The after-life of drugs: a responsible care initiative for reducing their environmental impact

Peter M J Fisher, David A Smith and Peter J Collignon
Med J Aust 2013; 199 (6): 388-390. || doi: 10.5694/mja12.10904
Published online: 16 September 2013

Best-practice training and protocols in drug disposal should form part of a pact between the health and water sectors

Few give much thought, if any, to the fate of medications and other chemicals that pass though the bodies of people and animals or are washed from their skins. The conventional wisdom is that the residual amounts of these substances are so minuscule that they are of little or no consequence. That penicillin was recovered from the urine of World War II soldiers was telling evidence that antibiotics, at least, do not just vanish. Even the discovery in 1976 that fish downstream from a Kansas sewerage plant were malformed as a result of exposure to the oestrogen, oestrone, related to contraceptive pill use, failed to change the mindset that the environmental burden of drugs was insignificant.1

Two decades then passed before German scientists, looking for herbicides in waterways, stumbled across a chemical they did not recognise.2 It was the cholesterol-lowering agent clofibrate, a close chemical relative of the weed killer 2,4-D. They investigated further and found analgesics (ibuprofen, diclofenac), antibiotics, lipid regulators (phenazone, fenofibrate), antiseptics, β-blockers, oestradiol, anticonvulsants and x-ray contrast agents. Similar cocktails were subsequently found in the waterways of the United States.3

Mixtures of chemicals from human activity are always present in the environment. It is commonly assumed that individual chemicals do not interact. However, a study of the impact of pesticides on Californian frogs4 highlighted that we have little understanding of synergistic effects between chemicals and of how chemical cocktails behave, because most toxicological studies evaluate individual compounds.

Making sense of the sewerage system

Doctors and health professionals need to be aware of what health care activities put into the sewerage and waste disposal systems. This is particularly important because there is a limited extent to which these systems can deal with the large number of drugs that are stable. Many do biodegrade, but others can be very persistent in their new setting.9

The number of compounds not (or only partially) degraded to recalcitrant metabolites (those resistant to biodegradation) in a treatment process depends on the technology used. Conventional wastewater treatment plants can and do break down or remove some of these compounds,10 but the overall quality of plant performance varies. A glance at annual reports on utility websites is informative in this regard. This variability in performance arises from differences in design and standards of expertise, and (significantly) differences in state EPA regulations. For example, in Sydney, the EPA permits the discharge of primary settled sewage, while in Queensland, there are very tight limits on parameters like nutrient reduction.

The most common treatment process for urban sewage in the developed world is the activated sludge process (ASP). It is capable of producing relatively high-clarity, low-nutrient water when managed correctly. ASP has been shown to remove more than 50% of certain chemicals.11 Other research has shown varying removal rates for synthetic chemicals, and some drugs are shown to be poorly removed by conventional treatment plants.12 As the use of recycled water increases, the quality of this water becomes more critical and good management of all sewer inputs by utilities becomes more important. Pharmaceuticals are being identified as a potential risk in recycled water risk-management systems of utilities such as South East Water in Melbourne, Australia, and Orange County Sanitation District in California in the US. This is leading to increased awareness of the waste contributions from domestic catchments and high-concentration point sources such as hospitals.

Treatment plants are the last barrier to the entry of synthesised chemicals to soil systems and waterways. Removal of chemicals at modern plants can be highly efficient, but there are many older, less effective plants. Even higher quality plants do not remove all chemicals foreign to life forms (xenobiotics). In any case, treating this problem at the source (“beginning of pipe”) is likely to be much cheaper and more effective than “end of pipe” solutions.

The ability of modern sewage plants to strip pharmaceuticals remains a work in progress. The inherent complexity is underscored by the fact that bacteria, normally friendly workhorses in sewage treatment, can also produce toxic breakdown products. An example is bacteria converting the non-steroidal anti-inflammatory drug (S)-naproxen to (R)-naproxen, which is highly toxic to the liver.13

When water is intended to be recycled, there is an added need for drugs to be removed. However, advanced processes such as microfiltration, ultrafiltration, ultraviolet radiation and ozonation are designed more for removing pathogens than for breaking down molecules. These processes are regulated by national guidelines and so tend to be of a similar standard around the country. Treatment involving combinations of reverse osmosis, advanced oxidation, ozonation and activated carbon are the preferred (but expensive) option if the removal of xenobiotics is a priority.

How can the health sector help?

Preventing, or at least minimising, the quantities of more toxic and persistent compounds that enter sewage is a fundamental complement to upgrading treatment plants. Thus, health care professionals should be aware of the need for pharmaceuticals to be managed as organic and persistent pollutants.

Hospitals and clinics constitute point sources of such pollutants, whereas patients in the community are diffuse sources, which are much harder to monitor and manage. While hospitals are hot spots, they are the source of only a modest proportion of all drugs used in people and animals that subsequently enter the environment. However, in the first instance, tackling hot spots in source control could make significant inroads on the drug load entering treatment plants — for example, as much as 25% of all human antibiotics are estimated to be administered in hospitals.14

Where waste disposal via sinks is unavoidable, xenobiotic waste streams should be treated before release to the sewer. Indeed, a treatment process at the source may be preferable to facing increased trade waste charges by utilities if they deem hospital wastewater inputs to be problematic.. Emptying the contents of half-empty syringes into wash basins (a likely common practice despite protocols to the contrary) should also be discouraged. Rubbish disposal systems that minimise medicines ending up in landfill are another area requiring attention, as sewage treatment plants regularly receive tankers containing leached material from rubbish tips.

Health sector reform to reduce the environmental burden of health care has five elements:

Provenance: Not commissioned; externally peer reviewed.

  • Peter M J Fisher1
  • David A Smith2
  • Peter J Collignon3,4

  • 1 School of Global Studies, Social Science and Planning, RMIT University, Melbourne, VIC.
  • 2 South East Water Ltd, Melbourne, VIC.
  • 3 Canberra Hospital, Canberra, ACT.
  • 4 Medical School, Australian National University, Canberra, ACT.


Competing interests:

No relevant disclosures.

  • 1. Hignite C, Azarnoff DL. Drugs and drug metabolites as environmental contaminants: chlorophenoxyisobutyrate and salicylic acid in sewage water effluent. Life Sci 1977; 20: 337-341.
  • 2. Heberer T, Stan HJ. Determination of clofibric acid and N-(phenylsulfonyl)-sarcosine in sewage, river and drinking water. Int J Environ Anal Chem 1997; 67: 113-124.
  • 3. Kolpin DW, Furlong ET, Meyer MT, et al. Pharmaceuticals, hormones, and other organic wastewater contaminants in US streams, 1999-2000: a national reconnaissance. Environ Sci Technol 2002; 36: 1202-1211.
  • 4. Hayes TB, Case P, Chui S, et al. Pesticide mixtures, endocrine disruption, and amphibian declines: are we underestimating the impact? Environ Health Perspect 2006; 114 Suppl 1: 40-50.
  • 5. Finley RL, Collignon P, Larsson DG, et al. The scourge of antibiotic resistance: the important role of the environment. Clin Infect Dis 2013; May 30. [Epub ahead of print.] doi: 10.1093/cid/cit355.
  • 6. Daughton CG. Environmental stewardship and drugs as pollutants. Lancet 2002; 360: 1035-1036.
  • 7. Directive 2013/39/EU of the European Parliament and of the Council of August 12 2013 amending directive 2000/60/EC and 2008/105/EC as regards priority substances in the field of water policy. (Text with EEA relevance.) PDF (accessed Sep 2013).
  • 8. Zucato E, Bagnati R, Fioretti F, et al. Environmental loads and detection of pharmaceuticals in Italy. In: Kümmerer K, editor. Pharmaceuticals in the environment: sources, fate, effects and risks. Berlin: Springer, 2001: 19-27.
  • 9. Watkinson AJ, Murby EJ, Costanzo SD. Removal of antibiotics in conventional and advanced wastewater treatment: implications for environmental discharge and wastewater recycling. Water Res 2007; 41: 4164-4176.
  • 10. Jelic A, Fatone F, Di Fabio S, et al. Tracing pharmaceuticals in a municipal plant for integrated wastewater and organic solid waste treatment. Sci Total Environ 2012; 433: 352-361.
  • 11. Martin Ruel S, Choubert JM, Budzinski H, et al. Occurrence and fate of relevant substances in wastewater treatment plants regarding Water Framework Directive and future legislations. Water Sci Technol 2012; 65: 1179-1189.
  • 12. Tan BL, Hawker DW, Müller JF, et al. Modelling of the fate of selected endocrine disruptors in a municipal wastewater treatment plant in South East Queensland, Australia. Chemosphere 2007; 69: 644-654.
  • 13. Hashim NH, Nghiem LD, Stuetz RM, Khan SJ. Enantiospecific fate of ibuprofen, ketoprofen and naproxen in a laboratory-scale membrane bioreactor. Water Res 2011; 45: 6249-6258.
  • 14. Kümmerer K, editor. Pharmaceuticals in the environment: sources, fate, effects and risks. Berlin: Springer, 2001.


remove_circle_outline Delete Author
add_circle_outline Add Author

Do you have any competing interests to declare? *

I/we agree to assign copyright to the Medical Journal of Australia and agree to the Conditions of publication *
I/we agree to the Terms of use of the Medical Journal of Australia *
Email me when people comment on this article

Online responses are no longer available. Please refer to our instructions for authors page for more information.