Mathieu Cladière

Priority pollutants in urban stormwater: Part 2 - Case of combined sewers

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.

Meta-analysis of environmental contamination by phthalates

Phthalate acid esters (PAE), commonly named phthalates, are toxics classified as endocrine-disrupting compounds; they are primarily used as additives to improve the flexibility in polyvinyl chloride. Many studies have reported the occurrence of phthalates in different environmental matrices; however, none of these studies has yet established a complete overview for those compounds in the water cycle within an urban environment. This review summarizes PAE concentrations for all environmental media throughout the water cycle, from atmosphere to receiving waters. Once the occurrences of compounds have been evaluated for each environmental compartment (urban wastewater, wastewater treatment plants, atmosphere, and the natural environment), we reviewed data in order to identify the fate of PAE in the environment and establish whether geographical and historical trends exist. Indeed, geographical and historical trends appear between Europe and other countries such as USA/Canada and China, however they remain location dependent. This study aimed at identifying both the correlations existing between environmental compartments and the processes influencing the fate and transport of these contaminants into the environment. In Europe, the concentrations measured in waterways today represent the background level of contamination, which provides evidence of a past diffuse pollution. In contrast, an increasing trend has actually been observed for developing countries, especially for China.

Alkylphenolic compounds and bisphenol A contamination within a heavily urbanized area: case study of Paris

This study evaluates the influence of a heavily urbanized area (Paris Metropolitan area), on receiving water contamination by both bisphenol A (BPA) and alkylphenol ethoxylate (APE) biodegradation product. The study began by investigating concentrations within urban sources. In addition to the more commonly studied wastewater treatment plant effluent, wet weather urban sources (including combined sewer overflows, urban runoff, and total atmospheric fallout) were considered. The initial results highlight a significant contamination of all urban sources (from a few nanograms per liter in atmospheric fallout to several micrograms per liter in the other sources) with clearly distinguishable distribution patterns. Secondly, concentration changes along the Seine River from upstream of the Paris Metropolitan area to downstream were investigated. While the concentrations of BPA and nonylphenoxy acetic acid (NP1EC) increase substantially due to urban sources, the 4-nonylphenol concentrations remain homogeneous along the Seine. These results suggest a broad dissemination of 4-nonylphenol at the scale of the Seine River basin. Moreover, the relationship between pollutant concentrations and Seine River flow was assessed both upstream and downstream of the Paris conurbation. Consequently, a sharp decrease in dissolved NP1EC concentrations relative to Seine River flow underscores the influence of single-point urban pollution on Seine River contamination. Conversely, dissolved 4-nonylphenol concentrations serve to reinforce the hypothesis of its widespread presence at the Seine River basin scale.

Endocrine disrupting compounds in gaseous and particulate outdoor air phases according to environmental factors

This study investigated, for the first time in France, the spatial and temporal patterns of 55 endocrine disrupting chemicals (EDCs) in ambient air at three sites (urban, suburban and forest) under two climatic periods (warm/cold) for 2 successive years. All EDCs, except tetrabromobisphenol A (TBBPA), were encountered with various frequencies of up to 100%. Phthalate diesters (PAEs) were the most abundant chemicals with total concentrations as the sum of compounds, ranging from 10 to 100 ng m(-3) of total air, followed by alkylphenols (APs) and polycyclic aromatic hydrocarbons (PAHs), which were both approximately 1 ng m(-3). Polychlorinated biphenyl (PCBs) and bisphenol A (BPA) concentrations were notably lower (approximately 0.1 ng m(-3)). Air concentrations, depending on the considered compounds, were from 1.2 to 2 times higher in the urban than the suburban area and from 2 to 5 times higher in the urban than the forest site. PAH emissions were higher in the cold period, due to combustion processes. This finding is contrary to the other EDCs that are more abundant in the summer and governed by volatilisation. Most of the EDCs were largely distributed in the gaseous phase (>80% in the summer). The octanol/air partition coefficient (KOA) and vapour pressure (Vp) were relevant parameters for predicting EDC partitioning and direct relationships (p < 0.001) were observed i) between log K particle/gas partitioning (log Kp) and log KOA and ii) between EDC ratios in the gaseous phase and log vapour pressure (log Vp).

Alkylphenol ethoxylates and bisphenol A in surface water within a heavily urbanized area, such as Paris

This work focused on alkylphenol ethoxylates (APEOs) and bisphenol A (BPA) in surface water at the scale of the upper part of the Seine basin Although this basin is vulnerable, since it undergoes a combination of strong human pressures (Paris conurbation) with very limited dilution via the Seine River, no comprehensive data was available for these compounds In this context, the evolution of the pollutant concentrations and loads was assessed during two sampling campaigns (April and July 2009) along a 300 km-transect Hence, 18 stations (10 sites on the Seine River, four tributaries and four wastewater treatment plants WWTPs) were considered Additional campaigns were also conducted over 2009 on four sites on the Seine River The BPA concentrations range from 7 2 to 127 ng l(1) in surface water, while higher concentrations of APEOs (324 +/- 153 ng l(1)) were observed Based on our first results, no spatial variability of concentrations between up- and downstream sites, or any seasonal variability, were highlighted During the longitudinal campaigns, an increase of the pollutant loads between up- and downstream sites was clearly noticed Contrary to BPA, for which a limited seasonal variation of loads was observed at the basin outlet (1,400 and 1,500 g d (1)), the APEO loads significantly vary (10,000 and 5,500 g d (1)) Mass balances between the inputs (tributaries + WWTPs) and the exported loads reveal that the BPA inputs are lower than the exported loads, suggesting that other inputs have to be considered along the transect studied For APEOs, the inputs appear higher than the exported loads, underscoring the in-stream removal of APEOs Globally, the results reveal that the removal of APEOs and the number of ethoxylate units are correlated the longer the ethoxylate chain, the higher the removal

Modelling the fate of nonylphenolic compounds in the Seine River--part 1: determination of in-situ attenuation rate constants.

Assessing the fate of endocrine disrupting compounds (EDCs) in the environment is currently a key issue for determining their impacts on aquatic ecosystems. The 4-nonylphenol (4-NP) is a well known EDC and results from the biodegradation of surfactant nonylphenol ethoxylates (NPnEOs). Fate mechanisms of NPnEO are well documented but their rate constants have been mainly determined through laboratory experiments. This study aims at evaluating the in-situ fate of 4-NP, nonylphenol monoethoxylate (NP1EO) and nonylphenolic acetic acid (NP1EC). Two sampling campaigns were carried out on the Seine River in July and September 2011, along a 28km-transect downstream Paris City. The field measurements are used for the calibration of a sub-model of NPnEO fate, included into a hydro-ecological model of the Seine River (ProSe). The timing of the sampling is based on the Seine River velocity in order to follow a volume of water. Based on our results, in-situ attenuation rate constants of 4-NP, NP1EO and NP1EC for both campaigns are evaluated. These rate constants vary greatly. Although the attenuation rate constants in July are especially high (higher than 1d(-1)), those obtained in September are lower and consistent with the literature. This is probably due to the biogeochemical conditions in the Seine River. Indeed, the July sampling campaign took place at the end of an algal bloom leading to an unusual bacterial biomass while the September campaign was carried out during common biogeochemical status. Finally, the uncertainties on measurements and on the calibration parameters are estimated through a sensitivity analysis. This study provides relevant information regarding the fate of biodegradable pollutants in an aquatic environment by coupling field measurements and a biogeochemical model. Such data may be very helpful in the future to better understand the fate of nonylphenolic compounds or any other pollutants at the basin scale.

Modelling the fate of nonylphenolic compounds in the Seine River — part 2: Assessing the impact of global change on daily concentrations

This study aims at modelling the daily concentrations of nonylphenolic compounds such as 4-nonylphenol (4-NP), nonylphenol monoethoxylate (NP1EO) and nonylphenoxy acetic acid (NP1EC) within the Seine River downstream of Paris City for over a year, firstly in the present state (year 2010) and for years 2050 and 2100 in order to assess the consequences of global change on the fate of nonylphenolic compounds in the Seine river. Concentrations were first simulated for the year 2010 and compared to monthly measured values downstream of Paris. To achieve this goal, the hydrodynamic and biogeochemical model, ProSe, was updated to simulate the fate of 4-NP, NP1EO and NP1EC. The Seine upstream and Oise River (tributaries of the Seine River) concentrations are estimated according to concentrations-flow relationships. For Seine Aval wastewater treatment plant (SA-WWTP), the concentrations are considered constant and the median values of 11 campaigns are used. The biodegradation kinetics of 4-NP, NP1EO and NP1EC in the Seine River were deduced from the results of the companion paper. The Nash-Sutcliffe coefficient indicates a good efficiency to simulate the concentrations of 4-NP, NP1EC and NP1EO over an entire year. Eight scenarios were built to forecast the impacts of global warming (flow decrease), population growth (SA-WWTP flow increase) and optimisation of wastewater treatment (improvement of the quality of effluents) on annual concentrations of 4-NP, NP1EO and NP1EC at Meulan by 2050 and 2100. As a result, global warming and population growth may increase the concentrations of 4-NP, NP1EC and NP1EO, especially during low-flow conditions, while the optimisation of wastewater treatment is an efficient solution to balance the global change by reducing WWTP outflows.

Contamination of soils by metals and organic micropollutants: case study of the Parisian conurbation

Soils are playing a central role in the transfer and accumulation of anthropogenic pollutants in urbanized regions. Hence, this study aimed at examining the contamination levels of selected soils collected within and around the Paris conurbation (France). This also evaluated factors controlling contamination. Twenty-three trace and major elements as well as 82 organic micropollutants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalates (PAEs), polybrominated diphenyl ethers (PBDEs), alkylphenols (APs), and perfluoroalkylated substances (PFASs) were analyzed. Results reinforced the concern raised by the occurrence and levels of metals such as Zn, Pb, Cu, and Hg, identified as metallic markers of anthropogenic activities, but also pointed out the ubiquitous contamination of soils by organic micropollutants in the 0.2–55,000-μg/kg dw range. For well-documented compounds like PAHs, PCBs, and to a lesser extent PBDEs, contents were in the range of background levels worldwide. The pollutant stock in tested soil was compared to the annual atmospheric input. For PAHs; Pb; and to a lesser extent Zn, Cu, Cd, Hg, Sb, PAEs, and APs, a significant stock was observed, far more important than the recent annual atmospheric fluxes. This resulted from both (i) the persistence of a fraction of pollutants in surface soils and (ii) the cumulative atmospheric inputs over several decades. Regarding PBDEs and PFASs, stronger atmospheric input contributions were observed, thereby highlighting their recent dispersal into the environment.