Chemotherapeutic drugs in Lebanese surface waters: estimation of population exposure and identification of high-risk drugs

Abstract Environmental risk assessment of anti-cancer drugs and their transformation products is a major concern worldwide due to two main factors: the consumption of chemotherapeutic agents is increasing throughout the years and conventional water treatment processes seem to be ineffective. The aim of the study is to investigate the consumption of anticancer drugs and assess their potential health hazard as contaminants of the Lebanese surface waters. Data on yearly consumption of 259 anti-neoplastic drugs over the years 2013 to 2018 were collected and the following parameters were calculated: yearly consumption of single active ingredients, yearly consumption of drug equivalents (for drugs belonging to the same pharmacologic class/ having the same active ingredient) and Predicted Environmental Concentrations (PECs). The classification of compounds into risk categories was based on exposure using PECs. The top five most commonly consumed drugs are Mycophenolate mofetil, Hydroxycarbamide, Capecitibine, Mycophenolic acid and Azathioprine. Based on the calculated PEC values of single active ingredients as well as their equivalents, six high risk priority compounds were identified: Mycophenolate mofetil, Hydroxycarbamide, Capecitibine, Mycophenolic acid and Azathioprine and 5-Fluorouracil. The impact of these micropollutants on animals as well as humans was analyzed. This research paper stresses the importance of further analysis of chemotherapy micropollutants with major focus on high risk drugs. Additionally, regulations should be set in place to ensure proper management of waste water and the development of efficient waste water treatment plants.