Predicted critical environmental concentrations for 500 pharmaceuticals.

A growing number of pharmaceuticals are found in surface waters worldwide, raising concerns about their effects on aquatic organisms and it is a major challenge to develop a rational strategy for prioritizing drugs on which to focus the most extensive environmental research efforts. However, in contrast to most other chemicals, very good understanding of the human potency of pharmaceuticals has been obtained through efficacy and safety testing. Assuming that a drug acts primarily through the same target(s) also in a non-target species, it would be possible to predict the likelihood for pharmacological interactions in wildlife. Among aquatic organisms, fish most often share drug targets with humans. In this study, we have calculated the predicted critical environmental concentration (CECs), i.e. the surface water concentration expected to cause a pharmacological effect in fish, for 500 pharmaceuticals, assuming equivalent pharmacological activity. The CECs are based on literature data on human potencies together with a predicted bioconcentration factor in fish for each drug based on lipophilicity. We propose that CECs could be used as preliminary indicators of specific drugs' potential to cause adverse pharmacological effects at specific water concentrations, used when selecting pharmaceuticals to include in screening campaigns and for assessing relevant detection limits.