Occurrence and environmental implications of pharmaceuticals in Chinese municipal sewage sludge

The presence of pharmaceuticals in aquatic environment has become a topic of concern because of their potential adverse effects on human health and wildlife species. A total of 45 dewatered sewage sludge samples were collected throughout China and analyzed for 30 commonly consumed pharmaceutical residues. Ofloxacin was found to be the dominant contaminant with concentrations up to 24 760 μg kg⁻¹, followed by oxytetracycline (5280 μg kg⁻¹), norfloxacin (5280 μg kg⁻¹) and ketoprofen (4458 μg kg⁻¹). The concentration of pharmaceutical residues varied greatly depending on the operation conditions of wastewater treatment plants and sampling locations. Poor agreement was found between the predicted (calculation based on the annual consumption and coefficient of sludge water partition) and detected concentrations of the pharmaceuticals indicating that the occurrence of pharmaceutical residues was affected by various factors such as loading rates, sewage properties and the chemical properties such as the contribution from polar groups. National wide fate and ecotoxicity study is required for the development of control strategies.