Suchergebnisse

The frenetic lifestyle in the developed countries has driven us to be deficient in some nutrients, which may be overcome by supplements. Microalgae, like spirulina (Arthrospira platensis) and chlorella (Chlorella ssp.) are widely used as supplements due to their high contents of macro- and micronutrients. Chlorella and spirulina can be grown naturally in a range of water bodies, showing their high adaptability to harsh environments. They are mainly produced in countries with poor water quality and sometimes inexistent water legislation, which can be a vector of micropollutant introduction into the food chain. Thus, a method for the simultaneous determination of 31 emerging contaminants commonly found as micropollutants in freshwater (pharmaceutical and personal care products, hormones, flame retardants and biocides) in two microalgae is presented. Target contaminants were extracted from the microalgae employing ultrasound-assisted matrix solid-phase dispersion followed by gas chromatography-mass spectrometry analysis. The method was validated for chlorella and spirulina with recoveries ranging from 70% to 111% at concentrations of 25 and 100 ng· ; g&minus ; 1, and good linearity in the range from 5 to 400 ng· ; g&minus ; 1 with limits of detection below 2.5 ng· ; g&minus ; 1, in both microalgae. The method validated was applied to a range of microalgae supplement foods and the results proved that the compounds studied were below limits of detection.

peer-reviewed ; The frenetic lifestyle in the developed countries has driven us to be deficient in some nutrients, which may be overcome by supplements. Microalgae, like spirulina (Arthrospira platensis) and chlorella (Chlorella ssp.) are widely used as supplements due to their high contents of macroand micronutrients. Chlorella and spirulina can be grown naturally in a range of water bodies, showing their high adaptability to harsh environments. They are mainly produced in countries with poor water quality and sometimes inexistent water legislation, which can be a vector of micropollutant introduction into the food chain. Thus, a method for the simultaneous determination of 31 emerging contaminants commonly found as micropollutants in freshwater (pharmaceutical and personal care products, hormones, flame retardants and biocides) in two microalgae is presented. Target contaminants were extracted from the microalgae employing ultrasound-assisted matrix solid-phase dispersion followed by gas chromatography-mass spectrometry analysis. The method was validated for chlorella and spirulina with recoveries ranging from 70% to 111% at concentrations of 25 and 100 ng·g −1 , and good linearity in the range from 5 to 400 ng·g −1 with limits of detection below 2.5 ng·g −1 , in both microalgae. The method validated was applied to a range of microalgae supplement foods and the results proved that the compounds studied were below limits of detection.

Water authorities and drinking water companies are challenged with the question if, where and how to abate contaminants of emerging concern in the urban water cycle. The most effective strategy under given conditions is often unclear to these stakeholders as it requires insight into several aspects of the contaminants such as sources, properties, and mitigation options. Furthermore the various parties in the urban water cycle are not always aware of each other's requirements and priorities. Processes to set priorities and come to agreements are lacking, hampering the articulation and implementation of possible solutions. To support decision makers with this task, a decision support system was developed to serve as a point of departure for getting the relevant stakeholders together and finding common ground. The decision support system was iteratively developed in stages. Stakeholders were interviewed and a decision support system prototype developed. Subsequently, this prototype was evaluated by the stakeholders and adjusted accordingly. The iterative process lead to a final system focused on the management of contaminants of emerging concern within the urban water cycle, from wastewater, surface water and groundwater to drinking water, that suggests mitigation methods beyond technical solutions. Possible wastewater and drinking water treatment techniques in combination with decentralised and non-technical methods were taken into account in an integrated way. The system contains background information on contaminants of emerging concern such as physical/chemical characteristics, toxicity and legislative frameworks, water cycle entrance pathways and a database with associated possible mitigation methods. Monitoring data can be uploaded to assess environmental and human health risks in a specific water system. The developed system was received with great interest by potential users, and implemented in an international water cycle network.

Increasing populations and shifting precipitation patterns put pressure on freshwater and food systems and incentivize governments and industries to exploit historically underutilized resources, such as recycled water and biosolids. Use of recycled water and biosolids in agricultural systems, however, comes with the potential risks of environmental and food contamination by trace organic contaminants including, contaminants of emerging concern (CECs). These compounds pose potential threats to humans and environmental health because they are designed to be biologically active at low concentrations and are considered "pseudo-persistent" due to their continuous release into the environment.Using 14C tracing, mass spectrometry, stable-isotope labeling, and enzyme extractions to assess the fate, metabolism, and biological effects of four environmentally prevalent CECs (i.e. sulfamethoxazole, diazepam, naproxen and methyl paraben) in terrestrial organisms in hydroponic and artificial soil cultivations. These organisms included an agricultural bioengineer (Eisiena fetida), a model plant (Arabidopsis thaliana) and two crop plants (Cucumis sativus, Raphanus sativus,). Compounds were selected based on environmental prevalence and test organisms were selected due to their use in the literature, commercial availability, and global range. Sulfamethoxazole was metabolized in A. thaliana cell cultures, and E. Fetida forming phase I and II metabolites. Diazepam was also metabolized in A. thaliana cell cultures and radish and cucumber seedlings, forming the phase I metabolites nordiazepam, temazepam and oxazepam, with the longevity corresponding to that of human metabolism. The major metabolites of naproxen and methyl paraben, O-desmethylnaproxen and p-hydroxybenzoic acid, respectively, were detected in treatment soils containing E. fetida and N4-acetylsulfamethoxazole was detected in E. fetida tissues, indicating CEC metabolism and excretion. Exposure to CECs resulted in changes to enzymes associated with detoxification and oxidative stress (i.e. glutathione-S-transerfase, glucuronosyl transferase, superoxide dismutase, and catalase) in crop plants and E. fetida. Our research indicates that terrestrial organisms can take and transform CECs and that CECs can change biochemistry of the exposed organisms. Accordingly, it is crucial to consider CEC fate, transformation and effects on non-target organisms of CECs when assessing risk in the agro-environment.

AbstractWater quality, in combination with design and operational data collected from multiple studies, was assessed to benchmark the performance of ozone‐biologically active filtration in reuse applications. A total of 149 contaminants of emerging concern, representative of multiple categories and chemical structures, were prioritized and systematically compared to elucidate apparent differences in removal capabilities as affected by multiple factors such as influent water matrix, ozone‐to‐organic carbon ratio, empty bed contact time, filtration media type, and initial media condition. The results were consistent with earlier findings for the removal of highly amenable compounds but demonstrate inconsistencies and knowledge gaps across multiple facilities for the more persistent compounds. Analysis of this multistudy data‐mining effort also demonstrates a complicated interplay between contaminant removal and numerous design and operational variables. Hence, further systematic investigation is warranted to elucidate the underlying removal mechanisms.