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.