Impatti, adattamento e vulnerabilita Le cause e le responsabilita dei cambiamenti climatici sono state trattate sul numero di ottobre della rivista Cda. Approfondiamo l’argomento presentando il documento: “Cambiamenti climatici 2007: impatti, adattamento e vulnerabilita” votato ad aprile 2007 dal secondo gruppo di lavoro del Comitato Intergovernativo sui Cambiamenti Climatici (Intergovernmental Panel on Climate Change). Si tratta del secondo di tre documenti che compongono il quarto rapporto sui cambiamenti climatici.

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Climate Change 2007: Impacts, Adaptation and Vulnerability.

Ozonation of drinking water: part I. Oxidation kinetics and product formation.

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Water Analysis: Emerging Contaminants and Current Issues

This study investigates the oxidation of pharmaceuticals during conventional ozonation and advanced oxidation processes (AOPs) applied in drinking water treatment. In a first step, second-order rate constants for the reactions of selected pharmaceuticals with ozone (k(O3)) and OH radicals (k(OH)) were determined in bench-scale experiments (in brackets apparent k(O3) at pH 7 and T = 20 degrees C): bezafibrate (590 +/- 50 M(-1) s(-1)), carbamazepine (approximately 3 x 10(5) M(-1) s(-1)), diazepam (0.75 +/- 0.15 M(-1) s(-1)), diclofenac (approximately 1 x 10(6) M(-1) s(-1)), 17alpha-ethinylestradiol (approximately 3 x 10(6) M(-1) s(-1)), ibuprofen (9.6 +/- 1.0 M(-1) s(-1)), iopromide ( 5 x 10(4) M(-1) s(-1), indicating that these compounds are completely transformed during ozonation processes. Values for k(OH) ranged from 3.3 to 9.8 x 10(9) M(-1) s(-1). Compared to other important micropollutants such as MTBE and atrazine, the selected pharmaceuticals reacted about two to three times faster with OH radicals. In the second part of the study, oxidation kinetics of the selected pharmaceuticals were investigated in ozonation experiments performed in different natural waters. It could be shown that the second-order rate constants determined in pure aqueous solution could be applied to predict the behavior of pharmaceuticals dissolved in natural waters. Overall it can be concluded that ozonation and AOPs are promising processes for an efficient removal of pharmaceuticals in drinking waters.

Oxidation of pharmaceuticals during ozonation and advanced oxidation processes

http://files.aprendiendoquimica7.webnode.com.co/200000006-1247d13423/Limousin,%20G%20et%20al.%20Sorption%20Isotherms%20A%20review%20on%20Physical%20Bases,%20modeling%20and%20measurement.pdf

Sorption isotherms: A review on physical bases, modeling and measurement

13C assimilation as well as functional gene abundance and expression elucidate the biodegradation of glyphosate in a field experiment.

BACKGROUND
Analytical constraints complicate environmental monitoring campaigns of the herbicide glyphosate and its major degradation product aminomethylphosphonic acid (AMPA): their strong sorption to soil minerals require harsh extraction conditions. Coextracted matrix compounds impair downstream analysis and must be removed before analysis.


RESULTS
A new extraction method combined with subsequent capillary electrophoresis-mass spectrometry for derivatization-free analysis of glyphosate and AMPA in soil and sediment was developed and applied to a suite of environmental samples. It was compared to three extraction methods from literature. We show that no extraction medium reached 100% recovery. The new phosphate-supported alkaline extraction method revealed 1) high recoveries of 70-90% for soils and aquatic sediments, 2) limits of detections below 20 μg kg-1 , and 3) a high robustness, because impairing matrix components (trivalent cations and humic acids) were precipitated prior to the analysis. Soil and sediment samples collected around Tübingen, Germany, revealed maximum glyphosate and AMPA residues of 80 and 2100 μg kg-1 , respectively, with residues observed along a core of lake sediments. Glyphosate and/or AMPA were found in 40% of arable soils and 57% of aquatic sediment samples.


CONCLUSION
In this work, we discuss soil parameters that influence (de)sorption and thus extraction. From our results we conclude that residues of glyphosate in environmental samples are easily underestimated. With its possible high throughput, the method presented here can resolve current limitations in monitoring campaigns of glyphosate by addressing soil and aquatic sediment samples with critical sorption characteristics. This article is protected by copyright. All rights reserved.

Phosphate addition enhances alkaline extraction of glyphosate from highly sorptive soils and aquatic sediments.

Powering biological nitrogen removal from the environment by geobatteries.

The consequences of urbanisation for Earth's biogeochemical cycles are largely unexplored. Copper (Cu) in urban soils is being accumulated mainly due to anthropogenic activities under rapid urbanisation. The increasing Cu concentrations may contribute to altering soil nitrogen (N) cycling in urban ecosystems through modulating denitrification processes. This research aims to identify how Cu impacts urban soil denitrification functions and denitrifier abundance. An urban park soil with a background total Cu concentration of 7.9μgg–1 was incubated anaerobically with different Cu amendments (10, 20, 40, 80 and 160μg Cu g–1 soil), similar to prevalent Cu contents in urban soils. We evaluated the soil denitrification functions using the acetylene (C2H2) inhibition method and assessed the denitrifier abundance by quantitative polymerase chain reaction (qPCR) analyses of denitrifying marker genes (nirK, nirS and nosZ). At the function level, we observed that both the potential soil denitrification activity and the N2O emission rate due to denitrification were significantly (P<0.05) inhibited by Cu; even the lowest Cu addition (10μg Cu g–1 soil) drastically affected the denitrification function. Moreover, Cu significantly (P<0.05) decreased the abundance of nirK and nirS genes at the additions of 160μg Cu g–1 soil and 40μg Cu g–1 soil, respectively, whereas it had no clear impact on nosZ gene copies. Further correlation analyses revealed that the potential denitrification activity was positively correlated to the copy numbers of nirK and nirS genes, but it was not correlated to nosZ gene abundance. These findings indicate that Cu additions inhibited soil denitrification function and decreased denitrifier abundance in the investigated urban park soil. Our results suggest that Cu accumulation in urban soils, resulting from urbanisation, may generally influence denitrification in urban ecosystems.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/EC33D9546BAC61E7A91F0522A4104C6E/S1755691018000592a.pdf/div-class-title-increased-copper-levels-inhibit-denitrification-in-urban-soils-div.pdf

Increased copper levels inhibit denitrification in urban soils

Ground-based heat exchanger systems need to be evaluated in terms of potential effects on groundwater quality due to the risk of leakage of borehole heat exchanger fluids. They contain glycols or inorganic brines as major components, but typically also various additives. As the identity of these additives is proprietary information, the major objective of this study was to obtain an overview of the identities and properties of individual additive compounds used in borehole heat exchanger fluids. Leading companies in the production and distribution of these fluids were invited to participate in a confidential data survey. A wide variety of additive compounds were assembled, which can be grouped into ten chemical classes: triazoles, carboxylic acids/carbonates, phosphonates, alcohols, aldehydes, ethers borates, silicates, nitrates and hydroxides. Among these substances some are also used in other applications, e.g. aircraft de-icing fluids and engine antifreeze formulations, and are of potential concern for groundwater quality. Based on their abundance in the investigated borehole heat exchangers and their concerning environmental behaviour in the subsurface, benzotriazoles, tolyltriazoles and some carbonates were selected for further biodegradation experiments.

Stefan B. Haderlein

Papers

13C assimilation as well as functional gene abundance and expression elucidate the biodegradation of glyphosate in a field experiment.

Phosphate addition enhances alkaline extraction of glyphosate from highly sorptive soils and aquatic sediments.

Powering biological nitrogen removal from the environment by geobatteries.

Increased copper levels inhibit denitrification in urban soils

Groundwater pollution potential of additives used in borehole heat exchanger fluids