Our study aims at making progress the estimate of herbicide and nutrient inputs to the Marennes-Oleron bay which could influence summer oysters mortalities, and to bring a better understanding of the impact on coastal ecosystems by modelling the dynamics of these compounds in the shellfish-farming area. The development of a strategy adapted to the river Charente and its estuary reveals that agricultural activity on the watershed area is omnipresent, as well on the level of the nitrogen as on the one of herbicides contributions. It is thus necessary to specify Charente fluxes, which is the main tributary of the Marennes-Oleron bay, in order to better characterize its impact on shellfish-farming activity. Hydrodynamic modelling will constitute an invaluable help in the risk assessment with respect to pesticides, by specifying the periods of the high and low concentrations of these molecules and the biotope exposure durations. Resume : Estimation des quantites d'herbicides et de nutriments apportees par la Charente au milieu cotier et modelisa- tion de la dispersion d'atrazine dans la Baie de Marennes-Oleron. Cette etude vise a faire progresser l'estimation des apports d'herbicides et de nutriments au bassin de Marennes-Oleron susceptibles d'influencer les episodes de mortalite estivale des huitres, et a apporter par la modelisation une meilleure comprehension de la dynamique de ces composes dans la zone de production conchylicole. La mise au point d'une strategie d'etude adaptee au fleuve Charente et a son estuaire revele que l'influence de l'activite agricole sur le bassin versant est omnipresente, tant au niveau des apports d'azote que d'herbicides. Il est donc necessaire de preciser les flux apportes par la Charente, principal affluent du bassin de Marennes- Oleron, afin de mieux caracteriser son impact sur l'activite conchylicole. L'utilisation d'un modele de dispersion constituera une aide precieuse dans l'evaluation du risque vis a vis des produits phytosanitaires, en precisant les niveaux de presence de ces molecules et les durees d'exposition du biotope.

Twenty-two pesticides and metabolites selected on the basis of a regional priority list, were surveyed in surface river waters by high performance liquid chromatography coupled in tandem with UV diode array detection and mass spectrometry, after an off-line pre-concentration step. Pesticide concentrations ranged between 0.07 and 4.8 μg/l according to the compound and sampling period. Analytical results were linked to the environmental risk of pesticides, evaluated by their system investigation of risk by integration of score (SIRIS) rank.

Marennes-Oldron Bay (France) is located at the mouth of the Charente River. The objectives of this research were to estimate fluxes of crop treatment products (particularly herbicides) through the mouth of the Charente River as accurately as possible and monitor their stability along the salinity gradient through the estuary. We demonstrated that, in 2001, the Charente River transported almost 1,400 kg of active ingredients into the estuary. Among the herbicides detected, 90% were triazine compounds, including 60% atrazine metabolites (DEA, DIA), simazine (DIA) and terbuthylazine (DET) metabolites. The remaining 10 percent consisted of phenylurea compounds : diuron and isoproturon. Furthermore, under the hydrological and biological conditions prevalent in 2001, we showed that triazines and phenylurea compounds exhibited conservative behaviour along the salinity gradient. It may thus be assumed that fluxes of dissolved herbicides transported by the Charente River into the estuary was equivalent to that exported into Marennes-Oleron Bay, where the oyster and mussel beds are located. These results were used as the basis for hydrodynamic modelling of the plumes of active substances released from the Charente River, in order to assess the extent of the exposure of the filter feeders in the bay to these pollutants.

Water samples were collected from the Amazon River system during a high flood period, in June 1989, and lipids associated with particles retained on GF/F filters were examined. Particles showed a highly variable organic carbon content (1.8–29.0%). Corresponding organic carbon concentrations varied from 0.36 to 1.13 mg/l. The flood conditions encountered during the sampling period may feed exceptional inputs of soil organic matter into the tributaries and the Amazon River. Composition and concentration of sterols, fatty acids and pigments were determined to estimate the relative portion of terrigenous and autochthonous fraction of this complex organic matter. Sterol distribution patterns were similar to other equatorial rivers, in the Orinoco (Venezuela) and Solo (Indonesia). In comparison with the dominant profile of the Amazon system, distinct patterns were found in the Trombetas River (29Δ 5,22 ∼ 27Δ 5 ∼ 29δ 5 ≫ 28Δ 5 , 28Δ 5,22 ) and in the Tapajos River (27Δ 5,22 > 27Δ 5 ≫ 29Δ 5 , 28Δ 5 , 28Δ 5,22 ). These fingerprints reflect different vegetation types of drainage basins and distinct planktonic pools. The distribution of even-carbon numbered saturated fatty acids in the carbon range of 24–36 revealed low inputs of constituents associated with cuticular waxes of vascular plants in Black waters and in the Tapajos River (∼200 ng/l), higher in White waters (328–483 ng/l) and highest in the Trombetas River (704 ng/l) and in stagnant waters of a small lake close to the Amazon (1088 ng/l). Pigment concentrations showed that in the main river and most tributaries vegetal carbon did not represent more than 2%, except for the Tapajos River (6.2%) and in relatively stagnant waters sampled along the main river (9.2%). Based on relative abundance of Chl b , Chl c , fucoxanthin, peridinin, alloxanthin, and zeaxanthin, various phytoplanktonic assemblages were evidenced in the Amazon River system. Branched fatty acids in the carbon range of 15–17 gave insight into bacterial signatures. They showed low microbial contribution to the fatty acid pool, with slightest higher contribution in a swamp of stagnant waters and in the White waters of the Solimoes River.

Activated sludge treatment is used to remove wastewater organic matter (OM) and residual OM is found at low levels in treated water. The molecular composition of OM of waters and sludge was determined In order to understand the fate of the organic substances during biological treatment and the nature of residual OM. Proteins, sugars, lipids and polyphenolic compounds were quantified in a municipal wastewater treatment plant via chromatographic analysis after chemical hydrolysis.The concentration of OM was decreased by more than 90% by biological treatment. However, if 63% of the OM were characterized in activated sludge, molecular analysis did not allow us to characterize all the OM in the water samples. Relatively higher amounts of total organic carbon (TOC) were identified in wastewater (50%) than in treated water (20%). Likewise, for total nitrogen, 33% were identified as amino acid nitrogen in wastewater, and only 10% in treated water. Analytical pyrolysis suggested that some of the difficulties in identifying OM of treated water with common analytical methods are due to the presence of complex structures, refractory to hydrolysis. These structures may also be refractory to microbial degradation since they are concentrated during the biological treatment of wastewater. Suggestions on the possible origin and structure of resistant OM were formulated according to the analytical results. (C) 2000 Elsevier Science Ltd. All rights reserved.

Activated sludge extracellular polymers (ECP) were extracted either by sonication or a combination of sonication and cation exchange resin treatment (CER). The chemical composition of the aqueous extract was investigated by chromatographic analysis of amino acids and sugars after hydrolysis. Up to 70 to 80% of the total organic carbon (TOC) of ECP was characterized. Proteins were found to be the major constituent of ECP, which was confirmed by pyrolysis/GC/MS analysis. Sugar and protein analysis led to complementary information both on the origin of extracellular material and on sludge floc structure. The monosaccharide composition in ECP and sludge allowed the proposal of different origins for extracellular polysaccharides. The predominance of proteins in ECP underlined their key role in the floc structure, and led to hypotheses on their origin. Proteins were better extracted than sugars when the CER extraction was combined with sonication. This supposed that proteins are more involved than sugars in electrostatic bonds with multivalent cations. Electrostatic bonds were found to be uniformly distributed in the floc and closely combined with hydrophobic bonds. About 25% of ECP amino acids were negatively charged and 24% exhibited hydrophobic properties, highlighting the specific role of proteins in the floc structure.

Monitoring of trace levels of phenylurea and chlorotriazine herbicides and their metabolites deispropylatrazine (DIA) and deethylatrazine (DEA) was performed on river, estuarine and coastal seawater by off-line (n-octadecyl silica, C18) and on-line (styrene-divinylbenzene copolymer-based, PRP1) preconcentration techniques using reversed-phase chromatography and UV and electrochemical detection. It is shown that off-line and on-line technology fit monitoring of trace-level phenylurea and triazine analysis (detection limit 10–50 ng/l) in freshwater as well as seawater and in natural water with high dissolved organic carbon (DOC) content. Clean-up was unnecessary for most of the surface water sample for both off-line and on-line techniques. Samples of surface water originating from various rivers (Seine, Charente, Garonne), canals (Marennes-Oléron) and estuaries (Charente, Seudre salinity gradient up to 30‰) were analysed. Dissolved organic carbon (DOC) contents varied from <1 to 15 mg/1 and provided numerous interferents and a major ‘hump’ whose intensity is correlated with DOC content, suggesting that a major part of the organic matter, namely humic substances, is retained on the solid phase and eluted as polar compounds.

Phenylureas and triazines were analysed by reversed-phase liquid chromatography using UV detection at 254 nm after an on-line preconcentration step on a PRP-1 copolymer in order to determine pesticides in river water at mu g/l level or lower. Running water was sampled in the Garonne from a station located at La Reole, upstream from Bordeaux and from a small tributary, the Dropt. Water samples were collected mainly at several periods between December 1989 and September 1990 at a low water time (December 1989) and during two high flood periods (February 1990 and May 1990). Atrazine, simazine, de-ethylatrazine, diuron, chlortoluron and isoproturon were detected and quantified. In the Garonne river, atrazine, simazine, de-ethylatrazine and diuron were usually present at the sampling time, whereas chlortoluron and isoproturon maximised during the winter flood (February). In the Dropt river, triazine concentrations were normally between 1.0 and 0.1 mu g/l and maximised at 2.2 mu g/l during the spring flood (June 1990). De-ethylatrazine/(Atrazine + Simazine) ratio seems to be significantly higher than in the Mississippi river and may be in relation to the use of simazine in the drainage basin. These data are in agreement with seasonal applications of phenylurea and triazine herbicides and hydrologic and pluviometric conditions.

Lignins associated to particles suspended in riverwater have been studied as specific signature of vascular plants. The thioacidolysis procedure, which combines a soft nucleophile, CH3CH2SH, and a hard Lewis acid, BF3 etherate, specifically degrades the beta-O-4 lignin structures to C6C3 trithioethyl phenylpropane compounds. These compounds are recovered in high yield as a 1:1 mixture of diastereoisomers from p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) involved in the beta-O-4 bonding pattern and are analyzed as trimethylsilyl derivatives by gas capillary chromatography and identified by GC-MS from a few milligrams of sample. Such treatment to suspended river fine particles collected in the Congo river at different periods shows a specific lignin signature. The evidence of H units as traces, of p-coumaric and ferulic units, and the S/G ratio observed, support the hypothesis that in this particular sample the main source of plant-derived organic matter is terrestrial grass plant. The main interest of this method is to provide a specific lignin imprint without any interference with other phenolics.

A multi-residue method for the trace-level determination of 34 pesticides and various transformation products was developed by using on-line solid-phase extraction and either ten 4.6-mm Empore extraction discs containing C18 or a conventional precolumn, packed with PRP-1 copolymer, followed by liquid chromatography—thermospray mass spectrometry with time-scheduled selected-ion monitoring. Two main ions (usually [M + H]+ and [M + NH4]+ or [M + CH3CN]+) were used for each pesticide in the positive-ion operational mode, while [M − H]− and [M + HCOO]− ions were used in the negative-ion mode. Losses of CH3NCO were also monitored for many of the carbamate pesticides. The proposed method requires 100 ml of sample for a limit of detection of 0.01–0.4 μ/1, depending on the particular compound and the operational mode. Calibration graphs were constructed by preconcentrating 100 ml of an estuarine water sample, spiked with the pesticide mixture at various concentration levels, varying from 0.025 to 1.2 μg/1. Good linearity was observed for sixteen of the analytes studied, the relative standard deviation (n = 5) being 4–13%. Some examples of the trace-level determination of various pesticides in European river and ground water samples are given.

Organic Mass SpectrometryVolume 28, Issue 11 p. 1365-1367 OMS Letter Double bond location in monounsaturated wax esters by gas chromatography/mass spectrometry of their dimethyl disulphide derivatives C. Pepe, Corresponding Author C. Pepe Laboratoire de Spectrochimie Moléculaire, URA CNRS 508 Université Pierre et Marie Curie, Boîte 49, 4 Place Jussieu, 75252 Paris cedex FranceLaboratoire de Spectrochimie Moléculaire, URA CNRS 508 Université Pierre et Marie Curie, Boîte 49, 4 Place Jussieu, 75252 Paris cedex FranceSearch for more papers by this authorJ. Dagaut, J. Dagaut Laboatoire de Physique et Chimie Marines, UA CNRS 5353, Université Pierre et Marie Curie, Boîte 134, 4 Place Jussieu, 75252 Paris cedex 05, FranceSearch for more papers by this authorP. Scribe, P. Scribe Laboatoire de Physique et Chimie Marines, UA CNRS 5353, Université Pierre et Marie Curie, Boîte 134, 4 Place Jussieu, 75252 Paris cedex 05, FranceSearch for more papers by this authorA. Saliot, A. Saliot Laboatoire de Physique et Chimie Marines, UA CNRS 5353, Université Pierre et Marie Curie, Boîte 134, 4 Place Jussieu, 75252 Paris cedex 05, FranceSearch for more papers by this author C. Pepe, Corresponding Author C. Pepe Laboratoire de Spectrochimie Moléculaire, URA CNRS 508 Université Pierre et Marie Curie, Boîte 49, 4 Place Jussieu, 75252 Paris cedex FranceLaboratoire de Spectrochimie Moléculaire, URA CNRS 508 Université Pierre et Marie Curie, Boîte 49, 4 Place Jussieu, 75252 Paris cedex FranceSearch for more papers by this authorJ. Dagaut, J. Dagaut Laboatoire de Physique et Chimie Marines, UA CNRS 5353, Université Pierre et Marie Curie, Boîte 134, 4 Place Jussieu, 75252 Paris cedex 05, FranceSearch for more papers by this authorP. Scribe, P. Scribe Laboatoire de Physique et Chimie Marines, UA CNRS 5353, Université Pierre et Marie Curie, Boîte 134, 4 Place Jussieu, 75252 Paris cedex 05, FranceSearch for more papers by this authorA. Saliot, A. Saliot Laboatoire de Physique et Chimie Marines, UA CNRS 5353, Université Pierre et Marie Curie, Boîte 134, 4 Place Jussieu, 75252 Paris cedex 05, FranceSearch for more papers by this author First published: November 1993 https://doi.org/10.1002/oms.1210281113Citations: 13AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume28, Issue11November 1993Pages 1365-1367 RelatedInformation