Quantification of Pharmaceuticals in Sludge Produced from Wastewater Treatment Plants in Jordan and Environmental Risk Assessment

Sewage sludge is increasingly recognized as a major reservoir for pharmaceuticals and emerging contaminants that are only partially removed by conventional wastewater treatment. This study provides the first comprehensive assessment of these contaminants in biosolids generated from ten major wastewater treatment plants (WWTPs) across Jordan. Different pharmaceuticals were quantified in the sludge samples generated. The results revealed concentrations ranging from 10 to over 2000 µg kg^-1, with antibiotics typically showing the highest enrichment (e.g., ciprofloxacin up to 2165 µg kg^-1, ofloxacin up to 303 µg kg^-1). Anti-inflammatory compounds such as diclofenac reached 196 µg kg^-1, while the antimicrobial triclosan exceeded 4700 µg kg^-1 in some sludge samples. Carbamazepine, a recalcitrant antiepileptic drug, ranged between 50 and 223 µg kg^-1, reflecting both widespread use and strong persistence. Elevated levels of quaternary ammonium compounds (QACs) were also detected. The highest levels were generally associated with large urban WWTPs and plants receiving industrial discharges. Environmental risk assessment (ERA) indicated that the risk for soil biota was acceptable for most cases for low application doses (5-10 t/ha) except for WWTP6-MD, WWTP8-S, and WWTP9-IC, where the risk was non-acceptable. Severe limitations in the risk assessment were noted: reliable toxicity endpoints in terrestrial soil organisms such as microbiota, collembola, and earthworms are few, while deriving endpoints via aquatic available data is not always reliable. Overall, the findings demonstrate that Jordanian sewage sludge contains environmentally relevant levels of pharmaceuticals and QACs and that risk assessment is, therefore, pertinent before any stabilization and realistic land application scenarios are chosen.