Environmental impact of medical prescriptions: assessing the risks and hazards of persistence, bioaccumulation and toxicity of pharmaceuticals.

In the context of increasing concerns regarding sustainable development, healthcare workers must consider practices that are not harmful to the environment. 'Primum non nocere' is of great value for the residues of pharmaceuticals and biocides resulting from medical prescriptions. Stockholm County Council has developed a simple classification system covering both environmental risks and hazards of pharmaceuticals according to their persistence, bioaccumulation and toxicity. This classification, which is easy to understand and well accepted among Swedish medical doctors, could be a model for other countries and useful to general medical doctors wishing to be environmentally conscious in their prescribing. Limited information is available on both the fate and ecotoxicity of pharmaceuticals and biocides in the aquatic environment. The primary concern regarding the environmental impact of pharmaceuticals seems to be drug classes such as antibiotics, oestrogens, cytostatic agents, contrast agents and disinfectants. Performing a full ecological risk assessment of pharmaceuticals and biocides is difficult because of a lack of data on exposure scenarios, target aquatic species and dose-response relationships.