L’objectif de la thèse vise à déterminer les facteurs et processus qui contrôlent l’origine et la qualité des eaux souterraines alluviales et ainsi à mieux comprendre le fonctionnement et la vulnérabilité des aquifères alluviaux qui occupent une place prééminente dans le paysage hydrogéologique mondial tant pour leur rôle économique - production d'eau potable, développement agricole - que pour leur rôle écologique. Des mesures hydrodynamiques, hydrochimiques (ions majeurs, traces, molécules phytosanitaires et pharmaceutiques) combinées à des déterminations isotopiques (oxygène-18, deuterium, carbone-13) ont ainsi été effectuées sur 19 points incluant puits, piézomètres et eaux de surface, de février 2011 à novembre 2012, afin d’évaluer l’origine et la qualité de l’eau souterraine dans l’aquifère alluvial de la rivière Allier, un des principaux tributaires de la Loire. La zone d’étude, située près de la ville de Clermont-Ferrand (France), joue par ailleurs un rôle socio-économique majeur, la nappe alluviale de l’Allier constituant la principale ressource en eau potable pour une population d’environ 100 000 habitants. D’un point de vue hydrodynamique, l'eau souterraine circule généralement du sud au nord, avec une alimentation naturelle à partir des coteaux adjacents, dans la partie non-pompée de l'aquifère. Dans la zone de pompage, cette circulation naturelle est modifiée par le pompage qui fait pénétrer l’eau de la rivière Allier dans l’aquifère. La recharge de l’aquifère dépend alors de quatre pôles de mélange : pluie, rivière Allier, coteaux adjacents et partie sud, non-pompée, de l’aquifère. Les résultats chimiques et isotopiques obtenus permettent de cartographier la contribution de chaque pôle de mélange. [...] Ces résultats mettent en évidence la vulnérabilité de l’aquifère face aux pollutions. Les parties méridionale et orientale du site sont affectées par des arrivées d’eaux de qualité médiocre démontrant l’importance de la définition d’un périmètre de protection adaptée. Près de l’Allier, une attention particulière doit être portée non seulement aux pollutions ponctuelles qui peuvent se produire sur le cours de la rivière, mais également aux pollutions chroniques liées notamment aux rejets des stations d’épuration pourvoyeurs de polluants tels les molécules pharmaceutiques. Toutes les informations acquises devront être incluses dans les stratégies de gestion d'eau souterraine afin protéger la durabilité de cette ressource de valeur. Les résultats s’appuient sur les investigations menées sur la nappe alluviale de l’Allier, néanmoins la méthodologie utilisée et sa transposition à des systèmes analogues est l’une des perspectives majeures de cette étude. / Hydrodynamic, hydrochemical (major ions, traces, pharmaceuticals and pesticides), and isotopic investigations (oxygen-18 and deuterium) were carried out on 19 points, including boreholes, piezometer, surface water, and springs from February 2011 to November 2012, to assess groundwater quality in the unconfined shallow alluvial aquifer of the Allier River (one of the main tributary of the Loire River). The study area, located near the city of Clermont-Ferrand (France), plays an important socio-economic role as the alluvial aquifer is the major source of drinking water for about 100 000 inhabitants. The objective of the project aims at understanding the functioning and the vulnerability of alluvial aquifers that occupy a pre-eminent position in the hydrogeologic landscape both for their economic role - production of drinking water and agricultural development - and for their ecological role. Moreover, this study also targets at determining the factors and processes controlling shallow groundwater quality and origin. The water circulates from the south, with a natural alimentation from the hills in the non-pumped part of the alluvial aquifer. In the pumping zone, this general behaviour is altered by the pumping that makes the water from the Allier River enter the system in a large proportion. Four end-members have been identified for the recharge of the alluvial groundwater: rainfall, Allier River, surrounding hills’ aquifer and the southern non-pumped part of the alluvial system. Results indicate that, despite the global Ca-HCO3 water type of the groundwater, spatial variations of physico-chemical parameters do exist in the study area. Ionic concentrations increase from the Allier River towards east due either to the increase in the residence time or a mixing with groundwater coming from the aquifer’s borders. Stable isotopes of the water molecule show the same results: boreholes close to the river bank are recharged by the Allier River (depleted values), while boreholes far from the river exhibit isotopic contents close to the values of hills’ spring or to the southern part of the alluvial aquifer, both recharged by local precipitation. One borehole (B65) does not follow this scheme of functioning and presents values attesting of a probable sealing of the Allier River banks. Based on these results, the contribution of each end-member has been calculated and the functioning of the alluvial system determined. According to this general scheme of functioning, origins of pollution (agricultural, urban) have been determined and clues to the protection of such hydrosystems defined.

This study identified new compounds with pest control activities. The two sources of candidates that were followed here were the main heartwood extract of Alaska Yellow Cedar (AYC) constituents and several semi-synthetic counterparts. Five compounds were isolated and identified for the first time in AYC heartwood in this research: two monoterpenes, two sesquiterpenes, and one lignan. The two monoterpenes were (1S)-2-oxo-3-p-menthenol (41) and (4R)-4-hydroxy-4-isopropyl-cyclohex-1-enecarboxylic acid (63). The two sesquiterpenes were (5S,7R,10R,11R)-eudesm-4(14)-ene-11,12-diol (46) and (4R,5S,7R)-1(10)- eremohpilen-11,12-diol (59). The lignan was (1R,2S,5R,6S)-2,6-bis-(3,5- dimethoxy-4-hydroxyphenyl)-3,7-dioxabicyclo-[3.3.0]octane,(67). Structures for these compounds were confirmed on the basis of spectroscopic techniques such as 1- and 2-D NMR, high resolution MS and IR. The pest control activity studies of 15 compounds isolated or semi-synthesized from AYC heartwood were conducted at the Centers for Disease Control and Prevention (CDC). Two types of studies were conducted--short-term (24h) and residual (over 1-4 weeks) activity for application against three types of pests related to human health - nymphal I. scapularis ticks, adult X cheopis fleas and adult Ae. eagypti mosquitoes. The 24 h studies revealed that nootkatone, valencene-13-aldehyde and valencene-13-ol were the most active among the studied compounds against the three pests. They exhibited highly improved pest control activities compared to valencene. This suggests that oxidation on both positions C-2 and C-13 of the eremophilane ring structure has an important effect on the activity. For compounds where the conformation of the eremophilane bicyclic ring has been altered, the activity seemed to diminish greatly. The above mentioned three compounds can be good candidates as pest control lead compounds. The residual studies revealed that the most active compounds exhibited activity profiles that generally decreased with time. Although the long-term safety of these compounds has yet to be evaluated, the natural origin and the long history of use of these compounds suggest that they can be promising candidates. This study revealed that the three most promising compounds in the 24 h study exhibited reasonably promising behavior, which makes them even stronger as pest control candidates. / Graduation date: 2004

<p>Pesticides are designed to control or eliminate pests such as insects, rodents, weeds,<br /> bacteria, and fungi. They are used at a global scale for agricultural produce. Although<br /> pesticides play a significant role in increasing food production and eliminating diseases,<br /> exposure to pesticides may be harmful to non-target organisms. As a result concern over<br /> safety and resistance to pesticides has increased and there is pressure to reduce use and<br /> search for more environmentally and toxicologically safe and efficacious pesticides. Most<br /> pesticides currently in use are synthetic / therefore an alternative to synthetic pesticides is<br /> the use of naturally occurring products/ botanicals with pesticidal properties.</p> <p>Two plants indigenous to South African with pesticidal properties were chosen for this<br /> study. Dicerothamnus rhinocerotis (D. rhinocerotis) and Galenia africana (G. africana)<br /> have potential antifungal properties thus, may have potential use on agricultural produce<br /> as fungicides. Galenia africana and D. rhinocerotis extracts inhibit growth of B. cinerea<br /> (a fungal pathogen) at concentrations greater than 31.25 mg/ml and 125mg/ml<br /> respectively. A major consideration in approving pesticides for use is whether they pose<br /> an unreasonable risk to humans and to the environment. Toxicity studies are required to<br /> determine the safety of the plant extracts.</p> <p>The purpose of this study was to evaluate potential toxicity of ethanol extracts of D.<br /> rhinocerotis and G. africana, which is important when designing practices to reduce or<br /> eliminate excess exposure to them. Natural plant products with pesticidal properties could<br /> provide an alternative to synthetic pesticides and may thus effectively reduce resistance<br /> levels.<br /> <br /> <br /> &nbsp / </p>

ContexteDe nombreux facteurs influencent l’exposition des agriculteurs aux produits phytopharmaceutiques (PP) : facteurs techniques (matériel de pulvérisation, forme et type des PP employés), agronomiques (pression parasitaire, doses employées, type de culture) et humains. La perception d'un risque est un facteur déterminant du comportement humain face à celui-ci. La perception du risque phytosanitaire chez les agriculteurs et ses conséquences sur l'exposition aux substances actives des utilisateurs sont peu étudiées.ObjectifL’objectif de ce travail est d’évaluer comment la perception du risque influe sur les pratiques des agriculteurs. Il vise aussi à décrire et évaluer les déterminants de cette perception, et leurs impacts sur le risque sanitaire des utilisateurs de PP. Méthode.Des entretiens individuels sont menés pour évaluer la perception du risque auprès d’utilisateurs de PP. Des mesures et modélisations d’exposition complètent ces observations. Les mesures se focalisent sur les paramètres influencés par la perception du risque décrits lors des entretiens. Les résultats des mesures d’exposition sont comparés aux pratiques observées et servent à qualifier et quantifier l’impact de la perception sur le risque sanitaire.RésultatsCe travail montre que la perception des agriculteurs du risque liés aux PP est empirique et se base sur des critères tels que l'odeur, le type, la forme ou l'efficacité des produits pour estimer le risque. Les comportements des agriculteurs pour réduire leur exposition sont corrélés à leur perception des produits employés. L'utilisation des équipements de protection individuelle (EPI) est le marqueur le plus fort de la perception. Plus le risque est perçu comme important, plus l'utilisation d'EPI est élevée. Mais les pratiques de réduction du risque ne sont pas toujours efficaces pour réduire l'exposition. En effet, les mesures d'exposition réalisées montrent que les opérateurs, même utilisateurs d'EPI, n'ont pas conscience des phénomènes de contaminations indirectes (cabine des tracteurs, environnement de travail). Combinés à un mauvais usage fréquent des EPI (réutilisation d'EPI à usage unique, utilisation partielle ou inadaptée), ces défauts de perception jouent sur l'exposition aux PP.Les modélisations et mesure d’exposition en fonction des pratiques observées ont permis de quantifier les conséquences sanitaires de ces comportements. Il ressort que le risque sanitaire lors de l'utilisation des PP dans le cadre des bonnes pratiques est acceptable. Cependant ces bonnes pratique sont théoriques et les observations montrent que les opérateurs ont des comportements qui s'éloignent des bonnes pratiques et les exposent aux PP, mais ces comportements ne sont pas perçus comme tels. Le risque sanitaire associé aux pratiques est très individuel et difficilement généralisable. Cependant, ce travail exploratoire a permis de mettre à jour des profils de risque et de décrire les déterminants forts de la perception. La sensation de maîtrise du risque est le déterminant clef dans l'acceptation du risque par les agriculteurs. ConclusionCe travail montre que la perception du risque joue un rôle décisif dans l'exposition totale des agriculteurs aux PP. Le risque sanitaire est sensiblement dépendant de la perception du risque. Les politiques de prévention des risques doivent s'appuyer sur cet aspect afin d'adapter les messages et d'éduquer les opérateurs aux pratiques exposantes telles que la contamination indirecte ou le mauvais usage des EPI, aujourd'hui peu pris en compte par les utilisateurs de pesticides. / IntroductionMany factors influence the exposure of farmers to pesticides. Technical (spraying equipment, type of pesticides used), agronomic (type of crop, doses used, frequency) and human factors. The perception of risk is a determinant key of human behavior and how human faces to risk. Pest risk perception among farmers and the consequences of exposure to active substances of farmers have not been clearly studied.AimsThe objective of this study is to evaluate how risk perception affects farmers' practices. It also aims to describe and assess the determinants of this perception, and their impact on the health risk of pesticides users.Individual interviews are conducted to describe the perception of risk of pesticides' users. Measurements and modeling of exposure complement these observations. The measures focus on the parameters influenced by the perception of risk described in the interviews. The results of exposure measurements are compared to practices observed and used to qualify and quantify the impact of perception on health risk.ResultsThis work shows that farmers' perceptions of risk related to pesticides used is empirical and based on criteria such as smell, type, form or effectiveness of products to estimate the risk. Farmers' behavior to reduce exposure is correlated with their perception of the products used. The use of personal protective equipment (PPE) is the strongest marker of perception. The higher the risk perceived, the greater the use of PPE is high. But the practical risk reductions are not always effective in reducing exposure. Indeed, exposure measurements show that operators, even in users of PPE, are unaware of indirect contamination (cab tractors, work environment). Combined with frequent misuse of PPE (reuse of disposable PPE, partial or improper use), these defects perception are increase exposure to pesticides.Modeling and exposure’s measurement based on observed practices are used to quantify the health consequences of these behaviors. It appears that the health risk of pesticides is acceptable when used as recommended. However, recommended practices are theoretical and observations show that operators have behaviors that deviate from recommended practices depending on pesticides used. But these behaviors are not perceived as risky. The health risks associated with individual practice is very difficult to generalize. However, this work highlights profiles of risk and describes strong determinants of perception. The risk-control feeling is the key determinant in risk acceptance by farmers.ConclusionThis work shows that the perception of risk plays a decisive role in the exposure to pesticide of farmers. The health risk is substantially dependent on the perception of risk. The risk prevention policies must support this risk perception to adapt messages and educate the operators to not adapted practices such as indirect contamination or improper use of PPE, few considered by some pesticides users.

<p>Pesticides are designed to control or eliminate pests such as insects, rodents, weeds,<br /> bacteria, and fungi. They are used at a global scale for agricultural produce. Although<br /> pesticides play a significant role in increasing food production and eliminating diseases,<br /> exposure to pesticides may be harmful to non-target organisms. As a result concern over<br /> safety and resistance to pesticides has increased and there is pressure to reduce use and<br /> search for more environmentally and toxicologically safe and efficacious pesticides. Most<br /> pesticides currently in use are synthetic / therefore an alternative to synthetic pesticides is<br /> the use of naturally occurring products/ botanicals with pesticidal properties.</p> <p>Two plants indigenous to South African with pesticidal properties were chosen for this<br /> study. Dicerothamnus rhinocerotis (D. rhinocerotis) and Galenia africana (G. africana)<br /> have potential antifungal properties thus, may have potential use on agricultural produce<br /> as fungicides. Galenia africana and D. rhinocerotis extracts inhibit growth of B. cinerea<br /> (a fungal pathogen) at concentrations greater than 31.25 mg/ml and 125mg/ml<br /> respectively. A major consideration in approving pesticides for use is whether they pose<br /> an unreasonable risk to humans and to the environment. Toxicity studies are required to<br /> determine the safety of the plant extracts.</p> <p>The purpose of this study was to evaluate potential toxicity of ethanol extracts of D.<br /> rhinocerotis and G. africana, which is important when designing practices to reduce or<br /> eliminate excess exposure to them. Natural plant products with pesticidal properties could<br /> provide an alternative to synthetic pesticides and may thus effectively reduce resistance<br /> levels.<br /> <br /> <br /> &nbsp / </p>

The Labiatae is a large family that occurs worldwide and have species that are adapted to almost all habitats and altitudes. Plectranthus is in this family. Plectranthus species are beautiful South African shrubs. The genus Plectranthus belongs to subfamily Nepetoideae of tribe Ocimeae. The test microorganisms were chosen carefully as each one belonged to a different taxonomic group of fungi and bacteria. Biologically active mono- and sesquiterpenoids are frequently found in many species of Plectranthus but there are little published data that directly link the presence of specific compounds in a species with the traditional uses of that species. Various Plectranthus spp. were collected and dried, followed by chemical extraction using various solvents. Dichloromethane extracts of P. fruticosus and P. ecklonii were screened for antibacterial and antifungal activities using the agar well and trench diffusion methods. It was found that both methods produced inconsistent results. The trench method required a bigger volume of plant extract to be filled into the well, hence, better biological activity was observed with that method. The well method required a smaller volume therefore poor activity was noted with this assay. The size of inhibition zones are dosage dependent. Overall, both plant extracts exhibited antibacterial but no antifungal properties. The pure compound (1), 11-Hydroxy-2-(4-hydroxybenzoyl)-5,7,9(11),13-abietatetraen-12-one, isolated from P. ecklonii was found to be the same as compound (10) which was isolated from P. lucidus. P. hadiensis was extracted using dichloromethane and hexane. The dichloromethane extract proved to contain much higher biological activity than the hexane extract. Three pure compounds, identified as diterpenes, were isolated from the crude dichloromethane extract of P. hadiensis. 6,7-Dihydroxyroyleanone-6,7,12-trihydroxy-8,12-abietadiene-ll,14-dione (2) and 7(alpha)-formoxy-6(beta)-hydroxyroyleanone (3) exhibited good antibacterial and antifungal activity but not against all the test organisms. The remaining pure compound, 7(alpha)-acetoxy-6(beta)hydroxyroyleanone (4), exerted good antifungal activity. This was measured by the inhibition zone which measured up to 14mm when compound 4 was tested against S. sclerotiorum. When testing the hexane extract against the Bacillus formulations, the pellets that were suspended once in Ringer's solution produced bigger inhibition zones than the pellets that were suspended twice. This could be due to bacterial cells washing out of the suspension. The dichloromethane extract of P. praetermissus proved to be very active against X campestris, producing an inhibition zone of 8 - 20mm. Two pure compounds were isolated from the crude extract and identified as diterpenes. Compound 5, 20(10--> 5)-abeo1( 10),6,8,11,13-abietapentaene-11,12,16-triol, and compound 6, 11,12,15-trihydroxy-20( 10-->5)-abeo-abieta-1-(10),6,8,11,13-pentaene are both known compounds which have previously been isolated from Salvia apiana. P. cilatus was extracted with chloroform and tested against various microorganisms for antifungal and antibacterial activities. It showed poor biological activity overall, except against S. sclerotiorum. The crude dichloromethane extract of P. zuluensis exhibited good antibacterial activity, which was limited to the Gram negative test organism. The extract produced an inhibition zone of 10-12mm when tested against X campestris. Pure compound 7, 2-hydroxy-4,6dimethoxyacetophenone, exerted excellent inhibition against B. subtilis and S. sclerotiorum. Neither compound 8, 1,2,4-trimethoxy-5-(2-propenyl)-benzene, nor compound 7, inhibited Candida spp., F. oxysporum and R. solani. Two diterpenes were isolated from the aerial plant parts of P. lucidus with dichloromethane and their structures elucidated by spectroscopic means. The pure compound 9, 11-hydroxy19-( 3-methyl-2-butenoyl)-5,7,9(11), 13-abietatetraen-12-one, showed moderate antifungal activity whereas compound 10, 11-hydroxy-2-(4-hroxybenzoyl)-5,7,9(11),13-abietatetraen12- one, showed high antifungal activity against R. solani, S. sclerotiorum and F. oxysporum. The crude and the pure compounds (formerly isolated from P. parviflorus) showed inhibition against X campestris. The dichloromethane extracts of P. purpuratus subsp. purpuratus and P. purpuratus subsp. tongaensis exhibit similar levels of biological activity when tested against the same test organisms. Poor antibacterial activity was noted with both extracts. However, excellent antifungal activity was depicted when both plant extracts were tested against F. oxysporum, R. solani and S. sclerotiorum. However, the highest biological activity was noted by R. solani which was totally inhibited by both dichloromethane extracts. The pure compound (11) isolated from P. purpuratus subsp. purpuratus was found to have the same chemical structure as compound (9) previously isolated from P. lucidus. The bioautography assay was used to detect and activity-guide the fractionation of antimicrobial compounds from all the Plectranthus spp. tested. The TLC fingerprint showed a zone of clearing around the lower bands of P. fruticosus and P. ecklonii when the plate was sprayed with a suspension of B. subtilis. This result is consistent with the agar well diffusion method. Clear zones were also noted on some bands of the extracts of P. zuluensis, P. ciliatus, P. hadiensis and P. praetermussis. Clear zones indicate inhibition of growth. Other plant extracts tested for biological activity were from the family Lamiaceae, however, not of the genus Plectranthus. Persicaria senegalensis, Pycnostachys reticulata and Ficus sur possessed moderate biological activity overall. It is interesting to note that P. senegalensis and F. sur exert high biological activity against Candida spp. This could be useful as herbal remedies for yeast infections. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 5 uppsatser.

Dans la littérature internationale, les expositions agricoles aux pesticides constituent une hypothèse privilégiée pour expliquer l’excès de tumeurs cérébrales observé chez les agriculteurs. L’objectif de cette thèse, élaborée à partir des données de la cohorte Agrican, était d’investiguer le rôle des expositions agricoles aux pesticides dans l’incidence des principaux types histologiques de tumeurs du système nerveux central. Avec plus de 180 000 participants suivis depuis 2005, la cohorte Agrican est une des plus grandes études sur la santé en milieu agricole. En tenant compte des principaux facteurs de confusion, des comparaisons internes ont fait apparaitre des augmentations de risque chez les agriculteurs, plus marquées chez les utilisateurs de pesticides, et avec de fortes variations selon les types de cultures et d’élevages. Suite à ces premières analyses, un travail de priorisation a permis d’identifier les pesticides carbamates comme prioritaires à étudier en lien avec les tumeurs cérébrales. La poursuite du développement de la matrice Pestimat a ensuite permis de reconstituer l’historique des utilisations de carbamates depuis 1950 dans les principaux contextes agricoles français. À l’issue de ces étapes intermédiaires, des analyses de survie menées chez les participants d’Agrican ont fait apparaître des augmentations de risque de gliomes et de méningiomes en lien avec les expositions professionnelles à des matières actives (dithio/thio)-carbamates, en particulier avec celles dont l’utilisation a été recommandée en viticulture, en arboriculture et sur cultures de pomme de terre et de betterave. Ces résultats renforcent les preuves de cancérogénicité pour les pesticides déjà suspectés pour d’autres cancers et attirent l’attention sur d’autres matières actives, moins documentées dans la littérature mais relativement homogènes au niveau des structures chimiques. Aussi, sur la base de ces résultats et dans un objectif de santé publique, il paraît essentiel de poursuivre les efforts engagés pour réduire les expositions aux pesticides des agriculteurs. / In the international literature, agricultural exposures to pesticides have been put forward as a key hypothesis to explain the excess of brain tumours observed in farmers. The aim of this thesis, based on data from the Agrican cohort, was to investigate the role of agricultural exposures to pesticides in the incidence of the main histological types of central nervous system tumours. With more than 180,000 participants followed since 2005, the Agrican cohort is one of the largest studies on health in agriculture. Internal comparisons adjusted for the main important confounders showed increases in risk among farmers, more pronounced risk among pesticide users, and with strong variations according to the types of crop and livestock farming. Following these initial analyses, work identified carbamate pesticides as a priority to study in relation to brain tumours. Next, further development of the Pestimat served to reconstitute the history of carbamate uses since 1950 in the main French agricultural contexts. After these intermediate steps, survival analyses conducted among Agrican participants showed increased risks of glioma and meningioma in farmers exposed to (dithio/thio)-carbamates, particularly with those recommended for use on vineyards, fruits, potatoes and beets. These findings reinforce the evidence of carcinogenicity among pesticides already suspected for other cancers, and draw attention to other active ingredients, less documented in the literature but relatively homogeneous in terms of chemical structures. Therefore, on the basis of these conclusions and with a public health objective in mind, it seems essential to pursue efforts to reduce farmers' exposure to pesticides.

L’augmentation globale de la démographie couplée à une amélioration du niveau de vie conduit à l’augmentation de la pression anthropique pesant sur les ressources en eau. Cette pression passe entre autre par une consommation et donc un rejet de multiples molécules organiques, parmi lesquelles les pesticides représentent des contaminants emblématiques. Longtemps utilisés en agriculture afin d’en augmenter la productivité, ces substances sont aujourd’hui utilisées également de façon importante dans notre quotidien (traitements vétérinaires, protection des matériaux de construction, peintures, papier, textiles, etc.). Cela conduit à identifier les rejets urbains comme des vecteurs de pesticides au travers des effluents de station de traitement des eaux usées ou des effluents d’exutoires pluviaux, qui viennent s’ajouter aux apports induits par l’agriculture. Cette multiplicité de sources couplée à une toxicité intrinsèque avérée en font des molécules à fort enjeu environnemental dont il est essentiel de hiérarchiser les apports afin de pouvoir mettre en place des mesures de réduction.Dans ce cadre, un continuum péri-urbain situé sur la Métropole de Bordeaux (France) a permis de mettre en évidence des profils de contamination différents entre les eaux naturelles, les effluents urbains et les exutoires pluviaux, tant sur l’aspect qualitatif que sur l’aspect quantitatif. Si les eaux de surface sont principalement quantitativement marquées par des phytopharmaceutiques (métolachlore, glyphosate), les molécules identifiées comme potentiellement impactantes (en termes d’effets potentiels) proviennent d’avantage d’effluents urbains (fipronil, imidaclopride). En effet, les stations de traitement des eaux usées sont identifiées comme d’importants vecteurs en biocides et antiparasitaires à usages vétérinaires en raison de leur faible capacité de traitement vis-à-vis de ces contaminants. Toutefois, ces effluents ne sont que le reflet des utilisations en amont du réseau. L’investigation de ce dernier a conduit à identifier les usages domestiques comme responsables de l’introduction de certaines molécules préoccupantes tels les antiparasitaires à usages vétérinaires (fipronil et imidaclopride). En parallèle, bien que non majoritaires en ce qui concerne les apports en pesticides, les exutoires pluviaux ne sont toutefois pas négligeables et apportent en quantités conséquentes des biocides de protection (comme la carbendazime, le diuron, le propiconazole ou la terbutryne) de par le lessivage de surfaces traitées en zones urbaines. Le cas du glyphosate semble complexe puisque aucune des voie d’apport n’est clairement identifiée comme majoritaire. L’apport est très global, probablement du fait de sa multiplicité d’usages, tant en agriculture que par certains professionnels ou par les particuliers.L’échantillonnage passif par les POCIS (Polar Organic Chemicals Integrative Sampler) a été appliqué avec succès afin de calculer des flux plus précis dans les eaux de surfaces, permettant ainsi une identification plus fine des sources majoritaires. Cet outil montre toutefois ses limites en ce qui concerne le suivi d’échantillons complexes telles que les eaux brutes, en présentant des cinétiques d’accumulation trop courtes pour permettre un suivi quantitatif du réseau d’assainissement sur de longues périodes. Ces observations ont été confirmées à l’occasion de calibrations in-situ en rivière et en entrée de station de traitement des eaux usées et qui ont donné lieu au développement de nouveaux outils. Les mini-POCIS et les POCIS-T, plus légers et plus petits ont été calibrés à la fois en laboratoire et en station de traitement des eaux usées. Ils se sont révélés plus adaptés que la forme classique pour suivre la contamination des eaux usées car ils permettent d’augmenter la durée du suivi. Ils représentent une alternative intéressante pour le suivi du réseau d’assainissement. / Global demographic increase coupled with standard of living increase drive water resources’ anthropic pressure. This phenomenon is linked with consumption habits and with chemicals dispersion in environment. Pesticides are part of the most concerning contaminants. They were firstly used to enhance agricultural productivity but nowadays these chemicals are used for our daily life needs (in building materials, veterinary treatments, papers, textile products, paints, etc.) and so urban effluents such as storm sewer or wastewater treatment plant effluents are identified as important vectors of pesticides which are added to agricultural inputs. The diversity of sources coupled to an intrinsic toxicity highlight pesticides as environmental concerning compounds and their sources have to be clearly identified and classified to consider source reduction actions.The study of an urban continuum in Bordeaux Metropolis (France) highlighted qualitative and quantitative differences in contamination profiles between river water, storm sewers and wastewater treatment plant effluents. River waters are contaminated with phytopharmaceuticals (metolachlor, glyphosate) but molecules of high ecotoxicological concern (fipronil, imidacloprid) are mostly brought by wastewater treatment plants. These structures are indeed not built for micropollutant treatment and biocides provided by wastewaters are discharged in surface water. Urban effluents reflect uses of wastewater network by private consumers and industries. Advanced investigations in the wastewater network allowed identifying them as providers of veterinary molecules such as fipronil and imidacloprid. In parallel, monitoring of rain effluents allowed to identify storm sewers as less important sources of pesticides that wastewaters but they have to be considered for some molecules. Indeed, they can locally increase contamination in natural water around the discharge site especially concerning biocides (carbendazime, diuron, propiconazole, terbutryne) because of runoff waters over treated surfaces. Case of glyphosate is much more complex because this molecule was found in every compartment and seemed to be introduced massively both by agriculture and urban effluents in link with its use by farmers but also private consumers and some professionals.Passive sampling of water resources with POCIS (Polar Organic Chemicals Integrative Sampler) was successfully applied, allowing to quantify pesticides at trace levels and to calculate precise fluxes leading to the confirmation of previous results. However, the usefulness of this tool is limited in the case of wastewater monitoring. Uptake kinetics are too rapid to allow a quantitative characterisation of raw wastewaters over long period of deployment. These observations were confirmed with the comparison of in-situ calibration performed both in river and in effluent of a wastewater treatment plant and leaded to the development of new version of POCIS. Mini-POCIS and POCIS-T (lighter and smaller than original ones) were calibrated both in laboratory and in real conditions. They are more adapted than classical devices to wastewater sampling allowing covering a much longer period of monitoring.

L'analyse des relations entre expositions environnementales et santé suscite un intérêt grandissant mais reste complexe à étudier. Elle fait appel à des disciplines comme l'épidémiologie et la toxicologie, mais celles-ci sont confrontées à des limites méthodologiques. La géographie et l'utilisation des SIG apportent de nouvelles perspectives d'analyse et des méthodes complémentaires, qui permettent de mieux comprendre certains phénomènes spatiaux et temporels de l’impact de l’environnement sur la santé. L'exemple de l’analyse des expositions aux pesticides sur la santé reflète ces difficultés et ces nécessités. Des méthodes SIG ont été développées au niveau international pour évaluer les expositions aux pesticides agricoles afin de comprendre les expositions à échelle fine, rétrospective et la dispersion des pesticides. Les projets menés par le Département Cancer Environnement du Centre Léon Bérard ont permis de développer de telles méthodes en France, à l’échelle individuelle en incluant les variables explicatives de l’exposition résidentielle et de façon rétrospective, qui peuvent ainsi être intégrées et utilisées dans des études épidémiologiques.Parallèlement à ces recherches, des études et des mesures de contrôle de présence de pesticides dans les milieux naturels sont effectuées par différents acteurs, mais ces informations restent souvent limitées à leurs créateurs. Pourtant, elles peuvent se révéler complémentaires dans différents domaines d’action environnementale ou sanitaire. La création d’un outil de partage et d’échange de données sur les pesticides a donc été initiée. La santé environnementale a une place croissante dans les différentes politiques publiques et territoriales, notamment par l'aménagement du territoire. Celles-ci nécessitent cependant des données et des outils pour pouvoir considérer les déterminants environnementaux et de santé. L'exposition aux pesticides peut ainsi être intégrée à ces politiques en renforçant le cadre règlementaire existant et en développant des approches nouvelles afin de réduire l’exposition de la population. / The analysis of the relationship between the environment and health is a growing concern but complex to study. It uses disciplines such as epidemiology and toxicology, but they know some methodological limitations. Geography and the use of GIS provide a new perspective of analysis and complementary methods that allow us to better understand spatial and temporal issues of environmental impact on health. The analysis of the effects of pesticides on health is an example that reflects these difficulties and needs. GIS methods have been developed at international scale to assess exposures to agricultural pesticides at fine scale, retrospective and pesticides dispersion. The Cancer Environment Department in the Centre Léon Bérard developed projects to create such methods in France, at individual level, including the explanatory variables of residential exposure, and retrospectively that can be integrated and used in epidemiological studies.In addition to this research, studies and measures for the control of presence of pesticides in natural environments are carried out by different actors, but the use of this information often stay limited to their creators. However, they may prove to be complementary and necessary in different areas of environmental or health action. The creation of a tool for sharing and exchange of data was initiated.Environmental health has a growing place in different public and territorial policies, including through territorial planning. However, these require data and tools to be able to consider environmental determinants and health. Exposure to pesticides can thus be incorporated into these policies by strengthening the regulatory framework existing and developing new approaches to reduce the exposure to pesticides of the population.