Archive for the ‘Hot Articles’ Category

Improving phosphorous monitoring

Improving our insight into nutrient cycling in lake systems is essential to appropriately tackle the problem of eutrophication. Researchers from the University of Oslo and the Norwegian Institute for Water Research present a technique for monitoring bioavailable phosphorous (P) concentrations, which can provide advantages over conventional water sampling and potentially open an exciting new direction for research in this field.

It is widely established that eutrophication causes serious deterioration of fresh and marine waters. The primary cause is an excessive input of plant nutrients (e.g. N and P) to water courses from human activities such as agriculture or sewage treatment, causing excessive development of algae, which severely disturbs aquatic ecosystems. The WHO has highlighted the key environmental and health risks associated with eutrophication and the need to adequately tackle this problem.

Current abatement actions, such as redirecting sewage wastewater and reducing the P input from agriculture have had limited effectiveness in many cases. This has brought attention to the role of the background flux of P in river catchments; for example, the input of Dissolved Natural Organic Matter (DNOM) and in particular the role of bioavailable low-molecular-weight organic phosphorus (LMWOP) compounds such as nucleic acid derivatives, phospholipids and sugar phosphates.

The fluctuating and very low concentrations of these compounds present major challenges in the monitoring of the bioavailable P fraction by conventional methods. This study by Christian Wilhelm Mohr and co-workers presents a technique for monitoring the ambient concentrations of dissolved reactive phosphorus (DRP) and dissolved organic phosphorus (DOP), especially the LMWOP DOP sub-fraction, using Diffusive Gradient in Thin Films (DGTs).

DGTs have been used as passive samplers based on their linear diffusive uptake of components, which allows time average concentrations to be determined for species commonly present in concentrations close to the limit of detection. However, the present challenge is how to use the amount of analyte determined from the DGTs to predict the ambient concentration of LMWOP and therefore gain better insight into the long- and short-term variation of DRP and DOP concentrations in different systems. Consequently, the ultimate aim is to use this technique to carry of real-world risk assessments.

In this study, DGTs fitted with phosphate adsorbent Fe-oxide binding gel were used to collect the orthophosphate and LMWOP compounds, adenosine monophosphate (AMP) and myo-inositol hexakisphosphate (IP6) respectively, in experimental test solutions. Theoretical modelling was used to determine diffusion coefficient (D) values, a key parameter relating the amount of analyte measured by the DGT to the time averaged ambient concentration. Validation of DGT data was performed by comparing concentrations of P fractions determined in water samples, collected via conventional means with concentrations using DGT, in three 1st order streams draining different types of catchments (e.g. forest, mixed and agriculture).

The authors discuss the appropriate use of DGT sampling data, explaining that because the relative distribution of LMWOP molecules will differ between different catchments, a range of model-derived D values should be investigated. It is suggested this could allow a ‘best fit’ of D values for different sites and a “tailored” D value for different individual water bodies to be determined in order to practically use the DGTs for estimating time average DOP.

It was shown that the DGT method was successful in the linear uptake of AMP and IP6, and could therefore potentially be applied to other LMWOP compounds. The catchment study indicated a reasonable agreement between the dissolved P fractions determined from water samples and by DGTs and that the stream water samples from the different catchments showed clear differences in relative and absolute concentrations of DRP and DOP. This study demonstrates that the use of DGT can help improve our insight into the cycling of P in eutrophic lakes and specifically the spatial variation of ambient levels of DRP and LMWOP in these systems. However, the models tested for estimating D for different LMWOP molecules are still too uncertain for practical use.

The authors note that more studies are needed to better quantify the distribution of DOP with molecular weight for a variety of catchments with different land-use. For example, further experimental and sampling studies will be needed to determine D values for a wider range of LMWOP molecules so that better calibration and validation of model performance can be performed and different environmental conditions (e.g. pH) can be investigated.

To access the full article, download a copy for free* by clicking the link below.

An in-depth assessment into simultaneous monitoring of dissolved reactive phosphorus (DRP) and low-molecular-weight organic phosphorus (LMWOP) in aquatic environments using diffusive gradients in thin films (DGT)
Christian Wilhelm Mohr, Rolf David Vogt, Oddvar Røyset, Tom Andersen and Neha Amit Parekh
Environ. Sci.: Processes Impacts, 2015, Advance Article
DOI: 10.1039/C4EM00688G

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About the webwriter

Ian Keyte is a Doctoral Researcher at the University of Birmingham. His research focuses on the sources, behavior and fate of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere.

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* Access is free through a registered RSC account.

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Timing is everything: renewable energy generation and air quality impacts

The time of day or year at which emissions of pollutants occur has a major impact on the air quality in ‘receptor’ areas downwind of their source. This study by researchers from the Department of Climate, Air and Sustainability at TNO in Utrecht, Netherlands, describes the significance of this observation for policy makers approaching the transition of energy generation, from fossil fuels to renewable sources.

Air pollution is currently a major threat to public health. Failure to adequately tackle this problem could have significant socio-economic consequences. Indeed the OECD predicts that poor ambient air quality is projected to be the leading environmental cause of mortality by 2050. It is almost universally acknowledged that fossil fuel combustion for energy generation is unsustainable and emits large volumes of greenhouse gases and pollutants (such as PM, NOx and SO2) that adversely affect public health.

Under EU regulation, at least 20% of energy generation will need to come from renewable sources by 2020. It is expected that most countries will increase their generation of electricity from wind and solar (PV) in order to achieve this. These energy sources are intermittent and will depend strongly on the prevailing weather conditions, so they will not be available at all times. In the short term, this means a ‘back-up’ of fossil fuel-generated energy will be needed at times when renewable supply is lower.

This will shift the temporal variability of emissions, which will impact upon the so called source receptor relations (SRRs) of air pollutant concentrations in different regions. It is essential that mitigation strategies to reduce greenhouse gas emissions are designed with an appreciation for what the air quality impacts will be. Currently, the integrated assessment modelling of SRRs is designed using invariant emission time profiles. This study by Hendricks and co-workers explores the impact of changing the time profiles of emissions on the observed air pollutant SRRs.

The investigation used the energy system model REMix (Renewable Energy Mix For Sustainable Electricity Supply) to calculate the hourly availability of renewable electricity based on meteorological conditions.

The emission profiles for the subsequent backup generation could then be derived. Two emissions scenarios were tested, assuming increased contributions from wind and solar PV to the total energy generation in Europe, replacing fossil fuels, as well as a ‘baseline’ scenario using the current energy mix. The time profiles were then used in the Chemistry Transport Model LOTOS-EURO, equipped with a source attribution module , to investigate the effect of emission timing on air concentrations and SRRs for key pollutants such as NOx, SO2 and PM10.

Increasing the contribution of renewable energy in place of fossil fuel combustion is expected to result in lower emissions of air pollutants, when emission profiles are assumed to be constant. However, the results of this study suggest that the air quality improvements are lower when the temporal variability in emissions due to the intermittent nature of wind and solar energy generation is taken into account by the integrated assessment models. Several temporal factors (including seasonality in emissions, occurrence of stagnant weather conditions reducing dispersion, and the diurnal cycles of atmospheric components) are shown to influence the air concentrations and SRRs of the pollutants studied.

This work demonstrates that there is a need to assess the impact of different emission timing scenarios on the air pollutant SRRs, when managing the transition from fossil fuel to renewable energy generation. With their observations, the authors warn that the assumption that current climate change policies will have associated co-benefits for air quality is too optimistic, and recommend the design of a more detailed emission model of the energy sector to carefullyexamine the impacts of energy transition.


To access the full article, download a copy for free* by clicking the link below.

A shift in emission time profiles of fossil fuel combustion due to energy transitions impacts source receptor matrices for air quality
Carlijn Hendriks, Jeroen Kuenen, Richard Kranenburg, Yvonne Scholz and Martijn Schaap
Environ. Sci.: Processes Impacts
, 2015,17, 510-524
DOI: 10.1039/C4EM00444B

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About the webwriter

Ian Keyte is a Doctoral Researcher at the University of Birmingham. His research focuses on the sources, behavior and fate of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere.

—————-

* Access is free through a registered RSC account

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February’s HOT Articles

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

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A review of arsenic and its impacts in groundwater of the Ganges–Brahmaputra–Meghna delta, Bangladesh
W. M. Edmunds, K. M. Ahmed and P. G. Whitehead
DOI: 10.1039/C4EM00673A,

10.1039/C4EM00673A

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In situ tryptophan-like fluorometers: assessing turbidity and temperature effects for freshwater applications
K. Khamis, J. P. R. Sorensen, C. Bradley, D. M. Hannah, D. J. Lapworth and R. Stevens
DOI: 10.1039/C5EM00030K

10.1039/C5EM00030K

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Check our Environmental Science: Processes & Impacts HOT Articles collection!

*Access is free until 16/04/15 through a publishing personal account. It’s quick, easy and free to register!

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January’s HOT Articles

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

A shift in emission time profiles of fossil fuel combustion due to energy transitions impacts source receptor matrices for air quality
Carlijn Hendriks, Jeroen Kuenen, Richard Kranenburg, Yvonne Scholz and Martijn Schaap
Environ. Sci.: Processes Impacts, 2015, Advance Article
DOI: 10.1039/C4EM00444B, Paper

Graphical abstract: A shift in emission time profiles of fossil fuel combustion due to energy transitions impacts source receptor matrices for air quality

Comparison of nickel speciation in workplace aerosol samples using sequential extraction analysis and X-ray absorption near-edge structure spectroscopy
Lisa L Van Loon, Mike D. Dutton and Cassidy Throssell
Environ. Sci.: Processes Impacts, 2015, Accepted Manuscript
DOI: 10.1039/C4EM00603H, Paper


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December’s HOT Articles

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

Development and field testing of a miniaturized sampling system for simultaneous sampling of vapours and droplets
Dietmar Breuer, George C. Dragan, Claudia Friedrich, Carsten Möhlmann and Ralf Zimmermann
Environ. Sci.: Processes Impacts, 2015, Advance Article
DOI: 10.1039/C4EM00602J, Paper

Graphical abstract: Development and field testing of a miniaturized sampling system for simultaneous sampling of vapours and droplets

Contaminant classification using cosine distances based on multiple conventional sensors
Shuming Liu, Han Che, Kate Smith and Tian Chang
Environ. Sci.: Processes Impacts, 2015, Advance Article
DOI: 10.1039/C4EM00580E, Paper

Graphical abstract: Contaminant classification using cosine distances based on multiple=

A statistical comparison of active and passive ammonia measurements collected at Clean Air Status and Trends Network (CASTNET) sites
Melissa A. Puchalski, Christopher M. Rogers, Ralph Baumgardner, Kevin P. Mishoe, Garry Price, Michael J. Smith, Nealson Watkins and Christopher M. Lehmann
Environ. Sci.: Processes Impacts, 2015, Advance Article
DOI: 10.1039/C4EM00531G, Paper

A statistical comparison of active and passive ammonia measurements collected at Clean Air Status and Trends Network (CASTNET) sites

Distinct photoproducts of hydroxylated polybromodiphenyl ethers from different photodegradation pathways: a case study of 2′-HO-BDE-68
Qing Xie, Jingwen Chen, Hongxia Zhao, Xingbao Wang and Hong-Bin Xie
Environ. Sci.: Processes Impacts, 2015, Advance Article
DOI: 10.1039/C4EM00395K, Paper

 Distinct photoproducts of hydroxylated polybromodiphenyl ethers from different photodegradation pathways: a case study of 2′-HO-BDE-68

Check our Environmental Science: Processes & Impacts 2014 HOT Articles Collection!

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November’s HOT Articles

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

A laboratory study of the performance of the handheld diffusion size classifier (DiSCmini) for various aerosols in the 15-400 nm range
S. Bau, B. Zimmermann, R. Payet and O. Witschger
Environ. Sci.: Processes Impacts, 2015, Advance Article
DOI: 10.1039/C4EM00491D, Paper
From themed collection AIRMON 2014



Effect of permafrost properties on gas hydrate petroleum system in the Qilian Mountains, Qinghai, Northwest China
Pingkang Wang, Xuhui Zhang, Youhai Zhu, Bing Li, Xia Huang, Shouji Pang, Shuai Zhang, Cheng Lu and Rui Xiao
Environ. Sci.: Processes Impacts, 2014,16, 2711-2720
DOI: 10.1039/C4EM00482E, Paper


Filamentous sludge bulking control by nano zero-valent iron in activated sludge treatment systems
Shengnan Xu, Minghao Sun, Chiqian Zhang, Rao Surampalli and Zhiqiang H
Environ. Sci.: Processes Impacts, 2014,16, 2721-2728
DOI: 10.1039/C4EM00333K, Paper



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2014 HOT Articles Collection!

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October’s Free HOT Articles!

These HOT articles, published in October 2014 were recommended by our referees and are free to access for 4 weeks*

Geochemical recovery of the Torna–Marcal river system after the Ajka red mud spill, Hungary
Á. D. Anton, O. Klebercz, Á. Magyar, I. T. Burke, A. P. Jarvis, K. Gruiza and W. M. Mayes
Environ. Sci.: Processes Impacts, 2014,16, 2677-2685
DOI: 10.1039/C4EM00452C



Filamentous sludge bulking control by nano zero-valent iron in activated sludge treatment systems
Shengnan Xu, Minghao Sun, Chiqian Zhang, Rao Surampalli and Zhiqiang Hu
Environ. Sci.: Processes Impacts, 2014,16, 2721-2728
DOI: 10.1039/C4EM00333K


Effect of permafrost properties on gas hydrate petroleum system in the Qilian Mountains, Qinghai, Northwest China
Pingkang Wang, Xuhui Zhang, Youhai Zhu, Bing Li, Xia Huang, Shouji Pang, Shuai Zhang, Cheng Lu and Rui Xiao
Environ. Sci.: Processes Impacts, 2014,16, 2711-2720
DOI: 10.1039/C4EM00482E



Check our Environmental Science: Processes & Impacts

2014 HOT Articles Collection!

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September’s Free HOT Articles

These HOT articles, published in September 2014 were recommended by our referees and are free to access for 4 weeks*

Contrasting physiological responses of ozone-tolerant Phaseolus vulgarisand Nicotiana tobaccum varieties to ozone and nitric acid
Cara M. Stripe, Louis S. Santiago and Pamela E. Padgett
Environ. Sci.: Processes Impacts, 2014,16, 2488-2495
DOI: 10.1039/C4EM00143E

ESPI HOT Article

Effects of long-term land use change on dissolved carbon characteristics in the permafrost streams of northeast China
Yuedong Guo, Changchun Song, Zhongmei Wan, Wenwen Tan, Yongzheng Lu and Tianhua Qiao
Environ. Sci.: Processes Impacts, 2014,16, 2496-2506
DOI: 10.1039/C4EM00283K

Products and kinetics of the heterogeneous reaction of particulate ametryn with NO3 radicals
Chang-Geng Liu, Ji-Nian Shu, Bo Yang and Peng Zhang
Environ. Sci.: Processes Impacts, 2014, Advance Article
DOI: 10.1039/C4EM00352G


Take a look at our Environmental Science: Processes & Impacts 2014 HOT Articles Collection!

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Hungary’s rivers in recovery after red mud disaster

Four years after Hungary’s disastrous red mud spill, Will Mayes and co-workers at the University of Hull, UK, have shown that implemented remediation measures have successfully limited the long term impacts of the spill on the affected Danube tributaries. Elemental and particle size analyses of fluvial sediments sampled downstream from the spill site in 2013 showed that the characteristic geochemical signature of the red mud was predominantly absent compared to in post-disaster surveys, highlighting that the contaminated material was mostly removed by intervention measures.

To read the full article please visit ChemistryWorld.

Geochemical recovery of the Torna–Marcal river system after the Ajka red mud spill, Hungary*
Á. D. Anton, O. Klebercz, Á. Magyar, I. T. Burke, A. P. Jarvis, K. Gruiz and   W. M. Mayes
Environ. Sci.: Processes Impacts, 2014,
DOI: 10.1039/C4EM00452C

*This paper is open access

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Concerns over chemical treatment of reclaimed fracking fluid

The study analysed water samples from shale gas wells in Marcellus (Pennsylvania), Eagle Ford (Texas), and Barnett (New Mexico) © Michael J Mullen Scranton Times-Tribune/AP/Press Association Images

Estimates suggest that in the next 50 years, over one trillion gallons of water will be used in shale gas extraction but research from scientists in the US suggests that environmentally detrimental compounds are being created when this fluid is recycled.

Shale gas is found in rock formations kilometres underground. Hydraulic fracturing, also known as fracking, facilitates the release of this energy dense fuel in a cost-effective and timely manner. Water, sand and a combination of other additives are pumped into the ground at high pressure, breaking the shale formations apart, allowing the gas to migrate to the surface where it can be collected.

To read the full article, please visit Chemistry World.

Organic compounds in produced waters from shale gas wells
Samuel J. Maguire-Boyle and Andrew R. Barron
Environ. Sci.: Processes Impacts, 2014, Advance Article
DOI: 10.1039/C4EM00376D, Paper

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