines.