Biodisponibilité des polluants du sol : définition, caractérisation et utilisation potentielle dans la gestion des sites et sols pollués

National audienceL'effet toxique d'un polluant du sol vis-à-vis des organismes sera fonction de la concentration totale de ce polluant dans le sol et de sa biodisponibilité. Ce dernier paramètre définit la fraction d'un contaminant qui sera réellement absorbée par un organisme. De nombreux travaux issus de la littérature internationale insistent sur l'importance de considérer la biodisponibilité d'un polluant en vue d'en évaluer l'impact réel sur un organisme. L'essentiel de ces travaux portent sur les végétaux (on parle alors de phytodisponibilité) ou les microorganismes du sol. Ces dernières années, des recherches ont également été menées pour estimer la biodisponibilité des polluants pour l'Homme via l'ingestion de terre contaminée, une des voies d'exposition majeure pour l'évaluation du risque dans ce domaine. Toutefois, en France, l'application de ce concept est relativement limitée. Ceci conduit à une estimation conservatoire de l'exposition humaine aux contaminants pour la voie " ingestion de terre ". L'objectif de cette communication est de définir la notion de biodisponibilité orale d'un polluant pour l'Homme et de présenter les méthodes de mesure disponibles pour caractériser chacun de ces paramètres. Ensuite, les possibilités et les limites d'intégration de ces notions dans la gestion des sites et sols pollués sont abordées

Development of air and dust sampling methods for quantitative measurements of polybromated diphenyl ethers (PBDEs) in offices

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Exposition des enfants par ingestion de sol et de poussières contaminés : quels choix pour les évaluations de risque ?

National audienceEn Evaluation Quantitative des Risques Sanitaires (EQRS), l'ingestion de sol est une voie d'exposition influente dans le calcul de la prédiction des expositions des populations. Le potentiel d'exposition aux polluants du sol est plus grand pour les enfants que les adultes, en raison notamment de comportements très différents, lors d'activités de jeu par exemple. Cette voie d'exposition est conditionnée par deux paramètres sensibles : la quantité de terre ingérée et la biodisponibilité pour l'homme du composé chimique à partir de la matrice sol. Ce dernier paramètre qui caractérise la fraction absorbée d'un polluant peut être approché par la bioaccessibilité (fraction dissoute du contaminant dans le tube digestif). Actuellement il est considéré qu'un enfant ingère entre 100 et 150 mg/j de terre et que la biodiponibilité d'un élément dans cette terre est totale.L'analyse des connaissances scientifiques disponibles a eu pour objectifs d'être à même de justifier d'éventuelles propositions : fixer une valeur ou une distribution de quantité de sol et de poussières ingérée pour l'enfant (hors pica et géophagie) ; examiner la façon dont les notions de biodisponibilité/bioaccessibilité des polluants dans le sol et les poussières ingérés pouvaient être intégrées dans les pratiques d'évaluation de risque

Problèmes posés par la définition de l'état de référence des sols en santé environnementale

National audienceEn santé environnementale, la comparaison entre états des sols a pour but de déterminer l'évolution de la pollution d'un territoire donné ou la part de contamination attribuable à une source de pollution spécifique. Mais sa caractérisation, tant qualitative que quantitative, est difficile..

Polybromodiphenyl ethers (PBDEs) exposure in French offices

Polybromodiphenyl ethers are a family of 209 congeners widely used as brominated flame retardants in consumer products (computers, polyurethane foams, carpet...). They have the potential to be released from the product into the environment and are suspected to be associated with endocrine disruption. PBDE are ubiquitous and persistent in environment, but the repartition in environmental media and the population exposure are not well known. The aims of this project, supported by ANSES and the French Ministry of Environment, was to compare measurements of PBDEs in dust and air from offices and in the blood of their occupants and to explain PBDE levels with declared exposures. The protocol was accepted by different ethic comities. The first step was to develop and optimize some sampling and analysis methods for blood, air and dust. Eleven congeners were studied. Methods qualified for this study are discussed in other papers. In the second step, about thirty volunteers and their own office were included in the study. They answered questionnaires, had air and dust sampling in their office and blood sampling. PBDEs concentrations in blood ranged from 0,2-12,5 ng/g serum (mean is 2 ng/g serum), the major congener is BDE209. For most congeners, values are in the range of those found in European studies. The project does not reveal any significant relationship between concentrations in the air and the dust deposited in the investigated offices and blood levels of the occupants. For this group of people, the organization of the offices (number of computers, windows opening, stage, etc.) doesn't significantly impact the blood concentrations. These results cannot be applied to other populations. Transports and fish consumption could have an impact on the concentrations. Those relationships could be further investigated in a larger group using most specific tools

Exposure assessment of phthalates in French pregnant women using reverse dosimetry and biomonitoring data from the Elfe pilot study

Phthalates are a family of chemicals that can be found in a wide array of consumer products, including food packaging, medications, cosmetics, perfumes, building materials, paints, adhesives, children's toys and medical equipments made with polyvinyl chloride (PVC) plastics (Berman et al., 2009). Phthalates are not chemically bound to the products such as PVC and can thus easily be released into the environment by direct release, migration, evaporation, leaching and abrasion of and from the products they are used in. The ubiquitous use of phthalate esters results in widespread general population exposure. Numerous studies focused on exposure to phthalates because several epidemiological studies have suggested adverse effects that were similar to reproductive toxicities observed in experimental animal. Some phthalates such as DnBP, DiBP, BBzP DiNP and DEHP are known as being reproductive and developmental toxicants in animals. This study reports urinary concentration measurements of phthalate metabolites for French pregnant women. Several phthalates metabolites of short-chain phthalates, DEP (MEP), DnBP (MnBP), DiBP (MiBP), BBzP (MBBzP), and long-chain phthalates, DEHP (5OH-MEHP, 5oxo-MEHP, 5cx-MEHP, 2cx-MEHP, MEHP), DiNP (MiNP, 7oxo-Summe-MeOP, 7OH-MeOP, 7cx-MeOP), DnOP( MnOP, MCPP,), DCHP (MCHP) were measured. The measured concentrations were compared to those obtained in other European or American biomonitoring studies on pregnant women and highlighted high levels of DEHP metabolites. Toxicokinetic modelling (Lorber et al., 2010), integrating all the different metabolites measured, was used in a reverse dosimetry approach to estimate the exposure to DEHP. It allowed to back calculate a mean daily intake of exposure to DEHP of 4.2 µg/kg BW/d. In addition, this modelling pointed out that MEHP concentration was significantly higher than expected whereas other metabolites concentrations were well described. This could have been due to a contamination of the samples or indicated a very recent exposure probably at the hospital (Vandentorren et al., 2011). Significant differences of MEHP urinary concentration were observed in function of the type of delivery suggesting rather a very recent exposure probably due to perfusion materials than a contamination

Biodisponibilité et bioaccessibilité des métaux et metalloïdes des sols pollués pour la voie orale chez l’homme

National audienceDans la gestion des sols contaminés, la notion de biodisponibilité des polluants des sols est fréquemment évoquée comme permettant d’optimiser l’évaluation du risque sanitaire. Toutefois, une certaine confusion existe entre les notions de biodisponibilité et bioaccessibilité des polluants dans les sols. Cela engendre des difficultés pour, d’une part, intégrer au mieux ces notions dans la gestion des sites et, d’autre part, sélectionner un protocole de mesure. L’objectif de cette synthèse est tout d’abord de définir les notions de biodisponibilité et bioaccessibilité pour l’homme des polluants des sols et d’établir les liens existant entre ces deux paramètres. Dans un second temps, différents protocoles permettant de caractériser ces deux paramètres sont décrits. Enfin, un retour d’expérience international faisant état de l’utilisation de ces deux paramètres dans la gestion effective des sites pollués est exposé

Exposure assessment of phthalates in French pregnant women : Results of ELFE pilot study

Phthalates are known reproductive and developmental toxicants in animal studies which suggest that such effects could occur for humans. There are few data on exposure of pregnant women, although pregnancy is a key period relative to developmental toxicity. This study reports the first assessment of exposure to phthalates in the French pregnant population. Several phthalates metabolites (MEP, 5OH-MEHP, 5oxo-MEHP, 5cx-MEHP, 2cx-MEHP, MEHP, MnBP, MiBP, MiNP, 7oxo-Summe-MeOP, 7OH-MeOP, 7cx-MeOP, MBzBP, MnOP, MCPP, MCHP) were measured in 279 urine samples of pregnant women from ELFE pilot study. The purpose of the ELFE (Étude Longitudinale Française depuis l'Enfance) project is to build a nationally representative cohort of 20,000 children to be followed from birth to adulthood using a multidisciplinary approach in order to characterise the relationship between environmental exposures and the socio-economic context on health and behaviours more thoroughly. A pilot study was carried out to validate the data collection methods in October 2007 in Seine Saint Denis county and Rhône Alpes region. The measured concentrations in urine of most of the metabolites were similar to other European or American studies on pregnant women. Calculations of the daily intake using the urinary concentrations were performed for the DEP, DEHP, DnBP, DiBP and showed that median exposure is below RfD (US EPA, 2007) and TDI values (EFSA, 2005) . A simple kinetics model was used to better characterize the exposure to DEHP

Self-reported parental exposure to pesticide during pregnancy and birth outcomes: the MecoExpo cohort study.

The MecoExpo study was performed in the Picardy region of northern France, in order to investigate the putative relationship between parental exposures to pesticides (as reported by the mother) on one hand and neonatal parameters on the other. The cohort comprised 993 mother-newborn pairs. Each mother completed a questionnaire that probed occupational, domestic, environmental and dietary sources of parental exposure to pesticides during her pregnancy. Multivariate regression analyses were then used to test for associations between the characteristics of parental pesticide exposure during pregnancy and the corresponding birth outcomes. Maternal occupational exposure was associated with an elevated risk of low birth weight (odds ratio (OR) [95% confidence interval]: 4.2 [1.2, 15.4]). Paternal occupational exposure to pesticides was associated with a lower than average gestational age at birth (-0.7 weeks; p = 0.0002) and an elevated risk of prematurity (OR: 3.7 [1.4, 9.7]). Levels of domestic exposure to veterinary antiparasitics and to pesticides for indoor plants were both associated with a low birth weight (-70 g; p = 0.02 and -160 g; p = 0.005, respectively). Babies born to women living in urban areas had a lower birth length and a higher risk of low birth length (-0.4 cm, p = 0.006 and OR: 2.9 [1.5, 5.5], respectively). The present study results mainly demonstrate a negative correlation between fetal development on one hand and parental occupational and domestic exposure to pesticides on the other. Our study highlights the need to perform a global and detailed screening of all potential physiological effects when assessing in utero exposure to pesticides