► Discussion on the feasibility of natural ventilation. ► Identification and application of performance indicators for natural ventilation. ► Determination of ventilation potentials for fixed and ...dynamic boundary conditions. ► Parametric determination of associated energy savings for moderate European climates. ► Comparison with an identical office room with mechanical ventilation.
Natural ventilation of buildings has the potential to significantly save cooling and fan electrical energy. However, it is still not widely applied, because only limited information is available on the thermal comfort and indoor air quality of office buildings without air conditioning. Steady state ventilation air flow rates were therefore systematically simulated using both analytical and airflow network methods for different boundary conditions such as temperature and pressure differences across openings for different opening types. Coupled airflow network and dynamic building simulations were carried out to determine the annual thermal comfort and energy savings. The results for the three moderate climate locations Germany, Italy and Turkey show that while indoor air quality can be easily maintained for all opening typologies, the summer cooling potential and thermal comfort strongly depends on the natural ventilation strategy. Control over the openings is crucial for all cases, as otherwise the office rooms tend to cool down too much even in summer conditions.
To detect site-specific, suspected and formerly unknown contaminants in a wastewater treatment plant effluent, we established a screening procedure based on liquid chromatography–high resolution mass ...spectrometry (LC–HRMS) with stepwise identification schemes. Based on automated substructure searches a list of 2160 suspected site-specific and documented water contaminants was reduced to those amenable to LC–HRMS. After searching chromatograms for exact masses of suspects, presumably false positive detections were stepwise excluded by retention time prediction, the evaluation of isotope patterns, ionization behavior, and HRMS/MS spectra. In nontarget analysis, peaks for identification were selected based on distinctive isotope patterns and intensity. The stepwise identification of nontarget compounds was automated by a plausibility check of molecular formulas using the Seven Golden Rules, an exclusion of compounds with presumably low commercial importance and an automated HRMS/MS evaluation. Six suspected and five nontarget chemicals were identified, of which two have not been previously reported as environmental pollutants.
•A LC–HRMS-based suspect and nontarget screening was applied to wastewater.•Manual data processing to identify candidate structures was accelerated by automated software-based procedure.•Identification was supported by sophisticated analytical methods such as deuterium exchange.•Eleven site-specific and formerly unknown compounds were identified.•We provide a framework to extend analytical procedures from target to suspect and nontarget compounds.
A screening procedure based on liquid chromatography–high resolution mass spectrometry (LC–HRMS) with a systematic data evaluation was established, which allowed detecting suspected and formerly unknown contaminants in wastewater.
A platform for archiving liquid chromatography high-resolution mass spectrometry (LC-HRMS) data was developed for the retrospective suspect screening of thousands of environmental pollutants with the ...ambition of becoming a European and possibly global standard. It was termed Digital Sample Freezing Platform (DSFP) and incorporates all the recent developments in the HRMS screening methods within the NORMAN Network. In the workflow, raw mass spectral data are converted into mzML, then mass spectral and chromatographic information on thousands of peaks of each sample is extracted into Data Collection Templates. The ‘digitally frozen’ samples can be retrospectively screened for the presence of virtually any compound amenable to LC–MS using a combination of information on its (i) exact mass, (ii) predicted retention time window in the chromatogram, (iii) isotopic fit and (iv) qualifier fragment ions. Its potential was demonstrated on monitoring of 670 antibiotics and 777 REACH chemicals from the Joint Black Sea Surveys (JBSS).
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•An overview of the current HRMS screening steps is presented in an automatized tool.•Digital archiving and retrospective suspect screening were integrated in DSFP.•DSFP enables enhanced data mining and visualization capabilities.•54 seawater, 19 sediment and 12 biota samples were screened for 1447 substances.•80 chemicals from the REACH registry and 12 antibiotics were detected.
There is an increasing need for comparable and harmonized retention times (t R) in liquid chromatography (LC) among different laboratories, to provide supplementary evidence for the identity of ...compounds in high-resolution mass spectrometry (HRMS)-based suspect and nontarget screening investigations. In this study, a rigorously tested, flexible, and less system-dependent unified retention time index (RTI) approach for LC is presented, based on the calibration of the elution pattern. Two sets of 18 calibrants were selected for each of ESI+ and ESI-based on the maximum overlap with the retention times and chemical similarity indices from a total set of 2123 compounds. The resulting calibration set, with RTI set to range between 1 and 1000, was proposed as the most appropriate RTI system after rigorous evaluation, coordinated by the NORMAN network. The validation of the proposed RTI system was done externally on different instrumentation and LC conditions. The RTI can also be used to check the reproducibility and quality of LC conditions. Two quantitative structure–retention relationship (QSRR)-based models were built based on the developed RTI systems, which assist in the removal of false-positive annotations. The applicability domains of the QSRR models allowed completing the identification process with higher confidence for substances within the domain, while indicating those substances for which results should be treated with caution. The proposed RTI system was used to improve confidence in suspect and nontarget screening and increase the comparability between laboratories as demonstrated for two examples. All RTI-related calculations can be performed online at http://rti.chem.uoa.gr/.
Aquatic environments are often contaminated with complex mixtures of chemicals that may pose a risk to ecosystems and human health. This contamination cannot be addressed with target analysis alone ...but tools are required to reduce this complexity and identify those chemicals that might cause adverse effects. Effect-directed analysis (EDA) is designed to meet this challenge and faces increasing interest in water and sediment quality monitoring. Thus, the present paper summarizes current experience with the EDA approach and the tools required, and provides practical advice on their application. The paper highlights the need for proper problem formulation and gives general advice for study design. As the EDA approach is directed by toxicity, basic principles for the selection of bioassays are given as well as a comprehensive compilation of appropriate assays, including their strengths and weaknesses. A specific focus is given to strategies for sampling, extraction and bioassay dosing since they strongly impact prioritization of toxicants in EDA. Reduction of sample complexity mainly relies on fractionation procedures, which are discussed in this paper, including quality assurance and quality control. Automated combinations of fractionation, biotesting and chemical analysis using so-called hyphenated tools can enhance the throughput and might reduce the risk of artifacts in laboratory work. The key to determining the chemical structures causing effects is analytical toxicant identification. The latest approaches, tools, software and databases for target-, suspect and non-target screening as well as unknown identification are discussed together with analytical and toxicological confirmation approaches. A better understanding of optimal use and combination of EDA tools will help to design efficient and successful toxicant identification studies in the context of quality monitoring in multiply stressed environments.
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•Effect-directed analysis is a powerful tool to support monitoring.•Multiple bioassays on specific and reactive toxicity direct toxicant identification•Combination of extraction and bioassay dosing is key for toxicant identification•Promising tools for LC–MS based toxicant identification are now available
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•366 chemicals detected in 56 European WWTP effluents at <1 ng/L to >100 µg/L.•Three different risk metrics (RQ, HU, TU) provided complementary information.•293 mixture components of ...concern exceeded the risk threshold.•32 consensus mixture risk contributors of high concern identified.•Activated carbon and ozonation treatments reduced toxic risks below thresholds.
In this study, 56 effluent samples from 52 European wastewater treatment plants (WWTPs) were investigated for the occurrence of 499 emerging chemicals (ECs) and their associated potential risks to the environment. The two main objectives were (i) to extend our knowledge on chemicals occurring in treated wastewater, and (ii) to identify and prioritize compounds of concern based on three different risk assessment approaches for the identification of consensus mixture risk drivers of concern. Approaches include (i) PNEC and EQS-based regulatory risk quotients (RQs), (ii) species sensitivity distribution (SSD)-based hazard units (HUs) and (iii) toxic units (TUs) for three biological quality elements (BQEs) algae, crustacean, and fish.
For this purpose, solid-phase extracts were analysed with wide-scope chemical target screening via liquid chromatography high-resolution mass spectrometry (LC-HRMS), resulting in 366 detected compounds, with concentrations ranging from < 1 ng/L to > 100 µg/L. The detected chemicals were categorized with respect to critical information relevant for risk assessment and management prioritization including: (1) frequency of occurrence, (2) measured concentrations, (3) use groups, (4) persistence & bioaccumulation, and (5) modes of action. A comprehensive assessment using RQ, HU and TU indicated exceedance of risk thresholds for the majority of effluents with RQ being the most sensitive metric. In total, 299 out of the 366 compounds were identified as mixture risk contributors in one of the approaches, while 32 chemicals were established as consensus mixture risk contributors of high concern, including a high percentage (66%) of pesticides and biocides. For samples which have passed an advanced treatment using ozonation or activated carbon (AC), consistently much lower risks were estimated.
Surface water can contain countless organic micropollutants, and targeted chemical analysis alone may only detect a small fraction of the chemicals present. Consequently, bioanalytical tools can be ...applied complementary to chemical analysis to detect the effects of complex chemical mixtures. In this study, bioassays indicative of activation of the aryl hydrocarbon receptor (AhR), activation of the pregnane X receptor (PXR), activation of the estrogen receptor (ER), adaptive stress responses to oxidative stress (Nrf2), genotoxicity (p53) and inflammation (NF-κB) and the fish embryo toxicity test were applied along with chemical analysis to water extracts from the Danube River. Mixture-toxicity modeling was applied to determine the contribution of detected chemicals to the biological effect. Effect concentrations for between 0 to 13 detected chemicals could be found in the literature for the different bioassays. Detected chemicals explained less than 0.2% of the biological effect in the PXR activation, adaptive stress response, and fish embryo toxicity assays, while five chemicals explained up to 80% of ER activation, and three chemicals explained up to 71% of AhR activation. This study highlights the importance of fingerprinting the effects of detected chemicals.
Wastewaters contain complex mixtures of chemicals, which can cause adverse toxic effects in the receiving environment. In the present study, the toxicity removal during wastewater treatment at seven ...municipal wastewater treatment plants (WWTPs) was investigated using an effect-based approach. A battery of eight bioassays was applied comprising of cytotoxicity, genotoxicity, endocrine disruption and fish embryo toxicity assays. Human cell-based CALUX assays, transgenic larval models and the fish embryo toxicity test were particularly sensitive to WWTP effluents. The results indicate that most effects were significantly reduced or completely removed during wastewater treatment (76–100%), while embryo toxicity, estrogenic activity and thyroid disruption were still detectable in the effluents suggesting that some harmful substances remain after treatment. The responsiveness of the bioassays was compared and the human cell-based CALUX assays showed highest responsiveness in the samples. Additionally, the fish embryo toxicity test and the transgenic larval models for endocrine disrupting effects showed high responsiveness at low sample concentrations in nearly all of the effluent samples. The results showed a similar effect pattern among all WWTPs investigated, indicating that the wastewater composition could be rather similar at different locations. There were no considerable differences in the toxicity removal efficiencies of the treatment plants and no correlation was observed with WWTP characteristics, such as process configuration or sludge age. This study demonstrated that a biotest battery comprising of multiple endpoints can serve as a powerful tool when assessing water quality or water treatment efficiency in a holistic manner. Rather than analyzing the concentrations of a few selected chemicals, bioassays can be used to complement traditional methods of monitoring in the future by assessing sum-parameter based effects, such as mixture effects, and tackling chemicals that are present at concentrations below chemical analytical detection limits.
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•Toxicity removal during wastewater treatment at 7 municipal WWTPs was investigated.•Removal efficiency was assessed by an effect-based approach comprising of multiple endpoints.•Large volumes of influent and effluent samples were extracted with a novel device.•Embryo toxicity, estrogenic activity and thyroid disruption were detected in effluent samples.•The results showed a similar effect pattern among all the WWTPs.
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•Screening of 610 chemicals in 445 stream water samples enables mixture assessment.•Chemical footprints: 504 detected compounds impact aquatic life in European streams.•74 % of the ...sites exceed risk thresholds for adverse effects to aquatic organisms.•Invertebrates most affected; over 70 chemicals surpass chronic risk thresholds.•Urban discharge doesn't correlate with footprints due to effluent-specific quality.
There is increasing awareness that chemical pollution of freshwater systems with complex mixtures of chemicals from domestic sources, agriculture and industry may cause a substantial chemical footprint on water organisms, pushing aquatic ecosystems outside the safe operating space. The present study defines chemical footprints as the risk that chemicals or chemical mixtures will have adverse effects on a specific group of organisms. The aim is to characterise these chemical footprints in European streams based on a unique and uniform screening of more than 600 chemicals in 445 surface water samples, and to derive site- and compound-specific information for management prioritisation purposes. In total, 504 pesticides, biocides, pharmaceuticals and other compounds have been detected, including frequently occurring and site-specific compounds with concentrations up to 74 µg/L. Key finding is that three-quarter of the investigated sites in 22 European river basins exceed established thresholds for chemical footprints in freshwater, leading to expected acute or chronic impacts on aquatic organisms. The largest footprints were recorded on invertebrates, followed by algae and fish. More than 70 chemicals exceed thresholds of chronic impacts on invertebrates. For all organism groups, pesticides and biocides were the main drivers of chemical footprints, while mixture impacts were particularly relevant for invertebrates. No clear significant correlation was found between chemical footprints and the urban discharge fractions, suggesting that effluent-specific quality rather than the total load of treated wastewater in the aquatic environment and the contribution of diffuse sources, e.g. from agriculture, determine chemical footprints.
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•Four types of tubes used for human samples show specific contamination patterns.•A medical-grade tube shows a lower contamination level than three other types.•A cleaning procedure ...reduces contamination, but releases specific contaminants.•Several polymer additives and surfactants were identified in the sample tubes.•The obtained dataset is available as a reference of potential background contamination.
Controlling and minimising background contamination is crucial for maintaining a high quality of samples in human biomonitoring targeting organic chemicals. We assessed the contamination of three previous types and one newly introduced medical-grade type of sample tubes used for storing human body fluids at the German Environmental Specimen Bank. Aqueous extracts from these tubes were analysed by non-targeted liquid chromatography-high resolution mass spectrometry (LC-HRMS) before and after a dedicated cleaning procedure. After peak detection using MZmine, Bayesian hypothesis testing was used to group peaks into those originating either from instrumental and laboratory background contamination, or actual tube contaminants, based on if their peak height was reduced, increased or not affected by the cleaning procedure. For all four tube types 80–90% of the 2475 peaks (1549 in positive and 926 in negative mode) were assigned to laboratory/instrumental background, which we have to consider as potential sample tube contaminants. Among the tube contaminants, results suggest a considerable difference in the contaminant peak inventory and the absolute level of contamination among the different sample tube types. The cleaning procedure did not affect the largest fraction of peaks (50–70%). For the medical grade tubes, the removal of contaminants by the cleaning procedure was strongest compared to the previous tubes, but in all cases a small fraction increased in intensity after cleaning, probably due to a release of oligomers or additives. The identified laboratory background contaminants were mainly semi-volatile polymer additives such as phthalates and phosphate esters. A few compounds could be assigned solely as tube-specific contaminants, such as N,N-dibutylformamide and several constituents of the oligomeric light stabiliser Tinuvin-622. A cleaning procedure before use is an effective way to standardise the used sample tubes and minimises the background contamination, and therefore increases sample quality and therewith analytical results.
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