Evolvement of carbamazepine under solar irradiation in the presence of chlorine: Efficiency, influences, degradation pathways and ecotoxicity

•CBZ was rapidly degraded during the chlorine/solar irradiation process.•·Cl and ·OH have significant contribution to CBZ degradation.•The degradation mechanism of CBZ under chlorine/solar irradiation was discussed.•TP179 and TP209 were defined as priority to control ecological safety.•Measures to control the elevated ecotoxicity of degraded CBZ was proposed.