Caracterisation de la matiere organique dissoute presente dans les eaux en cours d'affinage: Influence des traitements appliques et du climatCharacterization of dissolved organic matter in surface waters through polishing treatment: Influence of applied treatments and climate

Dissolved organic matter in treated surface waters (clarified, possibly ozonized, then GAC-filtered, Fig. 1), is fractionated by ultrafiltration into five molecular classes with MW < 300, 300–1000, 1000–5000, 5000–10000 or > 10,000. Dissolved organic carbon (DOC), oxidizability by KMnO₄ in hot alkaline medium and u.v. absorbances at 240, 254, 280, 300 nm are measured. Fourteen series of samples, distributed on an annual biological cycle are analysed (Figs 2 and 3); multivariate statistical analyses are performed.

By PCA (principal component analysis), variations in water supplying the activated carbon units appear to depend for 47% on ozonation and temperature; but river flow rate and quantity of flocculant added are no longer responsible for such variations (Fig. 4). Three groups of water appear (Fig. 5), according to the applied ozone level (zero, medium, high); among the medium ozonized waters, the cold ones differ from temperate ones.

Ozonation diminishes molecular size of compounds (Table 1): three major classes with MW < 5000 are present in non- or medium-ozonized waters, but only two, with MW < 1000, remain in highly ozonized waters. This treatment destroys MW > 10,000 and even 1000–5000 ones and yields MW < 300 products; it also minimizes u.v. absorbances and oxidizability. Seasonal variations occur in DOC content of medium ozonized waters, with maxima values in winter or spring and minima in summer or autumn (Fig. 6): occurrence of MW < 300 compounds follows that of DOC, but the presence of 5000–10000 ones is minimal in winter.

Quality of GAC-filtered waters varies by 19% with temperature (Fig. 7); ozonation effects are minimized: only previously highly ozonized waters distinguished themselves from the others (Fig. 8). Waters, non or medium ozonized before GAC-filtration, are divided into cold, temperate and warm waters. One, two or three major classes of compounds with MW < 5000, remain in GAC-filtered waters, according to the ozone level applied previously. This filtration reduces DOC by 17%, decreases u.v. absorbances and oxidizability and gives water with the same 0.30 mg O₂ mg⁻¹ C ratio (Table 2): MW 1000–5000 class is much less oxidizable after ozonation-GAC filtration but, on the other hand, MW < 300 class appears rather less oxidizable without ozonation before biological filtration. DOC content in effluent follows that in influent (Fig. 9), but variations are less marked. Total efficiency of the filtration increases with temperature, but behaviour of compounds differs from one class to another: MW 300–1000 and 5000–10000 classes are the most affected; MW 1000–5000 is not really modified. Elimination of MW < 300 or 5000–10000 compounds depends on temperature and may be due to biological phenomena, a but that of 1000–5000 and > 10,000 classes, independent of this parameter, may be related to adsorption mechanisms.     

Les effets de la matiere organique dissoute d''une eau douce sur la croissance de l''algue selenastrum capricornutum

A l'aide d'expériences réalisées avec des milieux dans lesquels différentes concentrations de matière organique (MO) d'origine aquatique sont dissoutes dans un substrat synthétique (PAAP) et dans une eau naturelle (eau du réservoir Desaulniers, baie James, Québec) on a démontré que la croissance et le taux de photosynthése de l'algue Selenastrum capricornutum sont influencés par les propriétés de la MO et que celles-ci varient au cours des saisons. II apparaît que la MO servirait comme source d'éléments nutritifs aussi bien que comme agent stimulateur ou inhibiteur de processus physiologiques. Les fractions à poids moléculaires faibles seraient physiologiquement plus actives que celles à poids moléculaires plus élevés.

Experiments have been conducted on media in which various concentrations of organic matter (OM) taken from water were dissolved in a synthetical substrate (PAAP) and in a freshwater (water of Desaulniers reservoir, James Bay, Quebec). The results proved that the growth and the rate of photosynthesis alga Selenastrum capricornutum are influenced by the properties of OM and that these vary with the change of seasons. OM appears to serve as a source of nutrient elements as well as a stimulatory or inhibitory agent for physiological processes. The fractions of low molecular weight seem to be physiologically more active than those of higher molecular weight.     

Combinaison d'une cellule d'extraction liquide-liquide en continu et d'un couplage CG-SM en vue de l'analyse des pesticides dans les eaux

The occurrence of synthetic organic chemicals in drinking water supplies has prompted the European Economic Community to establish standards for pesticides. Currently, the limit on total pesticides is 500 ng l⁻¹ with no individual pesticide to exceed 100 ng l⁻¹. The variability of pesticides, both in concentration and composition, indicates that composite rather than grab samples are desirable for analysis of the water quality. Furthermore, the variability in composition makes a broad spectrum analysis preferable to individual compound analysis so that many compounds can be analysed simultaneously.Although composite broad spectrum samples are desirable from a collection point of view, the occurrence of many pesticides in one sample presents a problem for individual compound quantification and identification. For this reason, gas chromatography (GC) is used to separate the compounds and mass spectrometry (MS) is used to identify and quantify the compounds. Coupled GS-MS avoids interferences which may occur in GC by using a separate method (other than retention time or volume) to identify compounds.This research compared liquid-liquid extraction (LLE) in the batch and continuous mode. The LLE process is accomplished in a continuous mode by mixing the water and solvent in a coil, allowing the water and solvent to separate in a quiescent decantation cell, then recirculating the solvent by a separate distillation cell while the water goes to waste. Tap water was spiked with pesticides at 10, 50 and 100 ng l⁻¹. Extraction efficiency was compared at each of the three spiking concentrations. The extracts were analysed on GC-MS using a moving needle injection technique to enhance sensitivity. The identification and quantification of compounds were accomplished by MS using the fragmentometry technique which enhance sensitivity of the analysis.The results indicate that continuous LLE will recover an average of 75% (± 14%) of the pesticides in the 10–100 ng l⁻¹ range recoverable by batch LLE. There was no significant difference in recovery for structurally different pesticides (chlorinated, nitrogenous or phosphoric) as all fell in the 75 ± 14% range. Eighteen pesticides were identified and quantified by the GC-MS in a 25 min analysis.This demonstrates that the continuous LLE technique can be used to automate collection of composite samples if the reduction in extraction efficiency is taken into account. The continuous LLE can handle much larger volumes of water than the batch LLE. Composite samples can be continuously collected over time, a sampling regime not possible with batch LLE. This technique when coupled with GC-MS can be used to identify and quantify pesticides at the ng l⁻¹ level and can be applied routinely for analysis of pesticides at approximately the same price as individual pesticides analysis.     

Recherches sur les risques pouvant resulter de la pollution chimique des eaux d'alimentation—II. Etudes comparatives de la toxicite a long terme et de la cytotoxicite des micropolluants organiques extraits des eaux utilisees pour la preparation des eaux d'alimentation

Micropollutants extracted by chloroform from raw river waters used for preparation of drinking waters have been divided into two categories pending the degree of cytotoxicity shown by another team of research using a given cellular system: fractions with high cytotoxicity and fractions with low cytotoxicity.In parallel groups of 50 rats and 60 mice, half male and female, were fed, from weaning, diets containing those fractions.Comparison of the results showed a correlation between the two types of results, only in the case of some biochemical parameters.In regard to the long term effects (lesions of the liver, increase in the incidence of malignant tumors in treated animals), no correlation could be found.

Résumé

Des micropolluants organiques préparés par extraction chloroformique d'eaux brutes ont été répartis en 2 catégories, en fonction des résultats obtenus dans les investigations d'une autre équipe de chercheurs sur un systéme cellulaire: fractions à cytotoxicité forte et fractions à cytotocixité faible.Parallélement, des groupes de 50 rats et de 60 souris, par moitié mâles et femelles, ont reçu dans leur régime, à partir du sevrage et pendant pratiquement toute leur vie, les deux catégories de micropolluants.La comparaison des résultats obtenus dans les 2 types d'investigations nà révélé de corrélation que dans le cas de certains paramétres biochimiques et encore seulement dans une certaine mesure. En ce qui concerne les effets à long terme observés chez les lots traités des 2 espéces animales soumises aux épreuves (nettes altérations hépatique, augmentation de l'incidence des tumeurs malignes), aucune corrélation n'a pu être établie entre les critéres toxicologiques retenus et le degré de cytotoxicité des micropolluants sur le système cellulaire utilisé.     

Toxicite des eaux de ruissellement de la fonte de neige en milieu urbain

There is a current paucity of information on the characteristics of water originating from melting snow in urbanized areas. In fact no data exist on the potential chronic toxicity of waters originating from melting snow combined with sewage waters of industrial and domestic activities. Bioassays were conducted on the green alga Selenastrum capricornutum to evaluate the composite effect of all pollutants occurring in waters originated from melting snow in urbanized areas and also to determine the long-term bioavailability of selected toxicants in these waters.The publication resumes a sampling study of two outfalls (Curotte-Papineau and Meilleur-Atlantique) from collector systems on the island of Montréal, Québec, Canada (see Fig. 1). Both sewer systems are of the combined surface runoff-wastewater type, are self contained and drain watersheds of 11.7 and 22.2 km² area respectively (see Table 1). The sampling program carried out in spring (March–May) 1978, was oriented towards the analysis of flow-quality relationships during two dry and three snowmelt periods. The flow from the intrusion of snowmelt into the sewage networks were due not only to high air temperature and solar radiation conditions but also to a heavy rainfall (9.67 mm; maximum intensity of 4.6 mm h⁻¹. The principal water quality parameters studied were BOD₅, COD, Cl⁻, N_in, P_i, Pb, Cr, Zn, Cn⁻ and SS (see Table 2).In addition a bioassay based on the fertility potential [the Selenastrum capricornutum Printz algal assay bottle test; U.S.E.P.A. (1978)] on filtered samples (1.2 μm GF/C) of waste water was used to detect any toxological qualities of the outfalls during both dry and snowmelt periods. An analysis of the relationship between chemical quality and the toxological properties of the samples from both sewage networks showed that water collected during a period of snowmelt without rain had a greater potential chronic toxicity and greater mean ratios of B_EDTA/B than combined water collected during a dry climatic period (see Table 3). This toxicity is due mainly to inorganic compounds. However, the increase in water discharge rate during periods of snowmelt accompanied by rain results in an apparent dilution of the aquatic toxicants. The potential chronic toxicity of water during the latter periods is consequently reduced compared with combined waters during dry periods.Knowledge of relationships between water flow and the chronic toxicity characteristics of waste water from urban snowmelt is necessary in the planning of any future combined water treatment system.     

Etudes des transformations des formes du carbone, azote, phosphore, soufre, et des principaux elements mineraux au cours de la mesure de la demande totale en oxygene—I. Transformation des formes du carbone et des principaux cations

Les expériences réalisées sur le D.T.O. mètre de laboratoire IONICS 225 de la Dow Chemical, ont permis de caractériser, aprés l'action catalytique à haute température, les formes stables du carbone, de l'hydrogéne et des cations sodium, potassium, calcium, magnésium.Dans l'intervalle 0–250 mg O₂ l ou la réponse du capteur d'oxygène est proportionnelle à la concentration en matière organique nous avons démontré expérimentalement que le carbone organique ou minéral est transformé en CO₂ l'hydrogène en H₂O, et les cations sodium, potassium, calcium, magnésium en leurs oxyde et hydroxyde correspondants.Les ions bicarbonates et carbonates sont réduits et créent une interference négative: par contre les cations sont oxydés et creent une interférence positive dans la mesure de l'équivalent oxygéne par le D.T.O. métre.     

Influence de la taille des mottes et du mode de compactage sur la perméabilité des sols

In the domain of impervious barriers, many factors influence the permeability of compacted soil layers. These factors can lead to discrepancy between the permeability results in the laboratory andin situ. In this context, a laboratory study showed the influence of the size of clods and the method of compaction on permeability of highly plastic marl, compacted dynamically with standard Proctor energy and statically at different stresses, under the same conditions of water content and dry density. This paper also presents the results of a comparative study which has been conducted on the influence of the method of compaction on the permeability of the marl and that of a low plastic silt.     

Influence de la structure des feldspaths sur les néoformations argileuses dans les massifs éruptifs

The geologist often has to search for concentrations of dangerous clays in the eruptive rock masses. Therefore, an attempt has been made to define the relations that might exist between the specific structural characteristics of the main feldspars and the orientation of the argillaceous new formations, with stress on the role of plagioclases. A distinction is made between the case of sub-surface alteration by water and superficial alteration by water and organic matters.     

Cinetiques et mecanismes de l'action oxydative de l'hypochlorite sur les acides α-amines lors de la desinfection des eaux

In the field of water treatment, one increased concern over the quality of the environment requires an understanding of the fate of compounds generated by the addition of chemicals. One area of considerable interest is the stability of chlorine compounds produced when chlorine is added to natural water or swimming pool water. It is desirable to be able to predict the lifetimes of these harmful compounds under various conditions. In this study we examine for a range of hypochlorite α-amino acid ratios and pH, the kinetics and mechanism of the decomposition of α(N-chloro) and α(N,N-dichloro) amino acid, one of the products of chlorination.The interaction of chlorine with amino acids has been studied by several investigators Langheld (1909) was the first who discussed the decomposition of the α(N-chloro) amino acids. He noted that hypochlorous acid salts react with α-amino acids in the same manner as they do with amines to form monochlorinated or dichlorinated derivatives. Then, the decomposition of chloro-amino acids leads to the corresponding aldehydes or ketones, ammonia, carbonic acid, and sodium chloride. As an intermediate step Langheld assumed an imine formation.Wright (1936) and Pereira et al. (1973) have investigated the decomposition products of α(N,N-dichloro) amino acids. Their results indicate rapid formation of carbon dioxide, chloride ion, and the corresponding nitrile.Recently, many authors have investigated the rates of α(N-chloro) amino acids decomposition and the stability of its products (William and Wendy, 1979; Yoshiro et al., 1980; Le Cloirec-Renaud, 1984). However, they have neither differentiated between the decomposition of α(N-chloro) amino acid and α(N,N-dichloro) amino acid, nor have they demonstrated the combined effect of pH and molar ratio of hypochlorite and α-amino acid.In this study the hypochlorite oxidation of simple α-amino acids in aqueous solution has been investigated in the dark. The concentration of α(N-chloro) amino acid and α(N,N-dichloro) amino acid was monitored by DPD-fast titrimetric method and by measuring the absorbance at 255 and 293 nm respectively, this is illustrated in Figs 3 and 4. These results and the amino acids determination (O-phtalaldehyde—2 mercapto ethanol method) suggest that the intermediates α(N-chloro) and α(N,N-dichloro) amino acid are formed rapidly at an initial stage. Then, they decompose spontaneously by first order kinetics as shown in Table 1, to give a mixture of aldehyde and nitrile.When equimolar (1:1 mmol) amounts of hypochlorite and amino acid are used at pH 7, only aldehyde, carbon dioxide, chloride and ammonia are formed. However the corresponding nitrile compound appears, when operating condition allow the formation of α(N,N-dichloro) amino acid (acid pH or basic aqueous solutions with high molar ratio of hypochlorite and amino acid). This is illustrated in Table 2. The rate constant shows a dependence on pH, which is caused by the various forms that can arise from addition of protons to or removal of protons from the amino and carboxyl groups of the molecule William and Wendy, 1979). We assume an intermediate step of imine for the decomposition of both compounds: α(N-chloro) and α(N,N-dichloro) amino acid (scheme 6). The reaction should be considered as a spontaneous decarbonylation followed by a rapid hydrolysis of the imine. Scheme 7 illustrated how α(N,N-dichloro) amino acid can lead to the corresponding nitrile and aldehyde, however the α(N-chloro) amino acid gives only the corresponding aldehyde.The products of decomposition of α(N-chloro) amino acid are relatively stable in aqueous solution. Although we noted at pH = 3.5–5 that aldehyde react with chloramines and lead to the formation of corresponding nitrile, as shown in scheme 9.It appears that α(N-chloro) and α(N,N-dichloro) amino acid formed during the chlorination of natural or swimming pool water will degrade in a few hours to what are probably irritating products (like as aldehydes). The production of decomposition are a function of molar ratio of hypochlorite and amino acid and pH. However, since most natural water has a pH in the range of 5.5–9, there will be little variation of the rate of decomposition with pH. It seems that it is only temperature dependent.     

Le carbone organique: Son interet dans le controle de la preozonation

The present study was performed on Seine River water and cultured water where algal growth was favoured. Multiple samples were collected during a 7-month period (November 1982–May 1983) at the Choisy-le-Roy water treatment plant. The effects of preozonation were assessed in all samples by measuring total organic carbon (TOC) and dissolved organic carbon (DOC). The latter measurements were made in ampoules on 10 ml samples after acidification and oxidation. Two different oxidation processes were tested: oxidation process No. 1 was made in the presence of 0.2 g of potassium peroxodisulphate during 5 h at 130°C; oxidation process No. 2 was made in the presence of 0.4 g of potassium peroxodisulphate during 7 h at 130°C. The CO₂ generated in the samples was measured with an infrared detector. This protocol was performed on raw water and on preozonated water. We thus had 8 variables: DOC and TOC measured in raw water and in preozonated water after two different oxidation treatments.Particular attention was paid to statistical analysis of data to improve their interpretation. Multivariate statistical analysis (principal components analysis) showed good correlations between variables (P < 0.01) (Table 5) and the importance of tested parameters on organic carbon values 98% of the total inertia is due to sampling period (75%), filtration (12.8%), different oxidation processes used for organic carbon measurement (7.5%) and preozonation (2.6%) (Table 6, Fig. 1). Representation of the samples in the principal planes (Figs 2, 3 and 4) showed gathering of points corresponding to the same sampling period (i.e. November, January, March, April, May), the points related to November and March being opposite. It seems thus they have a different behaviour with regards to the tested parameters. This was confirmed by values in Table 7 concerning mean ± SEM values of the predefined sampling periods.The univariate statistical analysis (variance analysis and paired Student test) showed the variability of the Seine River and the presence, throughout the tested period, of a significant amount of particulate organic carbon (Table 9). The influence of oxidation performed before the organic carbon measurement is generally more important for TOC evaluation than for DOC (Table 10). Table 11 confirms this result for November.The higher preozonation effect appears in DOC measured in Seine River water after the stronger oxidation (i.e. oxidation No. 2) (Table 12). Table 13 shows that on March samples this effect appears only in DOC measured after oxidation process No. 2. Increasing the preozonation rate did not reveal this effect (Table 14).The two oxidation processes tested were not sufficient for exact determination of TOC but they allowed us to discuss preozonation effect on organic matter, this effect being different in function of the sampling period.The statistical analysis used made possible the quantitative evaluation of the preozonation effect which is generally only suggested.     

Capteur de resine chelatante pour le prelevement la preconcentration et la determination de metaux traces toxiques (Zn, Cd, Hg, Pb) dans les eaux

The subject of this article is the elaboration of a catcher of toxic metals (Zn, Cd, Hg, Pb) which enables them to be determined at μg 1⁻¹ level.It is known that, at these low concentrations, it is advisable to prevent the sample from being altered in any way between the time of taking and the time of analysis; moreover, it is necessary to proceed, on the one hand, to the pre-concentration of the wanted elements and, on the other hand, to the elimination of the main elements present in water and likely to interfere at the time of analytical determination.We therefore made a catcher which makes it possible to achieve these two desired effects by chromatographic separation and to carry out the conditioning of the sample, in the field, in a well-defined, chemical form, stable in time as a small volume in a solid state, easy to carry and to store.The catcher is in the shape of a small, cylindrical capsule (diameter = 29 mm, thickness = 10 mm) in Makrolon (Lexan) whose bases are made of a nylon cloth and which contains a chelating resin load (Chelex-100, 100–200 mesh).At the time of use, the catcher is put into a dismountable filtering-apparatus which permits percolation of the solution containing the wanted metal traces.Then, to proceed to the analytical determination of the elements it is possible to use two methods: analysis in solution after elution;X-ray fluorescence spectrometry, or else activation analysis on the catcher dried and then pelletized when hot in an hydraulic press.The experimentation has included the following points:

1. 1. Determination of the conditions of chromatographic separation on Chelex-100 resin which permits optimal fixation of Zn, Cd, Hg and Pb and the elution of the main elements Ca, Mg and Fe. We chose soda-citrate medium 7.1 · 10⁻² M at pH = 7.00;

2. 2. Determination of the conditions of use of the catcher and its efficiency according to the main elements in the sample of water.

The process we chose involves a sample of 1 l. of water which is acidified at pH 1 by concentrated HNO₃ and then filtered through a membrane (0.45 μm).The solid residue is examined by X-ray fluorescence spectrometry.To the filtrate are added 100 ml of soda-citrate buffer 7.1 · 10⁻¹ M and the pH is set to seven by addition of NaOH. Then the filtrate is percolated through the Chelex-100 resin catcher (flux = 1.5 ml min⁻¹).Then, it is possible to proceed: either to the elution of toxic metals by HNO₂ 2M to determine them in solution (atomic absorption spectrophotometry, anodic stripping voltammetry); or to pelletizing of the catcher and to the analytical determination by X-ray fluorescence spectromy or activation analysis.The results of these methods are compared with different water: (1) spring warer: (2) over waters and (3) sea-water. The elution method as well as direct analysis of the pelletized catcher gave satisfactory agreement.     

Survie in vitro de Yersinia dans les eaux d'alimentation et recuperation par filtration sur membrane

This study was undertaken to determine the survival characters and optimal parameters for the recovery of Yersinia from drinking water samples. Experiments were done by artificial contamination of 4 different water samples with 4 Yersinia strains.The strains tested along this study are: Y. enterocolitica 4052, 0:3 and 4360, 0:9, Y. enterocolitica intermedia 3953, 0:17 and Y. pseudotuberculosis 0:1. The water samples are characterized by an increasing mineralization: Distillated water, Gerardmer water (

Full-size image (1K)

), Nancy water (-4500 ω cm⁻¹—H = 10°) and Vittel water (-730 ω cm⁻¹, H = 71°).Total mineralization does not significantly affect the survival of Yersinia at 20°C, but causes a dramatic decrease of the Yersinia strains at 4°C for the most mineralized water. There is no pH effect from alkaline, neutral and acidic values until pH 4.4 but Yersinia is greatly affected by more acidic pH.The previous stay of Yersinia strains in artificially contaminated water causes a reduction of kinetic growth during cultivation on peptone-water but does not change the recovery rate by filtration method.The recovery rate of the filtration method using cellulose acetate membranes (mean porosity = 0.45 μm) is very poor, ranging from 0 to 8%. The efficiency is significantly higher with the aid of polyester membranes treated by laser (Nucleopore−0.40 μm) ranging from 12 to 53% according to the mineralization of the water. The best recovery rate is obtained with the moderately mineralized water.These results can explain the poor results obtained with the use of water bacteriology classical methods for the search of Yersinia.Thus the best results can be predicted from the concentration of fairly mineralized water by filtration on polyester membrane at neutral, alkaline or weakly acidic pH.     

Les diagraphies et les essais de mecanique des sols en place

Bulletin of Engineering Geology and the Environment - La présente communication rapporte les développements et les mises au point de matériels effectués par les Laboratoires des...