Research by academics at the University of the West of England has discovered paracetamol and caffeine in Bristol’s floating harbour.
The presence of the drugs is a key indicator of sewage contamination, as they do not occur naturally in the environment.
Commonly used in cold and flu medication, paracetamol and caffeine are designed to be highly stable and resistant to degradation – and so can remain in the water for long periods of time.
This means that the effects could be far-reaching, as the drugs are incorporated into the food chain and then increase in concentration as you go upwards.
Pollution levels in the harbour generally fall within legal limits, though the latest report from Bristol Council advises that the water quality is currently ‘poor’.
Swimming is not allowed in the Floating Harbour, as e-coli and other fecal bacteria present in the water and can pose a significant health risk including stomach, ear, nose and throat infections.
Testing for specific drugs such as caffeine and paracetamol is a relatively new area of research, and consequently there is not much data available on the effect that their presence could be having on local harbour wildlife such as fish and swans.
However similar research has suggested that where anti-depressants contaminate water it can have a significant knock-on effect on fish populations.
In those tests fish such as perch who ingest the drugs become more anti-social – leaving the shoal and becoming more vulnerable to predation.
Going forward Dr Kevin Honeychurch, who is leading the research at UWE, says that they are aiming to extend the study to include the presence of illegal drugs.