Archive for the ‘Hot Articles’ Category

Semipermeable membrane devises (SPMDs) as models in dissolved hydrocarbon exposure studies

Crude oil spillages are a major ecological threat, exposing aquatic wildlife to high concentrations of toxic organic pollutants. This study by Van Scoy et al. demonstrates the potential usefulness of semi-permeable membrane devises (SPMDs) in monitoring the exposure of aquatic organisms to dissolved hydrocarbons from crude oil, and in assessing the toxic effects that these compounds may exert.

Oil spills and their environmental impacts are frequently in the public and media spotlight. In order to adequately address this issue it is essential to establish the most effective way to limit exposure to the toxic compounds released. It is common for chemical dispersants to be used following spillages. These accelerate the natural dispersion of oil by reducing the interfacial surface tension. While these are considered to be an effective treatment method, the ecological impact of dispersed oil needs to be considered.

In this study SPMDs were used to extract the bioavailable fraction of dissolved hydrocarbons present in both ‘undispersed’ and ‘chemically dispersed’ crude oil. SPMDs mimic the action of biological membranes by allowing passive diffusion of aqueous compounds through the lipid membrane. Here, this technique was used to monitor levels of key polycyclic aromatic hydrocarbons (PAHs), a class of pollutants shown to display toxic and bioaccumulative properties in aquatic organisms.

The use of SPMDs is favourable compared to living models in bioavailability studies, providing a relatively quick, economical and efficient method and also avoids biotransformation of compounds during the experiment. In this study, ultra high purity triolein (C57H104O6) was used to extract 7 PAHs, monitoring accumulation over a 24hr exposure time to simulate the initial period after a spillage. Concentrations of 7 PAHs were measured using gas chromatography with mass spectrometry (GC-MS).

It was shown that, while the initial crude oil loading was 8 times higher for the undispersed oil (2 g L-1) compared to the dispersed oil (0.25 g L-1), accumulation of PAHs was greater for the dispersed oil. This was attributed to the micelles, formed upon dispersant application, weathering over time. This would suggest the use of chemical dispersants as a remediation measure may increase the risk of exposure of aquatic organisms to toxic hydrocarbons.

The study demonstrates the usefulness of SPMDs in measuring concentrations of dissolved organic pollutants present in crude oil. Data from this technique, in combination with metabolomic data, could be a valuable tool in better understanding the bioavailability of dissolved hydrocarbons in crude oil and the possible toxic effects this can have on aquatic wildlife. The paper would therefore be of interest to ecotoxicologists investigating aquatic organisms in both saltwater and freshwater environments.

Use of semipermeable membrane devices (SPMDs) to characterize dissolved hydrocarbon fractions of both dispersed and undispersed oil by April R. Van Scoy, Jennifer Voorhees, Brian S. Anderson, Bryn M. Philips and Ronald S. Tjeerdema.  

DOI: 10.1039/C3EM00275F

This paper is part of the ESPI HOT articles series and is free to download* for the next 2 weeks  – grab it while it’s HOT!

*Free access to individuals is provided through an RSC Publishing personal account. It’s quick, easy and more importantly – free – to register!

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Free to access HOT articles!

These HOT articles were recommended by our referees and are free to access for 4 weeks*

Contaminated land: can acute exposure be a significant health risk? Two case studies and associated risk assessment methods George Kowalczyk, Mark Brown, Rebecca Twigg, William Welfare and Yolande Macklin  
DOI: 10.1039/C3EM00278K

The influence of glacial meltwater on alpine aquatic ecosystems: a review
Krista E. H. Slemmons, Jasmine E. Sarosa and Kevin Simon  
DOI: 10.1039/C3EM00243H

Use of semipermeable membrane devices (SPMDs) to characterize dissolved hydrocarbon fractions of both dispersed and undispersed oil
April R. Van Scoy, Jennifer Voorhees, Brian S. Anderson, Bryn M. Philips and Ronald S. Tjeerdema  
DOI: 10.1039/C3EM00275F

Release of TiO2 from paints containing pigment-TiO2 or nano-TiO2 by weathering
Ahmed Al-Kattan, Adrian Wichser, Roger Vonbank, Samuel Brunner, Andrea Ulrich, Stefano Zuin and Bernd Nowack  
DOI: 10.1039/C3EM00331K

Pilot-scale in situ bioremediation of HMX and RDX in soil pore water in Hawaii
Zachary M. Payne, Krishna M. Lamichhane, Roger W. Babcock and Stephen J. Turnbull  
DOI: 10.1039/C3EM00320E

The impact of an anti-idling campaign on outdoor air quality at four urban schools
Patrick H. Ryan, Tiina Reponen, Mark Simmons, Michael Yermakov, Ken Sharkey, Denisha Garland-Porter, Cynthia Eghbalniad and Sergey A. Grinshpun  
DOI: 10.1039/C3EM00377A

Influence of organic surface coatings on the sorption of anticonvulsants on mineral surfaces
Shen Qua and David M. Cwiertny  
DOI: 10.1039/C3EM00288H

Detection of multiple stresses in Scots pine growing at post-mining sites using visible to near-infrared spectroscopy Lhotáková Zuzana,  Brodský Lukáš, Kupková Lucie, Kopačková Veronika, Potůčková Markéta, Mišurec Jan, Klement Aleš,   Kovářová Monika and Albrechtová Jana  
DOI: 10.1039/C3EM00388D

 
Human exposure to aluminium
Christopher Exleya  
DOI: 10.1039/C3EM00374D

 
Lability, solubility and speciation of Cd, Pb and Zn in alluvial soils of the River Trent catchment UK
Maria Izquierdo, Andrew M. Tye and Simon R. Chenery  
DOI: 10.1039/C3EM00370A

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It’s an aluminium age: exploring human exposure

Aluminium is the most abundant metal in the Earth’s crust. Its range of desirable chemical and physical properties (e.g. low density, thermal conductivity, corrosion resistance etc) has made it the most widely used metal of the 21st century, utilised in a huge variety of products and applications, from kitchen utensils to aircraft parts, from food packaging to window frames. However, while the extracting and casting of this abundant resource yields many benefits, the disruption of natural geochemical and biochemical systems may expose organisms including humans to potential harm. It is of paramount importance that we fully understand the ways in which humans are exposed to aluminium and its behaviour within the body. This will allow the nature and extent of potential toxic effects to be assessed and enable people to live safely with these possible dangers.

In this article, which featured on the cover of Environmental Science: Processes & Impacts Issue 10, Christopher Exley provides a detailed and comprehensive critical review, addressing these issues. A broad range of specific aspects within the field of aluminium exposure are covered. The myriad ways in which humans are exposed to aluminium (including inhalation, diet and cosmetics) are discussed as well as the key impact routes (e.g. skin. nose, lung and gut), distribution networks within the body (e.g. blood) and excretion routes. The mechanisms through which aluminium can exert biochemical effects in humans (e.g. pro-oxidant activity, immunopotency and mutagenicity) are also described. Additionally, the article provides a complete and clear description of the aluminium ‘body burden’ (the balance between exposure and excretion).

This article challenges the current perception that aluminium is completely ‘safe’ and demonstrates the need to change our thinking regarding human exposure to metals like aluminium. Furthermore, several key knowledge gaps in this field are identified. Specific areas for future research, required to improve our understanding of aluminium exposure and toxicology, are outlined. In particular, the need to identify specific ‘targets’ within biological systems that may be more vulnerable to aluminium ‘attack’ than others is emphasised. Also, a need to establish an acceptable level of ‘safe’ exposure in humans is highlighted.

Exley suggests that gaining a full understanding of aluminium exposure and body burden in humans will require further data to be gathered from both laboratory and computer modelling approaches. This article will therefore be a valuable resource for researchers within these fields as well as for policy-makers at local and national levels.

Read the full article here:
Human exposure to aluminium, Christopher Exley, DOI : 10.1039/c3em00374d

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Nanoparticles on Fire!

schematic of nanoparticles in incineratorNanomaterials have become a ‘hot topic’ within many spheres of science, from their manufacture and use through to their toxicity.  However a critical review by Holder et al, has shed light on their disposal by incineration, an often overlooked area.

Incineration is a key route of disposal of many solid wastes, including from wastewater, which could be a significant source of silver nanoparticles.  Incineration is a complex process which could see nanomaterials released into the environment through several different pathways.

This very comprehensive article reviews social aspects of this topic, such as legislation from across the globe, as well physical scientific data on how nanomaterials behave under combustion conditions and their fate.

This article would be of interest to anyone keen to learn more about modern waste disposal, the manufacture of nanoparticles or the release and behaviour of antiparticles in the environment.

The review is free to access for the next 4 weeks, so pick it up while it’s hot!*

 *Free access to individuals is provided through an RSC Publishing personal account. It’s quick, easy and more importantly – free – to register!

Nanomaterial disposal by Incineration by Amara L. Holder, Eric P. Vejerano, Xinzhe Zhou and Linsey C. Marr. DOI: 10.1039/C3EM00224A

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HOT articles – free to access!

Take a look at our HOT articles recommended by our referees – these have been made free to access for 4 weeks*

Nanomaterial disposal by incineration
Amara L. Holder, Eric P. Vejerano, Xinzhe Zhou and Linsey C. Marr
DOI: 10.1039/C3EM00224A

GA

Combining multivariate statistics and analysis of variance to redesign a water quality monitoring network
Nathalie Guigues, Michèle Desenfant and Emmanuel Hance  
DOI: 10.1039/C3EM00168G

GA

The oxidative toxicity of Ag and ZnO nanoparticles towards the aquatic plant Spirodela punctuta and the role of testing media parameters
Melusi Thwala, Ndeke Musee, Lucky Sikhwivhilu and Victor Wepener
DOI: 10.1039/C3EM00235G

GA

Lability, solubility and speciation of Cd, Pb and Zn in alluvial soils of the River Trent catchment UK
Maria Izquierdo, Andrew M. Tye and Simon R. Chenery
DOI: 10.1039/C3EM00370A   

GA

Human exposure to aluminium
Christopher Exley
DOI: 10.1039/C3EM00374D

GA

Human biomonitoring issues related to lead exposure
Evert Nieboer, Leonard J. S. Tsuji, Ian D. Martin and Eric N. Liberda
DOI: 10.1039/C3EM00270E   

GA

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Real time identification of algal phyla

algae identificationAlgae are identified in variety of research fields and used as indicators of water quality.  Quantifying and identifying algae is often a laborious task and requires a high level of skill.  Although there are several automated techniques now available, commercial developments have been limited.  Several software techniques based on imaging have been previously presented, however they’re often limited to only a few algal types, so not applicable to field samples. 

This paper presents an innovative method which provides real time recognition of multiple algaes.  The software uses image segmentation, shape features i.e. contours, centroid spectrum calculations and pigmentation.  The set up uses relatively simple hardware and no sample processing or fixation.  Coltelli et al tested the method on both cultured strains and field samples with the method correctly identifing 96.6% of 24 different algal phyla from 3423 images.

This article would be of interest to anyone involved in algal identification, whether from lab based cultures or water samples from the field. 

Automatic and real time recognition of microalgae by means of pigment and shape
Primo Coltelli, Laura Barsanti, Evangelista, Anna Maria Frassanito, Vincenzo Passarelli and Paolo Gualtieri
DOI: 10.1039/C3EM00160A

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New fungal immunoassay

antibodiesFungal antigens, e.g. from damp homes, have been linked to a variety of illnesses and allergies.  Traditional techniques of identifying them, such as culture based-methods or microscopy, have several drawbacks including not being able to identify fungal fragments and limitations in species classification.  Currently available commercial monoclonal antibody-based ELISAs are avilable, however they have not been as successful in fungal identification as they have been in other common indoor allergens.   

This paper describes the development and validation of an enzyme sandwich ELISA designed to quantify A. versicolor antigens using polyclonal antibodies.  Samples from infected homes were collected and tested using the newly developed assay and the results were compared to the commercially available ELISA, colony forming units and fungi cultivations.

Proteins from A. versicolor spores and myecelia were extracted and subcutaneously injected into a rabbit.  The antibodies produced were then isolated and coated on to the plates to produce the immunoassays.   Positive and negative controls were run as well as the environmental samples. 

In brief the assay proved to be very sensitive (range = 0.12–4.5 ng mL-1) and precise with intra-assay coefficient of variation (CV) = 4% and inter-assay CV = 11%.  Cross reactivity with other moulds was observed, although at intensities significantly lower than A. versicolor.  The assay also appeared to be more successful in environmental analysis than the commercial assay, showing a positive result for 88% of dust and 89% of bulk samples, with the commercial AveX ELISA only indicating positive results for 27% and 24% respectively.  This may be partly attributed to all the A. versicolor samples cultured showing A. versicolor antigens, whereas only 12 contained identifiable AveX antigens.  A wide range of proteins were shown to be identifiable by the polycolonal A. versicolor antibodies, although not smaller proteins (20–6 KDa) from the myecelia.

This immunoassay has been demonstrated to be effective in environmental studies and could prove to be a significant technique for those identifying and quantifying fungal infestations.  

This HOT article would be of interest to anyone involved in fungal identification or the development of immunoassays.  You can access it from the website for free for the next couple of weeks*!

A new immunoassay to quantify antigens from the infoor mould Aspergillus versicolor
Eva Zahradnik, Sabine Kespohl, Ingrid Sander, Ursula Schies, Janett Khosravie-Hohn, Wolfgang Lorenz, Steffen Engelhart, Annette Kolk, Gerd Schneider, Thomas Brüning and Monika Raulf-Heimsoth  
DOI: 10.1039/C3EM30870G

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Free to access HOT articles!

 
These articles are HOT as recommended by the referees. And we’ve made them free to access for 4 weeks*

 

Bacterial community of iron tubercles from a drinking water distribution system and its occurrence in stagnant tap water
Lu Chen, Rui-Bao Jia and Li Li  
DOI: 10.1039/C3EM00171G


DGT measurement in low flow conditions: diffusive boundary layer and lability considerations
Emmanuelle Uher, Marie-Hélène Tusseau-Vuillemin and Catherine Gourlay-France
DOI: 10.1039/C3EM00151B


 

Quantitative and qualitative sensing techniques for biogenic volatile organic compounds and their oxidation products
Saewung Kim, Alex Guenther and Eric Apel  
DOI: 10.1039/C3EM00040K


A new immunoassay to quantify fungal antigens from the indoor mould Aspergillus versicolor
Eva Zahradnik, Sabine Kespohl, Ingrid Sander, Ursula Schies, Janett Khosravie-Hohn, Wolfgang Lorenz, Steffen Engelhart, Annette Kolk, Gerd Schneider, Thomas Brüning and Monika Raulf-Heimsoth
DOI: 10.1039/C3EM30870G

*Free access to individuals is provided through an RSC Publishing personal account. Registration is quick, free and simple

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Can nanotubes affect how polyaromatic hydrocarbons behave in soil?

Determining the fate of compounds once they’re released into the environment is a complex issue. However such study is vital in order to assess the persistence of a compound as well as its bioavailability.  

It is well-established that polyaromatic hydrocarbons (PAHs) bind to organic complexes through hydrophobic interactions and that this can occur within soils to matter such as humus and soot etc.  So how does the presence of multi-walled carbon nanotubes (MWNTs) impact this?  Particularly given they are organic particles with relatively high surface areas available for adsorption.  Given the increasing interest in MWNTs there is now an elevated risk of ‘traditional’ organic pollution being released into an environment where MWNTs are already present, co-released with them or for MWNTs to be released onto existing polluted soil.

Li et al. used batch equilibrium experiments to assess the relationship between soil types, MWNTs and PAHs.  The MWNTs used were 1-3 µm long, 11 nm diameter with relatively little bundling providing a high surface area.  The group assessed three soil types: sand, sandy loam and silt loam with 2 mg g-1 of MWNTs.  The compounds and concentrations of PAHs assessed were naphthalene 0.18–7.94 mg L-1, fluorine 0.16–1.62 mg L-1 and phenanthrene 0.1–0.91 mg L-1.  Sorption tests (HPLC-fluorescence) were carried out after 5 days, at which point the aqueous solution was removed and replaced with fresh and left for 24hrs under the same conditions to assess desorption.

The results confirmed that the sorption of these compounds increased with increasing organic content of the soil. However, the presence of MWNTs did not appear to influence this adsorption, even at these relatively high concentrations of MWNTs.  Desorption was minimal in all cases.

In addition, the group derived equations based on the ‘rule of mixtures’ capable of predicting the sorption coefficients of composite sorbents.  They found good correlations between predicted and experimental data using these equations despite limitations of the model, such as assuming no void spaces. 

This HOT article would be of interest to anyone carrying out batch equilibrium experiments, or is interested in the sorption of PAH and/or the fate of MWNTs.  You can access it from the website for free for the next 4 weeks*!

Polyaromatic hydrocarbons (PAHs) sorption behavior unaffected by the presence of multi-walled carbon nanotubes (MWNTs) in a natural soil system.
Shibin Li, Todd A. Anderson, Micah J. Green, Jonathan D. Maul and Jaclyn E. Cañas-Carrell
DOI: 10.1039/C3EM00099K

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How can you assess the impact of multiple methane sources to the environment?

In this HOT article, collaborators in Australia and California devise methods of assessing contributions of landfill and natural gas methane to mixtures in soil gas and groundwater. They use half-lives and concentration ratios to evaluate the age of release.

The group at URS Australia Pty Ltd, Geosyntec Consultants and Redwood Waste Management California, focus on the problem of methane from landfill gas migrating away underneath the surface of landfill sites. It is a particular problem due to methane’s flammable nature. Landfill gas is not the only source of migrating methane. Sources include natural organic matter decomposition, natural gas in supply lines, degradation of petroleum products and underground reservoirs of natural gas. There are many indicators used to determine the source of natural gas, such as the presence of CO2 being a marker for biodegradation. Carbon and hydrogen isotope composition is also used.

These researchers argue that using multiples of these indicators is the most reliable way to understand sources and migration pathways. This paper introduces a methodology to assess all of these different indicators at a complex site with multiple methane sources. Knowing the age of landfill gas using VOCs concentrations is a helpful parameter when assessing migration distance and time. This methodology using methane radioisotope data can distinguish on-going release from an inactive source and determine relative contributions of landfill gas and thermogenic methane to the environment. The theoretical basis for estimating landfill gas age is described in detail and applied to a case study at a municipal solid waste disposal facility in California.

As always, we’ve made this fascinating HOT research free to access for 4 weeks*!

Evaluation of the age of landfill gas methane in landfill gas–natural gas mixtures using co-occurring constituents
Henry B. Kerfoot, Benjamin Hagedorn and Mark Verwiel 
DOI: 10.1039/C3EM30971A

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