The Management of Human Pharmaceuticals in the Environment

Abstract

Abstract:

Pharmaceuticals and their metabolites, collectively known as pharmaceutically active compounds (PhACs), have been detected in surface water, groundwater, and drinking water, in a number of countries, since the mid-1990s. Pharmaceuticals can be used in human or veterinary medicine; human pharmaceuticals in the environment are the subject of this dissertation. Human pharmaceuticals enter the environment via wastewater treatment plants, after being consumed and excreted by humans, and through improper disposal, to toilets and garbage, among other routes of entry. Some PhACs have been found to have detrimental effects on aquatic organisms at low concentrations, such as the feminization of fish after exposure to low levels of 17-ethinylestradiol, the active ingredient in the birth control pill. Others are suspected of having effects on non-target species, but the impacts of long-term exposure to mixtures of PhACs generally remain poorly understood. Nevertheless, the precautionary principle suggests that management action to mitigate the environmental impacts of PhACs should be considered and possibly implemented. The purpose of this dissertation is to provide an analysis of precautionary management strategies to mitigate the environment impacts of human PhACs. Four underlying objectives are set. The first is to review the extant scientific understanding of human PhACs in the environment, so that this knowledge can be applied to the analysis of management strategies. The sources, transport, fate, and occurrence of PhACs are discussed, and several classes of PhACs of particular concern are highlighted. The effects of PhACs on humans and aquatic organisms are explored, in addition to the gaps in scientific understanding of PhACs in aquatic environments. Finally, a rough ranking of priority PhACs is conducted; the PhACs of greatest concern are found to be carbamazepine, clofibric acid, ifosfamid, 17a-ethinylestradiol, oxytetracycline, ciprofloxacin, and diclofenac. The second objective is to investigate how planning and management principles and theories can be applied to the problem of PhACs in the environment. The precautionary principle and the theory of adaptive planning are identified as essential tools in this regard. The application of the precautionary principle and adaptive planning to pharmaceuticals in the environment are discussed, and a management framework is developed. The third objective is to determine how human PhACs in the environment can be managed at a local scale, using a case study in the Region of Waterloo. Pharmaceuticals released from two wastewater treatment plans are found entering the local environment at concentrations similar to those in other cities internationally. Social surveys indicate that residents desire management action to prevent environmental contamination by pharmaceuticals, but at a limited cost. The surveys also indicate that many residents dispose of pharmaceuticals improperly; education to encourage proper drug disposal is therefore recommended as one of several management strategies. The other two recommended management strategies target the wastewater treatment plants. In Foxboro, where the wastewater treatment plant is functioning less than optimally, optimization without technological upgrades is suggested. In Kitchener, where the plant is functioning within ministerial guidelines, ozonation is suggested as a means of improving pharmaceutical removal without exceeding residents’ willingness to pay. The fourth and final objective is to assess how human pharmaceuticals can be managed at a broad scale, such as at the national scale. Stakeholder interviews are conducted with the purpose of gaining a deeper understanding of possible management strategies. A policy analysis is conducted to determine which combinations of management strategies are likely to optimally address the problem of PhACs in the environment, and some policy packages are recommended for implementation by governments – in particular, multiple levels of government in Canada. This dissertation is among the first research efforts to investigate the management of pharmaceuticals in the environment. Few efforts to date have combined natural scientific research, social scientific research, and an understanding of planning and management theories, to explore policy and management options for this issue. It is hoped that this research will provide assistance to various governments grappling with pharmaceuticals in the environment. Furthermore, the research provides insight into how environmental problems surrounded by high levels of scientific uncertainty can be managed. The framework for precautionary decision making developed in this study can provide guidance to planners, managers and policy makers faced with the problem of uncertain environmental risk.