Salmon like these are dying prematurely at fish farms in Norway - Copyright AFP BAY ISMOYO
With pharmaceutical waste, the goal is maintaining safety, environmental responsibility, and legal compliance.
Despite some technological advances and greater adherence to regulations, pharmaceutical waste remains an environmental concern. In many parts of the world, water entering the streams from wastewater treatment plants that are designed to break down pharmaceutical manufacturing waste contains concentrations of pharmaceuticals between multiple times higher than water released into the environment from standard utility plants.
Pharmaceutical waste includes antimicrobials (fuelling antimicrobial resistance among pathogenic species of bacteria), muscle relaxants, and opioids.
As well as environmental pollution, there are concerns about pharmaceuticals that are not processed but instead enter into illegal markets. Many nations have regulations designed to prevent this, such as the US Drug Enforcement Administration (DEA), which requires all controlled substances to be destroyed in a way that renders them "non-retrievable"; however, this does not entirely prevent theft and illegal trading.
Clobazam pollution
In terms of environmental impact, a recent study conducted in Sweden demonstrates the risks. Research reveals commonly detected environmental levels of clobazam -- a medication often prescribed for sleep disorders -- increased the river-to-sea migration success of juvenile salmon in the wild.
In addition, traces of the drug shortened the time it took for juvenile salmon to navigate through two hydropower dams along their migration route -- obstacles that typically hinder successful migration.
Clobazam is used for its anxiolytic effect and as an adjunctive therapy in epilepsy. The drug is a type of benzodiazepine, a class of central nervous system depressant medications. Clobazam has two major metabolites: N-desmethylclobazam and 4'-hydroxyclobazam, the former of which is active.
The scientists from the Swedish University of Agricultural Sciences employed slow-release pharmaceutical implants and animal-tracking transmitters to monitor how exposure to clobazam and the opioid painkiller tramadol -- another common pharmaceutical pollutant -- affected the behaviour and migration of juvenile Atlantic salmon (Salmo salar) in Sweden's River Dal as they migrated to the Baltic Sea.
Atlantic salmon are the largest species in the genus Salmo. After two years at sea, the fish average 71 to 76 cm (28 to 30 in) in length and 3.6 to 5.4 kg (7.9 to 11.9 lb) in weight.
This is significant because any change to the natural behaviour and ecology of a species is expected to have broader negative consequences both for that species and the surrounding wildlife community.
While the recent decline of Atlantic salmon is primarily attributed to overfishing, habitat loss, and fragmentation -- leading to their endangered status -- the study highlights how pharmaceutical pollution could also influence key life-history events in migratory fish.
Pharmaceutical pollutants are an emerging global issue
Commenting on the research, Dr Marcus Michelangeli from Griffith University's Australian Rivers Institute states: "Pharmaceutical pollutants are an emerging global issue, with over 900 different substances having now been detected in waterways around the world. Of particular concern are psychoactive substances like antidepressants and pain medications, which can significantly interfere with wildlife brain function and behaviour."
By designing drugs that break down more rapidly or become less harmful after use, pharmaceutical companies can improve and significantly mitigate the environmental impact of pharmaceutical pollution.
The research appears in the journal Science, titled "Pharmaceutical pollution influences river-to-sea migration in Atlantic salmon (Salmo salar)".