October 13, 2014

expert reaction to research on the impact of pharmaceuticals on the environment

Researchers writing in Philosophical Transactions of the Royal Society B have reported on the effect of discharge and build up of pharmaceutical substances in the environment, and on wildlife populations.

Dr Leon Barron, Lecturer in the Department of Pharmacy & Forensic Science at King’s College London, said:

“Pharmaceutically active contaminants occur in our environment and have done so for a number of years, including in the UK. They are likely to occur mostly where populations consume medications and excrete them, often via our sewage networks, only to end up in rivers, lakes, fields, plants and animals.  This collection of research is a very welcome addition to efforts aiming to understand their impacts on our environment and ultimately on us. Whilst they have yet to be proven to have widespread toxic effects at such low levels, they are, by design, bioactive. Accurate measurement of the breadth of their occurrence at environmentally realistic levels is an on-going challenge, not to mention understanding their combined effects on plants and animals. Even subtle effects on smaller organisms could have knock-on implications for us, for example, through our food or water supply.

“Any adverse effects, be they direct or indirect, need further study in order to address this important issue properly. It is exciting to see a high-profile collection of research from universities, research institutions, pharmaceutical companies and regulatory/conservation bodies brought together to raise public awareness of this issue.”

Prof Alastair Hay, Professor of Environmental Toxicology at the University of Leeds, said:

“This is a superb set of carefully written papers. The aim is to assemble evidence about the effects of pharmaceuticals on the environment and to raise the much needed questions about what studies are needed to assess their impact. How can studies be designed to identify pharmaceuticals causing a problem vs all other factors – such as air pollution, global warming, habitat loss, etc which are likely to affect all wildlife populations?

“There is good evidence for estradiol concentrations in water having impacts on wildlife, particularly fish. But the effects are likely to be far more widespread. Antidepressants such as fluoxetine (Prozac), present in food consumed by starlings when they may forage, appears to be linked with a decline in the birds to seek food. One non-steroidal anti-inflammatory drug was recognised to be a major threat to vultures in India such that alternatives had to be found urgently. Other vulture populations may be similarly at risk. The risk may be specific to this bird species because of the rate at which the drugs are metabolised. But this is just one class of drug and one species. Antibiotics, so widely used in intensive agriculture, and by the public, are also a threat, not least because of drug resistance issues.

“The above is just a snapshot of a much larger database of demonstrated effects of drugs on wildlife. With increasing populations, increasing longevity, predictions about the rising incidence of depression worldwide etc. drug use will continue to rise. So we need to better understand what is happening to drugs in the environment and their role on wildlife and perhaps on us too. This means better measures of assessing likely impacts, surrogate measures in other words before populations are damaged irretrievably. Pharmaceutical companies will almost certainly be key players in this process and will have to help in the design of test procedures. Drug regulators are already aware of potential problems, but require good evidence before they can implement controls.

“Pharmaceutical runoff in countries differs. In more developed countries sewage is likely to be processed. This means better opportunities to capture and clean water before it is recycled. But in less developed countries and where sewage may be flowing into septic tanks or directly into waterways there is a bigger problem. Engineers will be needed to come up with low-tech ways to filter water to a degree that not only removes bacteria and viruses but unwanted chemicals too. And money will be needed to support these endeavours.

“We, the drug-consuming public, also have a role to play. Do we always need to take medicines? If we do, we need to be responsible about what we do with unused/ unwanted drugs. Gone should be the days when we just flush everything down the toilet. If we can be bothered to visit the pharmacy to collect prescriptions we should be returning unused drugs to the same venue.”

Dr Oliver A.H. Jones, Lecturer in Analytical Chemistry at RMIT University in Melbourne, said

“This collection of papers is very timely. Interestingly, the topic of pharmaceuticals in the environment is not actually a newly discovered problem. In the 1970s, scientists working at a sewage treatment plant in Kansas found pharmaceuticals in its effluent, and the first review of the fate of pharmaceutical chemicals in British rivers was conducted in 1985; but not much more was done back then.

“The presence of pharmaceuticals in the environment has only really been a major issue in environmental chemistry and toxicology since the late nineties after the finding of diclofenac and ibuprofen in Swiss lakes and rivers by Buser et al., and the seminal 1999 paper by Christian Daughton and Thomas Ternes which really got the attention of the environmental science community. Since then a lot of work has been performed looking at the occurrence fate and behaviour of these compounds but while they are found nearly everywhere, they tend to occur at extremely low concentrations: nanogrammes per litre, the equivalent of a few drops of water in an Olympic sized swimming pool. Theoretically you would have to drink several such pools worth of water to get an effective dose of the compound. This is of course impossible and even if you could that amount of water would be far worse for you than the compounds in it.

“In short, environmental levels of pharmaceuticals are yet to be conclusively proved toxic; except in the case of Diclofenac in vultures, but that was rather an exception as most work in the area is carried out in the aquatic environment since wastewater is the major source for most of the human compounds and run off from fields (via urine and faces from treated animals) is the source of most veterinary drugs in the environment. However, there remain a lot unanswered questions, such as whether the presence of these compounds actually matters and whether mixtures of pollutants of all types are worse than the sum of their parts (which some seem to be).

“This lack of data also means that there is no cost/benefit balance to the use of these chemicals; once cannot say, for example, that ‘pharmaceuticals in water increases the risk of liver damage in your lifetime by a factor of 2, but decreases the average time you will spend ill by two years’, as nobody has ever looked into this. The other question is of course that here is little knowledge over the alternatives that might be used, since drugs are so important to human and animal health.

“In part, the latest findings simply reflect advances in analytical technology, which increase the ability of researchers to spot pollutants in water, so there is no need to stop taking your medication just yet; the medical benefits most likely far outweigh any possible environmental problems. But next time you reach for a pill, for whatever reason, it is certainly interesting to think about where it might end up.”

Professor Mark J Bailey, Director of the Centre for Ecology & Hydrology, said:

“As a major contributor, the NERC Centre for Ecology & Hydrology welcomes this review volume which highlights the serious issue of pharmaceuticals in the environment, and the acute and chronic effects these have on wildlife and the functioning of ecosystems.”

‘Assessing risks and impacts of pharmaceuticals in the environment on wildlife and ecosystems’ by numerous authors published in Philosophical Transactions of the Royal Society B on Monday 13 October 2014.

Declared interests

None declared