The presence of acidic and neutral drugs in treated sewage effluents and receiving waters in the Cornwallis and Annapolis River watersheds and the Mill CoveSewage Treatment Plant in Nova Scotia, Canada

Pharmaceuticals are designed to have physiological effects on target organisms. Their presence and effect in aquatic ecosystems in the Annapolis Valley in Nova Scotia is relatively unknown. Over-the-counter (OTC) and prescription drugs are continually introduced to aquatic ecosystems through treated sewage effluent outflows into rivers and other bodies of water. Fouracidic and two neutral pharmaceuticals were monitored in the effluents from nine sewage treatment plants in the Annapolis Valley and Halifax Regional Municipality (HRM) in Nova Scotia. Naproxen and ibuprofen, two highly used OTC drugs, were the most prominent and were detected at high ng/L to low μg/L levels. Caffeine, salicylic acid (a metabolite of acetylsalicylic acid) and cotinine were detected in the ng/L range. Warfarin was not detected above the detection limits. The urban sewage treatment plant in Mill Cove, HRM showed much higher concentrations of pharmaceuticals than rural facilities in the Annapolis Valley, despite the fact that more advanced facilities are used at the urban plant. Receiving waters both downstream and upstream from STP effluent outfalls were also studied, and trace levels of caffeine at several sites indicate some degree of pollution propagation into surrounding aquatic ecosystems.

► Six highly used pharmaceuticals were studied in two watersheds.
► Pharmaceuticals were detected in most sewage effluents.
► Trace levels of pharmaceuticals were found in receiving waters at several sites.
► The urban STP showed much higher level of pharmaceuticals than rural facilities.