Ecological risk assessment of pharmaceuticals in the receiving environment of pharmaceutical wastewater in Pakistan

- Pharmaceuticals were detected in wastewater, sludge, solid waste and soil.
- High concentration of pharmaceuticals was detected in wastewater (1.67 mg/L).
- High concentration of pharmaceuticals was detected in solids (7.27 mg/kg).
- Diclofenac, ibuprofen and ofloxacin pose the highest ecological risk.

The pharmaceutical industry of Pakistan is growing with an annual growth rate of 10%. Besides this growth, this industry is not complying with environmental standards, and discharging its effluent into domestic wastewater network. Only limited information is available about the occurrence of pharmaceutical compounds (PCs) in the environmental matrices of Pakistan that has motivated us to aim at the occurrence and ecological risk assessment of 11 PCs of different therapeutic classes in the wastewater of pharmaceutical industry and in its receiving environmental matrices such as sludge, solid waste and soil samples near the pharmaceutical formulation units along Shiekhupura road, Lahore, Pakistan. Target PCs (paracetamol, naproxen, diclofenac, ibuprofen, amlodipine, rosuvastatin, ofloxacin, ciprofloxacin, moxifloxacin, sparfloxacin and gemifloxacin) were quantified using in-house developed HPLC-UV. Ibuprofen (1673 µg/L, 6046 µg/kg, 1229 µg/kg and 610 µg/kg), diclofenac (836 µg/L, 4968 µg/kg, 6632 µg/kg and 257 µg/kg) and naproxen (464 µg/L, 7273 µg/kg, 4819 µg/kg and 199 µg/kg) showed the highest concentrations among 11 target PCs in wastewater, sludge, solid waste and soil samples, respectively. Ecological risk assessment, in terms of risk quotient (RQ), was also carried out based on the maximum measured concentration of PCs in wastewater. The maximum RQ values obtained were with paracetamol (64 against daphnia), naproxen (177 against fish), diclofenac (12,600 against Oncorhynchus mykiss), ibuprofen (167,300 against Oryzias latipes), ofloxacin (81,000 against Pseudomonas putida) and ciprofloxacin (440 against Microcystis aeruginosa). These results show a high level of ecological risk due to the discharge of untreated wastewater from pharmaceutical units. This risk may further lead to food web contamination and drug resistance in pathogens. Thus, further studies are needed to detect the PCs in crops as well as the government should strictly enforce environmental legislation on these pharmaceutical units.