Influence de la pollution sur divers parametres electriques de l'atmosphere et notamment sur le champ electrique terrestre

We have shown, on the site of LACQ, the modification of atmospheric electric parameters in connection with the fall-outs of polluants for various meteorological conditions. For some of these conditions, it seems possible to predict pollution by plume localization and SO₂ detection on the ground.     

Etude de l'accumulation du cadmium par une bacterie marine en fonction des conditions de cultures

The influence of different cultural conditions (temperature, salinity, pH, organic matter and cadmium concentration, presence of sulfhydryl groups) on the accumulation of cadmium by a Cd resistent marine bacterium was investigated. The results showed that each of these parameters modify to a certain extent both biomass production and cadmium accumulation. This work emphasizes the need for a higher standardization of toxicity tests to ensure a better reliability of results.     

Etude comparee de la resistance de trois souches virales en eau de mer et en eau de riviere

The authors made a comparative study of the resistance of three strains of virus, Sabin poliovirus I, Mahoney poliovirus I and réovirus I, in sea-water and in river water, “in vitro” and “in situ” in dialysis bags. The results show the preponderant role of the incubation temperature and the exchanges existing between bags on the resistance of the viral strains. The role of these different factors is discussed.     

Etude des variations des populations de coliphages et de bacteries fecales en eau de mer

The viral contamination of sea-water at different depths and in the sediments in the area near the discharge of treated domestic sewage, was investigated. The isolation frequency of viral particles was low: on 19 samples of sea-water, 4 are positive and on 6 samples of sediment, 1 is positive. Viral concentrations were not substantial: they varied from 2,9 to 5,9 Most Probable Number Cytopathic Unit (M.P.N.C.U.) in 500 ml of sea-water or in 500 g of sediment. No homogeneous distribution of viral particles in sea-water was observed.     

L'utilisation de souches de micro-organismes de collection pour l'etude de la biodegradabilite des pesticides

Use of Microbial strains from collection in the study of pesticide biodegradability. 5 different herbicides and 1 metabolite of herbicide were subjected to biodegradation by different microbial strains and simultaneously by soil suspensions.To take account of possible co-metabolisme a supplementary source of carbon was added in the culture media. Results were discussed.     

Seasonal dependence of the oxidation capacity of the city of Santiago de Chile

The oxidation capacity of the highly polluted urban area of Santiago de Chile has been evaluated during a winter measurement campaign from May 25 to June 07, 2005, with the results compared and contrasted with those previously evaluated during a summer campaign from March 8 to 20, 2005. The OH radical budget was evaluated in both campaigns employing a simple quasi-photostationary state model (PSS) constrained with simultaneous measurements of HONO, HCHO, O₃, NO, NO₂, j(O¹D), j(NO₂), 13 alkenes and meteorological parameters. In addition, a zero dimensional photochemical box model based on the Master Chemical Mechanism (MCMv3.1) has been used for the analysis of the radical budgets and concentrations of OH, HO₂ and RO₂. Besides the above parameters, the MCM model has been constrained by the measured CO and other volatile organic compounds (VOCs) including alkanes and aromatics. Total production and destruction rates of OH and HO₂ in winter are about two times lower than that during summer. Simulated OH levels by both PSS and MCM models are similar during the daytime for both winter and summer indicating that the primary OH sources and sinks included in the simple PSS model are predominant. On a 24 h basis, HONO photolysis was shown to be the most important primary OH radical source comprising 81% and 52% of the OH initiation rate during winter and summer, respectively followed by alkene ozonolysis (12.5% and 29%), photolysis of HCHO (6.1% and 15%), and photolysis of O₃ (<1% and 4%), respectively. During both winter and summer, there was a balance between the OH secondary production (HO₂ + NO) and destruction (OH + VOCs) showing that initiation sources of RO₂ and HO₂ are no net OH initiation sources. This result was found to be fulfilled also for all other studies investigated. Seasonal impacts on the radical budgets are also discussed.     

Photochimie et environnement X- evaluation de la toxicite des produits de phototransformation de l'hydroquinone et des chlorophenols en milieu aqueux

A test of acute toxicity on DAPHNIA MAGNA is suggested to evaluate the efficiency of the phototransformation as a route of abiotic degradation. This test is recommended for compounds phototransformed into a complex mixture of products. Hydroquinone, 2-chloro-, 4-chloro-, 2,4-dichloro-, 2,4,6-trichloro- and pentachlorophenol were studied as examples. In any case the phototransformation is an useful depollution technique on condition the irradiation to be completed as far as the ultimate step of phototransformation.     

Conditions d'acceptation ou de rejet des valeurs obtenues apres denombrement de virus ou bacteries sur milieux de culture solides

Enumeration of viruses or bacteria on solid culture media does not ever give statistically acceptable results. When counting is impossible, we must do it again. For accepting or not the counting, the authors established some probability Tables (95% and 99%) according to microbial densities.     

Utilisation de techniques spectroscopiques pour l'etude de particules atmospheriques produites par des sources ponctuelles

Secondary Ion Mass Spectrometry (SIMS) is used to study atmospheric particle production by an industrial source responsible for the acid precipitation phenomenon. A sampling network has been put in place at Rouyn-Noranda to collect local aerosols with cascade impactors. Aerosols have also been collected in the plume of the most important source of SO₂ in Quebec. Instruments have been developed and constructed to collect these samples. A multi-analytical technique approach permits physico-chemical analysis of individual aerosol: SIMS using a 1 μm ion probe and Scanning Electron Microscopy (SEM) coupled with an X-ray analyzer (EDAX) perform micro-analysis, whereas bulk analysis is provided by a SIMS using a 200 μm Argon ion probe. Devices used for localization of microparticles permit manipulation of samples without damaging them and allow analysis of individual aerosol particles with a SIMS after analysis with SEM-EDAX. Laser Microprobe Mass Analysis (LAMMA) is also possible. Negative and positive mass spectra, obtained with a SIMS-Ar⁺, have been analyzed with a multivariate statistical technique. Relations between these mass spectra and specific conditions existing during sampling have been determined.     

Microméthode de dosage simultané de l'alcool isopropylique et de son métabolite l'acétone

Simultaneous determination of Isopropyl Alcohol and Acetone prove to be necessary in cases of poisoning by this widely used alcohol. An aluminum capsule containing a sample of blood to be analyzed is introduced into a gas chromatograph equipped with a flameionization detector and a Carbowax 20 M - Chromosorb WHP column. Use of a small blood sample (0.50 μl) and high sensitivity of the method make it a selected procedure in the clinical diagosis of poisoning by Isopropyl Alcohol.     

Surveillance programme on dioxin levels in soils in the Campo de Gibraltar (southwest Spain)

The results of an epidemiologic study undertaken by the Spanish Council for Scientific Research (CSIC) after commission by the Spanish Parliament indicated that Huelva and Cádiz were the zones in Andalusia with elevated risk of cancer. A 6% (women) and 10% (men) cancer mortality excess was observed with respect to the other six Andalusian provinces. Huelva and Cádiz are located in the south-western region of Spain, and are characterized by a strong industrial activity concentrated in several industrial sites. This situation led to two environmental surveys in these areas, in which the presence of dioxins was studied among other parameters. A PCDD/F assessment in soils of the Campo de Gibraltar (Cádiz) was carried out from June 2003 to June 2004. A total of 20 samples were collected in this study divided in two sampling campaigns. The first 10 samples were taken in locations affected by high industrial activity zones as well as in landfills (hotspots). The rest of the samples were collected in areas that were not expected to be contaminated, such as agricultural zones and forests. I-TEQ values of the samples ranged from 0.26 to 15.08 ng/kg dm. In all, 85% of the samples were below the limit of 5 ng I-TEQ/kg I-TEQ concentrations of three samples only surpassed this limit. These zones corresponded to a landfill, a quarry used for dumping chemical product containers and a sample from the sewage system of the industrial site. These sites were used neither for agricultural nor for public purposes.     

Using chemical models for evaluating the geochemical confinement capacity of a geological barrier application to the Centre de Stockage de l'Aube (France)

The feasibility of using a chemical reaction-based approach for evaluating and modelling the role of adsorption reactions in determining the geochernical confinement capacity of natural geological barriers is being studied as part of an on-going R & D programme. The confined superficial aquifer underlying the Centre de Stockage de l'Aube facility, a geological barrier for this site, has been used as a case study with the following aims. First, development of a site characterisation protocol and demonstration of its use to determine the principal geochemical characteristics of aquifer materials using batch experiments and to represent the information obtained in terms of a chemical model. The experimental results obtained for Ni²⁺ partitioning as a function of total Ni, pH, total Ca and total solid can be satisfactorily represented in terms of reactions with an ion exchange site and a single amphoteric surface hydroxyl site with ferrihydrite reaction constants. A second objective is the incorporation of the reactions in a coupled geochemistry/transport code, and to verify the applicability of the coupled code predictions for Ni²⁺ mass transfer by comparison with the results obtained during column tracer experiments. The breakthrough curve and equilibrium solid phase Ni loading, predicted by a one-dimensional coupled model for a column tracer experiment, agree closely with observed data.Additional studies are underway to reduce model conditionality, to extend the adsorption model to other analogue cations and anions, to incorporate the effect of natural organic matter and to take into consideration precipitation/dissolution of amorphous Fe surface phases.     

Predominance of soot-mode ultrafine particles in Santiago de Chile: Possible sources

A monitoring campaign was performed in Santiago de Chile during a winter month of 2003 and 2006 (July) using several instruments to measure the size distribution of particulate material. For the first time, the size distribution of ultrafine particles was measured in Santiago, and an estimation of its sources was done by analyzing its temporal variation. The study was performed in three sites; one of them is located in the eastern part of Santiago, a sector with low particle concentration and about 100 m from a busy street. The other site is located in the western part, which is the sector that has the highest concentration of fine and coarse particle matter during winter, also located far from a street. The third site is located within 5 m from the busiest street in Santiago. In all stations traffic is the dominating source for fine and ultrafine particles and the size distribution is peaked towards 60–100 nm (soot mode). Only in the site near the street, it is possible to see a clear peak towards smaller sizes (10–30 nm). The size distribution measurements presented here indicate that aerosol dynamics play a more important role for the Santiago case as compared to cleaner cities in Europe. Changes in the particle size during different hours of the day reflect both variations in meteorological mixing conditions as well as effects of aerosol dynamic processes such as coagulation, condensation and dry deposition. A relative increase in the number of the larger ultrafine particles (d ≥ 70 nm), as compared to the number of smaller particles (d < 70 nm) correlated with wind speed is an indication of pollution transport with aged particles from other parts of the city.     

Ambient air quality and asthma cases in Niğde, Turkey

Urban air quality is one of the key factors affecting human health. Turkey has transformed itself into an urban society over the last 30 years. At the same time, air pollution has become a serious impairment to health in many urban areas in the country. This is due to many reasons. In this study, a nonparametric evaluation was conducted of health effects that are triggered by urban air pollution. Ni?de, the city which is the administrative centre of Nigde province was chosen of the effects of air pollution since, like many central Turkish cities, it is situated on a valley where atmospheric inversion occurs. In this paper, the relationship between ambient urban air quality, namely PM₁₀ and sulphur dioxide (SO₂), and human health, specifically asthma, during the winter season is examined. Air pollution data and asthma cases from 2006 to 2010 are covered in this study. The results of our study indicate that total asthma cases reported in Nigde between 2008 and 2010 were highly dependent on ambient SO₂ concentration. More asthma cases were recorded when 30 μg?m^?3 or higher SO₂ was present in the ambient air than those recorded under cleaner ambient air conditions. Moreover, it was determined that in Nigde in 2010, asthma cases reported in males aged between 45 and 64 were closely correlated with ambient SO₂ (α?=?0.05).     

Thermogravimetric desorption and de novo tests I: method development and validation

Thermogravimetric analysis (TGA) has been combined with evolved gas analysis (EGA) with the purpose of simulating the thermal behaviour of filter dust samples under inert (desorption) and de novo test oxidising conditions. Emphasis is on studying de novo formation of dioxins, surrogates and precursors arising from filter dust derived from thermal processes, such as municipal solid waste incineration and metallurgy. A new method is tested for sampling and analysing dioxin surrogates and precursors in the TGA effluent, which are collected on sampling tubes; the adsorbed compounds are eventually desorbed and quantified by TD-GC-MS. The major sources of error and losses are considered, including potential sorbent artefacts, possible breakthrough of volatiles through sampling tubes, or eventual losses of semi-volatiles due to their incomplete desorption or re-condensation inside the TG Analyser. The method is optimised and validated for di- to hexa-chlorinated benzenes in a range of 10-1000ppb with average recovery exceeding 85%. The results are compared with data obtained in similar studies, performed by other research groups. As a result, the method provides the means for simulating de novo synthesis of dioxins in fly-ash and facilitates reliable and easy estimation of de novo activity, comparable with results of other studies, in combination with wide flexibility of testing conditions.