Environmental risk assessment of diclofenac residues in surface waters and wastewater: a hidden global threat to aquatic ecosystem

Pharmaceuticals are chemical compounds employed as medicinal drugs. They have severe physic-chemical properties which make them destructive for non-target species. Consequently, their continuous addition in the environment may pose hazardous effects. Among these, diclofenac (DCF), a non-steroidal anti-inflammatory drug (NSAID), is extensively used in Pakistan which may lead to its accumulation in both terrestrial and aquatic environment. Present study aims to assess the presence and concentration of pharmaceutically active drug (DCF) in surface water and wastewater of twin cities of Pakistan (Rawalpindi and Islamabad). For this purpose, a validated high-performance liquid chromatography (HPLC) method was adopted involving solid-phase extraction procedure. Wastewater samples were collected from various sites of Rawalpindi and Islamabad. Results of HPLC analysis revealed that DCF was extant with considerably high concentration, not only in wastewater but also in surface water samples. Concentrations as high as 216 mug L(-1) was detected in Rawat industrial area and low as 8 mug L(-1) was detected in dairy farm wastewater samples collected from Taramri. However, maximum DCF levels in residential wastewater and hospital wastewater were detected to be 105 mug L(-1) and 34 mug L(-1), respectively. Moreover, the highest detected level (116 mug L(-1)) was found in surface water of Sawan River. Further, results of ecological risk assessment revealed its possible toxic effects of DCF on various aquatic organisms.