Biological hazard evaluation of a pharmaceutical effluent before and after a photo-Fenton treatment

The aim of this study was to evaluate the biological hazard of a pharmaceutical effluent before and after treatment. For the former, the determined 96 h-LC₅₀ value was 1.2%. The photo-Fenton treatment catalyzed with an iron-pillared clay reduced this parameter by 341.7%. Statistically significant increases with respect to the control group (P < 0.05) were observed at 12, 24, 48 and 72 h in HPC (50.2, 30.4, 66.9 and 43.3%), LPX (22, 83.2, 62.7 and 59.5%) and PCC (14.6, 23.6, 24.4 and 25.6%) and antioxidant enzymes SOD (29.4, 38.5, 32.7 and 49.5%) and CAT (48.4, 50.3, 38.8 and 46.1%) in Hyalella azteca before treatment. Also increases in damage index were observed before treatment of 53.1, 59.9, 66.6 and 72.1% at 12, 24, 48 and 72 h, respectively. After treatment the same biomarkers of oxidative stress decreased with respect to before treatment being to HPC (29.3, 22.5, 41.6 and 31.7%); LPX (14.2, 43.1, 30.7 and 35.5%); PCC (12.6, 21.3, 24.2 and 23.9%); SOD (39.2, 33.9, 49.5 and 37.9%) and CAT (28.6, 35.8, 33.7 and 31.7) at 12, 24, 48 and 72 h, respectively (P < 0.05). The damage index were decreased at 12, 24, 48 and 72 h in 48.9, 57.8, 67.3 and 72.1%, respectively. In conclusion, the obtained results demonstrate the need of performing bioassays in order to characterize an effluent before discharge and not base such a decision only upon current normativity. In addition, it was also concluded that the heterogeneous photo-Fenton process decreases the presence of PCT, oxidative stress, genotoxic damage and LC₅₀ in Hyalella azteca.