Carbamazepine Ozonation By-Products: Toxicity in Zebrafish (Danio rerio) Embryos and Chemical Stability

Carbamazepine (CBZ) is an anticonvulsant medication with highly persistent properties in the aquatic environment, where it has the potential to affect non-target biota. Since CBZ and many other pharmaceuticals are not readily removed in conventional sewage treatment plants (STP), additional STP effluent treatment technologies are being evaluated and implemented. Whole effluent ozonation is a prospective method to remove pharmaceuticals such as CBZ, yet knowledge on the toxicity of CBZ ozonation by-products (OBPs) is lacking. This study presents, for the first time, in vivo individual and mixture toxicity of four putative OBPs, i.e. carbamazepine 10,11-epoxide (CBZ-EP), 10,11 dihydro-carbamazepine (DI-CBZ), 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), and 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD) in developing zebrafish (Danio rerio) embryos. BQM and BQD were isolated from the ozonated solution as they were not commercially available. The study confirmed that the OBP mixture cau...