Occurrence and fate of pharmaceuticals in a wastewater treatment plant from southeast of Spain and risk assessment

Pharmaceutical and personal care products (PPCPs) can be incorporated into ecosystems and pose potential environmental and health hazards. These pollutants are becoming omnipresent in the environment because they are introduced by several sources, being particularly important the contribution of human-derived pharmaceuticals. The presence of PPCPs in waters has received increasing attention in recent years, resulting in great concern regarding their occurrence, transformation, fate and environmental risk. For that reason, the pharmaceuticals carbamazepine (CBZ), diclofenac (DIC), ibuprofen (IBU), ketoprofen (KET) and naproxen (NPX) were measured in the waters and sludge of several parts of a double step activated sludge wastewater treatment plant (WWTP) from Murcia (Spain). With these results, the biological degradation constant, the sorption coefficient and the pharmaceutical removal were calculated. Possible risks to humans and ecosystems were also evaluated. These showed good degradation of IBU and NPX (74.4 and 84.9%, respectively), while CBZ didn't display any degradation. DIC was the compound most likely to be sorbed into the sludge (3.09 L kg(-1)). The PPCPs removal in this double stage WWTP was compared to a previous data obtained in a WWTP of the same region with an activated sludge (single biological batch reactor). The results showed a decrease in the removal of the double stage plant, probably due to the lower hydraulic retention time employed. The study of the human and ecological risk quotients indicates a low risk of the selected pharmaceuticals (RQ < 0.1).