Samples of influent (untreated) and effluent (treated) from 18 sewage treatment plants (STPs) in 14 municipalities in Canada were analyzed for residues of selected prescription and nonprescription drugs. Several neutral and acidic drugs were detected in effluents, including analgesic/anti-inflammatory agents, lipid regulators, and an antiepileptic drug, carbamazepine. Residues were extracted from effluents by solid-phase extraction, followed by either methylation and analysis of acidic drugs by gas chromatography/mass spectrometry or direct analysis of neutral drugs by liquid chromatography/tandem mass spectrometry. Analgesic/anti-inflammatory drugs such as ibuprofen and naproxen, as well as the metabolite of acetylsalicyclic acid, salicylic acid, were often detected in final effluents at microg/L concentrations. The acidic lipid regulator, clofibric acid, and the analgesic/anti-inflammatory drug diclofenac were not detected in any final effluent samples, which is not consistent with data from Europe. The precursor to clofibric acid, clofibrate, is not widely prescribed as a lipid regulator in Canada. However, the lipid regulators bezafibrate and gemfibrozil were detected in some samples of influent and effluent. The chemotherapy drugs ifosfamide and cyclophosphamide and the anti-inflammatory phenazone were not detected in influent or effluent samples, but the vasodilator drug pentoxyfylline was detected at ng/L concentrations in some final effluents. The widespread occurrence of carbamazepine at concentrations as high as 2.3 microg/L may be explained by use of this drug for other therapeutic purposes besides treatment of epilepsy and its resistance to elimination in STPs. The rates of elimination of ibuprofen and naproxen appeared to be elevated in STPs with hydraulic retention times for sewage greater than 12 h.

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Alkylphenol ethoxylates and, in particular, nonylphenol ethoxylates have found many industrial, commercial, institutional and household uses in Canada. These nonionic surfactants are very efficient and cost effective. Their widespread use has led to the detection of the parent surfactants and their degradation products in various environmental matrices. Alkylphenol ethoxylates can be degraded aerobically and anaerobically in natural environments and sewage treatment plants.. The resulting degradation products are more persistent, more toxic, more lipophilic, less water soluble and more estrogenic than their parent compounds. This article reviews the occurrence of nonylphenol polyethoxylates and their degradation products as well as octylphenol poly-ethoxylates and their degradation products. There is limited information available about the concentrations of these substances in their original product formulations. The highest levels of the degradation products, especially nonylphenol, occur in the anaerobically digested sludge of sewage treatment plants. Sludge from these sewage treatment plants may be used as an amendment to agricultural soils. Various sewage treatment plants have wide ranges of discharged effluent concentrations of these compounds — some appear to be very efficient at removing alkylphenolics from their effluent stream. Little information is available about the fate of these substances in their receiving environment, and environmental concentrations and bioaccumulation factors of these contaminants in aquatic biota. More research is required on the uptake, persistence and bioaccumulation of alkylphenolic metabolites in fish, mussels and other aquatic organisms

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