A method to determine the effect of mineral dust aerosols on air quality

Natural mineral dust storms (DS) from the Arabo-African region blow over the Mediterranean, reach Israel, and add to the anthropogenic particulate pollution. The effects of mineral dust on air quality in Israel were investigated using only PM10 and PM2.5 automatic measurements. The method does not require any other inputs such as satellite observations, model back-trajectories, dust forecast models, or mineralogical analyses. The method employs an automatic algorithm with three thresholds: the half-hour PM10 average must be above 100, this level is maintained for at least 3 h, and the maximum concentration recorded is above 180 μg m^?3. The algorithm was designed for Israel, but can be adapted for other locations.The contribution of DS caused PM10 values to exceed the Israeli annual standard of 60 μg m^?3 year^?1 in 6 of the 12 years examined. The DS contribution to PM10 annual average ranged from 9.4% to 29.5%. The level recommended by WHO, 20 μg m^?3 year^?1, was exceeded every year even without the DS contribution. The number of days in which the daily Israeli standard (150 μg m^?3) was exceeded during the 12 years was 6–20 days per year. The number of days in which the daily standard was exceeded shows an increasing trend of 7 days per decade.PM2.5 in Israel is in the range 40–56% of PM10. PM2.5 values were over the recommended standard with and without DS. The contribution of DS to annual average of PM2.5 ranged from 3.6% to 19.1%.The automatic algorithm was calibrated with a list of Dust Storms identified by visual means supported by mineralogical analysis. Mineralogical analyses of single particles were performed using Environmental Scanning Electron Microscope (ESEM). Two representative samples are given. The main difference is that the particles of the Saudi-Arabian storm had much more palygorskite, while the North-African storm had more sea-salt and organic particles. The mineral composition differences indicate that analysis can differentiate between sources.     

Responses of juvenile European flounder (Platichthys flesus) to multistress in the Vilaine estuary, during a 6-month survey

Physiological and genetic responses of age 0+ Platichthys flesus were investigated in the eutrophicated and moderately contaminated Vilaine estuary, during a 6-month survey. The main objective of this study was to explore the biological responses of fishes during their juvenile period in an estuarine system in order to detect a possible selective pressure induced by the environmental stress. Our results showed a general convergence in physiological responses along the survey: an increase in genotoxicity was associated with an increase in mRNA expression of ATPase and betaine homocysteine methyltransferase. These results could suggest an increase of cellular damage, energetic request, and detoxification rate related to the growing exposure time to stress. Considering the aging of the cohort, the genetic characteristics of the Vilaine flounder cohort came closer to the one observed in a highly stressed system, the Seine estuary, suggesting a potential selective pressure mainly induced by the chemical stress.     

Aerosol physical,chemical and optical properties during the Rocky Mountain Airborne Nitrogen and Sulfur study

During the Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study, conducted during the spring and summer of 2006, a suite of instruments located near the eastern boundary of Rocky Mountain National Park (RMNP) measured aerosol physical, chemical and optical properties. Three instruments, a differential mobility particle sizer (DMPS), an optical particle counter (OPC), and an aerodynamic particle sizer (APS), measured aerosol size distributions. Aerosols were sampled by an Interagency Monitoring of Protected Visual Environments (IMPROVE) sampler and a URG denuder/filter-pack system for compositional analysis. An Optec integrating nephelometer measured aerosol light scattering. The spring time period had lower aerosol concentrations, with an average volume concentration of 2.2 ± 2.6 μm³ cm^?3 compared to 6.5 ± 3.9 μm³ cm^?3 in the summer. During the spring, soil was the single largest constituent of PM_2.5 mass, accounting for 32%. During the summer, organic carbon accounted for 60% of the PM_2.5 mass. Sulfates and nitrates had higher fractional contributions in the spring than the summer. Variability in aerosol number and volume concentrations and in composition was greater in the spring than in the summer, reflecting differing meteorological conditions. Aerosol scattering coefficients (b_sp) measured by the nephelometer compared well with those calculated from Mie theory using size distributions, composition data and modeled RH dependent water contents.     

Biliary PAH metabolites, EROD activity and DNA damage in dab (Limanda limanda) from Seine Estuary (France)

The Seine Estuary is well known to be widely contaminated by organic pollutants and especially by polycyclic aromatic hydrocarbons (PAHs). Fish are known to metabolize PAHs, leading to different toxic effects at both cellular and sub-cellular levels. In this work, we studied the relationships between the 7-ethoxyresorufin-O-deethylase (EROD) activity in the liver, the level of DNA strand breaks in blood cells and the concentration of PAH metabolites in the bile of the sentinel flatfish species Limanda limanda. Muscle and liver samples were analysed for parent PAH levels. Female and male dabs of two size classes (juveniles and adults) were collected by trawling in two sites with different degrees of pollution during March and September 2005 and 2006. Significant effects of sex, age, site and season were demonstrated on EROD activity and the level of strand breaks. Parent PAH concentrations in dabs did not allow discriminating of the two sampling sites. However, for PAH metabolites, significant differences were observed with sites and seasons. Dabs collected at the mouth of the estuary appeared to be the most impacted when looking at the results obtained with the three selected markers. The significant correlations observed between the level of PAH metabolites and the level of DNA lesions showed the importance of a combined analysis of chemical and biochemical markers to correctly assess the contribution of chemical contamination to the toxic effects measured in situ in fish.     

Microbiota and epigenetics: promising therapeutic approaches?

Environmental Science and Pollution Research - The direct/indirect responsibility of the gut microbiome in disease induction in and outside the digestive tract is well studied. These results are...     

How to get there? Assessing motorists' flash flood risk perception on daily itineraries

Flash floods are characterized by their suddenness, fast and violent movement, rarity, small scale but high level of damage. They are particularly difficult to forecast accurately and there is little lead time for warning. This makes motorists especially vulnerable. Assuming that these flash flood hazard specificities may be the significant factors leading to difficulties for drivers to perceive danger, we used cognitive mapping combined with GIS data processing to assess motorists' flash flood risk perception on their daily itineraries. The analysis of 200 mental maps collected allows planners to have maps highlighting dangerous areas where risk perception is weak and to identify reasons for this.     

‘Natural’ disaster? A retrospect into the causes of the late-2004 typhoon disaster in Eastern Luzon,Philippines

Between 14 November and 4 December 2004, four successive tropical depressions and typhoons lashed the Eastern coast of Luzon in the Philippines. Heavy rainfall triggered massive landslides and devastating flash floods, which brought tremendous damage and killed more than 1600 people. Immediately after the disaster, there was a media and political consensus to incrimate ‘extraordinary’ natural phenomena and widespread deforestation as responsible for the catastrophe. We argue that the tragedy that befell the municipalities of General Nakar, Infanta and Real, among other devastated areas, is enmeshed in a deeper tangle of causal factors that are political, socio-economic and demographic in nature. These factors include unmanaged population growth, difficult access to land and resources, corruption within the government, and power of the elite.     

A multiresidue method for the analysis of phenols and nitrophenols in the atmosphere

A method using GC-MS and derivatization with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) was developed for the analysis of 20 phenolic compounds in atmospheric samples (gas and particles). Air sampling was carried out using a Hi-Vol sampler with glass fibre filter and XAD-2 resin at a flow rate of 60 m(3) h(-1). The particle and gas phases were collected separately over a period of 4 h. Samples were Soxhlet extracted, evaporated to dryness under nitrogen and refilled with acetonitrile. 100 microl of these extracts were derivatized with 100 microl of MTBSTFA at 80 degrees C for 1 h under strong stirring. Phenolic compounds were injected into a GC-MS in splitless mode and quantified as their TBDMS derivatives in the SIM mode. Mass spectral analysis of the derivatives of the 20 compounds studied indicates that the spectra are highly specific showing an ion at [M - 57]+ which is useful for structure confirmation or analysis at low levels using selected ion monitoring. Quantification limits varied between 5 microg l(-1) and 10 microg l(-1) which correspond to 20 pg m(-3) and 40 pg m(-3) for 250 m(3) of air sampled. This method was successfully applied to atmospheric samples.