Health Care Without Harm Europe Newsletter - The Campaign for Environmentally Responsible Health Care

Beyond take-back: getting drugs out of our water

Take-back schemes are becoming more common as concerns grow about the effect which drugs in our water might have on our health. HCWH Europe goes down the pipes to look at the full extent of the problem and how best it might be solved.

It is becoming increasingly clear that the water we drink is being contaminated with a range of drugs and pharmacologically active compounds, from hormonal contraceptives and everyday painkillers, through to antibiotics and even the cytotoxic drugs used to treat cancer.

Although the levels in most places appear low, around one part per billion (1 ppb), concerns are growing about the effects this might have on our health. Although the levels being found in the environment are far below therapeutic concentrations, the exposure occurs over far longer periods of time then the drugs were designed for – or even have been tested for.

Improved understanding of how our hormonal system works and the role it plays in development only adds to the worries. Many drugs are endocrine disruptors: acting like hormones, they interfere with the chemical signalling between cells which tells them how to function.

Although exposure is to drugs at concentrations of only a few parts per billion, according to Terry Collins, Thomas Lord Professor of Chemistry at Carnegie Mellon University, it is “absolutely not true” the levels are too low to have an effect: one known endocrine disruptor, ethanol estradiol, is known to cause abnormalities in minnows at levels of one part per trillion.

Interruptions in hormone signalling do not have acutely toxic effects (to assume so is “looking in the wrong place toxicology-wise” says Collins) but instead cause chronic conditions such as testicular dysgenesis. Many such conditions are precursors to cancer in later life.

So with the health concerns of environmental exposure to pharmaceuticals in mind, we should ask where all the drugs are coming from in the first place.

Can take-back schemes solve the problem?

Without a doubt, many unused drugs are incorrectly disposed of. In 2005, a study found that only 12% of unused medicines in the UK were being returned to pharmacies – in spite of the EU issuing a Directive in 2004 instructing Member States to “ensure appropriate collection systems are in place for medicinal products that are unused or have expired”.

Since then, the introduction of payments to UK chemists for taking back unused medicines has improved the situation. Health Care Without Harm Europe’s (HCWHE) own survey of 10 random local councils has also found the correct advice being given for disposing of unused drugs. There is, however, a noticeable lack of public awareness campaigns.

Jamie Page, Executive Director of HCWHE, says: “The public needs to be properly informed about take-back schemes. It’s not enough to have information on a website or at the end of a phone – more needs to be done to raise general awareness of how to dispose of pharmaceuticals.”

Although take-back is the easiest way to prevent unused drugs being flushed down the toilet, there is a question about the overall difference this can make to pollution of the environment with pharmaceuticals.

According to Eric Meliton, an Environment Technologies Research Analyst at Frost and Sullivan, depending on where you are around 65-80% of drugs getting into the sewage system come from excretion rather than incorrect disposal.

For any given dose, a significant proportion will pass through the body either virtually unaltered or be excreted as active metabolites of the drug. The active compounds exit the body either in urine or faeces before entering the sewage system.

Therefore, since even the best and most tightly enforced pharmaceutical disposal regulation imaginable is likely to deal with at most 35% of the problem, any long-term solution has to look at dealing with excretion. A number of ideas have been put forward for dealing with this.

Beyond take-back

One initiative which has attracted a lot of attention in Europe is being piloted in Sweden. Over the past six years, Stockholm County Council has been profiling the vast majority of the most commonly-used drugs for environmental persistence (P), tendency to bioaccumulate up the food chain (B), and toxicity (T).

Each of the three properties is given a score between 0 and 3, with 3 being worst, such that each drug can be given a total PBT score from 0 to 9. This way, it is easy to identify which drugs present the greatest environmental hazard.

Then, when all other factors are equal, doctors can prescribe patients the least environmentally-hazardous drug appropriate for treatment of a given condition. The programme is now being introduced into doctors’ training in Stockholm County.

Although very important, this is not a solution which can work on its own – mainly because drugs are not, in general, designed to get a low score on a PBT profile. Indeed, drugs are designed to some extent to be persistent because in many cases it makes them work better, and can be good for the patient because it allows the drug toxicity to be reduced.

Why not design drugs to be greener? The problem is not just therapeutic efficacy: “Green chemistry is all about reducing and eliminating hazardous substances – obviously, you are better off if you don’t have the hazard. That’s the ideal,” explains Collins. “However, the investment in a new drug is already enormous. Adding another constraint is probably just not doable.”

Meliton agrees. “Manufacturers are not going to be reformulating their drugs any time soon,” he says. But if we can’t redesign the drugs, then what can we do? It is looking increasingly as though the only feasible answer is to develop water treatments which can remove pharmaceuticals.

Since the 1980s, attention has focused on using ultraviolet light and ozone to break down hormones. Although these remain expensive and are relatively untried technologies, larger municipalities in the US are beginning to install them. Meliton is, however, sceptical about how affordable these can be for smaller towns.

Collins has been investigating the use of an enzyme, Fe-TAML, to break down estradiols. Fe-TAML was designed to catalyse the action of hydrogen peroxide in breaking down proteins, and so far it seems to be working. Early indications suggest up to 99% of a range of pharmaceuticals could be removed from effluent using this process.

Although this should be cheaper than ozone technologies, is adding enzymes to water safe? Collins admits we can’t be certain. “We can only test for what we know about,” he says, “although at this stage it looks promising. Unless there is something horrible out there like a pineal disruption, then it looks like we’ve cracked it.”

So in the short term, we have to at least keep what we can out of the water, with effective take-back schemes and tightly enforced regulation to prevent pharmaceuticals being released in the manufacturing process. In the long term, we will need effective treatment technologies.

This is all the more urgent as global consumption of pharmaceuticals grows. Cheap generics are making drugs more affordable in developing countries and production is ramping up to meet demand.

A hint of the scale of the problem to come has already been seen in Hyderabad, India. The effluent of 90 bulk drug manufacturing plants is discharged into one river, where levels of the broad-spectrum antibiotic ciprofloxacin has been found to exceed 30,000 ppb, and five others to exceed 100 ppb: concentrations the researchers said were “no doubt” toxic.

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