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Partitioning of magnetic particles in PM10, PM2.5 and PM1 aerosols in the urban atmosphere of Barcelona (Spain) Full text
2014
Revuelta, María Aránzazu | McIntosh, Gregg | Pey, Jorge | Pérez, Noemi | Querol, X. (Xavier) | Alastuey, A. (Andrés)
A combined magnetic-chemical study of 15 daily, simultaneous PM10–PM2.5–PM1 urban background aerosol samples has been carried out. The magnetic properties are dominated by non-stoichiometric magnetite, with highest concentrations seen in PM10. Low temperature magnetic analyses showed that the superparamagnetic fraction is more abundant when coarse, multidomain particles are present, confirming that they may occur as an oxidized outer shell around coarser grains. A strong association of the magnetic parameters with a vehicular PM10 source has been identified. Strong correlations found with Cu and Sb suggests that this association is related to brake abrasion emissions rather than exhaust emissions. For PM1 the magnetic remanence parameters are more strongly associated with crustal sources. Two crustal sources are identified in PM1, one of which is of North African origin. The magnetic particles are related to this source and so may be used to distinguish North African dust from other sources in PM1.
Show more [+] Less [-]High tolerance of subalpine grassland to long-term ozone exposure is independent of N input and climatic drivers Full text
2014
Volk, Matthias | Wolff, Veronika | Bassin, Seraina | Ammann, Christof | Fuhrer, Jürg
In a seven-year study, we tested effects of increased N and O3 deposition and climatic conditions on biomass of subalpine grassland. Ozone risk was assessed as exposure (AOT40) and as stomatal flux (POD0,1). We hypothesized that productivity is higher under N- and lower under O3 deposition, with interactions with climatic conditions.Aboveground biomass was best correlated with growing-degree days for May (GDDMay). Nitrogen deposition increased biomass up to 60% in the highest treatment, and 30% in the lowest addition. Also belowground biomass showed a positive N-response. Ozone enrichment had no effect on biomass, and no interaction between O3 and N was observed. Growth response to N deposition was not correlated to GDDMay or precipitation, but indicated a cumulative effect over time.Productivity of subalpine grassland is tolerant to increasing ozone exposure, independent of N input and climatic drivers. N deposition rates at current critical loads, strongly increase the grassland yield.
Show more [+] Less [-]Coal-tar-based sealcoated pavement: A major PAH source to urban stream sediments Full text
2014
Witter, Amy E. | Nguyen, Minh H. | Baidar, Sunil | Sak, Peter B.
We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (∼1303 km2) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69–0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use.
Show more [+] Less [-]Impacts of metal and metal oxide nanoparticles on marine organisms Full text
2014
Baker, Tony J. | Tyler, Charles R. | Galloway, Tamara S.
Increasing use of metal and metal oxide nanoparticles [Me(O)NPs] in products means many will inevitably find their way into marine systems. Their likely fate here is sedimentation following hetero-aggregation with natural organic matter and/or free anions, putting benthic, sediment-dwelling and filter feeding organisms most at risk. In marine systems, Me(O)NPs can absorb to micro-organisms with potential for trophic transfer following consumption. Filter feeders, especially bivalves, accumulate Me(O)NPs through trapping them in mucus prior to ingestion. Benthic in-fauna may directly ingest sedimented Me(O)NPs. In fish, uptake is principally via the gut following drinking, whilst Me(O)NPs caught in gill mucus may affect respiratory processes and ion transport. Currently, environmentally-realistic Me(O)NP concentrations are unlikely to cause significant adverse acute health problems, however sub-lethal effects e.g. oxidative stresses have been noted in many organisms, often deriving from dissolution of Ag, Cu or Zn ions, and this could result in chronic health impacts.
Show more [+] Less [-]Detection of free and covalently bound microcystins in different tissues (liver, intestines, gills, and muscles) of rainbow trout (Oncorhynchus mykiss) by liquid chromatography–tandem mass spectrometry: Method characterization Full text
2014
Cadel-Six, Sabrina | Moyenga, David | Magny, Stéphanie | Trotereau, Sophie | Edery, Marc | Krys, Sophie
So far only a few publications have explored the development of extraction methods of cyanotoxin extracted from complex matrices. With regard to cyanobacterial microcystins (MCs), the data on the contamination of the flesh of aquatic organisms is hard to compare and very limited due to the lack of validated methods. In recent years, evidence that both free and bound fractions of toxin are found in these tissues has highlighted the need to develop effective methods of quantification. Several techniques do exist, but only the Lemieux oxidation has so far been used to investigate complex tissue matrices. In this study, protocols based on the Lemieux approach were adapted for the quantitative chemical analysis of free MC-LR and MMPB derived from bound toxin in the tissues of juvenile trout gavaged with MC-LR. Afterwards, the NF V03 110 guideline was used to characterize the protocols elaborated and evaluate their effectiveness.
Show more [+] Less [-]Evidence of altered fertility in female roach (Rutilus rutilus) from the River Seine (France) Full text
2014
Gerbron, M. | Geraudie, P. | Fernandes, D. | Rotchell, J.M. | Porte, C. | Minier, C.
A large variety of anthropogenic chemicals present in the aquatic environment have been shown to be able to alter the endocrine system of exposed organisms, potentially impacting their reproductive function. The aim of this study was to assess the effects of environmental pollution on the reproductive system of wild female roach (Rutilus rutilus) from the Seine River (Normandy, France). A suite of biomarkers of endocrine disruption including gonado-somatic index, plasmatic vitellogenin, gonadal aromatase activity and histological parameters (oocyte diameter and gonad maturation) were studied. Female fish from the polluted sites showed a number of reproductive alterations, including inhibited gonad maturation, reduced oocyte growth, reduced levels of plasmatic vitellogenin and 3-fold lower gonadal aromatase activity than females collected in the reference site. Overall, these results highlight the presence of endocrine disruption in female roach from the Seine River.
Show more [+] Less [-]Passive sampling of perfluorinated chemicals in water: In-situ calibration Full text
2014
Kaserzon, Sarit L. | Hawker, Darryl W. | Booij, Kees | O'Brien, Dominique S. | Kennedy, Karen | Vermeirssen, Etiënne L.M. | Mueller, Jochen F.
Perfluorinated chemicals (PFCs) have been recognised as environmental pollutants that require monitoring. A modified polar organic chemical integrative sampler (POCIS) is able to quantify aqueous PFCs. However, with varying external water velocity, PFC sampling rates (Rs) may change, affecting accuracy of derived water concentrations. To facilitate field deployment of this sampler, two methods of in-situ calibration were investigated: performance reference compounds (PRCs) and passive flow monitors (PFMs). Increased Rs's (by factors of 1.2–1.9) with PFM loss rate (g d−1) were observed for some PFCs. Results indicate PFMs can be used to correct PFC specific Rs's for more reliable estimates of environmental concentrations with a precision of about 0.01 L d−1. Empirical models presented provide an improved means for aquatic monitoring of PFCs. The PRC approach was unsuccessful, confirming concern as to its applicability with such samplers.
Show more [+] Less [-]Air pollution and hospital admissions for respiratory diseases in Lanzhou, China Full text
2014
Tao, Yan | Mi, Shengquan | Zhou, Shuhong | Wang, Shigong | Xie, Xiaoyun
Lanzhou is among the most seriously air-polluted cities in China as a whole, due to its unique topography, climate, industrial structure and so on. We studied the relationship between different air pollution and respiratory hospitalizations from 2001 to 2005, the total of respiratory hospital admissions were 28,057. The data were analyzed using Poisson regression models after controlling for the long time trend for air pollutants, the “day of week” effect and confounding meteorological factors. Three air pollutants (PM10, SO2, NO2) had a lag effect, the lag was 3–5 days for PM10, 1–3 days for SO2 and 1–4 days for NO2. The relative risks were calculated for increases in the inter-quartile range of the pollutants (139 μg/m3 in PM10, 61 μg/m3 in SO2 and 31 μg/m3 in NO2). Results showed that there were significant associations between air pollutants and respiratory hospital admissions, and stronger effects were observed for females and aged ≥65 yrs in Lanzhou.
Show more [+] Less [-]Different toxicity mechanisms between bare and polymer-coated copper oxide nanoparticles in Lemna gibba Full text
2014
Perreault, François | Popović, Radovan | Dewez, David
In this report, we investigated how the presence of a polymer shell (poly(styrene-co-butyl acrylate) alters the toxicity of CuO NPs in Lemna gibba. Based on total Cu concentration, core–shell CuO NPs were 10 times more toxic than CuO NPs, inducing a 50% decrease of growth rate at 0.4 g l−1 after 48-h of exposure while a concentration of 4.5 g l−1 was required for CuO NPs for a similar effect. Toxicity of CuO NPs was mainly due to NPs solubilization in the media. Based on the accumulated copper content in the plants, core–shell CuO NPs induced 4 times more reactive oxygen species compared to CuO NPs and copper sulfate, indicating that the presence of the polymer shell changed the toxic effect induced in L. gibba. This effect could not be attributed to the polymer alone and reveals that surface modification may change the nature of NPs toxicity.
Show more [+] Less [-]Role of particle size and composition in metal adsorption by solids deposited on urban road surfaces Full text
2014
Gunawardana, Chandima | Egodawatta, Prasanna | Goonetilleke, Ashantha
Despite common knowledge that the metal content adsorbed by fine particles is relatively higher compared to coarser particles, the reasons for this phenomenon have gained little research attention. The research study discussed in the paper investigated the variations in metal content for different particle sizes of solids associated with pollutant build-up on urban road surfaces. Data analysis confirmed that parameters favourable for metal adsorption to solids such as specific surface area, organic carbon content, effective cation exchange capacity and clay forming minerals content decrease with the increase in particle size. Furthermore, the mineralogical composition of solids was found to be the governing factor influencing the specific surface area and effective cation exchange capacity. There is high quartz content in particles >150 μm compared to particles <150 μm. As particle size reduces below 150 μm, the clay forming minerals content increases, providing favourable physical and chemical properties that influence adsorption.
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