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.     

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.     

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.     

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.     

Influence de la surface du tapis cellulaire dans la numeration des virus selon 2 techniques comparees : Plages et N.P.P. utilisant au moins 40 inoculums par dilution

For counting viruses, the plaque method and the M.P.N. method with at least 40 inoculum are both used with the same success. The precision of the results is quite equivalent for the two methods with the same volume inoculated whatever the total surface of KB cells.     

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.     

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.     

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.     

Concentrations en plomb du plancton de la Mer Ligure (Mediterrannee Nord-Occidentale)

Plankton samples were collected from different parts of the Ligurian Sea during 1980 and 1983. Lead, but also cadmium, copper and zinc have been determined in these samples. The results indicate that nearshore samples display significantly higher lead concentrations (7.8 μg g^?1) than offshore samples (1.9 μg g^?1).