A critical review, and up-to-date research progress on the occurrence, and removal of antiretroviral drugs in water

In the last decade, research on identification of antiretroviral drugs in water has intensified, especially in the developing countries. Concentrations reaching 33 µg/L for efavirenz have been reported in wastewater effluent which is released into the surface water. Some antiretroviral drugs have been found to possess toxic effects towards the aquatic organisms, and plants. This threatens the sustainability of high-quality vegetables as the water scarcity necessitates the practise of crop irrigation with used or treated water which is often contaminated with pharmaceuticals. This article reviewed the progress made on the removal of antiretroviral drugs in contaminated water, identified challenges, and gaps while outlining the possible future research direction. It observed that various degradation processes for antiretroviral drugs have been explored with limited information on the characterization of the degradation by-products, and their toxic effects. Adsorption process is also dominating for removal of antiretroviral drugs in water, while wetland removal, and plant uptake are least explored. An adsorption capacity as high as 833 mg/g has been reported for lopinavir using biochar modified with incorporating layered double hydroxide. Research on the removal of antiretroviral drugs in water is expected to continue with the inclusion of studies focussing on metabolites of these chemicals.