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For pharmacological reasons many active organic pharmaceutical substances (AOPSs) are singly or multiply halogenated. Halogenation can confer optimised steric fitting of an AOPS to its molecular receptor; moreover, by increasing the lipophilicity of a compound, passive permeation through bilipid membranes into target cells is enhanced. As halogenation is widely suspected to inhibit biodegradability in wastewater treatment plants, the relationship of halogenation vs. ready biodegradability was investigated. Among 230 AOPSs with empirical ready biodegradability data, all 70 halogenated AOPSs are not readily biodegradable, and halogenation is confirmed to be an impediment to ready biodegradability. As a counterexample to halogenation, hydrophilic substitutions (hydroxy, carboxylic-acid or terminal-amine groups) are positively correlated with ready biodegradability. Regarding halogenation, therefore, pharmacological goals stand in stark contrast to environmental goals. Possible ideas toward solutions for this contradiction are discussed.

International audience; Performic acid (PFA) is an emerging disinfectant applied for full-scale disinfection of wastewater effluent. While many studies have focused on assessing the microbial water quality during PFA disinfection, studies on the ability of PFA to oxidize organic micropollutants are still scarce. In this study, nontarget screening of wastewater secondary effluent during PFA treatment was performed using liquid chromatography−high-resolution mass spectrometry. A low dose (2 mg/L) of PFA was able to affect the organic matter composition within a short exposure time (10 min). Multivariate analysis as well as suspect screening indicated that PFA oxidation largely reduced the intensities of micropollutants with a tertiary amine moiety and led to the formation of their mono-oxygenated derivatives, N-oxides, a class of transformation products that are known as biologically stable but whose impact on aquatic organisms still needs to be assessed. Mechanistic studies were conducted on selected micropollutants (i.e., lidocaine, amisulpride, tramadol, and clarithromycin). The minimum apparent second-order rate constant of PFA with lidocaine was determined as 7.54 M −1 s −1 at pH 8.0. Lidocaine was mainly converted (∼95%) into its N-oxide via direct oxygen transfer from PFA. Overall results revealed a strong electrophilic reactivity of PFA toward electron-rich moieties (e.g., amines) of micropollutants.

International audience; Road runoff (RR) is an important vector of micropollutants towards groundwater and soils, threatening the environment and ecosystems. Through combined chemical and biological approaches, the purpose of this study was to get insights on specific toxicants present in RR from two sites differing by their traffic intensity and their toxicological risk assessment. Non-target screening was performed by HRMS on RR dissolved phase. Ecotoxicological risk was evaluated in a zebrafish embryos model and on rat liver mitochondrial respiratory chain. Specific HRMS fingerprints were obtained for each site, reflecting their respective traffic intensities. Several micropollutants, including 1,3-diphenylguanidine (DPG) and benzotriazole (BZT) were identified in greater concentrations at the high-traffic site. The origin of DPG was confirmed by analyzing HRMS fingerprints from shredded tires. RR samples from each site, DPG and BZT were of relatively low toxicity (no mortality) to zebrafish embryos, but all generated distinct and marked stress responses in the light–dark transition test, while DPG/BZT mixes abolished this effect. The moderate-traffic RR and DPG inhibited mitochondrial complex I. Our study highlights (i) the unpredictability of pollutants cocktail effect and (ii) the importance of a multi-approaches strategy to characterize environmental matrices, essential for their management at the source and optimization of depollution devices.

Projected changes in temperature and precipitation in mid-latitude wet regions are expected to significantly affect forest ecosystems. We studied the physiological and shoot growth responses of Abies holophylla and Abies koreana seedlings to warming (3◦C above ambient temperature) and increased precipitation (irrigation with 40% of rainfall) treatments under open-field conditions. The physiological parameters, quantified by the net photosynthetic rate, transpiration rate, stomatal conductance, and total chlorophyll content, were monitored from July to October 2018. Shoot growth (i.e., root collar diameter and height) was assessed in August and December 2018. Irrespective of the treatments, the physiological parameters of both species decreased from July to August under warming treatment due to heat stress before recovering in September and October. Warming alone (W) and warming along with increased precipitation (W*P) decreased the physiological activities of both species in July, August, and September, with more pronounced effects on A. koreana compared with A. holophylla. Increased precipitation resulted in the increased chlorophyll content of both species in October. Shoot growth was not generally affected by the treatments, except for a subtle reduction in height under W*P for A. koreana. A. holophylla had consistently higher values for the physiological parameters and shoot growth than A. koreana. Our results indicate that the physiological activities of the Abies species could be seriously reduced under climate change, with a more severe impact on A. koreana. Among the two species, A. holophylla appears to be a more robust candidate for future forest planting. Validerad;2022;Nivå 2;2022-02-16 (sofila);Funder: Agence de l’Eau Seine Normandie; Office Français de la Biodiversité;For correction, see: Gasperi, J.; Le Roux, J.; Deshayes, S.; Ayrault, S.; Bordier, L.; Boudahmane, L.; Budzinski, H.; Caupos, E.; Caubrière, N.; Flanagan, K.; Guillon, M.; Huynh, N.; Labadie, P.; Meffray, L.; Neveu, P.; Partibane, C.; Paupardin, J.; Saad, M.; Varnede, L.; Gromaire, M.-C. Correction: Gasperi et al. Micropollutants in Urban Runoff from Traffic Areas: Target and Non-Target Screening on Four Contrasted Sites. Water 2022, 14, 2215. https://doi.org/10.3390/w14142215

International audience

International audience; Monitoring the removal of organic micropollutants (OMPs) in advanced wastewater treatment facilities requires expensive and time-consuming analytical methods that cannot be installed online. Spectroscopic techniques such as fluorescence excitation/emission spectroscopy were demonstrated to offer the potential for monitoring OMPs removal in conventional wastewater treatment plants or ozonation pilots but their application to activated carbon (AC) adsorption processes was only investigated at lab scale and not in real treatment facilities. In this study, indexes from fluorescence emission/excitation matrices (EEMs) were used to find correlations with the removal of 28 OMPs from a large-scale AC pilot in fluidized bed employed for wastewater advanced treatment, as well as from batch experiments. Differences in OMPs removal could be observed depending on the operational conditions (i.e. pilot or batch experiments, contact time, type of AC) and the physico-chemical properties of the molecules. 7 PARAFAC components were derived from the fluorescence EEMs of 60 samples obtained before and after adsorption. Positive correlations were obtained between the removal of fluorescence indexes and most OMPs, and correlation coefficients were much higher than the ones obtained with UV254, confirming the interesting potential of fluorescence spectroscopy to accurately monitor adsorption performances at the industrial scale. The highest correlation coefficients were obtained for OMPs having the best removals while the ones that were refractory to adsorption, as well as to interactions with DOM, exhibited weak correlations. These results suggest that interactions between OMPs and fluorescing DOM and their subsequent co-adsorption onto AC were at the origin of the correlations found. Lower correlations were also found for the most biodegradable OMPs, which indicated that the occurrence of biological effects could make the monitoring of these compounds more challenging.

International audience; An old industrial site (brownfield) located south of Paris in a flooding plain and containing demolition disposal as well as a burning zone for metal recovery is being regenerated to satisfy local need for public green space. The main objective of the described study was therefore to assess the risk of remobilisation of trace metals, PAH and PCB present. The research focused on vertical migration due to rainfall (non-saturated flow) and to river flooding (saturated flow). To assess the remobilisation risk, representative soil profiles were reconstituted and eluted in columns with artificial rain and filtered river water for six weeks with an equivalent of 25 mm d−1. Soil analysis showed that both zones are highly contaminated, exceeding the French environmental standards. Though the superficial metal content was much higher in the burning zone with levels of g kg−1 than in the demolition zone, most metals showed higher levels in the eluents of the latter. The level of dissolved Zn in the burningzone eluent was 30 µg L−1 while in the demolition-zone it was 300 µg L−1 , 40 times the admissible level. Zn was thereby correlated to aromaticity parameter HIX, indicating a link with organic matter transformation. The Cu was only significantly released under saturated condition (up to 80 µg L−1) in the demolition soil, indicating as implicated mechanism manganese and iron oxide reduction rather than organic matter transformation. Despite the high PAH and PCB soil contents, these pollutants were not released. The total PAH content in the effluent was 30 ng L−1 in average and did not significantly differ between the two zones and the types of hydrology. Only Zn and Cu issued from demolition zone presented an eco-toxicological risk. Crossed statistical analysis of the results showed that the role of the soil type is preponderant in the pollutant release and that temporary flooding condition would induce a lower impact on the ground water quality than an equivalent amount of fallen rain. Though the burning site was far more contaminated in the upper soil than the demolition zone, it presented little risk compared to the demolition-zone, more profound and more permeable. The latter showed therefore significative trace metal release, up to 2.1 kg ha−1 year−1 for zinc, doubling the local atmospheric deposition.

International audience; Non-target screening (NTS) has gained interest in recent years for environmental monitoring purposes because it enables the analysis of a large number of pollutants without predefined lists of molecules. However, sample preparation methods are diverse, and few have been systematically compared in terms of the amount and relevance of the information obtained by subsequent NTS analysis. The goal of this work was to compare a large number of sample extraction methods for the unknown screening of urban waters. Various phases were tested for the solid-phase extraction of micropollutants from these waters. The evaluation of the different phases was assessed by statistical analysis based on the number of detected molecules, their range, and physicochemical properties (molecular weight, standard recoveries, polarity, and optical properties). Though each cartridge provided its own advantages, a multilayer cartridge combining several phases gathered more information in one single extraction by benefiting from the specificity of each one of its layers

International audience; Highlights 17 • 7 commercial µGACs were characterized and tested with real wastewater 18 • A percentage of microporous volume higher than 65% reduced OMPs adsorption 19 • DOM reduced the adsorption of negatively-charged OMPs more than positive ones 20 • OMPs charge, hydrophobicity and minimal projection area influenced their adsorption 21 • The µGACs particle size had an impact on UV254 removal in continuous column tests 22 Graphical abstract 23 2 24 Abstract 25 Most studies dedicated to organic micropollutants (OMPs) removal from wastewater effluents by adsorption 26 onto activated carbon (AC) only consider a few conventional AC properties. The link between OMPs removal 27 and these properties is often missing, which limits the understanding of the adsorption process and the 28 interpretation of the results. The chemical, physical and textural properties of seven newly commercialized 29 micro-grain activated carbons (µGACs) were determined to assess their influence on the removal of 28 OMPs. 30 Conventional batch tests with wastewater effluent showed that a high percentage of microporous volume (> 31 65%) was detrimental for the removal of 10 OMPs, probably due to a higher blockage of micropores by 32 dissolved organic matter (DOM). The removal of 5 OMPs was correlated with µGACs surface chemistry 33 properties (i.e. charge) which were potentially modified by DOM adsorption or inorganic species, thus 34 favoring the adsorption of positively-charge compounds. A combination of OMPs properties including their 35 charge, hydrophobicity and minimal projection area could explain their removal. Correlations were found 36 between the removal of several OMPs and UV254 and dissolved organic carbon, suggesting that DOM and 37 OMPs interacted with each other or followed similar adsorption mechanisms. A decrease in µGACs particle 38 size had a positive impact on UV254 removal under continuous-flow conditions in columns representative of a 39 large-scale pilot due to better expansion. 40

International audience

International audience; The potential formation of nitrogenous disinfection byproducts (N-DBPs) was investigated from the chloramination of nitrogenous and non-nitrogenous aromatic compounds. All molecules led to the formation of known N-DBPs (e.g., dichloroacetonitrile, dichloroacetamide) with various production yields. Resorcinol, a major precursor of chloroform, also formed di/trichloroacetonitrile, di/trichloroacetamide, and haloacetic acids, indicating that it is a precursor of both N-DBPs and carbonaceous DBPs (C-DBPs) upon chloramination. More detailed experiments were conducted on resorcinol to understand N-DBPs formation mechanisms and to identify reaction intermediates. Based on the accurate mass from high resolution Quadrupole Time-of-Flight GC–MS (GC–QTOF) and fragmentation patterns from electronic impact and positive chemical ionization modes, several products were tentatively identified as nitrogenous heterocyclic compounds (e.g., 3-chloro-5-hydroxy-1H-pyrrole-2-one with dichloromethyl group, 3-chloro-2,5-pyrroledione). These products were structurally similar to the heterocyclic compounds formed during chlorination, such as the highly mutagenic MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) or halogenated pyrroles. To our knowledge, this is the first time that the formation of halogenated nitrogenous heterocyclic compounds is reported from chloramination process. The formation of these nitrogenous byproducts during chloramination might be of concern considering their potential toxicity.

International audience; Advanced processes for the removal of organic micropollutants (OMPs) from wastewater effluents include adsorption onto activated carbon, ozonation, or a combination of both processes. The removal of 28 OMPs present in a real wastewater effluent was studied by ozonation coupled to activated carbon adsorption and compared to a sole adsorption. The influence of the specific ozone dose (0.09–1.29 gO3/gDOC) and the influence of the powdered activated carbon (PAC) dose (2, 5 and 10 mg/L) were first studied separately. OMPs removal increased with both the specific ozone dose (up to 80% for a dose higher than 0.60 gO3/gDOC) and the PAC dose. Ozonation performances decreased in presence of suspended solids, which were converted to dissolved organic carbon. A correction of the specific ozone dose according to the suspended solids levels, in addition to nitrite, should be considered. The influence of ozonation (0.09, 0.22, 0.94 and 1.29 gO3/gDOC) on OMPs adsorption was then assessed. OMPs adsorption didn’t change at low specific ozone doses but increased at higher specific ozone doses due to a decrease in DOM adsorption and competition with OMPs. At low ozone doses followed by adsorption (0.22 gO3/gDOC and 10 mg/L PAC), the two processes appeared complementary as OMPs with a low reactivity toward ozone were well absorbed onto PAC while most OMPs refractory to adsorption were well eliminated by ozone. Improved removals were obtained for all compounds with these selected doses, reaching more than 80% removal for most OMPs while limiting the formation of bromate ion.

Runoff infiltration in Sustainable Drainage Systems enables the interception of a part of urban contaminant fluxes owing to several processes. The soil's ability to retain dissolved pollutants is generally assessed via sorption isotherms obtained from batch studies; however, the experimental points are not always in the same range as runoff concentrations. The present work (i) explores the consequences of modelling runoff–soil interactions from out-of-range equilibrium concentrations and (ii) proposes an improved method to ensure that experimental points fall within the desired range. Uncertainty analysis demonstrates that for a non-linear isotherm, using an extrapolated relationship may introduce significant biases in the ensuing estimations. Therefore, the proposed method consists of anticipating the equilibrium state of batch tests to accurately set the experimental conditions and reach appropriate concentrations. It is successfully applied to the determination of the sorption properties of copper and zinc onto three soils with different electrolyte solutions, as well as those of bisphenol A and three alkylphenols onto one soil. The contrasting affinities between the studied species and the soil materials could be related to their intrinsic properties and the soils' pedological parameters, as well as the presence of salt or dissolved organic ligands which partially inhibited metal sorption.

The authors would like to thank Céline Briand and Julien Pouillaude (SIAAP), Barbara Giroud (ISA) and Séverine Bareilles (Saur).; International audience; Several advanced treatments, such as ozonation or activated carbon adsorption, are currently considered for the removal of organic micropollutants (OMPs) in wastewater treatment plants (WWTP). However, little is known on the overall performances of a WWTP upgraded with those processes and the benefits provided regarding the elimination of multiple families of OMPs. In this study, 5 sampling campaigns were performed to determine the removal of 48 OMPs in a WWTP followed by an activated carbon pilot. The primary treatment had no effect on OMPs (removals 60%). The additional elimination provided by the advanced treatment was not significant (30%) for recalcitrant OMPs. Removals higher than 60% were obtained for all OMPs (except azithromycin and sulfamethoxazole) over the WWTP and the activated carbon pilot. The adsorption conditions (10 g/m3 fresh activated carbon addition) were not sufficient to achieve the 80% removal targeted in Switzerland for compounds suggested as indicator substances for wastewater treatment. A higher dose of activated carbon or the combination with another advanced treatment should be used to achieve a satisfactory removal of those compounds.

International audience; The presence of dissolved organic matter (DOM) in wastewater effluents is recognized as the main factor limiting the adsorption of organic micropollutants (OMPs) onto activated carbon. The degree of the negative effect that DOM, depending on its quality, exerts on OMPs adsorption is still unclear. The influence of the interactions between DOM and OMPs on their removal is also not fully understood. Adsorption isotherms and conventional batch tests were performed in ultra-pure water and in wastewater effluent to study the influence of DOM on the adsorption of 12 OMPs onto powdered activated carbon. Best fit of adsorption pseudo-isotherms was obtained with the Freundlich equation and showed, as expected, that OMPs adsorption was higher in ultra-pure water than in wastewater effluent due to the presence of DOM leading to pore blockage and competition for adsorption sites. LC-OCD analysis revealed that biopolymers and hydrophobic molecules were the most adsorbed fractions while humic acids were not removed after a contact time of either 30 min or 72 h. The presence of DOM had a negative impact on the removal of all OMPs after 30 min of adsorption, but similar removals to ultra-pure water were obtained for 6 OMPs after 72 h of adsorption. This demonstrated that competition between DOM and OMPs for adsorption sites was not a major mechanism as compared to pore blockage, which only slowed down the adsorption and did not prevent it. The charge of OMPs had a clear impact: the adsorption of negatively charged compounds was reduced in the presence of wastewater effluent due to repulsive electrostatic interactions with the adsorbed DOM and the PAC surface. On the other hand, the removal of positively charged compounds was improved. A 24 h pre-equilibrium between OMPs and DOM improved their removal onto PAC, which suggest that OMPs and DOM interacted in solution which decreased the negative effects caused by the presence of DOM, e.g. through co-adsorption of an OMP-DOM complex.

International audience; Cet ouvrage synthétise les connaissances scientifiques récentes sur les micropolluants dans les agglomérations urbaines. Il a pour ambition d’apporter des éléments de réponse aux interrogations opérationnelles des acteurs du domaine de l’eau et de l’assainissement et de favoriser ainsi une prise de conscience et des actions pour une meilleure gestion des micropolluants.Il s’appuie essentiellement sur les travaux des trois observatoires français en hydrologie urbaine (OPUR à Paris, OTHU à Lyon et ONEVU à Nantes), structurés autour de partenariats durables entre chercheurs et acteurs opérationnels. Depuis une vingtaine d’années, ces observatoires produisent des données et des connaissances sur les sources et les transferts des micropolluants et sur l’efficacité des différentes stratégies de gestion des eaux urbaines.Élaboré au sein du groupe « Micropolluants » de l’association ARCEAU-IdF avec le soutien et le financement de l’Agence française pour la biodiversité, cet ouvrage représente une étape importante dans le transfert des connaissances entre les chercheurs et les opérationnels. Il constitue un premier outil pour l’animation et la construction d’actions en faveur de la protection de l’environnement.

International audience; The reclamation and disinfection of waters impacted by human activities (e.g., wastewater effluent discharges) are of growing interest for various applications but has been associated with the formation of toxic nitrogenous disinfection byproducts (N-DBPs). Monochloramine used as an alternative disinfectant to chlorine can be an additional source of nitrogen in the formation of N-DBPs. Individual toxicity assays have been performed on many DBPs, but few studies have been conducted with complex mixtures such as wastewater effluents. In this work, we compared the cytotoxicity and genotoxicity of wastewater effluent organic matter (EfOM) before and after chloramination. The toxicity of chloraminated EfOM was significantly higher than the toxicity of raw EfOM, and the more hydrophobic fraction (HPO) isolated on XAD-8 resin was more toxic than the fraction isolated on XAD-4 resin. More DBPs were also isolated on the XAD-8 resin. N-DBPs (i.e., haloacetonitriles or haloacetamides) were responsible for the majority of the cytotoxicity estimated from DBP concentrations measured in the XAD-8 and XAD-4 fractions (99.4% and 78.5%, respectively). Measured DBPs accounted for minor proportions of total brominated and chlorinated products, which means that many unknown halogenated compounds were formed and can be responsible for a significant part of the toxicity. Other non-halogenated byproducts (e.g., nitrosamines) may contribute to the toxicity of chloraminated effluents as well.

International audience

International audience; Peroxydisulfate (PDS) is an appealing oxidant for contaminated groundwater and toxic industrial wastewaters. Activation of PDS is necessary for application because of its low reactivity. Present activation processes always generate sulfate radicals as actual oxidants which unselectively oxidize organics and halide anions reducing oxidation capacity of PDS and producing toxic halogenated products. Here we report that copper oxide (CuO) can efficiently activate PDS under mild conditions without producing sulfate radicals. The PDS/CuO coupled process is most efficient at neutral pH for decomposing a model compound, 2,4-dichlorophenol (2,4-DCP). In a continuous-flow reaction with an empty-bed contact time of 0.55 min, over 90% of 2,4-DCP (initially 20 μM) and 90% of adsorbable organic chlorine (AOCl) can be removed at the PDS/2,4-DCP molar ratio of 1 and 4, respectively. Based on kinetic study and surface characterization, PDS is proposed to be first activated by CuO through outer-sphere interaction, the rate-limiting step, followed by a rapid reaction with 2,4-DCP present in the solution. In the presence of ubiquitous chloride ions in groundwater/industrial wastewater, the PDS/CuO oxidation shows significant advantages over sulfate radical oxidation by achieving much higher 2,4-DCP degradation capacity and avoiding the formation of highly chlorinated degradation products. This work provides a new way of PDS activation for contaminant removal.

This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Environmental Science and Technology, copyright © American Chemical Society after peer review. To access the final edited and published work, see http://pubs.acs.org/articlesonrequest/AOR-PZQAsn3W2QUHRHZIYIv7; International audience; The kinetics of decomposition of the pharmaceutical ranitidine (a major precursor of NDMA) during chloramination was investigated and some decomposition by-products were identified by using high performance liquid chromatography coupled with mass spectrometry (HPLC MS). The reaction between monochloramine and ranitidine followed second order kinetics and was acid-catalyzed. Decomposition of ranitidine formed different by-products depending on the applied monochloramine concentration. Most identified products were chlorinated and hydroxylated analogues of ranitidine. In excess of monochloramine, nucleophilic substitution between ranitidine and monochloramine led to by-products that are critical intermediates involved in the formation of NDMA, e.g. a carbocation formed from the decomposition of the methylfuran moiety of ranitidine. A complete mechanism is proposed to explain the high formation yield of NDMA from chloramination of ranitidine. These results are of great importance to understand the formation of NDMA by chloramination of tertiary amines.

International audience; Water treatment utilities are diversifying their water sources and often rely on waters enriched in nitrogen-containing compounds (e.g., ammonia, organic nitrogen such as amino acids). The disinfection of waters exhibiting high levels of nitrogen has been associated with the formation of nitrogenous disinfection byproducts (N-DBPs) such as haloacetonitriles (HANs) and haloacetamides (HAcAms). While the potential precursors of HANs have been extensively studied, only few investigations are available regarding the nature of HAcAm precursors. Previous research has suggested that HAcAms are hydrolysis products of HANs. Nevertheless, it has been recently suggested that HAcAms can be formed independently, especially during chloramination of humic substances. When used as a disinfectant, monochloramine can also be a source of nitrogen for N-DBPs. This study investigated the role of aromatic organic matter in the formation of N-DBPs (HAcAms and HANs) upon chloramination. Formation kinetics were performed from various fractions of organic matter isolated from surface waters or treated wastewater effluents. Experiments were conducted with (15)N-labeled monochloramine ((15)NH2Cl) to trace the origin of nitrogen. N-DBP formation showed a two-step profile: (1) a rapid formation following second-order reaction kinetics and incorporating nitrogen atom originating from the organic matrix (e.g., amine groups); and (2) a slower and linear increase correlated with exposure to chloramines, incorporating inorganic nitrogen ((15)N) from (15)NH2Cl into aromatic moieties. Organic matter isolates showing high aromatic character (i.e., high SUVA) exhibited high reactivity characterized by a major incorporation of (15)N in N-DBPs. A significantly lower incorporation was observed for low-aromatic-content organic matter. (15)N-DCAcAm and (15)N-DCAN formations exhibited a linear correlation, suggesting a similar behavior of (15)N incorporation as SUVA increases. Chloramination of aromatic model compounds (i.e., phenol and resorcinol) showed higher HAcAm and HAN formation potentials than nitrogenous precursors (i.e., amino acids) usually considered as main precursors of these N-DBPs. These results demonstrate the importance of aromatic organic compounds in the formation of N-DBPs, which is of significant importance for water treatment facilities using chloramines as final disinfectant.

International audience; The aim of this study was to assess the formation and the behavior of halogenated byproducts (regulated THMs and HAAs, as well as nitrogenous, brominated and iodinated DBPs including the emerging iodo-THMs) along the treatment train of full-scale desalination plants. One thermal multi-stage flash distillation (MSF) plant and two reverse osmosis (RO) plants located on the Red Sea coast of Saudi Arabia. DBPs formed during the prechlorination step were efficiently removed along the treatment processes (MSF or RO). Desalination plants fed with good seawater quality and using intermittent chlorine injection did not show high DBP formation and discharge. One RO plant with a lower raw water quality and using continuous chlorination at the intake formed more DBPs. In this plant, some non-regulated DBPs (e.g., dibromoacetonitrile and iodo-THMs) reached the product water in low concentrations (< 1.5 μg/L). Regulated THMs and HAAs were far below their maximum contamination levels set by the US Environmental Protection Agency. Substantial amounts of DBPs are disposed to the sea, low concentrations of DBPs were indeed detected in the water on shore of the desalination plants.

The aim of this work was to study the formation of haloacetamides (HAcAms) and other DBPs during chlorination and chloramination of algal organic matter (AlOM). The HAcAms formation potentials of different precursors (amino acids, simulated algal blooms grown in the Red Sea) were evaluated. Experiments with simulated algal blooms were conducted in the presence of bromide ion (synthetic seawater containing 800 μg/L Br−) to assess the formation of brominated analogues of HAcAms in conditions close to the disinfection of real seawater. Chlorination produced more HAcAms than chloramination from real algae (Synecococcus sp.), thus indicating that the nitrogen of HAcAms comes predominantly from DON through the decarboxylation of amino acids rather than from NH2Cl. Dibrominated species of DBPs (i.e., DBAcAm, DBAA and DBAN) were the dominant species formed by both chlorination and chloramination of algal bloom samples. Chloramination of the amino acid asparagine produced an important amount of DCAcAm as compared to chlorination, indicating the existence of a specific reaction pathway.

This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Environmental Science and Technology, copyright © American Chemical Society after peer review. To access the final edited and published work, see http://pubs.acs.org/articlesonrequest/AOR-6RuSadaMistH66ezzxrD; International audience; The formation of NDMA and other DBPs (including THMs, HANs, HKs) has been investigated by chloramination of several tertiary amines in the absence and in the presence of bromide ion. NDMA formation from the most reactive tertiary amines (e.g. dimethylaminomethylfurfuryl alcohol or DMP30) was enhanced in the presence of bromide due to the formation of brominated oxidant species such as bromochloramine (NHBrCl) and the hypothetical UDMH-Br as an intermediate. The formation of NDMA by chloramination of less reactive model compounds was inhibited in the presence of bromide. This can be explained by competitive reactions leading to the production of brominated DBPs (i.e. THMs). In the presence of bromide, the formation of brominated THMs during chloramination can be attributed to the presence of small amounts of HOBr produced by the decomposition of chloramines and bromamines. The results are of particular interest to understand NDMA formation mechanisms, especially during chloramination of wastewaters impacted by anthropogenic tertiary amines and containing bromide ion.

©IWA Publishing 2011. The definitive peer-reviewed and edited version of this article is published in Water Research 45(10), Pages 3164–3174, 2011, DOI: 10.1016/j.watres.2011.03.035 and is available at www.iwapublishing.com.; International audience; Disinfection with chloramines is often used to reduce the production of regulated disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). However, chloramination can lead to the formation of N-nitrosamines, including N-nitrosodimethylamine (NDMA), a probable human carcinogen. Previous research used dimethylamine (DMA) as a model precursor of NDMA, but certain widely used tertiary dimethylamines (e.g. the pharmaceutical ranitidine) show much higher conversion rates to NDMA than DMA. This study investigates the NDMA formation potential of several tertiary amines including pharmaceuticals and herbicides. The reactivity of these molecules with monochloramine (NH2Cl) is studied through the formation of NDMA, and other halogenated DBPs such as haloacetonitriles (HANs) and AOX (Adsorbable Organic Halides). Several compounds investigated formed NDMA in greater amounts than DMA, revealing the importance of structural characteristics of tertiary amines for NDMA formation. Among these compounds, the pharmaceutical ranitidine showed the highest molar conversion to NDMA. The pH and dissolved oxygen content of the solution were found to play a major role for the formation of NDMA from ranitidine. NDMA was formed in higher amounts at pH around pH 8 and a lower concentration of dissolved oxygen dramatically decreased NDMA yields. These findings seem to indicate that dichloramine (NHCl2) is not involved into the formation of NDMA from ranitidine. Dissolved oxygen was also found to influence the formation of other oxygen-containing DBPs (i.e. trichloronitromethane and haloketones), which shows that dissolved oxygen could be incorporated into those DBPs. The results of this study identify several anthropic precursors of NDMA, indicating that chloramination of waters impacted by these tertiary amines could lead to the formation of important amounts of NDMA and other non-regulated DBPs of potential health concern (e.g. dichloroacetonitrile or trichloronitromethane). This could be of particular importance for the chloramination of wastewater effluents, especially during water reuse processes.

International audience; Disinfection with chloramines is known to significantly reduce the formation of regulated disinfection by-products (i.e. trihalomethanes and haloacetic acids) as compared to chlorination. Moreover, monochloramine can be added to wastewater prior to reuse processes to avoid biofouling of membranes. However, chloramination favors the formation of N-nitrosamines, including N-nitrosodimethylamine (NDMA), a probable human carcinogen. The formation mechanisms of NDMA are not fully understood. Proposed mechanisms used dimethylamine as a model precursor, but some studies indicated that amounts of dimethylamine present in surface waters or secondary municipal wastewaters cannot be sufficient to explain the amount of NDMA formed. The potential importance of tertiary amines presenting dimethylamine functional groups (e.g. ranitidine, a histamine antagonist often used for peptic ulcer treatment) has been pointed out. In this study, NDMA formation potential of several nitrogen-containing organic compounds from the reaction with monochloramine is investigated. All of these compounds are tertiary amines presenting DMA functional groups. The variety of compounds was chosen to understand the role of molecular structures in the formation of NDMA. Simultaneous analysis of nitrosamines in aqueous samples is based on a solid-phase extraction procedure followed by gas chromatography/mass spectrometry analysis in electron impact ionization mode. This method reaches extraction efficiencies of ~85 %, and a method detection limit of 33 ng/L. Preformed monochloramine with a Cl:N molar ratio of 1:1.2 is used for chloramination experiments. Compounds presenting heterocyclic rings substituted with DMA functions (e.g. dimethylaminomethylfurfuryl alcohol) show much higher conversion rates to NDMA than other tertiary amines or DMA. New formation mechanisms have to be proposed to explain the importance of structural characteristics of tertiary amines compounds for NDMA formation. The concentration of dissolved oxygen was found to play a major role for NDMA formation. With ranitidine, in absence of dissolved oxygen almost no NDMA was formed, while the NDMA molar yield was 54 % in saturated O2 solution. The presence of bromide also significantly enhanced the formation of NDMA during the chloramination of dimethylamine and dimethylaminomethyl-furfuryl alcohol. This is of great concern regarding wastewater reuse, because the chloramination of bromide-containing wastewaters could lead to significant amounts of NDMA.

International audience; Chloramination is used to reduce the formation of regulated disinfection by-products (i.e. trihalomethanes and haloacetic acids), or to avoid biofouling of membranes during wastewater reclamation processes. However, chloramination favors the formation of N-nitrosodimethylamine (NDMA), a human carcinogen. Proposed NDMA formation mechanisms used dimethylamine as a model precursor, but some anthropogenic tertiary amines presenting dimethylamine (DMA) functional groups have been demonstrated to lead to important amounts of NDMA (e.g. the pharmaceutical ranitidine). In this study, the mechanisms of NDMA formation by chloramination of tertiary amines (including model compounds presenting aromatic or heterocyclic rings, e.g. (dimethylaminomethyl)furfuryl alcohol (DFUR) or ranitidine) were studied. Compounds presenting heterocyclic rings substituted with DMA functions (e.g. DFUR, ranitidine) show much higher conversion rates to NDMA than other tertiary amines or DMA. A mechanism is proposed to explain the high yields of NDMA obtained from the decomposition of these tertiary amines during chloramination. This mechanism is based on the production of a carbocation intermediate formed from the methylated aromatic moieties present in the compounds, favouring the release of NDMA.