Most drugs are designed to do good. This is also true of anticancer drugs. But as they are intended to kill cancer cells, they are toxic. This can also make them a danger to other cells, which is why the PHARMAS consortium decided to focus the largest part of its research on these toxic pharmaceuticals.

Antibiotics, on the other hand, have long been in the public eye for fear that overusing them will diminish their effectiveness and ultimately create antibiotic-resistant bacteria. Evidently, if they are present in the environment and potentially our drinking water, constant exposure of bacteria to antibiotics could contribute to resistance development.

To conduct a sound risk assessment, PHARMAS needed to measure environmental concentrations and effects on aquatic organisms. “We looked at algae as a single-cell plant, the water flea daphnia, a small invertebrate, and juvenile as well as adult fish,” explains project coordinator John Sumpter of Brunel University London.

“The results were very clear: it is possible to cause adverse effects, but you need very high concentrations of the drugs to do so, much higher than those found in the aquatic environment.”

PHARMAS measurements showed that anticancer drug concentrations in the environment were in the region of nanograms per litre. To cause adverse effects in fish or daphnia, milligrams per litre would be necessary. Furthermore, the researchers did not detect any traces of the pharmaceuticals in question in our drinking water. These are reassuring results at first glance.

‘Something for nothing’

What happens with mixtures of pharmaceuticals, though? For instance, a sample may contain 15 different kinds of antibiotics, each one of them at a concentration too low to cause a measurable effect. Yet, together, they will have an impact, creating ‘something for nothing’, PHARMAS found.

Mixtures of pharmaceuticals and chemicals in general are of great concern to the scientific community. “You have hundreds, if not thousands of chemicals circulating in your blood which were not in that of your grandparents,” Sumpter points out. “The question is not really: does the flame retardant in your blood cause an effect? The real issue is: does the collective mixture of chemicals cause an effect?”

Should the answer be ‘no’, there would be no reason to worry about individual substances, according to Sumpter. If the answer is ‘yes’, however, research would have to tease out which ones are of most concern and contribute most to the overall effect.

Research has its work cut out

In addition to encouraging the industry to develop new drugs that are ‘green by design’ and thus fully metabolised in the patient, the aim must be to identify the biggest culprits without testing all 3 000 pharmaceutical products and then reduce their usage. This is not an easy feat in itself, and even more difficult given limited resources.

In this context, a pharmaceuticals classification system would be a step in the right direction. It could help a medic determine which one out of 24 beta-blockers with the same clinical effect licensed in the EU, for instance, is the one of least environmental concern. Ultimately, this should alter doctors’ prescribing practices.

Work on such a system has already begun in Sweden, and PHARMAS used this as a basis for developing its own web-based prototype classification system. Improving and expanding this kind of tool to all 28 EU countries would, however, cost in excess of €100 million, Sumpter estimates.