Prescription drug residues in natural water sources

The world is rightly concerned about the presence of prescription drugs in natural water sources. Everywhere you look, in wastewater discharges from hospitals, in lakes and rivers, and in drinking water, drug residues can be found.

Some address patient requests for unnecessary prescriptions in order to reduce the impact on disposal, and save money too, though a focus on issuing the prescription and greater care by GPs would be far more appropriate. Still others prefer to place controls of wastewater discharges from hospitals, sometimes with a heavy hand of regulation and threats of penalty if anyone is caught disposing pharmaceutical wastes into a drain. Rightly so, but as we have discussed previously on the Clinical Waste Discussion Forum the problem is entirely different, with the bulk of pollutants leaving the body in urine. And, of course, patients in the community consume and subsequently excrete prescription medicines.

Out it comes, whether patients are in hospital or at home. Prescription medicines and their metabolites. And residues from the millions of tonnes of non-prescription medicines consumed worldwide. So, the logical control would be for wastewater treatment, which might be applied to hospital wastewater outflows, of more generally with better and more effective sewage treatment facilities. In essence, the source of pollutant pharmaceutical residues is the sewage treatment plant that fails to remove these compounds, unsurprisingly since the process was developed by the Victorians to remove suspended solids and faecal bacteria, but not the residues of drugs the Victorians could not even dream of.

So, what to do? We might follow the approach of the Environment Agency who love to bully and demand special arrangements for process wastewater of autoclaves treating clinical wastes that might have a few blister packs within it. That redundant thinking is simply ridiculous while other sources continue to flow without the slightest concern. It’s the elephant in the room!

A recent news report tells of Lake Michigan ‘drowning in prescription drug waste’ with experts recommending water treatment plants install carbon filters to catch pharmaceuticals.

Now if that were to be all water treatment plants rather than just those tacked onto the back of hospitals and operating locally, and thus including also the small, probably infinitesimally small, contribution from clinical waste treatment facilities, then a real improvement might be expected.

In the case of Lake Michigan, scientists tested effluent from two sewage outfalls and water and sediment from the lake (up to two miles from the outfalls) for 54 chemicals used in pharmaceuticals and personal care products. Twenty-seven chemicals were found in the lake, with four found most frequently: an anti-diabetic drug called metformin, caffeine, the antibiotic sulfamethoxazole and triclosan, an antibacterial and antifungal compound found in some soaps, toothpastes and other consumer products.

It is far from clear what is the impact of these growing concentrations of chemicals, and of the millions of others that do not currently appear on our radar but which are ever present in the treatment residues from heat-treated clinical wastes, and from domestic and other industrial/commercial wastes, manufacturing wastes, effluents from incineration, AD plants, composting, and all those farm animals and household pets, even those lucky badgers – the ones so far to escape the government cull – who defecate and urinate onto land. If you look for those chemical residues, any of them, you will find them.

The concentrations will rise inexorably, as now detected in Lake Michigan. Dealing aggressively, as some regulators do, with the smallest traces of some pharmaceutical residues, but not others, that might be found in a bag of clinical waste or an empty syringe, is something of a regulatory farce. These are concentrations generally below limits of detection, while the concentration of that same drug passed in urine is several tens of million times greater, ignores that which should be patently obvious. Unless perhaps its a matter of control, of mischief making, that has been a feature of clinical waste regulation in England for some years now.

This approach to regulation is wrong. It generates far more waste, and is both environmentally and scientifically unsound. To make it worse, those same regulators haven’t thought about the soluble degradation products from all those heated plastics processed in the clinical waste autoclave. This might include rigid and other plastics, the waste sacks themselves, even the blister pack that contained that stray tablet or capsule. And all those antiseptic and other chemicals that are not prescription-only medicines, of those myriad complex of organic chemicals. The contribution and impact may in fact be substantial, but we do not know, and until assays are available cannot assess this.

Data from Lake Michigan suggests high concentrations of caffeine. Do we regulate disposal of coffee grounds? Or instant? And what about those many cups of coffee that keep us going day after day; do we need to treat urine to remove caffeine residues?

This nonsense should stop, to allow us all to concentrate on the heart of the problem.


see Blair BD, Crago JP, Hedman CJ, Klaper RD. Pharmaceuticals and personal care products found in the Great Lakes above concentrations of environmental concern. Chemosphere 2013.


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