Drug residues in drinking water are a growing problem, according to environmental experts. More than 150 active ingredients have been detected several times in the environment in research projects and special measurement programs – mostly in lakes, streams and rivers. According to the Federal Environment Agency, the most common substances found in the environment and, accordingly, in our drinking water are antihypertensives, beta blockers, antiepileptics, painkillers such as diclofenac and ibuprofen, antibiotics and, above all, X-ray contrast media. Researchers suspect that given the aging society and the associated increased consumption of medications, water contamination will continue to rise.
Drugs enter the water cycle through many pathways
How do drugs get into drinking water? Let’s look at this question using diclofenac as an example: around 85 metric tons of the painkiller are consumed in Germany every year. However, 70 percent of the active ingredient leaves the body again naturally – ending up in wastewater. Around 60 metric tons of diclofenac enter the water cycle through urine.
If a person drinks an average of two liters of water a day throughout their life, they will consume over 50,000 liters of water in 80 years. It is almost impossible to calculate how many drug residues are absorbed in the process.
Very little is known about possible reactions when all the residues of the 3,000 or so drugs approved in Europe come together. However, it is known from the animal world that in fish, for example, living at sewage treatment plant outlets, sex changes have been observed after estrogen intake (ethinylestradiol from the contraceptive pill).
Drugs in water: improper disposal and animal husbandry
However, according to the Federal Environment Agency, another problem is that ignorant or overly convenient consumers simply dispose of unused or expired medicines in the toilet or sink. From there, they end up in groundwater and surface water. Conventional sewage treatment plants and water treatment technology are usually poor at filtering the residues.
And another problem arises thanks to intensive livestock farming: due to the slurry treatment of meadows and fields, there is an additional load of drugs from veterinary medicine – antibiotics, hormones, etc. In fish farming, antibiotics and vermifuges are discharged directly into surface waters.
Need for research exists
True, the detected agents in drinking water are many times lower than the prescribed daily dose. But that does not mean they are harmless. A scientifically based assessment of the risk does not yet exist. In particular, the effect that could result if consumers ingested several active ingredients simultaneously in low concentrations via drinking water for many years is still unclear.
But there is a great need for research in this area. This is because two very worrying trends are associated with drug residues in water: the increasing incidence of fertility disorders and of multiresistant microorganisms.
