Partitioning of pharmaceuticals and personal care products in secondary wastewater treatment and estimated loadings and potential effects to the receiving environment.

Thirty pharmaceuticals and personal care products (PPCPs) were measured in the liquid (influent and effluent) and solid (influent solids and sludge) streams in a conventional activated sludge secondary wastewater treatment plant, and their loadings to the receiving environment and potential toxicity levels were assessed. Most compound loadings were reduced by treatment, although there were none that were completely degraded by the process, and five were higher in the output than input (carbamazepine, clarithromycin, diltiazem, oxytetracycline, and warfarin). The treatment process did result in the partitioning of some influent liquid phase compounds to the sludge, although the highest potential loadings to the receiving environment were via the final effluent liquid phase. Concentrations of all compounds were well below predicted and known toxicity levels for aquatic and terrestrial receiving environments, suggesting they are not likely to be toxic in the marine environment around the treatment plant outfall. The treatment plant did have a net positive impact on the reduction of PPCPs in wastewater, resulting in lower concentrations and loadings being discharged to the receiving environment.