Occurrence of pharmaceuticals in municipal wastewater treatment plants and receiving surface waters in Central and Southern Finland

Abstract

The presence of five selected pharmaceuticals, four anti-inflammatory drugs, diclofenac, ibuprofen, ketoprofen, naproxen, and an antiepileptic drug carbamazepine, was determined at four municipal wastewater treatment plants (WWTPs) and in the receiving waterway near the city of Jyväskylä, in central Finland and also in the River Vantaa. First, an analytical method was developed including a pretreatment and purification followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The studied pharmaceuticals were detected from influents and effluents of four municipal WWTPs and from surface water of eight locations along the water way and northern Lake Päijänne. In addition, samples of sedimented particles were collected among the water samples from five locations near the discharge point of the effluent. Furthermore, the studied compounds were sampled from the surface water of northern Lake Päijänne and the River Vantaa both by grab sampling and passive sampling. Passive sampling was performed by using the Chemcatcher® sampler with a SDB-RPS Empore disk as a receiving phase. In Lake Päijänne, the passive sampling was conducted at four locations near the discharge point of a wastewater treatment plant and at four locations along the River Vantaa. The concentrations in the influents and effluents ranged from hundreds of nanograms per liter to micrograms per liter. In lake water, the concentrations ranged from tens of nanograms per liter in northern parts of the waterway to hundreds of nanograms per liter in northern Lake Päijänne near the city area. The concentrations of ketoprofen in sedimented particles ranged from tens to over one hundred micrograms per gram, while only trace amounts of other selected pharmaceuticals were detected. The results indicate that the concentrations of pharmaceuticals are affected by not only the biological and chemical reactions occurring in the wastewater treatment processes, but also by the UV light in the photic layer of Lake Päijänne. Seasonal variation in the surface water of Lake Päijänne was studied by comparing the concentrations collected in the winter and in the summer. The concentrations were higher in the winter compared to summer time in surface water due to decreased temperature and solar irradiation. On the other hand, higher concentrations of ibuprofen, ketoprofen, and naproxen were found in summer at the WWTPs, possibly due to seasonal variations in consumption. It can be concluded that considerable amounts of selected pharmaceuticals are present in the influent and effluent of municipal WWTPs, in the water and sedimented particles of along the waterway and northern Lake Päijänne, and in the River Vantaa. Additionally, the results suggest that the Chemcatcher passive samplers are suitable for detecting pharmaceuticals both in lake and river waters.