Determination of emerging contaminants in environmental matrices

Los contaminantes emergentes (CEs) son compuestos químicos que pueden poseer el potencial de causar efectos adversos al medio ambiente y/o a la salud humana. También pueden ser considerados emergentes si se ha descubierto una nueva fuente o una nueva vía de introducción al medio ambiente. Hoy en día, las siguientes familias de compuestos pueden ser clasificados como CEs: biocidas, retardantes de llama, hidrocarburos aromáticos policíclicos (HAPs), plastificantes, surfactantes, hormonas, productos de higiene personal, compuestos farmacéuticos y nanopartículas. Debido al elevado uso de estos compuestos y su continua emisión pueden denominarse como pseudo-persistentes, haciendo que sea una prioridad monitorear su presencia en el medio ambiente. Estos CEs son generados principalmente en hospitales, granjas y zonas urbanas e industriales. La principal vía de introducción en el medio ambiente es a través de las aguas residuales. Los CEs no son eliminados completamente en las depuradoras y, consecuentemente, son introducidos en el medio ambiente a traves de los efluentes. Además, los lodos de depuradora y los residuos orgánicos de las granjas son usados en la agricultura para aumentar el contenido de materia orgánica y nutrientes en el suelo, siendo otra fuente de introducción de CEs en el medio ambiente. Sin embargo, aunque las fuentes de contaminación son conocidas, es necesario estudiar la presencia y el comportamiento de los CEs en los diferentes compartimentos del medio ambiente. Para evaluar la presencia de estos compuestos se requieren métodos multirresiduos robustos. Así, en esta tesis, se presentan seis trabajos para evaluar los CEs en varias matrices: fármacos en lodos de depuradora; retardantes de llama, HAPs y biocidas en gallinaza; fármacos y biocidas en el suelo, compuestos representativos de los CEs en plantas acuáticas y nanopartículas de plata en muestras acuosas. Para la determinación de fármacos en lodos de depuradora se desarrolló un método usando la técnica “supported liquid extraction” y su detección mediante GC-MS/MS. El método se validó y usó para evaluar la presencia de fármacos en lodos recogidos en España, donde la cafeína, el ibuprofeno, el ácido salicílico y el fenoprofeno fueron detectados en todas las muestras analizadas. Un método multirresiduos para detectar 41 contaminantes incluyendo retardantes de llama, HAPs y biocidas en gallinaza se desarrolló basado en una modificación del método “QuEChERS” y en su posterior determinación mediante GC-MS. Una vez validado el método se aplicó a muestras recogidas en diferentes granjas de Castilla y León. Se confirmó la presencia de los siguientes compuestos: biocidas, HAPs y 4,4’DDT y sus metabolitos. Para evaluar la presencia de CEs en suelo se desarrollaron dos métodos. Un primer método para la detección de 15 fármacos (ácidos, neutros y básicos) en suelo, basado en la extracción asistida por ultrasonidos seguido de GC-MS se aplicó a suelos agrícolas de diferentes regiones de España (Segovia, Murcia y Valencia). El análisis mostró la presencia ubicua de varios compuestos como ácido salicílico y paracetamol en las tres áreas estudiadas, así como fenoprofeno en Segovia y alopurinol y carbamacepina en Valencia. El segundo método fue desarrollado para detectar 10 piretroides en suelos agrícolas mediante la extracción asistida por ultrasonidos y GC-MS. El método fue aplicado para monitorear la presencia de los compuestos seleccionados en campos de arroz en Valencia, mostrando su ubicua presencia así como la identificación de las aguas de depuradoras como una de las principales fuentes de contaminación usando sistemas de información geográfica. Otro método multirresiduos fue desarrollado para la determinación de 31 CEs en plantas acuáticas por GC-MS, donde la técnica la dispersión de la matriz en fase sólida asistida por ultrasonidos fue utilizada para extraer los compuestos de interés de Typha angustifolia, Arundo donax, Oryza sativa and Lemna minor. El método fue validado y aplicado a las plantas recolectadas en tres ríos de tres regiones españolas (Madrid, Andalucía y Valencia). Seis de los treinta y un compuestos estudiados (biocidas y productos de higiene personal) fueros cuantificados. Para finalizar, se puso a punto una metodología para detectar y caracterizar el tamaño y distribución (PSD) de nanopartículas de plata (Ag-NPs) en productos de consumo y aguas ambientales usando SP-ICP-MS. El pretratamiento de la muestra (AF4 o filtración por centrifugación) no mejoraron la medida directa del SP-ICP-MS. El método se aplicó a productos de consumo, permitiendo la caracterización en tiritas del PSD de las Ag-NPs. Similarmente, en las aguas filtradas se pudo caracterizar con éxito las nanopartículas en términos de tamaño y número. Sin embargo, las concentraciones encontradas en aguas recolectadas en Italia estuvieron por debajo del límite de detección del ICP-MS. ABSTRACT Emerging contaminants (ECs) are chemicals that may have the potential to cause adverse ecological and/or human health effects. They can also be considered emerging contaminants because of the discovery of a new source or a new pathway of introduction to the environment. Nowadays, the following families of compounds have been classified as ECs: biocides, flame retardants, polycyclic aromatic hydrocarbons (PAHs), plasticizers, surfactants, hormones, personal care products, pharmaceuticals and nanoparticles. Due to the high use of these compounds and their continuous release they can be classified as pseudo-persistent, making it a priority to monitor their occurrence. These ECs are generated principally in hospitals, farms and urban and industrial areas. The main pathways of introduction into the environment are the polluted residual waters. Most of these polluted waters will reach a wastewater treatment plant (WWTP), but even in this case, most of the ECs are not completely degraded during the depuration processes and are discharged in the effluent waters, resulting in contamination of the environment. Moreover, sewage sludge from WWTPs and animal litter or manure from farms are used in agriculture to increase the content of organic matter and nutrients in soil, which may be another source of introduction of ECs into the environment. However, although the input sources are well-known, the fate and behavior of these emerging contaminants in the different environment compartments need further work. Thus, reliable and robust multiresidue methods are needed to assess their presence into different environmental matrices. In this thesis, six works are presented to assess the occurrences of ECs in various matrices: pharmaceutical compounds in sludge; flame retardants, PAHs and biocides in poultry manure; pharmaceuticals and biocides in soil; representative ECs in aquatic plants and silver nanoparticles in aqueous matrices. A method to determine pharmaceutical compounds in sludge was developed using supported liquid extraction and GS-MS/MS detection. The method was validated and used to assess the occurrence of pharmaceutical compounds in sludge samples collected in Spain, where caffeine, ibuprofen, salicylic acid and fenoprofen were detected in all the samples analyzed. A multiresidue method to detect 41 selected contaminants including flame retardants, PAHs and biocides in poultry manure was developed, based on a modified QuEChERS method and GC-MS determination. The validated method was applied to poultry manure samples collected from farms located in Castilla-León. The presence of some of the studied contaminants was confirmed, being biocides, PAHs and 4,4' DDT and its metabolites the compounds mainly detected. To assess the presence of ECs in soil two methods were developed. Firstly, a multiresidue method to detect 15 pharmaceutical compounds (acid, neutral and basic) in soil, based on an ultrasound assisted extraction procedure followed by GC-MS was validated and applied to agricultural soils from several Spanish areas (Segovia, Murcia and Valencia), showing the ubiquitous presence of various pharmaceutical compounds, such as salicylic acid and paracetamol, in the three areas studied, as well as fenoprofen in Segovia and allopurinol and carbamazepine in Valencia. The second method was developed to detect ten pyrethroids in agricultural soils by ultrasound-assisted extraction and GC-MS. The method was validated and applied to monitor their presence in a paddy field area in Valencia, showing the ubiquitous presence of them as well as the identification of WWTPs effluents as one of the main sources of pollution using a GIS program. A multiresidue method was developed for the determination of 31 ECs in aquatic plants, where ultrasound-assisted MSPD was applied to extract the studied compounds from Typha angustifolia, Arundo donax, Oryza sativa and Lemna minor followed by GC-MS determination. The method was validated and applied to aquatic plants collected from three rivers located in different Spanish regions (Madrid, Andalucia and Valencia). Six of the thirty one compounds studied (biocides and personal care products) were found and quantified. Finally, a methodology to detect and characterize the particle size distribution (PSD) of Ag-NPs in consumer products and environmental waters using SP-ICP-MS was evaluated. The sample pretreatment (AF4 fraction collection or centrifugal filtration) did not improve the analytical performance of direct SP-ICP-MS analysis. The procedure was applied to consumer products and plasters, allowing the determination of the complete PSD just for plasters. Similarly, the PSDs of Ag-NPs in filtered tap waters were successfully characterized in terms of size and number. However, the concentration levels found in freshwater samples from Italy were below the ICP-MS method dynamic range

Multiresidue Analysis of Insecticides and Other Selected Environmental Contaminants in Poultry Manure by Gas Chromatography/Mass Spectrometry

An analytical method was developed for the simultaneous determination in poultry manure of 41 organic contaminants belonging to different chemical classes: pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and polybrominated diphenyl ethers. Poultry manure was extracted with a modified QuEChERS method, and the extracts were analyzed by isotope dilution GC/MS. Recovery of these contaminants from samples spiked at levels ranging from 25 to 100 ng/g was satisfactory for all the compounds. The developed procedure provided LODs from 0.8 to 9.6 ng/g. The analysis of poultry manure samples collected on different farms confirmed the presence of some of the studied contaminants. Pyrethroids and polycyclic aromatic hydrocarbons were the main contaminants detected

Semantische Analyse der Suchkomponente des Information Retrieval Systems MESSENGER

TIB Hannover: RO 9515(7) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Re-employment dynamics of disabled workers

In dem Beitrag wird der Erfolg des niederlaendischen Behindertenversicherungsprogramms untersucht. Hierzu wurden 1991 bis 1994 Teilnehmer zu drei Zeitpunkten interviewt. Ausserdem wird ein Arbeitsnachfragemodell abgeleitet, und es werden die Auswirkungen moeglicher Aenderungen des Programms bis hin zu dessen Streichung geschaetzt. (IAB)'The author investigates the duration of time until the first work resumption for a cohort of people who receive disability insurance benefits. One of the peculiarities of the disability insurance program under investigation is that the level of benefits not only depends on previous wages, but also declines over time according to a schedule based on age, the amount of work experience, and the level of disability. As a result, different people will face different benefit schedules and hence are likely to make different choices regarding a return to work. To fully absorb the structural aspect of the disability program, the author specifies and estimates a behavioral labor supply model where individuals receive job offers that they con accept or decline. Possible reforms of the disability program are evaluated, including ending the disability program altogether.' (author's abstract)German title: Wiederbeschaeftigungsdynamik von behinderten ArbeitnehmernAvailable from ftp://repec.iza.org/RePEc/Discussionpaper/dp269.pdf / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Simultaneous determination of multiclass emerging contaminants in aquatic plants by ultrasound assisted matrix solid phase dispersion and GC-MS

A multiresidue method was developed for the simultaneous determination of 31 emerging contaminants (pharmaceutical compounds, hormones, personal care products, biocides and flame retardants) in aquatic plants. Analytes were extracted by ultrasound assisted-matrix solid phase dispersion (UA-MSPD) and determined by gas chromatography-mass spectrometry after sylilation. The method was validated for different aquatic plants (Typha angustifolia, Arundo donax and Lemna minor) and a semiaquatic cultivated plant (Oryza sativa) with good recoveries at concentrations of 100 and 25 ng g-1 wet weight, ranging from 70 to 120 %, and low method detection limits (0.3 to 2.2 ng g-1 wet weight). A significant difference of the chromatographic response was observed for some compounds in neat solvent versus matrix extracts and therefore quantification was carried out using matrix-matched standards in order to overcome this matrix effect. Aquatic plants taken from rivers located at three Spanish regions were analyzed and the compounds detected were parabens, bisphenol A, benzophenone-3, cyfluthrin and cypermethrin. The levels found ranged from 6 to 25 ng g-1 wet weight except for cypermethrin that was detected at 235 ng g-1 wet weight in Oryza sativa samples

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

International audienceBackground: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

Background: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society