Ecopharmacodynamics of Antiretrovirals: From Use to Involuntary Re-Exposure

This study investigates the ecopharmacodynamics of antiretrovirals (ARVs) through an integrated cyclic model that correlates population consumption, environmental fate, and human re-exposure. In the assessed scenario, incomplete excretion introduces approximately 6.5 × 104 kg/year of unchanged drugs into sewage, led by darunavir (1.8 × 104 kg/year) and tenofovir disoproxil (1.0 × 104 kg/year). The ineffectiveness of conventional treatment plants (average removal of 59.8%) allows substantial fractions to reach water bodies or to partition strongly into residual sludge, reaching concentrations of 314 ng/g for zidovudine and 299 ng/g for lamivudine. In surface waters, elevated levels of nevirapine (81.1 µg/L) and lamivudine (30.2 µg/L) are observed, accompanied by significant sedimentary accumulation (zidovudine at 314 ng/g). Crucially, drinking water treatment systems prove unable to retain these compounds, culminating in the presence of abacavir (2.9 × 103 ng/L) and atazanavir (2.7 × 103 ng/L) in the drinking water supplied to the population. These data confirm that ARVs do not disappear after consumption but operate in an open anthropo-circulatory circuit, in which continuous water intake perpetually reinitiates human exposure, requiring advanced polishing technologies and One Health surveillance.