Risk and asset-based strategies in health: priorities in biomedical, life and environmental science literature since the early twentieth century. A rapid review.

BACKGROUND: In biomedical, life or environmental science research, two different strategies exist depending on the starting point of the researchers: "what makes us ill? " or "what makes us healthy?". Indeed, a risk-based strategy (RBS) attempts to minimize risk factors increasing the likelihood of developing a disease, while an asset-based strategy (ABS) attempts to promote and strengthen the factors that support good health and wellbeing. We provided an up-to-date overview of both research strategies in peer-reviewed scientific literature, in the fields of human health, animal and plant health and ecosystem health, to fit with the One Health framework. More particularly, we focused on human health by studying publications related to the COVID-19 at the beginning of the pandemic. DESIGN: A rapid review of research science literature was carried out to identify in the PubMed/MEDLINE database the proportion of peer-reviewed articles adopting either a RBS or an ABS, in the main global environment fields from January 01, 1900 to December 31, 2019 and, related to COVID-19, from December 1, 2019 to May 31, 2020. RESULTS: The number of published articles resulting from our search was 1,957,905, including 91.3% with an RBS and 8.7% with an ABS. When examining each field, we found that only 10.5% of human health articles deal with ABS, 5.5% for animal health, 2.2% for ecosystem health, 1.0% for plant health and 2.7% for environmental media. We noted that articles adopting both strategies were published in all health fields. Among the articles concerning COVID-19, 5,854 (55.9%), 542 articles (5.2%) adopted RBS and ABS, respectively, while 4069 (38.9%) simultaneously presenting both strategies. CONCLUSION: Our results have allowed us to take stock of the biomedical research strategies prioritized during the twentieth century. It seems highly likely that the two strategies we have analyzed can now be chosen in such a way as to promote a balance in public health measures, at every level to guide One Health interventions aimed at helping people, animals, and plants to lead healthier lives.

Impact of perinatal environmental health education intervention on exposure to endocrine disruptors during pregnancy-PREVED study: study protocol for a randomized controlled trial.

BACKGROUND: The suspected or actual effects on health of endocrine-disrupting chemicals (EDC) and their ubiquitous presence in everyday life justify the implementation of health promotion interventions. These interventions should ideally be applied during critical windows like pregnancy. Perinatal environmental health education interventions may help to reduce EDC exposure during pregnancy. METHODS/DESIGN: PREVED (Pregnancy, PreVention, Endocrine Disruptors) is an open-label randomized controlled trial assessing the impact of environmental health education intervention on EDC exposure during pregnancy. Inclusion, consent, and randomization take place during the first trimester. The participants are randomly allocated into three groups: (i) control group (information leaflet on EDCs), (ii) intervention group in neutral location (information leaflet and workshops in a meeting room), and (iii) intervention group in contextualized location (information leaflet and workshops in a real apartment). Workshops are organized between the second and third trimesters of pregnancy. Main outcome is the percentage of participants who reported consuming manufactured/industrial food. Secondary outcomes are as follows: (i) psycho-social dimensions, (ii) EDC concentrations in urine, (iii) EDC concentration in colostrum, and (iv) percentage of participants who reported consuming paraben-free personal care products. DISCUSSION: PREVED is a ground-breaking intervention research project dedicated to perinatal environmental health education that aims to identify pollutant sources in daily life and to offer accessible and realistic alternative solutions, by promoting the sharing of know-how and experience in a positive and non-alarmist approach. TRIAL REGISTRATION: ClinicalTrials.gov : NCT03233984 (current status: ongoing). Retrospectively registered on 31 July 2017 ( https://clinicaltrials.gov/ct2/show/NCT03233984 ) because when the first participant was enrolled in this non-drug intervention, ClinicalTrials.gov was centered in therapeutic trials. The World Health Organization Trial Registration Data Set is in Additional file 1.

Comparison of the Effect on Fetal Growth of a Mixture of Atrazine and Nitrates in Drinking Water and of Active Tobacco Exposure during Pregnancy.

Active tobacco exposure during pregnancy is a known determinant of fetal growth. Nitrates and atrazine metabolites in drinking water may affect fetal growth as a mixture of endocrine disruptors (ED). We aimed to determine whether EDC have an additional effect on fetal growth compared to active tobacco exposure. A historic cohort study was carried out with a sample stratified with regard to the maternity unit, drinking water exposure, and year of birth. The women included were living in Deux-Sèvres, had given birth between 2005 and 2010 in three selected maternity units, and ultrasound data were available in their obstetrical records. Mixed linear models were used to analyze fetal weight evolution from the second trimester to the time of birth according to drinking water exposure to EDC mixture and active tobacco exposure. We included 558 mother-neonate couples, of whom 9% were exposed to high doses of the mixture and 21% to active tobacco smoking. There was no difference in fetal weight evolution according to drinking water mixture exposure (0.97 g; 95% CI [-3.01; 4.94]). We could not show a supplementary effect of mixture exposure in drinking-water on fetal growth as compared to active tobacco exposure. Further research is needed, using more precise methods to estimate EDC exposure.

Perinatal Environmental Health Education Intervention to Reduce Exposure to Endocrine Disruptors: The PREVED Project.

Environmental health promotion interventions may reduce endocrine disruptor (ED) exposure. The PREVED (PREgnancy, preVention, Endocrine Disruptors) project was developed to improve knowledge, to enhance risk perception, and to change exposure behavior. Our objective was to present the phases of the PREVED project using the RE-AIM method. PREVED intervention consisted of three workshops during pregnancy. Reach, adoption, and implementation phases were assessed with qualitative studies. Efficacy study consisted of a three-arm randomized controlled trial (RCT) on 268 pregnant women: (i) control group (leaflet), (ii) intervention group in neutral location, (iii) intervention group in contextualized location. The main outcome was the percentage evolution of participants who reported consuming canned food. Secondary outcomes were evolution of psycho-social scores, evolution of ED presence in urine, and ED presence in colostrum. The intervention adoption was centered on upper-privileged women, but implementation assessment showed that key features (highly practical intervention) seemed to be carried out and had initiated some behavior changes. A total of 268 pregnant women participated in the intervention and 230 in a randomized controlled trial (control group: 86 and intervention groups: 172). We found no significant differences in consumption of canned food and in percentage of women having a decrease of bisphenol A or parabens in urine, but we found a significant increase in the evolution of risk perception score and overall psychosocial score in intervention groups (respectively: +15.73 control versus +21.03 intervention, p = 0.003 and +12.39 versus +16.20, p = 0.02). We found a significant difference in percentage of women with butylparaben detection between control group and intervention groups (13% versus 3%, p = 0.03). PREVED intervention is the first intervention research dedicated to perinatal environmental health education in France. By sharing know-how/experience in a positive non-alarmist approach, it improved risk perception, which is key to behavior change, aiming to reduce perinatal ED exposure. Including women in precarious situations remains a major issue.

How to Educate Pregnant Women about Endocrine Disruptors?

Background: Despite mediatization, only half of pregnant women are informed about endocrine disruptors (EDs). We wished to inquire about appropriate environmental health education procedures during pregnancy: Who, when, and how? Methods: The question stems from a comprehensive population health intervention research project. It includes qualitative studies aimed at constructing an educational program in environmental health and an accompanying assessment tool. The validation of a customized questionnaire (PREVED© for Pregnancy Prevention Endocrine Disruptors) about the knowledge, attitudes, and practices (KAP) of pregnant women regarding exposure to EDs was carried out in a quantitative study. Results: Health education by a prenatal professional with communication skills should take place as early as possible, during the preconception period or early pregnancy, as part of individual consultation or group workshops. In order to customize the discourse and to develop women's empowerment, concomitant presentation of the risks by the products used in each room and of previous solutions is recommended. Conclusion: Appropriate health education procedures on EDs should be done at every contact but taking the KAP of pregnant women into account first. We propose all educational actions should be accompanied by questioning of the KAP of pregnant women; for example, with questions from the PREVED© questionnaire.

Simultaneous determination of bisphenol A and its chlorinated derivatives in human plasma: Development, validation and application of a UHPLC-MS/MS method.

Bisphenol A (BPA) is a well-known ubiquitous chemical found in polycarbonate, polysulfone and epoxy resins, used in mass production for many consumer products. BPA exhibits endocrine disruptor properties that can potentially induce adverse health effects. In aquatic environments, it can react with chlorine to produce chlorinated derivatives (ClxBPAs). ClxBPAs exhibit oestrogenic activity 10 to 105 times higher than BPA itself. Assessing human exposure to endocrine disrupting chemicals is mandatory to assess health risk. Blood, as well as urine matrix, are commonly used to perform human biomonitoring. We therefore developed, fully validated and applied a method based on Ultra High Performance Liquid Chromatography couples to a Triple Quad Mass Spectrometer to determine BPA, monochlorobisphenol A (MCBPA), dichlorobisphenol A (DCBPA), trichlorobisphenol A (TCBPA) and tetrachlorobisphenol A (TTCBPA) in human blood plasma. The European Medicines Agency guidelines for bioanalytical method validation have been applied. Precision and trueness of the method were <15% at medium and high levels of quality control and <20% at the limits of quantification (LOQs). The LOQs were settled at 0.1 ng/mL for BPA, 0.02 ng/mL for TTCBPA and 0.005 ng/mL for MCBPA, DCBPA, and TCBPA. The analytical method was applied to ten patients suffering from end stage renal disease. BPA was quantified in all ten patients while MCBPA, DCBPA and TTCBPA were determined in three and TCBPA in four. In conclusion, we have successfully developed a highly sensitive method to determine BPA and ClxBPAs in human plasma. Thanks to this method, for the first time, we could demonstrate ClxBPAs occurrence in human blood.

Environmental Health Knowledge, Attitudes, and Practices of French Prenatal Professionals Working with a Socially Underprivileged Population: A Qualitative Study.

: Introduction: As environmental health knowledge of population is associated with social economic status, the objective of this study was to determine environmental health knowledge, attitudes, and practices of French prenatal professionals working with a socially underprivileged population. MATERIAL AND METHODS: A focus group with eleven prenatal professionals working with socially underprivileged population was carried out in France in 2015. Content analysis of verbatim explanation was conducted with choice-of-subject categories carried out according to the triangulation principle, and topic trees were generated and applied. RESULTS: The professionals have non-specialized experimental knowledge of emergent risks and were essentially preoccupied by infectious biological risks. In practice, however, they became increasingly cognizant of emergent risks. Their educational practices take cultural context into account but educational tools with imagination and affectivity have to be developed in order to reach socially underprivileged population. DISCUSSION: Professionals are often sensitized to the field of environmental health in their apprehension of polluted biological environments, which they associate with social contexts and behavioral factors. In this study, we recommend adapted training programs and updated professional guidelines in view of reducing prenatal emergent risk exposures and social inequalities of health.

Development and validation of an LC-MS/MS method for the simultaneous determination of bisphenol A and its chlorinated derivatives in adipose tissue.

Bisphenol A (BPA) and its chlorinated derivatives (Clx-BPA) are environmental pollutants exhibiting endocrine-disrupting (ED) properties suspected to be involved in the pathogenesis of hormone-dependent cancers, such as breast and prostate cancers. Due to their lipophilic properties, they may accumulate in adipose tissue which could therefore be a suitable matrix to assess long-term exposure to these compounds and relationships with the tumorigenesis of these cancers. An LC-MS/MS assay for the determination of BPA and Clx-BPA in adipose tissue samples was developed and fully validated according to current bioanalytical validation guidelines. Ionization was achieved using an electrospray source operating in the negative mode and quantification of target analytes was obtained in the multiple reaction monitoring mode. Both standard and quality control (QC) samples were prepared in blank adipose tissue samples. Linearity was demonstrated over the ranges 0.125 to 8.000 and 0.0125-0.8000 ng/mL for BPA and Clx-BPA, respectively. Accuracy and precision were demonstrated over the whole concentration range: intra and inter-day bias values were in the 85-114% range and imprecision of the method did not exceed 14%. Lower limits of quantification were validated using QCs at 0.1250 and 0.0125 ng/mL for BPA and Clx-BPA, respectively. Internal standard-corrected matrix effects were comparable in breast and prostate adipose tissues, demonstrating that this method could be used to reliably assay BPA and Clx-BPA in both tissues. The method was sensitive enough to determine BPA and Clx-BPA in breast adipose tissue obtained from women undergoing breast surgery, enabling identification of different patterns of exposure to these ED chemicals. The method enables the reliable quantification of BPA and Clx-BPA in adipose tissue and could be used to assess long-term exposure to these compounds and potential associations with hormone-dependent cancers.

Determinants of Risk Perception Related to Exposure to Endocrine Disruptors during Pregnancy: A Qualitative and Quantitative Study on French Women.

Endocrine disruptors (EDCs) are known as environmental exposure factors. However, they are rarely reported by health professionals in clinical practice, particularly during pregnancy, even though they are associated with many deleterious consequences. The objectives of this study were to estimate the risk perception of pregnant women related to EDC exposure and to evaluate its determinants. A qualitative study based on the Health Belief Model was carried out through interviews of pregnant women and focus group with perinatal, environmental health and prevention professionals in 2015 in the city of Poitiers, France. Then, determinants of risk perception were included in a questionnaire administered to 300 women in the perinatal period through a quantitative study. Scores were subsequently calculated. Perception of EDC risk was defined as perceived severity for different stages of the infant's development and perceived susceptibility to EDC exposure. The determinants reported in the qualitative study were: age, strong maternal figure, socio-professional category, level of knowledge, and involuntariness of exposure. Age and level of knowledge were confirmed in our statistical model as determinants. Mean score of EDC risk perception was 55.0 ± 18.3 on 100 points. Our study should guide healthcare providers when advising pregnant women about EDC and environmental exposure. Our score for perceived EDC risk and assessment of its known determinants may help to assess the impact and the relevance of prevention programs dedicated to reducing exposure to EDC during pregnancy.

Endocrine Disruptors and Pregnancy: Knowledge, Attitudes and Prevention Behaviors of French Women.

Endocrine disrupting chemicals (EDC) are environmental exposure factors that are rarely reported in clinical practice, particularly during pregnancy. This study aimed to describe women's knowledge, attitudes and behaviors towards EDC exposure. A study was conducted in the French Department of Vienne between 2014 and 2016 and comprised semi-structured interviews with pregnant women, a focus group of professionals in perinatology and environmental health, and the administration of a psychosocial questionnaire comprising scores in 300 pregnant or in postpartum period women. The mean score of knowledge was 42.9 ± 9.8 out of 100 (from 13.5 to 75.7). Exposure attitude was determined by risk perception. Mean level of cues to action to reduce their EDC exposure was estimated at 56.9 ± 22.5 out of 100 (from 0 to 100). Anxiety was significantly increased after the questionnaire. Anxiety about EDC was associated with a high score of knowledge (OR = 2.30, 95% CI (1.12-4.71)) and with no pregnancy anxiety (OR = 0.57, 95% CI (0.34-0.95)). Our findings suggest that healthcare providers should consider pregnant women's knowledge and perceptions, possibilities of action, and be careful not to increase their anxiety when advising them about EDC and environmental exposure.

Association between Exposure to Endocrine Disruptors in Drinking Water and Preterm Birth, Taking Neighborhood Deprivation into Account: A Historic Cohort Study.

BACKGROUND: The relationship between preterm birth (PTB) and endocrine disruptor exposure in drinking-water has only occasionally been studied. The objective of this work was to investigate the relation between exposure to atrazine metabolites, or atrazine/nitrate mixtures, in drinking-water during pregnancy and prevalence of PTB neonates, while taking neighborhood deprivation into account. METHOD: A historic cohort study in Deux-Sèvres, France, between 2005 and 2010 with a multiple imputation model for data of exposure to atrazine metabolites and a logistic regression were carried out. RESULTS: We included 13,654 mother/neonate pairs living in 279 different census districts. The prevalence of PTB was 4%. Average atrazine metabolite concentration was 0.019 ± 0.009 (0.014-0.080) µg/L and 39% of mothers lived in less deprived areas. The individual data were associated with risk of PTB. The risk of PTB when exposed to highest concentration of atrazine metabolite adjusted for confounders, was ORa 1.625 95% CI [0.975; 2.710]. Taking, or not, neighborhood deprivation into account did not change the result. Exposure to atrazine/nitrate mixtures remained non-significant. CONCLUSIONS: Even if we took neighborhood deprivation into account, we could not show a significant relationship between exposure to atrazine metabolites, or mixtures, in drinking-water during the second trimester of pregnancy and PTB.

Estimating drinking-water ingestion and dermal contact with water in a French population of pregnant women: the EDDS cohort study.

The aim of the present study, a part of the Endocrine Disruptor Deux-Sèvres (EDDS) cohort study, was to estimate water-use habits of pregnant French women. The study population consisted of 132 pregnant women living in Deux-Sèvres (France) in 2012-2013, in areas where drinking water is exclusively produced by surface water. Drinking-water data included ingested water (tap, bottled and filtered) and ingestion place (home, work and elsewhere). Dermal contact with water included showering, bathing, swimming, spa use, hand-washing and other water activities. Data were collected through face-to-face interviews at second and third trimesters of pregnancy with a 1-day-recall questionnaire. Intertrimestral differences in water-use habits were assessed. Predictors of water ingestion and duration of dermal contact with water were assessed with multiple linear regressions. At the second trimester of pregnancy, the mean total drinking-water ingestion was 1.8±0.6 l per day (mean and SD), 71% of which was tap water. Total drinking-water ingestion was not different between both trimesters but ingestion place differed. Dermal contact with water estimate was 188±118 and 173±92 min/week at second and third trimesters, respectively. Smoking increased water ingestion 777 ml/day 95% CI (171-1384). Duration of dermal contact in spring was 30 min/week 95% CI (13-48) higher than in winter. Obese women spend 26 min/week 95% CI (2-50) more showering than women with recommended weight. Our estimates of pregnant French women's exposure to water will help researchers to better assess water pollutant risks.

Bisphenol a and its chlorinated derivatives in human colostrum.

The health effects related to bisphenol A (BPA) and its exposure sources have undergone extensive investigation, but no consensus has been reached. Hitherto, the major source of human BPA exposure considered in the literature remains food-contact material. However, the chlorine present in drinking water may react with BPA to form chlorinated derivatives (ClxBPA), which have indeed been shown to have a heightened level of estrogenic activity. In this study, we have evaluated colostrum concentrations of BPA and ClxBPA in order to confirm our hypothesis according to which BPA water contamination leads to ClxBPA human exposure. BPA and its ClxBPA were assessed through online solid-phase extraction coupled to ultra high-performance liquid chromatography tandem mass spectrometry (SPE-UPLC-MS/MS) using the isotope dilution method in the colostrums of 21 women who had completed a water exposure questionnaire. BPA was detected in 19 colostrums and its ClxBPA in 21 colostrums. Mean concentrations were 1.87 ± 1.38 ng mL(-1) (n = 19) for BPA, 1.87 ± 1.23 ng mL(-1) (n = 7) and 1.56 ± 0.74 (n = 18) ng mL(-1) for 2,2'-Cl2BPA and 2,6-Cl2BPA, respectively, and 0.68 ng mL(-1) (n = 1) for trichloro-BPA. These findings confirm our hypothesis that ClxBPA should be taken into account in human health risk assessment.

Reliable quantification of bisphenol A and its chlorinated derivatives in human breast milk using UPLC-MS/MS method.

Bisphenol A is a widespread industrial chemical which over the past decade has demonstrated its toxicity as an endocrine disruptor. Chlorine present in drinking water may react with bisphenol A to form chlorinated derivatives, which have demonstrated a heightened level of estrogenic activity. In this work, we have comprehensively validated a method using on-line SPE-UPLC-MS/MS and isotope dilution quantification to measure bisphenol A and its chlorinated derivatives in human breast milk according to accepted guidelines. Deutered bisphenol A was used as internal standard. The matrix calibration curve ranged from 0.40 to 6.40 ng/mL for each of the target compounds and provided good linearity (r²>0.99).This method was precise (the intra and inter-day coefficient of variation was <20% at two different concentrations (0.40 and 3.20 ng/mL) and accurate (recovery ranged from 81% to 119%). The limits of detection obtained for BPA and its chlorinated derivatives ranged from 0.01 to 0.09 ng/mL. The limit of quantification for all the compounds validated at 0.40 ng/mL when using 500 µL of milk was found to be suitable for the concentration existing in real samples. The analytical method developed in this study is in accordance with the requirements applicable to biomonitoring of BPA and its chlorinated derivatives in human breast milk.

Quantification of bisphenol A, 353-nonylphenol and their chlorinated derivatives in drinking water treatment plants.

Bisphenol A (BPA) and nonylphenols (NP) are of major concern to public health due to their high potential for human exposure and to their demonstrated toxicity (endocrine disruptor effect). A limited number of studies have shown that BPA and NP are present in drinking water. The chlorinated derivatives that may be formed during the chlorination step in drinking water treatment plants (DWTP) exhibit a higher level of estrogenic activity than their parent compounds. The aim of this study was to investigate BPA, 353NP, and their chlorinated derivative concentrations using an accurate and reproducible method of quantification. This method was applied to both surface and treated water samples from eight French DWTPs producing from surface water. Solid-phase extraction followed by liquid chromatography-tandem mass spectrometry was developed in order to quantify target compounds from water samples. The limits of detection ranged from 0.3 to 2.3 ng/L for BPA and chlorinated BPA and from 1.4 to 63.0 ng/L for 353NP and chlorinated 353NP. BPA and 353NP were found in most analyzed water samples, at a level ranging from 2.0 to 29.7 ng/L and from 0 to 124.9 ng/L, respectively. In most of DWTPs a decrease of BPA and 353NP was observed between surface water and treated water (36.6 to 78.9 % and 2.2 to 100.0 % for BPA and 353NP, respectively). Neither chlorinated BPA nor chlorinated 353NP was detected. Even though BPA and 353NP have been largely removed in the DWTPs studied, they have not been completely eliminated, and drinking water may consequently remain a source of human exposure.

Oxidation of bisphenol A by ozone in aqueous solution.

Based on the literature data, an efficient removal of bisphenol A (BPA) during ozonation can be expected under water treatment conditions. However, up to now, the degradation products have not been identified. This has been the main point of this study. Aqueous solutions of BPA have been analyzed by LC-UV, LC-MS or MS/MS at different ozone doses. Under our experimental conditions, up to five major transformation products were evidenced. According to UV, MS and MS/MS spectra characteristics, chemical structures are consistent with catechol, orthoquinone, muconic acid derivatives of BPA, benzoquinone and 2-(4-hydroxyphenyl)-propan-2-ol. Moreover, three additional minor transformation products have been observed for which chemical structures have been tentatively proposed. In the case of major transformation products, the reaction pathway may involve an initial ozone reaction by electrophilic substitution or 1,3-dipolar cycloaddition. In the presence of ozone, these primary transformation products were shown to be unstable. Further transformation products, with smaller molecular weight and more polar character such as aliphatic acids or aldehydes, are then expected during ozonation. The identification of minor transformation products was more complex to assess. However, oligomeric structures have been evidenced, certainly arising from secondary reaction between various oxidation products of BPA. The formation of these latter products would not be favored under water treatment conditions.

Kinetic and mechanistic investigations of progesterone reaction with ozone.

The removal of progesterone by ozone in aqueous solution was studied in this work. The absolute rate constant was evaluated and first by-products were identified. The reaction was studied in the 2.0-8.0 pH range and was found to be a second-order reaction, first-order relative to each compound concentration. The rate constant, determined by kinetic experiments in presence of an OH radical scavenger (tert-butanol), was independent of pH. The value was evaluated to be equal to 480+/-30 M(-1)s(-1) by two kinetic methods. Mass spectrometry analyses were performed to investigate primary degradation products generated by the reaction of ozone with progesterone. Two by-products were evidenced. According to these results, a degradation pathway of progesterone reacting with ozone was proposed.

Kinetics of aqueous ozone-induced oxidation of some endocrine disruptors.

This study investigated aqueous ozone-induced oxidation of six endocrine disruptors (EDs: 4-n-nonylphenol, bisphenol A, 17alpha-ethinylestradiol, 17beta-estradiol, estrone, and estriol). In the first part, ED ozonation kinetics were studied over a pH range of 2.5-10.5 at 20 +/- 2 degrees C and in the presence of tert-butyl alcohol. Under these conditions, for each studied compound, the apparent ozone rates presented minima at acidic pH (pH < 5) and maxima at basic pH (pH > 10). In the second part, to explain this pH dependence, elementary reactions, i.e., reactions of ozone with neutral and ionized ED species, were proposed, and the intrinsic constants of each of them were calculated. The reactivity of ozone with ionized EDs (i.e. 1.06 x 10(9)-6.83 x 10(9) M(-1) s(-1)) was found to be 10(4)-10(5) times higher than with neutral EDs (i.e. 1.68 x 10(4) M(-1) s(-1)-2.21 x 10(5) M(-1) s(-1)). At pH > 5, ozone reacted to the greatest extent with dissociated ED forms. Finally, to assess the potential of ozone for inducing ED oxidation in water treatment conditions, the expected removal rates for each of the studied EDs were determined on the basis of the kinetic study at pH = 7 and 20 +/- 2 degrees C. For all EDs considered, O3 exposures of only approximately 2 x 10(-3) mg min L(-1) were calculated to achieve > or = 95% removal efficiency. The ozonation process could thus highly oxidize the studied EDs under water treatment conditions.