Pharmaceutical residues in fresh water pose growing environmental risk: study

Pharmaceutical concentration in the world’s freshwater sources have reached the point of potentially causing damaging ecological effects, according to a study published today in Environmental Research Letters.

Researchers on the study say levels of the antibiotic ciprofloxacin have increased significantly over the past 20 years and more widespread data gathering is needed around the world to truly understand the full impact.

“Getting an accurate picture of the environmental risks of pharmaceuticals around the world depends on the availability of data, which is limited,” said Rik Oldenkamp, lead author of the article and AIGHD postdoctoral fellow, adding that existing models are often only applicable to places where a large amount of data already exists, such as rivers in Europe.

The new model developed by the researchers, which builds on an existing model with a lower resolution, makes it possible to come up with worldwide predictions for individual ecoregions.

For the two pharmaceuticals investigated in the study – carbamazepine, an anti-epileptic drug, and ciprofloxacin, an antibiotic – the environmental risks were found to be 10 to 20 times higher in 2015 than in 1995.

This study was completed during Rik’s tenure at Radboud University and is linked to his current work at AIGHD, which seeks to better understand antimicrobial resistance (AMR) patterns and drivers. AMR is one of AIGHD’s research priorities.

“As a modeler with an interest in human health, I always look for new challenges and the fact that AMR is so complex makes me want to contribute to solving it,” he said. “AMR is not linear – it constantly adapts and evolves and is an urgent global health issue. The first step is to better understand what causes it, then we can predict what we can do better and ultimately come up with proactive solutions.”

While it would take a significant amount of exposure to pharmaceutical contaminated water for humans to suffer direct effects, the potential indirect effects of antibiotics in the environment, such as the development of AMR, are still largely unknown.

“Generally, antibiotic resistance is seen as a problem for the health sector, as resistant bacteria can be spread within hospitals or through livestock but there’s little awareness of the role of the environment in this problem, why is which our work in this field is so crucial,” he added.

“If we can better understand how antibiotic resistance occurs and spreads, we can create more tailored prevention and treatment efforts. It’s a field where there’s a lot to gain still in terms of understanding.”

Read Rik’s full study, Aquatic risks from human pharmaceuticals – modelling temporal trends of carbamazepine and  ciprofloxacin at the global scale, in Environmental Research Letters.