The widespread contamination of ecosystems with pharmaceuticals poses a serious and growing threat to biodiversity, ecosystem services and public health.
Urgent action is needed to design greener drugs that maintain efficacy while minimising environmental impact, according to an international study published in Nature Sustainability and involving Monash University researchers.
"In our increasingly medicated world, pharmaceuticals are essential to modern healthcare, having revolutionised disease prevention and treatment," said co-lead author of the study Dr Michael Bertram, an Assistant Professor at the Swedish University of Agricultural Sciences, Umeå, Sweden, who also holds an adjunct position at the Monash University School of Biological Sciences.
"However, our growing dependence on pharmaceuticals comes at a major cost," he said.
"Discharges during drug production, use and disposal have led to global contamination of ecosystems with mixtures of pharmaceuticals and their breakdown products. In fact, when patients take medicines, only a portion of those drugs are absorbed by the body, with the remainder being excreted and often released directly into the environment."
Pharmaceutical contaminants have now been detected in environmental samples and the tissues of wildlife across all continents on Earth, including Antarctica. The pervasive spread of these contaminants, which are also found in groundwater used for drinking water, has led to the inclusion of several pharmaceuticals as priority substances in the new update to the European Water Framework Directive, a Europe-wide wastewater regulation.
"Evidence has been mounting for decades that trace concentrations of pharmaceutical pollutants and their mixtures can cause severe developmental, physiological, morphological, and behavioural changes in wildlife," said co-author of the study Professor Bob Wong, from the Monash University School of Biological Sciences.
"For example, male fish exposed to estrogens found in the birth control pill exhibit feminisation and reproductive failure, leading to population collapse, while vultures exposed to anti-inflammatory drugs have undergone severe population crashes due to toxic effects," he said.
"The impacts of pharmaceutical pollutants can have cascading effects on the ecology and evolution of wildlife populations and communities, potentially causing population declines and local extinctions."
Pharmaceutical pollution poses threats to both wildlife and humans, such as the release of antibiotics into the environment promoting the spread of antibiotic resistance genes.
This issue is exacerbated by other anthropogenic pressures, including climate change, habitat destruction and invasive species. Interactions between chemical pollutants and these other stressors can be additive or synergistic, further endangering biodiversity and ecosystem services.
"To address drug pollution, we urgently need to implement strategies to minimise environmental impacts across the entire pharmaceutical life cycle," said study co-author Dr Lauren May, from the Monash Institute of Pharmaceutical Sciences.
"This includes promoting sustainable prescribing practices, increasing public awareness about the environmental impact of medicines, enhancing wastewater treatment processes, and actively pursuing eco-friendly drug design," she said.
"Key to tackling this issue at its source is the design of greener pharmaceuticals that degrade more rapidly and completely in the environment," says co-author Dr Manuela Jorg, also from the Monash Institute of Pharmaceutical Sciences.
The researchers say that greener pharmaceuticals should be designed for environmental degradation. The study argues that regulatory agencies should set standardised cut-off values for environmental persistence of pharmaceuticals, to limit the presence of harmful drugs in the environment.
