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Determination and occurrence of secondary alkane sulfonates (SAS) in aquatic environments
2013
Baena-Nogueras, Rosa María | González-Mazo, Eduardo | Lara-Martín, Pablo A.
A new methodology has been developed for the determination of secondary alkane sulfonates (SAS), an anionic surfactant, in environmental matrices. Sediment and sludge samples were extracted using pressurized liquid extraction and sonication, whereas wastewater and surface water samples were processed using solid-phase extraction. Extraction recoveries were acceptable for both aqueous (78–120%) and solid samples (83–100%). Determination of SAS was carried out by high or ultra performance liquid chromatography – mass spectrometry using ion trap and time-of-flight detectors. The methodology was applied to samples from Guadalete River (SW Spain), where SAS concentrations below 1 μg L−1 were measured in surface water, and from 72 to 9737 μg kg−1 in sediments. Differential partitioning was observed for SAS homologues as those having a longer hydrocarbon chain which preferentially sorbed onto particulate matter. A preliminary environmental risk assessment also showed that SAS measured levels were not harmful to the aquatic community in the sampling area.
Afficher plus [+] Moins [-]Are nanoplastics able to bind significant amount of metals? The lead example
2019
Davranche, Mélanie | Veclin, Cloé | Pierson-Wickmann, Anne-Catherine | El Hadri, Hind | Grassl, Bruno | Rowenczyk, Laura | Dia, Aline | Ter Halle, Alexandra | Blancho, Florent | Reynaud, Stéphanie | Gigault, Julien
The nanoscale size of plastic debris makes them potential efficient vectors of many pollutants and more especially of metals. In order to evaluate this ability, nanoplastics were produced from microplastics collected on a beach exposed to the North Atlantic Gyre. The nanoplastics were characterized using multi-dimensional methods: asymmetrical flow field flow fractionation and dynamic light scattering coupled to several detectors. Lead (II) adsorption kinetics, isotherm and pH-edge were then carried out. The sorption reached a steady state after around 200 min. The maximum sorption capacity varied between 97% and 78.5% for both tested Pb concentrations. Lead (II) adsorption kinetics is controlled by chemical reactions with the nanoplastics surface and to a lesser extent by intraparticle diffusion. Adsorption isotherm modeling using Freundlich model demonstrated that NPG are strong adsorbents equivalent to hydrous ferric oxides such as ferrihydrite (log Kadsfreundlich=8.36 against 11.76 for NPG and ferrihydrite, respectively). The adsorption is dependent upon pH, in response to the Pb(II) adsorption by the oxygenated binding sites developed on account of the surface UV oxidation under environmental conditions. They could be able to compete with Fe or humic colloids for Pb binding regards to their amount and specific areas. Nanoplastics could therefore be efficient vectors of Pb and probably of many other metals as well in the environment.
Afficher plus [+] Moins [-]Impact of pile-driving on Hector's dolphin in Lyttelton Harbour, New Zealand
2019
Leunissen, Eva M. | Rayment, William J. | Dawson, Stephen M.
Several dolphin species occur close inshore and in harbours, where underwater noise generated by pile-driving used in wharf construction may constitute an important impact. Such impacts are likely to be greatest on species such as the endangered Hector's dolphin (Cephalorhynchus hectori), which has small home ranges and uses this habitat type routinely. Using automated echolocation detectors in Lyttelton Harbour (New Zealand), we studied the distribution of Hector's dolphins using a gradient sampling design over 92 days within which pile-driving occurred on 46 days. During piling operations, dolphin positive minutes per day decreased at the detector closest to the piling but increased at the mid-harbour detector. Finer-grained analyses showed that close to the piling operation, detections decreased with increasing sound exposure level, that longer piling events were associated with longer reductions in detections, and that effects were long-lasting - detection rates took up to 83 h to return to pre-piling levels.
Afficher plus [+] Moins [-]Indoor air quality investigation of the school environment and estimated health risks: Two-season measurements in primary schools in Kozani, Greece
2016
Kalimeri, Krystallia K. | Saraga, Dikaia E. | Lazaridis, Vasileios D. | Legkas, Nikolaos A. | Missia, Dafni A. | Tolis, Evangelos I. | Bartzis, John G.
Two primary schools and one kindergarten were selected in the city of Kozani, Greece in order to investigate the school environment, the indoor air pollutants that children are exposed to and possible health risks at school. In each school three classrooms and one outdoor position were monitored from Monday to Friday, in both non-heating (26/09/2011–14/10/2011) and heating (23/01/2012–10/02/2012) period. Temperature, relative humidity and CO2, were continuously monitored. Formaldehyde, benzene, trichloroethylene, pinene, limonene, NO2 and O3 were measured with diffusive samplers. CO was monitored every day (30 min/day). Radon was measured for four weeks with short term radon detectors. PM2.5 was gravimetrically determined while PM2.5 and PM10 fractions were measured using the optical light scattering technique. Building material emission testing for VOCs was performed using the Field and Laboratory Emission Cell (FLEC). The ventilation rate for each classroom was calculated based on the CO2 measurements.Results indicated that indoor air concentrations of the measured pollutants were within accepted limits with indicative ranges 1.5–9.4 μg/m3 for benzene, 2.3–28.5 μg/m3 for formaldehyde, 4.6–43 μg/m3 for NO2 and 0.1–15.6 μg/m3 for O3. Emissions from building materials seem to have a significant contribution to the indoor air quality. Very low ventilation rates (0.1–3.7 L/s per person) were observed, indicating inadequate ventilation and possible indoor air quality problems requiring intervention measures. The estimated average lifetime cancer risks for benzene, formaldehyde and trichloroethylene were very low.
Afficher plus [+] Moins [-]Estimating the near-surface daily fine aerosol load using hourly Radon-222 observations
2013
Crawford, Jagoda | Zahorowski, Wlodek | Cohen, David D. | Chambers, Scott | Stelcer, Eduard | Werczynski, Sylvester
We investigate the extent to which hourly radon observations can be used to estimate daily PM2.5 loading near the ground. We formulate, test and apply a model that expresses the mean daily PM2.5 load as a linear combination of observed radon concentrations and differences on a given day. The model was developed using two consecutive years of observations (2007–2008) at four sites near Sydney, Australia, instrumented with aerosol samplers and radon detectors. Model performance was subsequently evaluated against observations in 2009. After successfully reproducing mean daily radon concentrations (r2≥0.98), we used the model to estimate daily PM2.5 mass, as well as that of selected elements (Si, K, Fe, Zn, H, S and Black Carbon). When parameterizing the model for elemental mass estimates the highest r2 values were generally obtained for H, BC, K and Si. Separating results by season, the r2 values for K and BC were higher in winter for all sites, a period of time where higher concentrations of these elements are seen and a rapid estimation tool would be of particular benefit. The best overall results were obtained in winter for H and BC [r2 = 0.50, 0.68, 0.70, 0.63 (H) and 0.57, 0.57, 0.78, 0.44 (BC)], respectively for Warrawong, Lucas Heights, Richmond and Muswellbrook. Evaluation of model PM2.5 estimates was most successful for days with typical aerosol loads; loads were usually underestimated for, the less frequent, high–to–extreme pollution days. The best elemental results were obtained for BC at Richmond in winter (r2 = 0.68). However, for Warrawong and Lucas Heights r2 values increased from 0.26 to 0.60, and from 0.33 to 0.73, respectively, when several particularly high concentration events were excluded from the analysis. The model performed best at Richmond, an inland site with relatively flat terrain. However, model parameters need to be evaluated for each site.
Afficher plus [+] Moins [-]Evaluation of polycyclic aromatic hydrocarbons bioavailability on Santos Bay (Brazil) through levels of biliary metabolites
2018
de Albergaria-Barbosa, Ana Cecília Rizzatti | da Silva, Denis Albuquerque Moreira | da Silva Rocha, Arthur José | Taniguchi, Satie | Patire, Vinicius Faria | Dias, June Ferraz | Fernandez, Wellington Silva | Bícego, Marcia Caruso
This study evaluated the PAH bioavailability from Santos Bay (Brazil) in 4 species of fish, using PAH biliary metabolites. The collection was done monthly, between July and December, in three different regions of Santos Bay. The metabolites were analyzed through a high performance liquid chromatograph with fluorescence detectors. Total metabolites concentrations ranged from 65.5 to 589μgg−1 of bile, evidencing PAH bioavailability on Santos Bay. Levels of phenanthrene and benzo[a]pyrene metabolites were in the classification range of areas moderate contaminated. Those concentrations were lower in Nebris microps and higher in Sphoeroides testudineus (p<0.05). Naphthalene metabolites concentrations did not differ significantly among fish species and were in the classification range of low contaminated areas. There were no significant spatial and temporal differences in levels among sampled areas. These results are environmentally important given the high levels of urbanization and the absence of biomonitoring data in this area.
Afficher plus [+] Moins [-]Assessment of natural radioactivity and 137Cs in some coastal areas of the Saudi Arabian gulf
2016
Al-Ghamdi, H. | Al-Muqrin, A. | El-Sharkawy, A.
The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO2. Shore sediment samples were analyzed for 226Ra, 228Ra (232Th), 4°K and 137Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected.
Afficher plus [+] Moins [-]Pyrolysis–gas chromatography–mass spectrometry with electron-ionization or resonance-enhanced-multi-photon-ionization for characterization of polycyclic aromatic hydrocarbons in the Baltic Sea
2015
Otto, Stefan | Streibel, Thorsten | Erdmann, Sabrina | Klingbeil, Sophie | Schulz-Bull, Detlef | Zimmermann, Ralf
Polycyclic aromatic hydrocarbons (PAH), as a part of dissolved organic matter (DOM), are environmental pollutants of the marine compartment. This study investigates the origin of PAH, which is supposed to derive mainly from anthropogenic activities, and their alteration along the salinity gradient of the Baltic Sea. Pyrolysis in combination with gas chromatography and two mass selective detectors in one measurement cycle are utilized as a tool for an efficient trace analysis of such complex samples, by which it is possible to detect degradation products of high molecular structures. Along the north–south transect of the Baltic Sea a slightly rising trend for PAH is visible. Their concentration profiles correspond to the ship traffic as a known anthropogenic source, underlined by the value of special isomer ratios such as phenanthrene and anthracene (0.31–0.45) or pyrene and fluoranthene (0.44–0.53). The detection of naphthalene and the distribution of its alkylated representatives support this statement.
Afficher plus [+] Moins [-]The measurement of gamma-emitting radionuclides in beach sand cores of coastal regions of Ramsar, Iran using HPGe detectors
2013
Tari, Marziyeh | Moussavi Zarandi, Sayyed Ali | Mohammadi, Kheirollah | Zare, Mohammad Reza
Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. 226Ra, 235U, 232Th, 40K and 137Cs analysis has been carried out in sand samples collected at six depth levels, from eight locations of the northern coast of Iran, Ramsar, using high-resolution gamma-ray spectroscopy. The average Specific activities of natural radionuclides viz., 226Ra, 235U, 232Th, 40K and 137Cs, in the 0–36cm depth sand were found as: 19.2±0.04, 2.67±0.17, 17.9±0.06, 337.5±0.61 and 3.35±0.12 Bqkg−1, respectively. The effects of organic matter content and pH value of sand samples on the natural radionuclide levels were also investigated. Finally, the measured radionuclide concentrations in the Ramsar beach were compared with the world average values, as reported by UNSCEAR (2000). None of the studied beaches were considered as a radiological risk.
Afficher plus [+] Moins [-]Solventless Microextraction Techniques for Determination of Trihalomethanes by Gas Chromatography in Drinking Water
2012
Rosero, Milton Moreano | Aguirre, Mauricio | Pezo, Davinson | Taborda, Gonzalo | Dussán, Carmen | Nerin, Cristina
Three different solventless sample preparation techniques based on microextraction, membrane extraction, and headspace extraction have been developed and optimized for determination of trihalomethanes in drinking water by gas chromatography electron capture detector and mass spectrometry detection. The techniques employed were headspace (HS) solid-phase microextraction, hollow fiber liquid-phase microextraction (HFLPME) and HS extraction. All techniques used were optimized with different experimental designs in order to select the most relevant variables which significantly affect the different processes. The different analytical figures of merit such as limit of detection (LOD), limit of quantification, reproducibility, accuracy, and linear dynamic range were obtained. The new HFLPME method applied used a hollow fiber membrane of polypropylene and the optimized variables were extraction time, extraction temperature, and salting-out effect. The software MODDE 6.0 was used and its design was one central composite on face with a total of 17 runs. The best conditions for the HFLPME were 20 min, 40°C, and 10% NaCl, respectively. The LODs ranged from 0.018 μg·L−1 (for CHClBr2) to 0.049 μg·L−1 (for CHBr3), being this technique the most sensitive one among those studied. Finally, after having optimized the sample preparation techniques and chromatographic conditions, several water samples were taken in two different water treatment plants in Spain (Zaragoza) and Colombia (Viterbo, Caldas). The results obtained are shown and discussed.
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