Characterization of Five Portuguese Wastewater Treatment Plants: Removal Efficiency of Pharmaceutical Active Compounds through Conventional Treatment Processes and Environmental Risk

Abstract

Due to the high consumption and incorrect disposal of pharmaceutical active compounds (PhACs), they are recognized as contaminants of emerging concern. Wastewater treatment plants (WWTPs) may be inefficient in removing PhACs, therefore discharging them into surface waters. The removal efficiencies of five WWTPs located in the south of Portugal (Alentejo) were evaluated in 2020. Twenty-six PhACs were analyzed in wastewater influents, effluents, and surface waters, upstream and downstream of the WWTPs by solid-phase extraction (SPE) and ultra-performance liquid chromatography coupled with tandem mass detection (UPLC–MS/MS). The most representative PhACs in influents were acetaminophen, caffeine, naproxen, ibuprofen, and diclofenac with minimum-maximum concentrations of 49–225 µg/L, 26–46 µg/L, 5.9–13 µg/L, 5.2–22 µg/L, and 1.3–2.5 µg/L, respectively. For effluents, it was acetaminophen, caffeine, and diclofenac with minimum-maximum concentrations of 0.054–7.8 µg/L, 0.084–4.8 µg/L, and 0.28–3.3 µg/L, respectively. The highest removal efficiencies were observed for acetaminophen, sulfadiazine, cortisone, testosterone, metoprolol, and propranolol (100%). The lowest removal efficiencies were observed for carbamazepine (2.7%) and diclofenac (−13.2%). The risk quotient of sulfamethoxazole and diclofenac were higher than 1 for receiving waters, indicating they probably pose high risks to aquatic organisms.

A look to surface water and wastewaters in Beira Baixa, Portugal: wastewater treatment plants and environmental risk

“…The material and apparatus are described in detail in a previous study. 8 Briefly, quantitative filter paper, 1.0 μm glass microfiber, and 0.45 μm nylon membrane purchased from Waters Corporation (Milford, Massachusetts, USA), and polytetrafluoroethylene (PTFE) syringe filters (13 mm × 0.45 μm) from Millipore for sample filtration.…”

“…The tandem mass spectrometer operated in both positive and negative ion ESI modes using multiple reaction monitoring (MRM) mode. 8…”

“…For the assessment of target pharmaceuticals, we employed a methodology previously implemented and validated by our research group that is based on liquid chromatographytandem mass spectrometry (LC-MS/MS) after clean-up and concentration of target compounds by solid-phase extraction (SPE) method. 8,9,24 To obtain the maximum sensitivity and resolution for the target PhACs, two chromatographic methods were developed for the analysis of wastewater samples: an acidic and a basic chromatographic method were optimized, each run with a total analysis time of 14 and 11 min, respectively (Table S1 †). The employed analytical methodology provides linear calibration curves of all target PhACs over a concentration range from 0.76 to 87 μg L −1 with a determination coefficient (R 2 ) between 0.9983 and 0.9999 and a coefficient of variation between 1.6% and 6.7%.…”

“…Endocrine-disrupting, mutagenicity, and antibiotic resistance are the most prevalent issues related to their potential toxic effects. 8 Wastewater treatment plants (WWTPs) are the major contributors to PhACs in the environment. Many parent compounds and their metabolites are continuously introduced into sewage systems, mainly through urination, excretion, disposal of unused or expired medicines, or directly from pharmaceutical manufacturer discharges.…”

“…Research has shown that the elimination of some PhACs during WWTP processes is relatively low, and some of them exhibit recalcitrant properties. [8][9][10] In previously published work, 8 the authors analysed the PhACs in influents, effluents, and surrounding surface waters of five wastewater treatment plants (WWTPs) located in the Évora district in Portugal. As stated, this region is frequently affected by drought and therefore, the objectives of that study were to determine the quality (regarding selected PhACs concentrations) of those samples, assess the impact of effluents in receiving water bodies, and determine whether wastewaters could be safe to use to reverse drought in streams and rivers.…”