Abstract:
The recent outbreak of respiratory syndrome-coronavirus-2 (SARS-CoV-2), which causes
coronavirus disease (COVID-19), has led to the widespread use of therapeutics, including dexamethasone
(DEXA). DEXA, a synthetic glucocorticoid, is among the widely administered drugs used
to treat hospitalized COVID-19 patients. The global COVID-19 surge in infections, consequent
increasing hospitalizations, and other DEXA applications have raised concerns on eminent adverse
ecological implications to aquatic ecosystems. Here, we aim to summarize published studies on
DEXA occurrence, fate, and effects on organisms in natural and engineered systems as, pre-COVID,
the drug has been identified as an emerging environmental contaminant. The results demonstrated a
significant reduction of DEXA in wastewater treatment plants, with a small portion, including its
transformation products (TPs), being released into downstream waters. Fish and crustaceans are
the most susceptible species to DEXA exposure in the parts-per-billion range, suggesting potential
deleterious ecological effects. However, there are data deficits on the implications of DEXA to marine
and estuarine systems and wildlife. To improve DEXA management, toxicological outcomes of
DEXA and formed TPs should entail long-term studies from whole organisms to molecular effects in
actual environmental matrices and at realistic exposure concentrations. This can aid in striking a fine
balance of saving human lives and protecting ecological integrity.
Description:
SUPPLEMENTARY MATERIAL : Table S1: The ecotoxicological effects of DEXA on organisms at different levels of organization, Table S2: Removal of DEXA during wastewater treatment in WWTPs, with techniques utilized across geographical regions globally in selected studies.