Hazardous drugs (NIOSH's list-group 1) in healthcare settings: Also a hazard for the environment?

Healthcare workers can be exposed to dangerous drugs during their daily practice. The National Institute for Occupational Safety and Health (NIOSH) considers "hazardous drugs" as those that had shown one or more of the following characteristic in studies with animals, humans or in vitro systems: carcinogenicity, teratogenicity or other toxicity for development, reproductive toxicity, organ toxicity at low doses, or genotoxicity. In the actual list (draft list 2020), drugs classified in group 1 are those with carcinogenic effects. Moreover, the global human and veterinary cancer is expected to grow, so antineoplastic drug consumption may consequently grow, leading to an increase of anticancer pharmaceuticals in the environment. Not all drugs pertaining to group 1 can be classified as "antineoplastic" or "cytostatic". Since most of the research on environment presence and ecotoxicological effects of pharmaceuticals has been focused on this therapeutic class, other carcinogenic drugs belonging to different therapeutic groups may have been omitted in previous studies. In this study we aim to review the presence in the environment of the hazardous drugs (NIOSH group 1) and their possible environmental impact. Of the 90 drugs considered, there is evidence of presence in the environment for 19. Drugs with more studies reporting positive detections are: the antibiotic chloramphenicol (55), the alkylating agents cyclophosphamide (39) and ifosfamide (30), and the estrogen receptor modulator tamoxifen (18). Although the original purpose of the NIOSH list and related documents is to provide guidance to healthcare professionals in order to adequately protect them from the hazards posed by these drugs in healthcare settings, we believe they can be useful for environmentalists too. Absence of data regarding the potential of environmental risk of certain hazardous drugs might tell us which drugs ought to be prioritized in the future.