The fate and behavior of selected endocrine disrupting chemicals in full scale wastewater and sludge treatment unit processes

Endocrine disrupting chemicals are discharged into the environment mainly through wastewater treatment processes. There is a need for better understanding of the fate of these compounds in the unit processes of treatment plant to optimize their removal. The fate of oestrone, 17β-estradiol, 17α-ethinyestradiol and nonylphenol in the unit processes of full scale wastewater treatment plants in the UK, including activated sludge plant, oxidation ditch, biofilter and rotating biological contractor were investigated. The overall removal efficiencies of all the compounds ranged from 41 % to 100 %. The removals were predominantly during the secondary biological treatment with the rates of removal related to the nitrification rates and the sludge age. The removal efficiency of the treatment processes were in the order activated sludge > oxidation ditch > biofilter > rotating biological contractors. Activated sludge plant configured for biological nutrient removal showed better removal of the endocrine disrupting chemicals compared to conventional activated sludge plant effluents. Tertiary treatment was also significant in the removal process through solids removal. Overall mechanisms of removal were biodegradation and sorption unto sludge biomass. Phytoremediation was also significant in the removal processes. The endocrine disrupting chemicals persisted in the anaerobic sludge digestion process with percentage removals ranging fro 10-48 %. Sorption of the endocrine disrupting chemicals onto the sludge increased with increasing values for the partitioning coefficients and the organic carbon contents of the sludge

Distribution d'estrogènes et de bêtabloquants dans les stations d'épuration des eaux résiduaires et dans les eaux de surface

Estrogens and beta blockers are daily excreted by human beings and wastewater treatment plants are recognised as the main pathway of these emerging micropollutants to the aquatic environment. This study aims at analyzing 5 estrogens (estrone, 17α- and 17β-estradiol, estriol, 17α-ethynylestradiol) and 10 beta blockers (acebutolol, atenolol, betaxolol, bisoprolol, metoprolol, nadolol, oxprenolol, propranolol, sotalol et timolol) in urban wastewater treatment plants and surface waters. First of all, methods were developed for the analysis of target molecules in sewage sludge and suspended particulate matters. Then, estrogens and beta blockers were studied in urban wastewater treatment plants. Generally, wastewater treatments are efficients to remove estrogens from wastewater with mean removal rates above 90%. For beta blockers, acebutolol and nadolol are efficiently removed (mean removal rates of about 80%), while sotalol and propranolol are hardly impacted by wastewater treatment (mean removal rates below 20%). Other studied beta blockers present intermediate removal rates (between 40 and 70%). Except propranolol which is the less hydrophilic molecule among the different studied beta blockers, target molecules are not adsorbed on suspended particulate matters (mean proportion of 90% of the target molecules are present in the dissolved phase) and are not concentrated into sludge. So, calculated removal rates correspond, except for propranolol, to biodegradation and not to transfer into sludge. Residual molecules which are not removed by wastewater treatment reach the aquatic environment. The impact of wastewater treatment plants on the receiving rivers was studied showing a clear increase of target molecules concentrations near the wastewater treatment plants outfall. However, only propranolol presented an environmental risk ratio in the range or above 1 showing a possible environmental risk in 4 studied receiving waters out of 15. Nevertheless, even if no specific toxic effects are pointed out, each molecule contributes to the overall toxic potential of the substances present in the aquatic environment.Les estrogènes et les bêtabloquants transitent quotidiennement par les réseaux d'assainissement et les stations d'épuration des eaux résiduaires urbaines. Une première partie de ce travail a consisté à développer des méthodes pour analyser ces micropolluants émergents dans les boues de station d'épuration et les matières en suspension. L'efficacité des traitements épuratoires a ensuite été évaluée vis-à-vis de l'élimination de ces molécules. En règle générale, les 5 estrogènes étudiés (estrone, 17α- et 17β-estradiol, estriol, 17α-éthinylestradiol) sont plutôt bien éliminés par les stations d'épuration avec des efficacités d'élimination généralement supérieures à 90%. Pour les 10 bêtabloquants analysés (acébutolol, aténolol, bêtaxolol, bisoprolol, métoprolol, nadolol, oxprénolol, propranolol, sotalol et timolol), des comportements différents ont été observés. Alors que l'acébutolol et le nadolol sont éliminés (abattements moyens supérieurs à 80%), d'autres molécules comme le sotalol et le propranolol ne sont que peu impactées par les traitements épuratoires (abattements moyens inférieurs à 20%). Pour les autres bêtabloquants étudiés, des abattements intermédiaires (entre 40 et 70%) sont observés. Excepté le propranolol, qui est le plus hydrophobe des bêtabloquants étudiés, les molécules ciblées dans cette étude s'adsorbent peu sur les matières en suspension (en moyenne 90% des molécules se trouvent dans la phase dissoute) et ne sont pas concentrées dans les boues ; les abattements mesurés correspondent donc, sauf pour le propranolol, à une biodégradation et pas à un transfert des micropolluants vers les boues. Les molécules résiduelles non éliminées par le traitement épuratoire rejoignent le milieu aquatique récepteur. Les rejets de station d'épuration représentent en effet une source de contamination pour les milieux aquatiques et l'impact de ces rejets est visible, notamment en termes d'augmentation des concentrations de micropolluants mesurées dans le milieu. Néanmoins, les faibles concentrations mesurées ne semblent pas individuellement représenter de risque environnemental majeur ; seul le propranolol a présenté sur 4 des 15 sites étudiés un quotient de risque supérieur à 1 ce qui indique un risque environnemental probable. Cependant, même si le risque associé à une molécule est faible, chaque molécule présente dans l'environnement contribue au potentiel toxique global des substances présentes dans 'environnement

Développement et validation d'une méthode d'analyse par LC/MS/MS pour la quantification des estrogènes dans les boues

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [Axe_IRSTEA]TED-EPURE [TR2_IRSTEA]BELCAInternational audienceA sensitive method for the simultaneous analysis of five estrogens in sewage sludge was developed. The extraction and purification steps were optimized and the matrix effects were evaluated. The chromatographic gradient was optimized to limit matrix effects and the analysis step was performed by LC-MS/MS. The method consists of an ASE® extraction with a solvent mixture water/methanol 80/20v/v at 100°C followed by two consecutive purifications on Oasis HLB® and florisil cartridges. A thorough validation of the developed method was performed. Recoveries determined at two different spiking levels ranged between 86% and 126% depending on the molecule. Repeatability was evaluated on five replicates of the same sludge sample spiked at two different levels and measuring native estrogens in triplicates of 12 sludge samples. Relative standard deviations obtained a range of between 2% and 27%. Reproducibility was also studied by analyzing the same sludge on four different days: the relative standard deviation ranged between 14% and 20% for E1, βE2 and E3. For αE2, poor reproducibility (68%) was observed but it was linked to the very low quantity of αE2 present in the sludge sample and not to the method performance. The specificity of the method was evaluated on various sludge samples spiked at different spiking levels showing that performances of the proposed method were not modified by matrix effects. Finally, sensitivity of the method was evaluated taking into account both instrumental sensitivity and matrices; the estimated limits of quantification were around 1 ng/g for E1, between 2 and 4 ng/g for αE2, βE2, and E3 and around 5 ng/g for EE2