Environmental Science: Processes & Impacts blog

Researchers at the University of Toronto, Canada, have evaluated the Ambient Ion Monitor-Ion Chromatograph (AIM-IC) system’s performance and accuracy for the measurement of the water-soluble chemical composition of atmospheric fine particulate matter (PM_2.5).

The team, led by Jennifer Murphy, determined the system’s detection limits for gas phase NH_3(g), SO_2(g), and HNO_3(g) and particle phase NH₄⁺, SO₄²⁻, and NO₃⁻. The group also evaluated the system for response time to changing compound concentrations, with a variety of different membranes.

Read more about the study here – the paper is free to access for 4 weeks:

Characterization and optimization of an online system for the simultaneous measurement of atmospheric water-soluble constituents in the gas and particle phases
Milos Z. Markovic, Trevor C. VandenBoer and Jennifer G. Murphy
DOI: 10.1039/C2EM00004K

A quantitative model to predict arsenic concentration patterns in the area surrounding abandoned mining sites has been developed in this recently published HOT paper.

The model looks at the fluvial transport of arsenic from mine waste in semi-arid areas, which has a significant contribution in the distribution of contaminants from the original source – particularly after heavy rain.   Despite the important role of fluvial transport, it has been somewhat overlooked to date – perhaps because of the intermittent and unpredictable nature of our weather systems.

James Rytuba from the U.S. Geological Survey, and colleagues from Chapman University hope that their model will help inform environmental remediation strategies for arsenic and other related contaminants in similar environments.

Read the details of the model here – the paper is free to access for 4 weeks:

Fluvial transport and surface enrichment of arsenic in semi-arid mining regions: examples from the Mojave Desert, California
Christopher S. Kim,  David H. Stack and James J. Rytuba
DOI: 10.1039/C2EM30135K

This critical review, written by Michael Dodd from the University of Washington, focuses on the role that wastewater treatment plants play in the removal of antibiotic resistance genes from the wastewater to stop the spread of antibiotic resistant bacteria to non-resistant communities.

Although most treatments inactivate antibiotic resistant bacteria, stopping horizontal gene transfer processes, antibiotic resistance genes can be left in cell debris in the water, allowing natural transformation and/or transduction of the DNA into non-resistant bacteria. The review introduces these topics and processes fully (along with their environmental implications), and describes five common wastewater treatments, along with their effects on antibiotic resistant bacteria and antibiotic resistance genes.

Potential impacts of disinfection processes on elimination and deactivation of antibiotic resistance genes during water and wastewater treatment
Michael C. Dodd
DOI: 10.1039/C2EM00006G

This HOT article is free to access for the next four weeks following a simple registration for individual users.

Scientists at Colorado State University, USA, have performed statistical analysis on publicly available data relating to in situ recovery uranium mining at a Wyoming mine to evaluate the efficacy of groundwater sweep remediation with reverse osmosis and H₂S (chemical reductant) treatment, and also to evaluate the time needed for site stabilization and the immobilization of target contaminants.

The team concluded that groundwater sweep remediation, combined with reverse osmosis treatment, provided a very good level of remediation. Additional chemical reductant treatment did not appear to improve the contaminant levels. With regards to the immobilization of target contaminants, the team believe that natural attenuation is likely to be the major factor in immobilizing residual concentrations, stopping them from moving outside the mined area. Additional studies are needed to collect more data to improve the understanding of the environmental impacts of the different remediation techniques.

Determination of contaminant levels and remediation efficacy in groundwater at a former in situ recovery uranium mine
Thomas Borch, Nicholas Roche and Thomas E. Johnson
DOI: 10.1039/C2EM30077J

This HOT article is free to access for the next four weeks following a simple registration for individual users.

The air above a small forest in the Campine region of Flanders, Belgium, was the subject of this decade-long study to understand ozone flux patterns.  The data, which was presented at the COST International Conference on Ozone, Climate Change and Forests in June last year, shows that rain had a significant effect on the deposition of O₃ in the tree canopy.

R. Ceulemans and colleagues found that during the day a dry canopy was the best sink for ozone, whereas at night the converse was true – a wet canopy showed the highest ozone deposition. Read the article for their speculations about non-stomatal deposition:

Insights into ozone deposition patterns from decade-long ozone flux measurements over a mixed temperate forest
J. Neirynck ,  B. Gielen ,  I. A. Janssens and R. Ceulemans
DOI: 10.1039/C2EM10937A

This article is part of the collection: Ozone

This HOT article is free to access for the next four weeks following a simple registration for individual users.

Although the use of the pesticide DDT has been banned in many countries since the 1970’s, the infamous organochlorine molecule is stubbornly persistent and can remain in soil for up to 30 years.  Earthworms have shown potential in removing organic pollutants from soil, and this study investigates the possibility of earthworms degrading DDT.

Fang-bai Li and colleagues from South China Agricultural University and Guangdong Institute of Eco-Environmental and Soil Sciences found two earthworm species, E. foetida and A. robustus E. Perrier, significantly enhanced the degradation of DDT to its metabolites DDD, DDE and DDMU and explored the mechanism of bioremediation.

Enhancement effect of two ecological earthworm species (Eisenia foetida and Amynthas robustus E. Perrier) on removal and degradation processes of soil DDT
Zhong Lin, Xiao-min Li, Yong-tao Li, De-yin Huang, Jun Dong and Fang-bai Li
DOI: 10.1039/C2EM30160A

This HOT article is free to access for the next four weeks following a simple registration for individual users.

The first HOT paper this week comes from Yuefeng Xie and colleagues at The Pennsylvania State University. They investigated the effect that treatment at watewater treatment plants (WWTPs) had on disinfection by-product (DBP) precursors. Eight different WWTPs were studied, and an additional plant that carries out two biological treatment processes was also investigated as a comparative study. The level of DBP precursors was established in the wastewater of each WWTP, and this was then compared to the levels after the processing had occurred. Amongst other results, they found that WWTPs that removed the most organic matter and accomplished better nitrification resulted in lower disinfection by-product formation potentials in the effluent. They state the study can be used by water and wastewater professionals to ‘better control wastewater-derived DBPs in downstream potable water supplies’.

Disinfection by-product formation potentials in wastewater effluents and their reductions in a wastewater treatment plant
Hao L. Tang, Yen-Chih Chen, John M. Regan and Yuefeng F. Xie
DOI: 10.1039/C2EM00015F

The second HOT paper comes from Tomei Gianfranco and co-workers at the University of Rome. They measured blood benzene and two urinary acid levels in traffic policemen, police drivers and roadmen. Benzene exposure was higher for urban workers than the general population and comparable in non-smoker traffic policemen and police drivers, and was increased in (non-smoker) urban workers when compared to rural workers. There was significant correlation in the levels of airborne benzene and blood benzene in non-smoker urban workers.

Environmental and biological monitoring of benzene in traffic policemen, police drivers and rural outdoor male workers
Ciarrocca Manuela, Tomei Francesco, Caciari Tiziana, Capozzella Assunta, Scimitto Lara, Nardone Nadia, Andreozzi Giorgia, Scala Barbara, Fiaschetti Maria, Cetica Carlotta, Di Giorgio Valeria, Schifano Maria Pia, Tomei Gianfranco and Sancini Angela
DOI: 10.1039/C2EM30120B

Both these papers are free to access for 4 weeks following a simple registration for individual users.

The first HOT article this week comes from Kevin Jones and colleagues at Lancaster University, who have developed a novel passive sampler using diffusive gradients in thin films (DGT) for organics in the aquatic environment. The sampler can measure quantitatively without field calibration.

The team indicate that the sampler could be used to investigate bioavailability and interactions of organic compounds (including pharmaceutical antibiotics) in soils and sediments.

A novel passive water sampler for in situ sampling of antibiotics
Chang-Er Chen, Hao Zhang and Kevin C. Jones
DOI: 10.1039/C2EM30091E

The second HOT article comes from Steven Hughes and colleagues, who investigated the recovery of sulfate saturated soils in the Plynlimon catchments in mid-Wales, following the reduction between the 1980s and 2011 in atmospheric S inputs.

The team investigated sulfate adsorption and desorption isotherms of stagnopodzol, brown podzolic soil, gleyed podzol and stagnohumic gley B-horizon soils from soil samples collected from sites in the Plynlimon catchments in the 1980s. Additionally, samples collected  in 2002 and from 2010 to 2011 from selected sites that were revisited were also analysed for comparison. Some of the soil samples from 2002 were further investigated to study the effects of increasing concentrations of dissolved organic carbon on sulfate adsorption.

Recovery of sulfate saturated soils in the Plynlimon catchments, mid-Wales following reductions in atmospheric S inputs from the 1980s to 2011
Steven Hughes, Brian Reynolds, David A. Norris, Sarah A. Brittain, Ashlee L. Dere, Clive Woods, Linda K. Armstrong, Sarah A. Harman and Heather D. Wickham
DOI: 10.1039/C2EM30070B

Both these papers are free to access for 4 weeks following a simple registration for individual users.

Two new HOT articles for you this week – the first comes from Lynda Webster and colleagues at Marine Scotland Science and the University of Brighton. They have investigated the fate of polycyclic aromatic hydrocarbons (PAHs) released from an aluminium smelter (from 1907 to 2000) into Loch Leven in Scotland. Using a monitoring programme that ran from 2004 to 2008, they found no evidence of recovery of PAH levels, which they predict may be due to mixing of the sediments in the basins and persistence of the hydrocarbons. In the upper basin of the loch, they found that the levels of all the PAHs investigated (apart from naphthalene) were above the Effects Range Low values, indicating there is a risk of chronic effects to marine life in the loch.

Long-term fate of polycyclic aromatic hydrocarbons (PAH) in sediments from Loch Leven after closure of an aluminium smelter
A. D. McIntosh, R. J. Fryer, L. Webster and A. B. Cundy
DOI: 10.1039/C2EM11006G

The second comes from Christopher Faßbender and colleagues at the University of Heidelberg and RWTH Aachen University. In their paper, they introduce Gene-TEQs – genotoxicity equivalent factors that can be used to directly compare environmental samples from different studies. Three directly acting and three indirectly acting genotoxic compounds were investigated for their cytotoxic and genotoxic concentration-response profiles. One of the tested compounds was selected as the reference compound, and the effects of other substances were calculated as percentages of the maximum reference compound’s effect, allowing relative Gene-TEQs to be provided. The method was also used to compare the effects of sediment samples from the upper Danube River in the same way. The group predict that the Gene-TEQ could also be used for comparing in vitro and in vivo data, increasing our understanding of the bioavailability of pollutants.

Gene-TEQ—a standardized comparative assessment of effects in the comet assay using genotoxicity equivalents
Christopher Faßbender, Thomas Braunbeck and Steffen H. Keiter
DOI: 10.1039/C2EM10947F

Both these papers are free to access for 4 weeks following a simple registration for individual users.