Targeting the environmental risk assessment of pharmaceuticals: Facts and fantasies

In contrast to industrial chemicals, pharmaceuticals and pesticides are designed to show specific pharmacological actions or biocidal activities. Despite this difference, the same principles for environmental risk assessment, e.g., risk characterization by comparing compartment-specific exposure and effect, are applied to both nonspecifically and specifically acting substances. In addition, many pharmaceuticals are relatively hydrophilic, polar, or charged compounds. However, standardized guidelines for generating fate and effects data have been developed predominantly for neutral substances. For these reasons, the risk characterization of biologically active pharmaceuticals might contain a considerable degree of uncertainty. In this paper, we propose a conceptual approach for a targeted environmental risk assessment to reduce the uncertainties of risk characterization for pharmaceuticals by using the information provided in the nonenvironmental part of the regulatory dossier. Three steps have been defined for this purpose: 1) The first is collation of specific information contained in regulatory dossiers for pharmaceuticals, e.g., data produced to understand the interaction of the active substance with biological structures, 2) Based on this information, conclusions might be drawn with regard to environmental compartments likely to be exposed and organisms likely to be affected, and 3) Selection can be made of single-species or multispecies tests to generate additional information for the ecotoxicological risk characterization of pharmaceuticals. Furthermore, some thoughts will be presented on the integration of targeted testing strategies into conceptual regulatory guidance.