Suchergebnisse

A monitoring campaign was conducted which collected seven-day composite effluent samples (n=33) from 33 conventional wastewater treatment plants (WWTPs) across Germany to measure the concentrations of linear alkylbenzene sulfonates (LAS) and alkyl ethoxysulfates (AES). In addition, seven-day composite influent samples of four WWTPs were taken and analyzed for the same set of compounds, to determine the removal rates of the aforementioned surfactants during conventional wastewater treatment. This study encompasses the analysis of four LAS homologs (C10–C13) and two AES homologs with each 10 ethoxymers (C12 and C14 with 0-9 ethoxy units). Sample pretreatment was carried out by removing the aqueous phase using a rotational vacuum concentrator and reconstituting the analytes in a defined volume of ultra-pure water and acetonitrile. The identification and quantification of target compounds were performed by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The analytical performance of the methods was validated in tap water and effluent water, obtaining good trueness and precision for both matrices. Based on the estimated average effluent concentrations of individual LAS homologs, the average total LAS concentration in monitored WWTP effluents was 14.4 μg/L. Total AES effluent concentrations were lower compared to LAS, with an average total AES effluent concentration of 0.57 μg/L. No correlation between total LAS and AES effluent concentrations was found. Total LAS influent concentrations averaged at 3,200 μg/L, which translates to an average removal rate of 99.6%. The average total influent concentration of AES was 680 μg/L, indicating an average removal rate greater than 99.9%. Retrospective screening of 1,564 suspect list surfactants and their transformation products (TP) by a second laboratory was performed using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). The LAS-byproducts dialkyltetralin sulfonates (DATSs), the metabolites sulfophenyl alkyl carboxylic acids (SPACs) and sulfo-tetralin alkyl carboxylic acids (STACs) reached maximum concentration levels of 19 μg/L, 17 μg/L and 5.3 μg/L, respectively. It was shown that in many cases the sum of concentrations of all LAS-related byproducts and TPs surpassed the concentration of the four precursor LAS homologs (C10 – C13) themselves. High concentrations of up to 7.4 μg/L for 41 polyethylenoglycols (PEGs), the longest homolog series so far reported for PEGs, were detected. All quantified surfactants and their TPs and by-products together accounted for concentrations of up to 82 μg/L in effluent wastewater.

This study presents the development and validation of a comprehensive quantitative target methodology for the analysis of 2316 emerging pollutants in water based on Ultra-Performance Liquid Chromatography Quadrupole-Time-Of-Flight Mass Spectrometry (UPLC-Q-ToF-HRMS/MS). Target compounds include pesticides, pharmaceuticals, drugs of abuse, industrial chemicals, doping compounds, surfactants and transformation products, among others. The method was validated for 195 analytes, chosen to be representative of the chemical space of the target list, enabling the assessment of the performance of the method. The method involves a generic sample preparation based on mixed mode solid phase extraction, a UPLC-QTOF-MS/MS screening method using Data Independent Acquisition (DIA) mode, which provides MS and MS/MS spectra simultaneously and an elaborate strong post-acquisition evaluation of the data. The processing method was optimized to provide a successful identification rate >95 % and to minimize the number of false positive results (< 5 %). Decision limit (CCα) and detection capability (CCβ) were also introduced in the validation scheme to provide more realistic metrics on the performance of a HRMS-based wide-scope screening method. A new system of identification points (IPs) based on the one described in the Commission Decision 2002/657/EC was applied to communicate the confidence level in the identification of the analytes. This system considers retention time, mass accuracy, isotopic fit and fragmentation; taking full advantage of the capacities of the HRMS instruments. Finally, 398 contaminants were detected and quantified in real wastewater ; This project was implemented under the Operational Program "Education and Lifelong Learning" and funded by the European Union (European Social Fund) and Greek National Resources – ARISTEIA 624 (TREMEPOL project). Pablo Gago-Ferrero acknowledges the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement Smart-Workflow ...

The APC was funded by the COST Action 'European Energy Poverty: Agenda Co-Creation and Knowledge Innovation' (ENGAGER 2017-2021, CA16232) funded by European Cooperation in Science and Technology-www.cost.eu"(accessed 5 December 2020), and the EPIU-Energy poverty intelligence unit (Funded by UE-European Regional Development Fund, UIA04-212 (EPIU)-https://hogaressaludables.getafe.es/(accessed 5 December 2020). ; The intensity and duration of hot weather and the number of extreme weather events, such as heatwaves, are increasing, leading to a growing need for space cooling energy demand. Together with the building stock's low energy performance, this phenomenon may also increase households' energy consumption. On the other hand, the low level of ownership of cooling equip-ment can cause low energy consumption, leading to a lack of indoor thermal comfort and several health-related problems, yet increasing the risk of energy poverty in summer. Understanding future temperature variations and the associated impacts on building cooling demand will allow mitigat-ing future issues related to a warmer climate. In this respect, this paper analyses the effects of change in temperatures in the residential sector cooling demand in 2050 for a case study of nineteen cities across seven countries: Cyprus, Finland, Greece, Israel, Portugal, Slovakia, and Spain, by estimating cooling degree days and hours (CDD and CDH). CDD and CDH are calculated using both fixed and adaptive thermal comfort temperature thresholds for 2020 and 2050, understanding their strengths and weaknesses to assess the effects of warmer temperatures. Results suggest a noticeable average increase in CDD and CDH values, up to double, by using both thresholds for 2050, with a particular interest in northern countries where structural modifications in the building stock and occupants' behavior should be anticipated. Furthermore, the use of the adaptive thermal comfort threshold shows that the projected temperature increases for 2050 might affect people's capability to adapt their comfort band (i.e., indoor habitability) as temperatures would be higher than the maximum admissible values for people's comfort and health. ; publishersversion ; published

Abstract

Background
The Max Weaver Dye Library (MWDL) from North Carolina State University is a repository of around 98,000 synthetic dyes. Historically, the uses for these dyes included the coloration of textiles, paper, packaging, cosmetic and household products. However, little is reported about their ecotoxicological properties. It is anticipated that prediction models could be used to help provide this type information. Thus, the purpose of this work was to determine whether a recently developed QSAR (quantitative structure–activity relationships) model, based on ACO-SVM techniques, would be suitable for this purpose.


Results
We selected a representative subset of the MWDL, composed of 15 dyes, for testing under controlled conditions. First, the molecular structure and purity of each dye was confirmed, followed by predictions of their solubility and pKa to set up the appropriate test conditions. Only ten of the 15 dyes showed acute toxicity in Daphnia, with EC50 values ranging from 0.35 to 2.95 mg L−1. These values were then used to determine the ability of the ACO-SVM model to predict the aquatic toxicity. In this regard, we observed a good prediction capacity for the 10 dyes, with 90% of deviations within one order of magnitude. The reasons for this outcome were probably the high quality of the experimental data, the consideration of solubility limitations, as well as the high purity and confirmed chemical structures of the tested dyes. We were not able to verify the ability of the model to predict the toxicity of the remaining 5 dyes, because it was not possible to determine their EC50.


Conclusions
We observed a good prediction capacity for the 10 of the 15 tested dyes of the MWDL, but more dyes should be tested to extend the existing training set with similar dyes, to obtain a reliable prediction model that is applicable to the full MWDL.