Investigation of pharmaceutical drugs in Hospital liquid wastes of Gondar Referral Hospital and river water in Gondar city, Ethiopia using HPLC-DAD method

Hospitals generate liquid waste containing diverse pharmaceutical contaminants. Consequently, hospital liquid wastes (HLWs) represent significant point sources of environmental pollution and may pose considerable risks to both human health and aquatic ecosystems. The occurrence and persistence of pharmaceutical residues in aquatic environments are a serious environmental concern. Despite this issue, scientific data on the occurrence of pharmaceutical contaminants in Ethiopia remain very limited, highlighting a critical knowledge gap that warrants systematic investigation. This study investigated five pharmaceutical compounds amoxicillin, ciprofloxacin, paracetamol azithromycin, and hydrochlorothiazide in HLWs and River waters in Gondar city. A total of ten samples were collected from HLWs and River water. Sample extraction and preconcentration were performed using solid-phase extraction (SPE) followed by analysis using high-performance liquid chromatography coupled with a diode array detector (HPLC–DAD). Three SPE cartridges-Bond Elut Plexa PCA, Bond Elut PAX, and C18 were evaluated for sample cleanup and enrichment, among which the C18 cartridge exhibited the highest recovery efficiency. Excellent linearity was obtained for all analyte, with correlation coefficients (R 2 ) > 0.9947. The limits of detection (LODs) ranged from 2.49 to 2.78 mg/L while the limits of quantification (LOQs) ranged from 8.05 to 11.47 mg/L. Acceptable recoveries between 71.48% and 102.73% were achieved. The results showed that amoxicillin was detected at concentrations ranging from below detection limit (BDL) to 5.37±1.16 mg/L, hydrochlolotized from 2.55±0.45 to 9.93±1.82 mg/L and azithromycin from 3.95±0.84 to 10.73±7.46 mg/L in HLW and river samples; whereas ciprofloxacin was below detection limit in all samples. Paracetamol was detected in Qeha (2.93±0.49 mg/L), Shinta (2.72±0.04 mg/L) and Dimaza (2.93±0.49 mg/L) Rivers. The presence of these pharmaceuticals in river waters may pose adverse environmental and public health implications. These findings provide valuable insight into the occurrence of pharmaceuticals in the aquatic environment. This study recommends the establishment of a long-term monitoring program and interdisciplinary research to better understand of pharmaceutical contamination in aquatic ecosystems.