Predicted occurrence, ecotoxicological risk and environmentally acquired resistance of antiviral drugs associated with COVID-19 in environmental waters

Abstract

Antiviral drugs have been used to treat the ever-growing number of coronavirus disease 2019 (COVID-19) patients. Consequently, unprecedented amounts of such drug residues discharging into ambient waters raise concerns on the potential ecotoxicological effects to aquatic lives, as well as development of antiviral drug-resistance in wildlife. Here, we estimated the occurrence, fate and ecotoxicological risk of 11 therapeutic agents suggested as drugs for COVID-19 treatment and their 13 metabolites in wastewater and environmental waters, based on drug consumption, physical-chemical property using quantitative structure-activity relationship (QSAR), and ecotoxicological and pharmacological data for the drugs. Our results suggest that the removal efficiencies at conventional wastewater treatment plants will remain low (< 20%) for half of the substances, and consequently, high drug residues (e.g. 7402 ng/L ribavirin, 4231 ng/L favipiravir, 730 ng/L lopinavir, 319 ng/L remdesivir; each combined for both unchanged forms and metabolites; and when each drug is administered to 100 patients out of 100,000 populations on a day) can be present in secondary effluents and persist in the environmental waters. Ecotoxicological risk in receiving river waters can be high (risk quotient > 1) by a use of favipiravir, lopinavir, umifenovir and ritonavir, and medium (risk quotient > 0.1) by a use of chloroquine, hydroxychloroquine, remdesivir, and ribavirin, while the risk will remain small (risk quotient < 0.1) for dexamethasone and oseltamivir. The potential of wild animals acquiring antiviral drug resistance is estimated to be small. Our prediction suggests a pressing need for proper usage and waste management of antiviral drugs as well as for improving removal efficiencies of drug residues in wastewater.