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Medicines in the Environment: A Growing Threat to Wildlife and Drinking Water

There is increasing evidence that human and veterinary medicines are damaging wildlife, a new report launched today by the environmental charity CHEM Trust shows. The report Pharmaceuticals in the Environment: A growing threat to our tap water and wildlife” highlights that medicines [1] are polluting rivers and have harmed wild birds and fish. Other species too have been affected, and people are also worryingly exposed.

This report comes at a time of growing global concern about the environmental effects of pharmaceuticals. Later this month a United Nations Environment Programme (UNEP) meeting [2] will decide whether ‘Pharmaceuticals in the Environment’ should be recommended to be designated an emerging global policy issue. 

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The author of the report, Gwynne Lyons, Director of Policy at CHEM Trust, said:

“Most people would probably be surprised that in general they excrete between 30-90% of any medicine they take. With so many medicines now being found in our rivers, action on all fronts is needed to protect wildlife and drinking water.”

She added:

“The long term implications of many highly active medicines in our environment may come back to haunt us. The current situation is mind-boggling with fish contaminated with the birth control pill, antidepressants (such as Prozac), sedatives, antibiotics, painkillers, anti-cancer drugs and goodness knows what else.”

The report, an extensive analysis of the scientific literature and government reports, finds that there is a lack of adequate controls:

  • 613 pharmaceuticals have been reported in the environment worldwide, but analytical detection methods are not even available for many of the thousands of medicines in use.
  • Rivers in the UK[3] (and in all regions of the world)[4] are now contaminated with many medicines.
  • In England, anti-inflammatories and pain killers (ibuprofen and diclofenac) have been found in fur taken from otters.
  • In Sweden, samples of perch fish were found to be contaminated with 23 pharmaceuticals, including antidepressants (such as Prozac), sedatives, antibiotics, painkillers and anti-cancer drugs.
  • Baltic Sea salmon has been found contaminated with ethinyl estradiol, used in the contraceptive pill.
  • Several medicines have been shown to harm laboratory animals at the levels found in the environment, but there is little monitoring for effects in wildlife.[5]
  • Assessments of the environmental risks from human medicines in use before 30th October 2005 were not required and are often absent.
  • Dozens of medicines have been found in samples of drinking water in EU countries with larger monitoring programmes (eg. in France, Sweden, Spain and Germany) (For UK see[6]). Yet legal standards for residues of medicines in rivers and drinking waters are lacking.

The report by CHEM Trust concludes that individuals, companies and governments can all help to reduce this problem by ensuring that:

  • Unused medicines are disposed of at pharmacies and NOT by flushing them down the toilet
  • New medicines are designed so that they don’t persist in the environment, and
  • Sewage treatment works are improved

In addition, the European Union should strengthen laws relating to the pollution of rivers with pharmaceuticals, and there also needs to be better international coordination on this issue.

Elizabeth Chadwick of the Cardiff University otter project, who is part of a three- year study looking at pharmaceuticals in otter tissue, said: “As the population grows and gets older, the level of pharmaceuticals being pumped into the environment is ever- increasing. It is one of the most serious threats to our environmental health.”Last year a study by Chadwick showed bones in the reproductive organs of male otters had got lighter over time. She believes exposure to hormone-mimicking chemicals is to blame.

“Most studies look at the effects of one chemical at a time. Individually you might say that it is unlikely to cause harm at low levels, but it is difficult to work out the effects of exposure to a cocktail of chemicals,” she added.


  • At the Open Ended working group meeting in December 2014 (see note [2]) it was decided that environmentally persistent pharmaceuticals in the environment should be proposed as an emerging policy issue at the 4th International Conference on Chemicals Management on 28th Sep-2nd October 2015 in Geneva
  • Health Care Without Harm are now co-ordinating a “Safer Pharma” campaign, which aims to to protect the environment from pharmaceutical pollution.


NB: The now widely used US spellings of estrogen & estradiol are used in the report and press release rather than the traditional UK spellings of oestrogen & oestradiol.

[1] Between 1990 and 2007 in the EU, the retail value of the market for prescription and non-prescription human medicines quadrupled (up to £169.7 billion from £38 billion). Global per capita consumption is increasing, a trend which looks set to continue with our ageing population.

[2] The Open-ended Working Group of the International Conference on Chemicals Management, under SAICM (Strategic Approach to International Chemicals Management) meets in Geneva, 15–17 December 2014. See http://www.saicm.org/index.php?option=com_content&view=category&id=92&Itemid=487

[3] Several pharmaceutical compounds have been detected in some UK rivers, including:

  • ibuprofen;
  • mefenamic acid;
  • diclofenac (all three used for pain and inflammation)
  • propranolol (used for angina, high blood pressure and other heart problems);
  • dextropropoxyphene (a pain killer formerly prescribed as ‘distalgesic’.);
  • erythromycin;
  • trimethoprim (both antibitiotics);
  • acetyl sulfamethoxazole (a metabolite of the antibiotic sulfamethoxazole).

A larger monitoring programme is planned for England and Wales in 2015 (see p12 of the report).

[4] Over a dozen pharmaceuticals have been reported in the environment at many locations worldwide, including:

  • diclofenac (for pain and inflammation);
  • carbamazepine (an anti-epileptic);
  • ibuprofen (for pain and inflammation);
  • sulphamethazole (an antibiotic);
  • naproxen (for pain and inflammation);
  • trimethoprim (an antibiotic);
  • paracetamol (for pain);
  • clofibric acid (from the lipid lowering drug);
  • ciprofloxacin (an antibiotic);
  • ofloxacin (an antibiotic);
  • norfloxacin (an antibiotic);
  • acetylsalicylic acid (aspirin, a pain killer);
  • as well as residues of estrogenic substances, used in the contraceptive pill and to treat the menopause

[5] Concerns about effects on wildlife include – but are not limited to – the following:

  • Ethinyl estradiol (from the contraceptive pill and to treat the menopause): At many locations downstream of sewage treatment works, male fish have been feminised and have reduced sperm production. Many of these male fish abnormally make the female egg yolk protein and have eggs in their testes. Research has shown that ethinyl estradiol has contributed to causing these effects, often in combination with other hormones or hormone mimicking substance.
  • Diclofenac (an anti-inflammatory): In Asia, diclofenac caused the death of thousands upon thousands of vultures between 1996 and 2007. Diclofenac was mainly given to cattle for relief of pain and inflammation associated with disease or wounds. As the meat of cattle is not eaten by people in India, vultures would feast on them and take up all remaining diclofenac residues.
    Fish and other wildlife species may also be under threat from diclofenac, because concentrations in many rivers worldwide on occasion exceed the predicted no effect concentration. In the UK, a recent research paper, using modelled data and comparing with actual available data, suggested that this level might be exceeded in 4.5% of river reaches. Also, for example, a laboratory study has noted that environmentally realistic concentrations of diclofenac can impair osmo-regulation in the shore crab (Carcinus maenas).
  • Ibuprofen (an anti-inflammatory and analgesic): Recent research has suggested that ibuprofen poses an unacceptable risk in 49.5% of river reaches across 22 catchments in Britain. Ibuprofen has been reported to have a number of effects in laboratory studies. For example, in studies on effects on fish reproduction, ibuprofen was reported to cause male fish to abnormally make the female egg yolk protein, vitellogenin, and parental exposure to levels as low as 0.0001 mg/L ibuprofen delayed the hatching of eggs, an effect which can increase the risk of predation.
  • Medicines used to treat parasites: Ivermectin is a veterinary drug that has caused effects in the wild. It is excreted in the faeces of treated animals and adversely affects invertebrate organisms that live in or feed on dung. It can therefore also reduce the amount of food available to birds and bats.
    Pharmaceuticals used to treat sea-lice parasites in fish farms can also cause environmental damage. For example, emamectin benzoate is widely used in the Scottish salmon farming industry, and is highly toxic to marine crustacean. There are some anecdotal reports of harm to wild shellfish. For example, dead and dying Nephrops (also known as the Norway lobster or Dublin Bay prawn) were reported in Loch Shell following sea-lice treatments.
  • Antidepressants: There is strong evidence to suggest that antidepressant pharmaceuticals are affecting aquatic invertebrates at concentrations now commonly found in the environment. Effects reported in laboratory studies include altered spawning and larval release in bivalves – disrupted locomotion and reduced fecundity in snails – altered behaviour in freshwater and marine amphipod – altered aggressive behaviour in crayfish – altered learning in cuttlefish – and in daphnia (water fleas) altered reproduction and development. However, more research is needed to confirm some of the concerns and to find out just what effects antidepressants are causing in the wild.
  • Oxazepam (a benzodiazepine sedative): This tranquilliser is reported to alter behaviour and feeding rate of wild European perch at concentrations encountered in effluent-influenced surface waters. The perch exhibited increased activity, reduced sociality and higher feeding rate.
  • Antibiotics: These can cause harm to environmental bacteria and algae. For example, environmental concentrations of chlortetracycline are in the range that inhibit the protein biosynthesis activity of planktonic bacterial communities.
    Also, for example, an EU funded research project (PHARMAS) has also highlighted that model predictions show that ciprofoxacin and levofloxacin (used for urinary tract infections) in some European rivers may approach concentration levels that could trigger ecological damage.
  • Clofibric acid (a metabolite of medicines used to regulate lipid): This is reported to cause effects on reproduction in fish, including detrimental effects on fish sperm. Some of these reproductive effects occurred only at a high levels, but others occurred at levels near or similar to those reported in rivers.

[6] A small study of tap water in 2011 (in England and Wales) was focussed on looking for just 16 pharmaceuticals in drinking water. It found the following medicines were present:

  • Carbamazepine (an anticonvulsant used for epilepsy)
  • Ibuprofen (used for pain and inflammation)
  • Naproxen (used for pain and inflammation
  • Benzoylecgonine (a metabolite of cocaine).

In more extensive monitoring studies of tap water carried out in other EU countries between 31 and 50 pharmaceuticals have been reported.