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Figure 3. Sucy-en-Brie watershedFigure 4. Noisy-le-Grand watershedSo, this research attempt at performing a whole innovative screening of the 88 listed urbanpollutants on stormwater on both the dissolved and the particulate phases. For samples withlow SS, large volume of water samples, (i.e., 24 litres) will be filtrated to collect enoughparticles for analyses. Finally, in order to compare the analyses on both dissolved andparticulate phases to the current analyses (i.e., on bulk samples), these two procedures will becarried out on the same sample.Screening preparation samplesAfter a rain event, samples are collected, and bottles are mixed to get a mean sample of theevent. From plastic bottles, sample is targeted to ordinary quality parameters and metalsanalyses while the bulk samples from glass bottles is also mixed, filtrated in a glass filtrationunit in order to get the dissolved phase for organic contaminants. This latter is sent to thecertified laboratory for analysis within 24 hours. Filters with suspended solids are deep-frozen,then lyophilized and stored at 4°C prior to analysis.The analytical procedures used by the laboratory follow the existing French (AFNOR) orinternational (ISO) standards. When no standard was available, the laboratory has developedand validated its own methods. During analysis and in case where other substances areidentified we will attempt to quantify them. In addition, field blanks will be done on automaticwater samplers and on the whole analytical procedure.Figure 5. Two automatics samplers Bühler 1029Figure 6. Pluviometer at SucySCREENING METHODOLOGYAll the analyses are carried out by a certified laboratory. This laboratory was chosen among 10laboratories that answered to our specifications and its capacity to carry analyses on these 88substances in both the dissolved and the particulate phases.Generally, when suspended solids (SS) concentration is above 500 mg/l analyses are made onthese phases separately after filtration.In most cases, analyses were made on bulk water sample without any specific analyses onsuspended solids. This case can generate a misinterpretation of the results:- Analyses carried out on unfiltered samples will provide poor-quality data with regard to therepresentativity of the contamination in water and also poor comparability between data fromdifferent laboratories (Coquery et al., 2005),- For organic pollutants having log Kp > 3, their concentration should preferably be measuredin SS rather than in the bulk water sample or dissolved phase. As a matter of fact, solventextraction of bulk water samples with high SS concentrations will be much less efficient forthose substances than if performed on the SS itself, using extraction methods designed forsolid phases, such as sediment or soil (Coquery et al., 2005).So, the results of dissolved and SS pollutant concentrations should be given separately, as suchdata are often lacking from monitoring databanks. These pose some interesting challenges foranalytical testing laboratories:- Water samples with low SS concentrations need large volumes, up to 10 litres to be filteredto get a suitable mass to perform reproducible analyses on solids,- In some cases, analytical methods have not been fully validated for the solid phase incertified laboratories whereas they are analysed in routine in research laboratories.CONCLUSIONThis research work started in November 2006 within the framework research programmeOPUR. All sampling equipments are installed on three separated sewer networks in ParisCentre and its suburb. Sampling procedures have been validated. The innovative screeningmethodology is described for the 88 urban pollutants on both the particulate and the dissolved.Analyses will be carried out by a French certified laboratory which has validated its analyticalprocedures in order to analyse for the first time stormwater samples, not only on bulk samplebut also on both the particulate and the dissolved phases. Additionally, the screening of the 88urban pollutants can be applied on different types of water samples such as wastewater fromcombined sewers collected at the outlet of urban watersheds, but also runoff from the differenttypes of urban surfaces. Effective monitoring campaigns have started on these sites. In a firstattempt, stormwater from storm sewers will be investigated followed by wastewater andrunoff. So, this research will provide the first database concentrations for the 88 pollutants indissolved and particulate phases for different kind of urban water samples collected from siteswith different land uses pattern.ACKNOWLEDGMENTSThe authors gratefully acknowledge the Seine-Normandy Water Agency (AESN), theInterdepartmental Association for Sewage Disposal in Paris Conurbation (SIAAP), the ParisMunicipality, the Water and Sewage Disposal Departmental Administrations of Seine SaintDenis (DEA93), the Water and Sewage Disposal Departmental Administration of Val deMarne (DSEA94) and Regional Council of “Ile de France” (CRIF) for their financial supportwithin the framework of the OPUR programme research.WWW-YES 2008, Paris 13 – 16 May 2008 183WWW-YES 2008, Paris 13 – 16 May 2008 184