The toxicity potential of pharmaceuticals found in the Douro River estuary (Portugal)-Experimental assessment using a zebrafish embryo test

► The toxicity potential of two mixtures of pharmaceuticals was evaluated using a zebrafish embryo test. ► One of the mixtures corresponds to an environmentally realistic scenario and both have carbamazepine, fenofibric acid, propranolol, trimethoprim and sulfamethoxazole. ► Results evidenced morphological alterations, such as spinal deformities and yolk-sac oedemas. Moreover, heart rate decreased after both mixture exposures, and the tail lengths also diminished. Toxicological effects were concentration dependent. ► Mortality, hatching rate and the number of spontaneous movements were not affected. ► The low levels of pharmaceuticals did interfere with the normal development of zebrafish, which suggests risks for wild organisms.