The occurrence of acidic drugs and caffeine in sewage effluents and receiving waters from three coastal watersheds in Atlantic Canada

Pharmaceuticals, by design, induce biological responses in animals and humans at very low doses, making their presence in the aquatic environment an issue of concern. Prescription and over-the-counter drugs commonly found in wastewater are discharged on a continuous basis into the waters of two coastal watersheds in Atlantic Canada. Ten acidic drugs and caffeine were observed in the final effluents of sewage treatment facilities in Millcove (Halifax watershed), and Trenton (Pictou watershed), Nova Scotia. Naproxen and ibuprofen, two highly used non-steroidal anti-inflammatory drugs (NSAIDs), and caffeine, were the predominant compounds. Naproxen, ibuprofen, salicylic acid (metabolite of acetylsalicylic acid), diclofenac (NSAID) and gemfibrozil (lipid regulator) were also detected in the low ng/L range in the receiving waters of treated and untreated sewage outflows. Acidic drugs were not detected in the marine waters of the Cocagne watershed located in southeast New Brunswick. This watershed was evaluated for the possibility of contamination of near-shore coastal waters from domestic septic systems in the vicinity of a densely populated cottage area. The observation of traces of caffeine suggests some organic pollution in the area.