Published:27 Aug 2015
Pharmaceuticals are increasingly used in large amounts in human and veterinary medicine around the world and concern has been growing about their rising concentrations in the environment. The active ingredients in pharmaceutical products, as well as some of their breakdown products, have the potential to cause adverse health effects in humans, animals, fish and birds. Several routes exist by which pharmaceuticals can enter the environment, the most common of which is via normal consumer use of medicines and their excretion into sewer and wastewater treatment systems. Others include: improper disposal of unused medicines down toilets and drains; discharges from manufacturing plants or hospitals; application of biosolids from sewage treatment to land; direct excretion to land by farm animals and birds that have been treated with veterinary medicines; and from fish farms, landfill leachate, etc. Perhaps the best-known cases of harm arising from pharmaceuticals in the environment are the feminisation of fish in rivers downstream from sewage treatment plants, which has been attributed to the presence of oestrogens in the water, and the death of birds of prey caused by diclofenac in animal carcasses which they consumed.
This book contains contributions from an international group of experts engaged in work on pharmaceuticals in a variety of contexts and provides a balanced view of their environmental impacts. David Taylor, who also was key to the selection of the overall topic for this book, has written the opening chapter, which is concerned with the nature of the pharmaceutical industry. His objective was to provide a backdrop to the business so that the challenges of the issue of pharmaceuticals in the environment can be better understood. An account is given of the development of the industry and the ways in which new drug development occurs, emphasising the distinction between research-based pharma companies and the generic companies that produce the vast majority of pharmaceuticals sold. The factors determining the sale price of a new pharmaceutical are described.
Chapter 2, by Benoit Roig and Vince D’Aco, is concerned with the distribution of pharmaceutical residues in the environment and deals with both occurrence data and modelling studies. Antibiotics and analgesic/anti-inflammatories are the main pharmaceutical classes measured (and detected) in surface water and wastewater; the difficulties of applying complex analytical methods in the field can sometimes be bypassed by the use of relatively inexpensive modelling techniques. Pharmaceuticals in the marine environment are discussed in Chapter 3 by Sally Gaw, Kevin Thomas and Tom Hutchinson. Particular attention is given to coastal environments where rising populations result in increased discharges of wastewater and an increasing demand for farmed seafood brings unique problems that impact on marine organisms and human health. Then in Chapter 4, Dan Caldwell reviews the sources of pharmaceutical residues in the environment and their control, pointing out that the contribution of pharmaceutical manufacturing activities to the levels of active pharmaceutical ingredients in the environment is low when compared with the amounts excreted by patients consuming drugs and by improper disposal of unused medicines. Moreover, the concentrations of pharmaceutical ingredients are mostly at such low levels that, as yet, they pose little risk to human health.
Pharmaceutical residues in sewage treatment works and their fate in the receiving environment are discussed in Chapter 5 by Nick Voulvoulis, Damia Barceló and Paola Verlicchi. They explain that the release of antibiotics and steroids to the environment has generated most of the concern to date but that the toxicological significance for non-target (especially aquatic) organisms is still poorly understood. The effectiveness of conventional and advanced wastewater treatment in removing pharmaceuticals is examined alongside the associated economic, environmental and health-benefit costs. In Chapter 6, Mitchell Kostich and Reinhard Länge examine the ecotoxicology, environmental risk assessment and potential impacts on human health and aquatic life associated with pharmaceuticals in the environment. Their review deals with a wide range of pharmacological substances, addresses the question of what is a ‘safe’ level and pays particular attention to the development and spread of antibiotic resistance. They conclude that risks are generally low.
By contrast, in Chapter 7, Mark Taggart, Ngaio Richards and Chad Kinney present a detailed review of the impacts of pharmaceuticals on terrestrial wildlife. Their focus is on the virtual extirpation over the past two decades of Old World Gyps vultures on the Indian subcontinent due to non-target exposure to the synthetic pharmaceutical compound diclofenac, which is widely used as a non-steroidal anti-inflammatory drug. However, the chapter also examines the wider issues of pharmaceutical impacts on non-target species and highlights other concerns such as the use of sodium pentobarbital to euthanise horses, livestock and companion animals, which has resulted in the death of numerous wild avian and mammalian scavengers, as well as domesticated and captive wild animals exposed to tainted feed. Veterinary pharmaceuticals are given specific attention in the final chapter by Boris Kolar, Caroline Moermond and Silke Hickmann. Some of these can be extremely toxic for non-target organisms and may have long-term effects on ecosystems. For example, antiparasitics (used in aquaculture and for pasture animals) were mainly designed as insecticides and as such are extremely toxic to invertebrates. Antimicrobials also are much used in veterinary medicine and pose the risk of resistance developing in the receiving species. The need for enhanced ecopharmacovigilance is stressed.
With authors from the UK, France, USA, New Zealand, Norway, Italy, Spain, Germany, Slovenia and The Netherlands, this book can justly claim a truly international perspective on the issues arising from the rising levels of pharmaceutical products in the environment. The inclusion of authors drawn from the pharmaceutical industry as well as from public health and environment agencies and academia ensures a well-balanced approach to the often-controversial subject matter. The book will be of value to the many scientists and engineers working in this area, environmentalists and pharmacists alike, and to policy makers as well as students engaged in environmental science and technology courses and, of course, in pharmacy and pharmacology programmes.
Ronald E. Hester
Roy M. Harrison