Evolution of plant protection active substances in Europe: the disappearance of chemicals in favour of biocontrol agents

Environmental Science and Pollution Research - With the entry into force of Regulation EC 1107/2009 and the important cut-off of a number of existing active substances from before 2011, which was...     

Long term measurement and source apportionment of non-methane hydrocarbons in three French rural areas

Since 1990, the MERA (MEsure des Retombées Atmosphériques, French acronym for background air pollution monitoring) network has been focused on the composition of the lower troposphere within the EMEP program. In particular, 46 non-methane hydrocarbon (NMHC) concentrations have been measured between 1997 and 2006 at three MERA sites.The analysis of temporal trends using Mann-Kendall and Sen methods showed a global decrease of anthropogenic NMHC. These results are in accordance with the trends observed on other sites in Europe and follow the decrease of VOCs emissions in France. Nevertheless the concentrations of long-life species like ethane seem to remain steady showing the growing influence of most distant source areas. In addition isoprene concentrations are typically higher in France than in other countries in Europe and slightly rising. Data analysis was performed using positive matrix factorization (PMF). Five similar PMF factors are identified as aged profiles for the three sites. The examination of factor contributions made it possible to determine a hierarchy in source influence. A higher contribution of evaporative sources was observed on the southern site while residential heating was the main factor for the other two. This work was completed by a clustering analysis (K-means) of air mass trajectories in order to apportion source contribution depending on air mass origins. Two main groups have been distinguished: (1) older and diluted air masses from an oceanic origin; and (2) anthropogenic and closer sources indicating continental influence.     

Development and validation of a thermally regulated atmospheric simulation chamber (THALAMOS): A versatile tool to simulate atmospheric processes

Atmospheric simulation chambers, are unique tools for investigating atmospheric processes in the gas and heterogeneous phases. They can provide a controlled yet realistic environment that simulates atmospheric conditions. In the current study, a Teflon atmospheric simulation chamber of 600 L, named THALAMOS (thermally regulated atmospheric simulation chamber) has been developed and cross-validated. THALAMOS can be operated over the temperature range 233 to 373 K under both static and flow conditions. It is equipped with state of the art instrumentation (selective ion flow tube mass spectrometry (SIFT-MS), long path Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), various analyzers) for the in-line monitoring of both reactants and products. THALAMOS was validated by measuring the rate coefficients of well documented reactions, i.e. the reaction of ethanol with OH radicals and the reaction of dichloromethane with Cl atoms, in a wide temperature range. Two different detection techniques were used in parallel, FTIR and SIFT-MS, to internally cross-validate the obtained results. The measured rate coefficients are in excellent agreement, both between each other and with the literature recommended values. Furthermore, the gas phase oxidation of toluene by Cl atoms (kinetics and product yields) was studied in the temperature range of 253 to 333 K. To the best of our knowledge, THALAMOS is a unique facility on national level and among a few smog chambers internationally that can be operated in such a wide temperature range providing the scientific community with a versatile tool to simulate both outdoor and indoor physicochemical processes.     

USABILITY ASSESSMENTS FOR HYDROLOGIC FORECASTING DSS1

ABSTRACT: Usability assessments were used to obtain feedback on the development of a flood forecasting decision support system. The feedback was used to guide design of system functionality, interface, training, implementation, and operations. The usability process was user focused and was dependent upon implementation of a prototype system in an operational setting. This paper describes concepts and methods applied to collect reflective and objective data on DSS components and information outputs. The general structure of the usability assessments is discussed and results of assessments are summarized.     

Preliminary evidence of the role of hydrogen peroxide in the degradation of benzo[a]pyrene by a non-white rot fungus Fusarium solani

In order to study the enzymatic mechanisms involved in the successive steps of BaP degradation by a Deuteromycete fungus Fusarium solani, we developed an indirect approach by using inhibitors of enzymes. We used either specific inhibitors of peroxidases (i.e. salicylhydroxamic acid) and of cytochrome P-450 (i.e. piperonyl butoxyde) or inhibitors of both enzymes (i.e. potassium cyanide). Surprisingly, no expected decrease of BaP degradation was observed with most inhibitors tested. On the contrary, more BaP was degraded. Only butylated hydroxytoluene, which acts as a free radical scavenger, inhibited BaP degradation. The inhibition of these enzymes, which use H(2)O(2) as a cosubstrate, might have resulted in an increase of hydrogen peroxide availability in the fungal cultures. This enhancement could induce formation of reactive oxygen species (ROS) which might be the agents that initiate benzo[a]pyrene oxidation. This study proposed a hypothetic alternative metabolic pathway involved in PAH metabolism by Fusarium solani.     

Effects of Exposure Conditions on Antioxidant Depletion,Tensile Strength,and Creep Modulus of Corrugated HDPE Pipes Made With or Without Recycled Resins

Journal of Polymers and the Environment - The service lifetime of corrugated high-density polyethylene (HDPE) pipes used in transportation infrastructure applications has been the subject of...