Biodegradation of Chemicals in Unspiked Surface Waters Downstream of Wastewater Treatment Plants

2019 | Environ. Sci. Technol. | 53 (4) (1884-1892)

Insights into the O : C-dependent mechanisms controlling the evaporation of alpha-pinene secondary organic aerosol particles

Buchholz, A; Lambe, AT; Ylisirnio, A; Li, ZJ; Tikkanen, OP; Faiola, C; Kari, E; Hao, LQ; Luoma, O; Huang, W; Mohr, C; Worsnop, DR; Nizkorodov, SA; Yli-Juuti, T; Schobesberger, S; Virtanen, A
2019 | Atmos. Chem. Phys. | 19 (6) (4061-4073)
absorption-model , gas , high-resolution , isothermal dilution , kinetics , mass-spectrometer , oxidation , phase , thermodenuder , volatility basis-set
The volatility of oxidation products of volatile organic compounds (VOCs) in the atmosphere is a key factor to determine if they partition into the particle phase contributing to secondary organic aerosol (SOA) mass. Thus, linking volatility and measured particle composition will provide insights into SOA formation and its fate in the atmosphere. We produced alpha-pinene SOA with three different oxidation levels (characterized by average oxygen-to-carbon ratio; (O:C) over bar = 0.53, 0.69, and 0.96) in an oxidation flow reactor. We investigated the particle volatility by isothermal evaporation in clean air as a function of relative humidity (RH < 2 %, 40 %, and 80 %) and used a filter-based thermal desorption method to gain volatility and chemical composition information. We observed reduced particle evaporation for particles with increasing <(O:C )over bar> ratio, indicating that particles become more resilient to evaporation with oxidative aging. Particle evaporation was increased in the presence of water vapour and presumably particulate water; at the same time the resistance of the residual particles to thermal desorption was increased as well. For SOA with (O:C ) over bar = 0.96, the unexpectedly large increase in mean thermal desorption temperature and changes in the thermogram shapes under wet conditions (80 % RH) were an indication of aqueous phase chemistry. For the lower (O:C ) over bar cases, some water-induced composition changes were observed. However, the enhanced evaporation under wet conditions could be explained by the reduction in particle viscosity from the semi-solid to liquid-like range, and the observed higher desorption temperature of the residual particles is a direct consequence of the increased removal of high-volatility and the continued presence of low-volatility compounds.

High-throughput evaluation of organic contaminant removal efficiency in a wastewater treatment plant using direct injection UHPLC-Orbitrap-MS/MS

Li, Z.; Undeman, E.; Papa, E.; McLachlan, M.S.
2018 | Environ. Sci.: Processes Impacts | 20 (561-571)

A strategic screening approach to identify transformation products of organic micropollutants formed in natural waters

Li, Z.; Kaserzon, S.L.; Plassmann, M.M.; Sobek, A.; Gómez Ramos, M.J.; Radke, M.
2017 | Environ. Sci.: Processes Impacts | 19 (4) (488-498)

An integrated approach to study the formation and environmental behavior of transformation products from organic micropollutants

Li, Z.; Sobek, A.; Radke, M.
2016 | Society of Environmental Toxicology and Chemistry (SETAC)

7th SETAC World Congress / SETAC North America 37th Annual Meeting | November 6, 2016 | Orlando, FL, USA

Exploring trends of C and N isotope fractionation to trace transformation reactions of diclofenac in natural and engineered systems

Maier, M.P.; Prasse, C.; Pati, S.G.; Nitsche, S.; Li, Z.; Radke, M.; Meyer, A.; Hofstetter, T.B.; Ternes, T.A.; Elsner, M.
2016 | Environ. Sci. Technol. | 50 (20) (10933-10942)

Although diclofenac ranks among the most frequently detected pharmaceuticals in the urban water cycle, its environmental transformation reactions remain imperfectly understood. Biodegradation-induced changes in 15N/14N ratios (εN = −7.1‰ ± 0.4‰) have indicated that compound-specific isotope analysis (CSIA) may detect diclofenac degradation. This singular observation warrants exploration for further transformation reactions. The present study surveys carbon and nitrogen isotope fractionation in other environmental and engineered transformation reactions of diclofenac. While carbon isotope fractionation was generally small, observed nitrogen isotope fractionation in degradation by MnO2 (εN = −7.3‰ ± 0.3‰), photolysis (εN = +1.9‰ ± 0.1‰), and ozonation (εN = +1.5‰ ± 0.2‰) revealed distinct trends for different oxidative transformation reactions. The small, secondary isotope effect associated with ozonation suggests an attack of O3 in a molecular position distant from the N atom. Model reactants for outer-sphere single electron transfer generated large inverse nitrogen isotope fractionation (εN = +5.7‰ ± 0.3‰), ruling out this mechanism for biodegradation and transformation by MnO2. In a river model, isotope fractionation-derived degradation estimates agreed well with concentration mass balances, providing a proof-of-principle validation for assessing micropollutant degradation in river sediment. Our study highlights the prospect of combining CSIA with transformation product analysis for a better assessment of transformation reactions within the environmental life of diclofenac.

Fate of pharmaceuticals and their transformation products in four small European rivers receiving treated wastewater

Li, Z.; Sobek, A.; Radke, M.
2016 | Environ. Sci. Technol. | 50 (11) (5614-5621)

A considerable knowledge gap exists with respect to the fate and environmental relevance of transformation products (TPs) of polar organic micropollutants in surface water. To narrow this gap we investigated the fate of 20 parent compounds (PCs) and 11 characteristic TPs in four wastewater-impacted rivers. Samples were obtained from time-integrated active sampling as well as passive sampling using polar organic chemical integrative samplers (POCIS). Seventeen out of the 20 PCs were detected in at least one of the rivers. All the PCs except acesulfame, carbamazepine, and fluconazole were attenuated along the studied river stretches, with the largest decrease found in the smallest river which had an intense surface water-pore water exchange. Seven TPs were detected, all of which were already present directly downstream of the WWTP outfall, suggesting that the WWTPs were a major source of TPs to the recipients. For anionic compounds, attenuation was the highest in the two rivers with the lowest discharge, while the pattern was not as clear for neutral or cationic compounds. For most compounds the results obtained from active sampling were not significantly different from those using POCIS, demonstrating that the cost and labor efficient POCIS is suitable to determine the attenuation of organic micropollutants in rivers.

Fate of Pharmaceuticals and Their Transformation Products in Rivers: An integration of target analysis and screening methods to study attenuation processes

2016 | SU | ISBN: 978-91-7649-292-5

Pharmaceuticals are environmental contaminants causing steadily increasing concern due to their high usage, ubiquitous distribution in the aquatic environment, and potential to exert adverse effects on the ecosystems. After being discharged from wastewater treatment plants (WWTPs), pharmaceuticals can undergo transformation processes in surface waters, of which microbial degradation in river sediments is considered highly significant. In spite of a substantial number of studies on the occurrence of pharmaceuticals in aquatic systems, a comprehensive understanding of their environmental fate is still limited. First of all, very few consistent datasets from lab-based experiments to field studies exist to allow for a straightforward comparison of observations. Secondly, data on the identity and occurrence of transformation products (TPs) is insufficient and the relation of the behavior of TPs to that of their parent compounds (PCs) is poorly understood. In this thesis, these knowledge gaps were addressed by integrating the TP identification using suspect/non-target screening approaches and PC/TP fate determination. The overarching objective was to improve the understanding of the fate of pharmaceuticals in rivers, with a specific focus on water-sediment interactions, and formation and behavior of TPs. In paper I, 11 pharmaceutical TPs were identified in water-sediment incubation experiments using non-target screening. Bench-scale flume experiments were conducted in paper II to simultaneously investigate the behavior of PCs and TPs in both water and sediment compartments under more complex and realistic hydraulic conditions. The results illustrate that water-sediment interactions play a significant role for efficient attenuation of PCs, and demonstrate that TPs are formed in sediment and released back to surface water. In paper III the environmental behavior of PCs along stretches of four wastewater-impacted rivers was related to that of their TPs. The attenuation of PCs is highly compound and site specific. The highest attenuation rates of the PCs were observed in the river with the most efficient river water-pore water exchange. This research also indicates that WWTPs can be a major source of TPs to the receiving waters. In paper IV, suspect screening with a case-control concept was applied on water samples collected at both ends of the river stretches, which led to the identification of several key TPs formed along the stretches. The process-oriented strategies applied in this thesis provide a basis for prioritizing and identifying the critical PCs and TPs with respect to environmental relevance in future fate studies.

Flume experiments to investigate the environmental fate of pharmaceuticals and their transformation products in streams

Li, Z.; Sobek, A.; Radke, M.
2015 | Environ. Sci. Technol. | 49 (10) (6009-6017)

A strategic screening approach to identify transformation products of emerging organic micropollutants along rivers

Li, Z.; Kaserzon, S.L; Plassmann, M.M.; Goméz Ramos, M.J.; Sobek, A.; Mueller, J.F.; Radke, M.
2015 | Society of Environmental Toxicology and Chemistry (SETAC)

SETAC North America 36th Annual Meeting | Salt Lake City, Utah, USA

Fate of pharmaceuticals and their transformation products in four small European rivers receiving treated wastewater

Li, Z.; Sobek, A.; Radke, M.
2015 | Society of Environmental Toxicology and Chemistry (SETAC)

SETAC North America 36th Annual Meeting | Salt Lake City, Utah, USA

Screening for pharmaceutical transformation products formed in river sediment by combining ultrahigh performance liquid chromatography/high resolution mass spectrometry with a rapid data-processing method

Li, Z.; Maier, M.P.; Radke, M.
2014 | Anal. Chim. Acta | 810 (61-70)
biodegradation , biotransformation , pharmaceuticals , sediment , transformation products

While the occurrence of pharmaceuticals in the aquatic environment has been extensively investigated, their environmental fate is less thoroughly explored. Scarce information on their transformation pathways and the generated transformation products (TPs) limitsconventional target analytical approaches. In this study, samples from water/sediment tests were analyzed by ultrahigh performance liquid chromatography interfaced with quadrupole time-of-flight mass spectrometry (UHPLC/QToF-MS). A data processing method based on peak detection, time-trend filtration and structure assignment was established to provide an efficient way for identifying the key TPs in terms of persistence; all software used for the individual steps of this method is freely available. The accurate mass and meaningful time-trends were major contributors in facilitating the isolation of plausible TP peaks. In total, 16 TPs from 9 parent pharmaceuticals were identified. Eleven out of the 16 TPs were confirmed by corresponding reference standards; no standards were available for the remaining TPs. For additional 6 potential TPs, a molecular formula was suggested but no additional structural information could be generated. Among the TPs identified in the water/sediment tests, carbamazepine-10,11-epoxide (parent: carbamazepine), saluamine (parent: furosemide), chlorothiazide and 4-amino-6-chloro-1,3-benzenedisulfonamide (parent of both: hydrochlorothiazide), and 1-naphthol (parent: propranolol) are those that accumulated over the entire incubation period of 35 days.

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