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The objective of this study was to examine the occurrence of parabens (5 congeners), triclosan (TCS) and triclocarban (TCC) at the scale of the Parisian sewer network and to provide representative knowledge on these compounds in France for a large area. For this purpose and in collaboration with the Parisian public sanitation service (SIAAP) in charge of the collect and treatment of the Parisian wastewater, this study focused on seven main sewer trunks of the Paris conurbation, accounting for 1900,000 m(3) d(-1), i.e., about 8 million inhabitants. Concentrations lying in the 2000-20000 ng l(-1) ranges were found in wastewater, confirming the ubiquity of parabens, TCS and TCC in our environment and household products. Parabens (>97%) and to a lesser extent TCS (68% in median) were mainly associated to the dissolved fraction, as demonstrated by low KD and KOC values. For the first time, this study also evaluated the pollutant mass loads per population equivalent (PE) of parabens, TCS and TCC at the large and representative scale of the Parisian conurbation. Hence, the median mass loads varied from 176 to 3040 μg PE(-1) d(-1) for parabens and from 26 to 762 μg PE(-1) d(-1) for TCS and TCC. Based on these results and according to the assumptions done, the extrapolation of the mass loads at the national scale pointed out an annual mass loads between 51.8 and 100.7 ty(-1) for methyl paraben (MeP) and between 11.2 and 23.5 ty(-1) for TCS. Mass loads per equivalent habitant and national mass loads are both extremely relevant and innovative data. Contrary to other countries, such data are nowadays rather difficult to gain in France and neither enquiry nor database provides access to information on the use and production of these chemicals. Since cosmetic industries are voluntarily and fully engaged in the substitution of parabens, triclosan and triclocarban in personal care product, this study could constitute a "time reference status" which could be used as a basis for future monitoring., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The characterization and control of runoff pollution from nonpoint sources in urban areas are a major issue for the protection of aquatic environments. We propose a methodology to quantify the sources of pollutants in an urban catchment and to analyze the associated uncertainties. After describing the methodology, we illustrate it through an application to the sources of Cu, Pb, Zn, and polycyclic aromatic hydrocarbons (PAH) from a residential catchment (228 ha) in the Paris region. In this application, we suggest several procedures that can be applied for the analysis of other pollutants in different catchments, including an estimation of the total extent of roof accessories (gutters and downspouts, watertight joints and valleys) in a catchment. These accessories result as the major source of Pb and as an important source of Zn in the example catchment, while activity-related sources (traffic, heating) are dominant for Cu (brake pad wear) and PAH (tire wear, atmospheric deposition).

Three catchments, equipped with sustainable urban drainage systems (SUDS: vegetated roof, underground pipeline or tank, swale, grassed detention pond) for peak flow mitigation, have been compared to a reference catchment drained by a conventional separate sewer system in terms of hydraulic behaviour and discharged contaminant fluxes (organic matter, organic micropollutants, metals). A runoff and contaminant emission model has been developed in order to overcome land use differences. It has been demonstrated that the presence of peak flow control systems induces flow attenuation even for frequent rain events and reduces water discharges at a rate of about 50% depending on the site characteristics. This research has also demonstrated that this type of SUDS contributes to a significant reduction of runoff pollutant discharges, by 20%-80%. This level of reduction varies depending on the considered contaminant and on the design of the drainage system but is mostly correlated with the decrease in runoff volume. It could be improved if the design of these SUDS focused not only on the control of exceptional events but also targeted more explicitly the interception of frequent rain events., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Today, urban runoff is considered as an important source of environmental pollution. Roofing materials, in particular, the metallic ones, are considered as a major source of urban runoff metal contaminations. In the context of the European Water Directive (2000/60 CE), an accurate evaluation of contaminant flows from roofs is thus required on the city scale, and therefore the development of assessment tools is needed. However, on this scale, there is an important diversity of roofing materials. In addition, given the size of a city, a complete census of the materials of the different roofing elements represents a difficult task. Information relating roofing materials and their surfaces on an urban district do not currently exist in urban databases. The objective of this paper is to develop a new method of evaluating annual contaminant flow emissions from the different roofing material elements (e.g., gutter, rooftop) on the city scale. This method is based on using and adapting existing urban databases combined with a statistical approach. Different rules for identifying the materials of the different roofing elements on the city scale have been defined. The methodology is explained through its application to the evaluation of zinc emissions on the scale of the city of Créteil.

This study has evaluated the quality of combined sewer overflows (CSOs) in an urban watershed, such as Paris, by providing accurate data on the occurrence of priority pollutants (PPs) and additional substances, as well as on the significance of their concentrations in comparison with wastewater and stormwater. Of the 88 substances monitored, 49 PPs were detected, with most of these also being frequently encountered in wastewater and stormwater, thus confirming their ubiquity in urban settings. For the majority of organic substances, concentrations range between 0.01 and 1 μgl(-1), while metals tend to display concentrations above 10 μgl(-1). Despite this ubiquity, CSO, wastewater and stormwater feature a number of differences in both their concentration ranges and pollutant patterns. For most hydrophobic organic pollutants and some particulate-bound metals, CSOs exhibit higher concentrations than those found in stormwater and wastewater, due to the contribution of in-sewer deposit erosion. For pesticides and Zn, CSOs have shown concentrations close to those of stormwater, suggesting runoff as the major contributor, while wastewater appears to be the main source of volatile organic compounds. Surprisingly, similar concentration ranges have been found for DEHP and tributyltin compounds in CSOs, wastewater and stormwater. The last section of this article identifies substances for which CSO discharges might constitute a major risk of exceeding Environmental Quality Standards in receiving waters and moreover indicates a significant risk for PAHs, tributyltin compounds and chloroalkanes. The data generated during this survey can subsequently be used to identify PPs of potential significance that merit further investigation., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Organic and mineral pollutants have become part of today's urban environment. During a rain event, stormwater quality as well as the corresponding contaminant loads is affected by both atmospheric deposition and the various types of impervious surfaces (roads, rooftops, parking lots etc.) on which runoff occurs. This study provides results on stormwater pollution in Paris and its suburbs from three separate storm sewers (n=20 samples). These results show that the stormwater had been contaminated by 55 chemical substances out of the 88 investigated. A particular attention was given to stormwater particle contamination. Concentrations are provided for: metals, PAHs, PCBs, organotins, alkylphenols, phthalates, pesticides, and VOCs. Our findings are among the first available in the literature since the relevant analyses were all conducted on both the particulate (P) and dissolved (D) phases. For most substances, particles from the three storm sewers were more heavily contaminated than dredged sediments and settleable particles from the Seine River. As a consequence of this finding, the release of untreated stormwater discharges may impact the receiving waters and contribute to sediment contamination., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

A method for benzalkonium analysis has been developed to measure benzalkonium concentration in dissolved and particulate fractions from urban runoff samples. The analysis was performed by liquid chromatography coupled with mass spectrometry (LC-MS/MS). The dissolved matrix was extracted by Solid Phase Extraction (SPE), with cationic exchange and the particles by microwave extraction with acidified methanol. Recovery percentages were closed to 100% for benzalkonium C12 and C14. The protocol was applied to roof runoff samples collected after a roof demossing treatment, and to separative stormwater samples from a 200 ha catchment. The results illustrate an important contamination of the roof runoff, with a maximum concentration close to 27 mg/L during the first rain. The benzalkonium concentration (sum of C12 and C14) stayed high (up to 1 mg/L) even 5 months after the treatment. Benzalkonium concentration measured in stormwaters was low (0.2 μg/L) but with contaminated suspended solids (up to 80 μg/g)., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

This paper presents results about the occurrence, the concentrations of urban priority substances on both the dissolved and the particulate phases in stormwater. Samples were collected at the outlet of a dense urban catchment in Paris suburb (2.30 km(2)). 13 chemical groups were investigated including 88 individual substances. Results showed that stormwater discharges contained 45 substances among them some metals, organotins, PAHs, PCBs, alkylphenols, pesticides, phthalates, cholorophenols and one volatile organic compound, i.e. methylene chloride. With respect to the European Water Framework Directive, these substances included 47% of the priority hazardous substances (n = 8), 38% of the priority substances (n = 10). The remaining substances (n = 27) belong to a list of others specific urban substances not included in the Water Framework Directive but monitored during this work. Finally, stormwater quality was evaluated by comparing the substance concentrations to environmental quality standards (EQS) and the particulate content to Canadian sediment quality guidelines. This showed that stormwater was highly contaminated and should be treated before being discharged to receiving waters in order to avoid any adverse impact on the river quality., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

This study investigates the occurrence of all priority substances (n = 41) listed in the Water Framework Directive and additional substances (n = 47) in raw sewage, as well as the removal performance of lamella clarification and biofiltration techniques. Once the efficiency of both types of techniques has been assessed for typical wastewater parameters, the differences in each technique's ability to remove pollutants becomes obvious; nevertheless, pollutant removal in quantitative terms still depends on the physico-chemical properties of the compounds used and operating conditions within the selected facility. For lamella clarification, the removal of organic chemicals was found to be primarily correlated with their sorption potential and, hence, strongly dependent upon log K(ow) of the compound under study. Compounds with a strong hydrophobic character (log K(ow) > 4.5) are removed to a significant extent (approx. 85%), while hydrophilic compounds (log K(ow) < 3.5) are poorly removed (<20%). For biofiltration, the removal of chemicals appears to be compound-dependent, although this outcome involves several mechanisms, namely: i) physical filtration of total suspended solids, ii) volatilisation, iii) sorption, and iv) biotransformation of substances. Even if the complex processes within a biofilter system do not yield an accurate prediction of pollutant removal, two groups of chemicals can still be clearly identified: i) hydrophobic or volatile compounds, for which moderate to high removal rates are observed (from 50% to over 80%); and ii) hydrophilic, non-volatile and refractory compounds for which a low removal rate would be expected (<20%).

The knowledge of the pollution stored in combined sewers is of prime importance in terms of management of wet weather flow pollution since sewer deposits play a significant role as source of pollution in combined sewer overflows. This work, which focused on the hydrocarbon (aliphatic and aromatic hydrocarbons) and metallic (Fe, Zn, Pb, Cu and Cd) pollution fixed to the different kinds of sewer deposits (gross bed sediment [GBS], organic layer [OL] and biofilm), was performed in order to provide a complete overview of the contaminant storage in the 'Le Marais' combined sewer (Central Paris, France). Firstly, our results have shown that, for all kinds of pollutants, a major part was stored in the GBS (87 to 98%), a lesser part in the OL (2 to 13%) and an insignificant part in the biofilm (<1%). These results demonstrated that the potential contribution of biofilm to wet weather pollution was negligible compared to the OL one. Secondly, the investigation of hydrocarbon fingerprints in each deposit has provided relevant information about contamination origins: (1) aliphatic hydrocarbon distributions were indicative of petroleum input in the GBS and reflected a mixture of biogenic and petroleum inputs in the OL and biofilm, (2) aromatic hydrocarbon distributions suggested an important pyrolytic contamination in all the deposits. Finally, the study of pollutant fingerprints in the different deposits and in the suspended solids going through the collector has shown that: (1) the suspended solids were the major component of OL and biofilm while urban runoff seemed to be the main transport mechanism introducing pollutants in the GBS and (2) the residence times in sewer of OL and biofilm were quite short compared to those for GBS.

Over a period of two years (2000-2001), sediment samples were extracted from 40 silt traps (STs) spread through the combined sewer system of Paris. All sediment samples were analysed for physico-chemical parameters (pH, organic matter content, grain size distribution), with total hydrocarbons (THs) and 16 polycyclic aromatic hydrocarbons (PAHs) selected from the priority list of the US-EPA. The two main objectives of the study were (1) to determine the hydrocarbon contamination levels in the sediments of the Paris combined sewer system and (2) to investigate the PAH fingerprints in order to assess their spatial variability and to elucidate the PAH origins. The results show that there is some important inter-site and intra-site variations in hydrocarbon contents. Despite this variability, TH and PAH contamination levels (50th percentile) in the Parisian sewer sediment are estimated at 530 and 18 microg g(-1), respectively. The investigation of the aromatic compound distributions in all of the 40 STs has underlined that there is, at the Paris sewer system scale, a homogeneous PAH background pollution. Moreover, the study of the PAH fingerprints, using specific ratios, suggests the predominance of a pyrolytic origin for those PAHs fixed to the sewer sediment.

Aliphatic hydrocarbons were assessed in runoff and waste waters from an urban catchment located in Paris. Runoff were sampled from different types of urban surfaces (11 roofs representing four different covering materials, two courtyards and six streets). Waste water samples were collected at the catchment outlet during dry and wet weather periods as well. This paper gives an overview of the results on the concentration and distribution points of view for both the particulate and the dissolved phases. Results were discussed on the basis of the median. Accordingly, the temporal variability was taken into account. Thus, the concentration medians ranged from 345 to 827, from 297 to 790, and from 393 to 1,359 microg L(-1) in the roof, courtyard and street samples, respectively. The levels found at the catchment outlet during dry and wet weather periods were of the same order of magnitude, i.e. 700 microgL(-1). The particulate phase represented 85% of the total aliphatic hydrocarbon content whatever the sample.