Former chair of the Environmental and Sustainability Network Dr Rob Burrell writes about how to dispose of drugs in a way that is best for the environment:
Ampoules and contents should go into sharps bins. Syringe contents (+/- syringes) should go into a yellow bag, or a sharps bin (if there are sharps, or if you are concerned about diversion).
The best place to put drugs is into the patient. Not only is this what we do well, it enables drug metabolism, reducing environmental exposure.
New Zealand has not been particularly good at keeping pharmaceuticals out of our water and ground. Whilst large amounts of drugs pass through patients’ livers and kidneys, and metabolites go to municipal sewage schemes, there has been little pressure to deal well with waste drugs. In fact, (hospital) pharmacies have been putting waste drugs, expired medicines, and recalled pharmaceuticals into kitchen blenders, and pouring them down the sink in enormous quantities. With little regulation, hospitals and individuals have been free to do what they wish.
The problem arises when the drugs get to the sewage plants. Without data about what is entering the system, those plants are not monitoring what leaves and enters the ocean or treated water outflow. And many medicines are poorly broken down by sewage plants. Sewage plants do not want our unused drugs and are making efforts to keep them out.
An alternative place to put unused drugs might be domestic landfill, (white bags). It is cheap (~$80/tonne). Municipal landfills are lined with plastic, to prevent the contents escaping. But the disaster at Fox River should make us very cautious.
The liquid that sinks to the bottom of an intact landfill (the leachate) is removed. After limited processing, it is usually put down the nearest municipal sewer. So, the white bag solution may only delay drugs from entering the environment.
There is also no incineration in New Zealand. The only drugs incinerated are cytotoxics, which go into purple bags and bins, and are exported at considerable expense.
Yellow bags (~$1000/tonne) and the contents of sharps bins (~$35 for a large one) share a common fate: sterilised by steam in a pressurised rotating vessel (rotaclaved), shredded, and “sealed” into a higher standard of landfill. Again, leachate can ultimately make its way to municipal sewers, and the sea.
Unfortunately, we don’t know enough about the fate of pharmaceuticals under these conditions, and some may remain biologically active. The drugs of most concern include antibiotics, local anaesthetics, sympathomimetics, and propofol (said to be very thermally stable). And then there are the legislative requirements of opioid disposal to consider. Sadly, pressurised steam sterilization is our current best option.
There are two types of sharps bins in common use: the (Daniels) hard plastic, reusable ones, and softer (BD make one) versions, destroyed with their contents. The hard-shell versions get washed out before being returned to users. It is not always clear where the water goes after washing out sharps bins, however preventing intact drugs from hitting the sewers or ground water would be a worthy aim, possibly not able to be universally achieved. Talk to your waste contractor for specifics on how they treat hospital waste.
With the above information in mind, a reasonable conclusion is that all unused drugs should go down the pathway most likely to result in destruction, and least likely to leak into the environment. That means yellow bags or sharps bins, perhaps with absorbents to prevent loss, diversion, and rapid leaching rather optimistically, and that empty syringes might be okay in domestic waste.