Dissertations / Theses on the topic 'Pesticidal activities'

The primary aim of the work described in this thesis is to establish a foundation for the applicability of a biochemical biomarker, cholinesterase (ChE) activity in food animal species, as an instrument for evaluating exposure to pollutants as well as predicting high-level effects on public health. Secondary aims are to increase the awareness of pesticide users of anti-ChE exposure, to decide whether poisoning episodes involve anti-ChE by measuring residual effects in tissues, and to identify sources of contamination in food animal tissues. The ChE are specialized carboxylic ester hydrolases that break down esters of choline. They are classified as either acetylcholinesterase (AChE) or butyrylcholinesterase (BChE). Both AChE and BChE activities were found to be higher in cattle than in sheep and higher in erythrocytes than in plasma and serum. The anticoagulant heparin significantly affects AChE activity in plasma compared with EDTA. Of the different tissue tested, the mean of ChE activities was found to be highest in tissue from the liver, followed by lung, muscle, kidney and heart for sheep and cattle. In pigs, the ChE activities tested higher in kidney, liver, lung, muscle and heart. The effect of freezing on ChE activities in liver and muscle tissues was significant inhibition after 6 months at -80 °C, whereas decreased after 3 months at -20 °C. A technique to improve the purification of AChE in sheep tissue was developed. BW284c51 strongly reduced acetylthiocholine iodide (AcTChI) and propionylthiocholine iodide (PrTChI) hydrolysis and slightly affected that of butyrylthiocholine iodide (BuTChI) in the liver, while iso-OMPA had no significant effect for muscle BuTChI of sheep and pigs. Histochemical study of liver tissue found AChE localised mainly in the cytoplasm of the cell lining in the sinusoids. The optimal pH values of AChE and BChE in liver and muscle ranged between 7.8 and 8.5. Both AChE and BChE activities increased when increase the time course and temperature. The half maximal inhibitory concentration (IC50) was found to be higher for carbaryl than dichlorvos (DDVP) and diazinon (DZN). Very little residual AChE activity was seen in the liver, but more was found in muscles. In general, the rate constants of inhibition (ki) values for liver and muscles were increased in different pHs according to the rank order of 8.5 > 7.5 > 6.5, while in plasma it was decreased in different temperatures as follows: 20 °C > 30 °C > 40 °C. The final experiments were carried out at the rate of spontaneous reactivation (ks) of inhibited AChE by DDVP and DZN from liver and muscle was found to be higher in sheep compared to cattle and pig, while the aging of phosphorylated AChE (ka) was found to be higher in cattle compared to sheep and pig. In addition, this study indicated that the developed bispyridinium symmetric (K048) oxime seems to be promising reactivated to DDVP-inhibited AChE for sheep and pigs while HI-6 was effective in cattle.

Suite au Grenelle de l’environnement proposant une réduction de 50% des pesticides dans l’agriculture française, l’objet central de cette thèse est d’estimer les potentiels progrès de productivité et de diminution de ces inputs pour les grandes cultures. Dans cette perspective, le recours aux modèles d’analyse d’activités et les estimations de fonction de coût par des approches non paramétriques comme Data Envelopment Analysis (DEA) et/ou Free Disposal Hull (FDH) sont mobilisés afin d’évaluer les réductions potentielles de coût global et des dépenses en pesticide pour ce type de cultures. S’appuyant d’une part sur un panel reprenant environ 600 exploitations situées dans le département de la Meuse au cours de la période 1992-2003 et d’autre part sur un échantillon de 700 exploitations de l’Eure & Loir observées en 2008, notre recherche vise à établir une relation de dominance coût entre les technologies utilisant plus ou moins de pesticide à l’hectare. En conséquence deux fonctions de coût caractérisées par des niveaux de dépenses de pesticides à l’hectare différents (haut et faible) sont comparées. La fonction de coût non paramétrique est estimée de manière robuste pour réduire la sensibilité des résultats à l’éventuelle présence d’outliers. Les résultats indiquent que des réductions substantielles de coût sont envisageables si les agriculteurs géraient leurs inputs plus efficacement. De plus, les pratiques culturales utilisant moins de pesticide à l’hectare apparaissent plus compétitives en matière de coût. Cette conclusion indique que l’adoption de ces nouvelles pratiques économes en intrants et donc plus favorables à l’environnement serait bénéfique à la fois pour les agriculteurs et pour l’ensemble de la société
In the context of the agreement of about 50% reduction in pesticide uses according to the accords du “Grenelle de l’environnement” (the Environment Round Table) in France, the central part of this study is to use some efficiency analysis to estimate the substantial productivity improvements and cost reductions on French farms. By employing Activity Analysis Models and estimating cost frontiers with non-parametric approaches such as Data Envelopment Analysis (DEA) and Free Disposal Hull (FDH)], total cost and/or pesticide expense reductions are evaluated on crop farms. Based on this, a sample of 600 and 700 farms in the Meuse and Eure & Loir departments were respectively observed over a 12 year period (1992-2003) and in year 2008. A non parametric cost function is essentially employed to assess the cost efficiency dominance between technologies using either more or less pesticide and a robust approach frontier is introduced in order to reduce the sensitivity of the cost frontier to the influence of potential outliers, thus improving the accuracy of the result. With respect to this, two cost functions characterized by a relatively lower or higher pesticide level per ha are compared. The estimated efficiency scores indicated that substantial efficiency improvements are possible on French crop farms with a strong potential for cost decreases if farmers could manage inputs more efficiently. Therefore, agricultural practices using less pesticide per ha are more cost competitive which does not only benefit the farmers but also the society, thereby promoting new agricultural practices that are more environmentally friendly

La fertilité, la pollution de l’écosystème sol sont devenues aujourd’hui des préoccupations etdes problèmes écologiques majeurs. L’objectif de cette étude est d’arriver à travers l’activitémicrobienne (hydrolyse de la FDA) et un large panel de 16 enzymes (phosphatases,hétérosidases, polysaccharidases, oligosaccharidases, oxydasses), à appréhender l’impact depolluants et d’amendement. Cinq sols aux caractéristiques physico-chimiques différentes ontété étudiés, et ont été soumis à différents traitements réalisés en microcosmes. Ces traitementsont porté sur l’ajout de zinc, cadmium, d’un herbicide, d’un insecticide, d’un fongicide, d’unnématicide et de fumier.L’expression des activités enzymatiques dépend fortement du type de sol. Ainsi lafraction limoneuse du sol jouerait un rôle crucial dans l’expression des enzymes telluriques. Parailleurs les résultats obtenus ont montré que des sols très proches d’un point de vu physicochimiquene le sont pas forcément au niveau enzymatique et microbien.L’ajout du fumier dans nos différents sols a entraîné quelque soit le type de sol defortes modifications positives des activités microbiennes et enzymatiques. L’effet stimulateurdu fumier sur l’activité microbienne et enzymatique dépend non seulement des paramètres dusol mais surtout de son activité initiale. Entre autre, l’impact positif du fumier est moinsmarqué dans les sols ayant des activités enzymatique ou des quantités de matière organiquefaibles. La tendance semble s’inversée concernant l’activité microbienne.L’impact des métaux lourds sur l’activité microbienne et les enzymes testées esttributaire des paramètres (argile, M.O), et de la nature des métaux lourds. Le cadmium s’avèreplus néfaste que le zinc. Si la majorité des activités enzymatiques sont diminuées par laprésence de métaux lourds d’autres en revanche ne sont pas impactées.La présence de pesticides dans nos sols révèle une grande disparité de résultat. Selon letype de sol, le type d’enzyme, une inhibition, un effet neutre ou bien une stimulation del’activité microbienne ou enzymatique par les pesticides ont été observés.Cette étude a permis de montrer que les enzymes sont très réactives aux différentesperturbations anthropiques quelque soit le type de sol considéré. Cependant cette réactivité setraduit par une très grande diversité des réponses. Cette diversité de réponse résulte d’ungrand nombre de paramètres liés aussi bien aux caractéristiques physico-chimiques quebiologiques du sol. Il n’a donc pas été possible de définir une enzyme ou groupe d’enzymesusceptible d’être utilisée comme indicateur pour l’ensemble des sols ou des traitements
Fertility and pollution of the soil ecosystem have become today’s concern and major ecologicalproblems. The objective ofthis study is to estimate through microbial activity (hydrolysis ofFDA) and a wide range of 16 enzymes (phosphatases, heterosidases, polysacchridases,oligosaccharidases, oxydase), the impact of pollutants and amendment in soil. The five soilsstudied are different regarding their physical and chemical characteristics. This soils are areexposed to different treatments in microcosms. These treatments consist to pollute our soilswith heavy metals (zinc, cadmium), pesticides (herbicide, insecticide, fungicide, nematicide)or to add manure.Our results showed that the expression of enzymatic activities depends on soil type.Thus, the silt fraction of soil plays a crucial role in this expression of soil enzymes. The soilswith physico-chemical characters are very similars, have not necessarily the same enzymaticprofile and expression or microbial activity.The presence of manure on our differents soils greatly increased the enzymatic andmicrobial activities. The stimulatory effect of manure depends on soil parameters but also theinitial enzymatic and microbial soil activities. The results showed that the positive impact ofmanure is less pronouncing in soils where the initial enzyme activity and organic matterquantity are low.The impact of heavy metals on microbial activity and enzymes tested depends on soilparameters (clay, organic matter, pH, ...) and nature of heavy metal. Cadmium is more toxicand longer decreases enzymatic and microbial activities than zinc. The presence of heavymetals in soils has reduced most of enzymes activity. Other enzymes are also unchanged orincreased by the pollutants.Soil pollution by pesticides show a large disparity and diversity of results. Dependingon soil type or the enzyme tested, the diffrents results showed an increase, neutral effect ordecrease by pesticides of enzymes and microbial activities.Watever the type of soil considered, this study has shown that soil enzymes are verysensitive and responsive to human disturbance. The reactivity of telluric enzymes is manifestedby a very large diversity of responses. Diversity responses of soil enzymes is depended tophysico-chemical characters and also soil biological parameters. In this study, it is verydifficult to define one or group of enzymes as a bioindicator for all soil disturbances

Les pesticides utilisés pour protéger les plantes des insectes nuisibles constituent une menace pour les organismes non cibles tels que les vers de terre. En raison de leur activité de bioturbation de sol, les vers de terre sont en contact direct avec les particules et les micro-organismes du sol, ainsi qu'avec les polluants, notamment les pesticides. L‘objectif de ce travail est d‘étudier (1) l‘effet d‘un organophosphoré (OP) «éthyl-parathion» sur la sensibilité de deux espèces de vers de terre endogés, Aporrectodea caliginosa et Allolobophora chlorotica; et (2) le rôle du microbiote intestinal, en synergie avec les voies de détoxification du ver de terre, dans la tolérance ou la détoxification des pesticides. Dans la première partie, les réponses biochimiques et comportementales ont montré que A. caliginosa est plus sensible à l'exposition à «l‘éthyl-parathion» que A. Chlorotica. Les résultats portent sur l‘analyse de biomarqueurs physiologiques (poids), biochimiques (AChE, CbEs, GST) et comportementaux (production de turricules et activité de creusement). Nous avons montré que la sensibilité de A. caliginosa semble liée à la sensibilité intrinsèque de l‘AChE à «l‘éthyl-parathion». De plus, le rôle des carboxylestérases, capables de piéger les insecticides OP, ainsi que le rôle de détoxification des GST notamment, ne semblaient pas être des mécanismes efficaces impliqués dans la tolérance de A. chlorotica. Dans la deuxième partie, nous avons caractérisé, en présence ou non d‘insecticide, le microbiote dans le sol ingéré, les turricules et les intestins des 2 vers de terre. Nos résultats ont montré des différences dans la composition microbienne de ces compartiments. A cet égard, nous avons suggéré que chacune de ces espèces hébergent un microbiote spécifique de l‘espèce dans leur intestin. Nos résultats ont notamment montré que l‘intestin du ver de terre agit comme un «filtre biologique» pour les communautés microbiennes ingérées lors du passage dans l‘intestin. A ce niveau, nous avons identifié, au niveau bactérien, quatre genres dominants dans l'intestin de A. caliginosa et deux genres dominants dans l'intestin de A. chlorotica. Nous avons notamment identifié une souche de Rhodococcus, très abondante dans l'intestin de A. chlorotica. Des études ont montré que des souches de Rhodococcus peuvent dégrader certains groupes de pesticides. Nous suggérons que la présence de cette souche pourrait contribuer à la tolérance de A. chlorotica. Enfin, nous avons montré que l‘effet de l‘éthyl-parathion sur les activités enzymatiques du sol dépend principalement de la texture du sol et non pas de la présence et/ou de l‘espèce de ver de terre.Selon nos conclusions, il est extrêmement important d'inclure plus d'une espèce pour évaluer la toxicité des insecticides organophosphorés, en raison des différences interspécifiques pouvant se produire au sein d'une même catégorie écologique. De plus, l'identification et l'analyse fonctionnelle des micro-organismes présents au niveau de l‘intestin et susceptibles d'intervenir dans la détoxication des pesticides permettraient d‘améliorer nos connaissances sur le devenir du pesticide dans l'organisme et pourraient constituer un outil important dans les programmes de bioremédiation
Pesticides used to protect plants from pests, threat grievously non-target organisms such as earthworms. Due to their feeding and burrowing activities, earthworms are in direct contact with soil particles and microorganisms, as well as pollutants including pesticides. This work investigated (1) the effect of an organophosphate “ethyl-parathion” on the sensitivity of two endogeic earthworms’ species, Aporrectodea caliginosa and Allolobophora chlorotica; and (2) the role of the gut-microbiota, in synergy with the earthworm’s detoxification pathways, in pesticide tolerance or detoxification. In the first part, biochemical and behavioral responses showed that A. caliginosa is more sensitive to “ethyl-parathion” exposure than A. chlorotica. The endpoints measured ranged from physiological (weight), biochemical (AChE, CbEs, GST) to behavioral biomarkers (cast production and burrowing activity). Our findings showed that the sensitivity of A. caliginosa could be mainly due to the intrinsic sensitivity of its AChE to “ethyl-parathion”. The role of the carboxylesterases, acting as bioscavenger of OP, and the role of the detoxifying enzymes GST did not appear to be efficient mechanisms involved in A. chlorotica tolerance. In the second part, we aimed to characterize the microbiome within the ingested soil, the cast and the gut tissue of A. caliginosa and A. chlorotica in control or polluted soils. Our results showed differences in the microbial composition between these compartments. In this line, we suggested that these two earthworms’ species harbor a species-specific microbiome in their gut. In particular, our findings showed that the earthworm’s gut acts as a “biological filter” for ingested microbial communities during the gut passage. At the level of the gut, we identified four dominated genus within the gut of A. caliginosa versus two dominated genus in the gut of A. chlorotica. Notably, we identified a Rhodococcus strain, which is highly abundant in the gut of A. chlorotica. Previous studies reported Rhodococcus strains for their ability to degrade some group of pesticides. We suggest that the presence of this strain could contribute to the tolerance of A. chlorotica. Finally, we showed that the effect of ethyl-parathion on soil enzyme activities mainly depend on soil texture rather than the presence and/or the species of earthworms. According to our findings, it is of considerable importance to include more than one species to assess toxicity from organophosphorus insecticides, due to the interspecific differences that can occur within the same ecological category. Moreover, the identification and the functional analysis of the microorganisms found in the earthworm’s gut and able to intervene in pesticide detoxification could enhance our knowledge about the fate of the pesticide inside the organism, and could be an important tool for bioremediation program

L'auteur a essaye tout au long de ce travail, de realiser une analogie structurale avec des acides amines en synthetisant divers acides aminoboroniques, diversifiant les substituants portes par l'atome d'azote et en modifiant la distance azote-bore, en vue d'une etude structure-activite phytosanitaire. Apres un bref apercu sur l'activite biologique que presentent les acides boroniques et plus specialement les acides aminoboroniques, il rapporte dans un premier chapitre les differents essais d'obtention d'acides -aminoboroniques. Le deuxieme chapitre est centre sur la synthese d'acides -aminoboroniques par reaction d'hydroboration. Une etude prealable de l'hydroboration d'amines allyliques avec divers substituants de l'atome d'azote est effectuee. L'acces aux acides b-aminoboroniques par reaction d'hydroboration fait l'objet du troisieme chapitre. Des intermediaires de structures enamines ont donc ete synthetises par voie photochimique

Phan Me is a midland-mountainous commune of Phu Luong district, Thai Nguyen province, Vietnam where the agricultural activities are predominant occupation. The investigation on the use of plant protection products in here showed that chemical pesticides have been commonly used in agricultural activities. Although some local people have a good attitude in using plant protection products, the status of using chemical pesticides that were not recommended (like Vofatox) has been quite popular due to the old cultivation customs. The local people have not applied any measures for wastewater treatment, or plant protection product package treatment. Besides, the use of plant protection products in higher concentration than recommendation for vegetables or crops caused the residues of toxics in agricultural products as well as in cultivation soil. The accumulation of toxic residues in the environment is a serious matter of concern because of their significant impact on the environment, agricultural ecosystem and human health
Phấn Mễ là một xã trung du miền núi của huyện Phú Lương, tỉnh Thái Nguyên, Việt Nam với hoạt động sản xuất nông nghiệp là chủ yếu. Qua thực tế điều tra tình hình sử dụng thuốc bảo vệ thực vật (BVTV) tại đây cho thấy hầu hết các loại hình sản xuất nông nghiệp đều sử dụng thuốc BVTV. Một số người dân đã có ý thức trong việc sử dụng thuốc BVTV tuy nhiên do tập quán canh tác từ lâu đời nên việc sử dụng các loại thuốc bị khuyến cáo, chẳng hạn như Vofatox, vẫn còn khá phổ biến. Người dân chưa tiến hành các biện pháp để xử lý nước thải, bao bì, vỏ chai thuốc BVTV sau khi sử dụng. Bên canh đó, họ còn sử dụng thuốc BVTV không đúng liều lượng cho một số loại cây rau để lại dư lượng thuốc trên nông sản cũng như đất canh tác. Sự tích lũy dư lượng của những chất độc hại này trong môi trường là vấn đề đáng lo ngại do sự ảnh hưởng nghiêm trọng của chúng đối với môi trường sống, hệ sinh thái nông nghiệp và sức khỏe con người

Humans are modifying the global landscape at an unprecedented scale and pace. As a result, species are declining and going extinct at an alarming rate. Here, I investigate two main aspects of species’ declines: what factors are contributing to their declines and how effective our conservation efforts have been. I assessed one of the main mechanisms for protecting species by looking at the Endangered Species Act (ESA) in the United States. I examined three separate indicators of species declines for different groups of species: range contractions in Canadian imperilled species, declines in abundance in global amphibian populations and increases in temporal variability in abundance in North American breeding birds. I found that change in recovery status of ESA listed species was only very weakly related to the number of years listed, number of years with a recovery plan, and funding. These tools combined explained very little of the variation in recovery status among species. Either these tools are not very effective in promoting species’ recovery, or species recovery data are so poor that it is impossible to tell whether the tools are effective or not. I examined patterns of species’ declines in three different groups in relation to a number of anthropogenic variables. I found high losses of Canadian imperiled bird, mammal, amphibian and reptile species in regions with high proportions of agricultural land cover. However, losses of imperiled species are significantly more strongly related to the proportion of the region treated with agricultural pesticides. This is consistent with the hypothesis that agricultural pesticide use, or something strongly collinear with it (perhaps intensive agriculture more generally), has contributed significantly to the decline of imperiled species in Canada. Global increases in UV radiation do not appear to be a major cause of amphibian population declines. At individual sites, temporal changes in amphibian abundance are not predictably related to changes in UV intensity. Variability in species’ abundance of North American breeding birds, after accounting for mean abundance, is not systematically higher in areas of high human-dominated land cover or climate change. Rather, it appears that areas with a high proportion of human-dominated cover come to have a higher proportion of highly abundant, and thus more variable, species.

En Afrique Sub-Saharienne, les problématiques de contamination de la ressource en eau par les pesticides et les résidus pharmaceutiques commencent à être mises en évidence. La problématique de la thèse porte sur la caractérisation de l’impact des activités humaines sur la qualité de la ressource en eau, par l’étude de la contamination par les pesticides et les résidus pharmaceutiques. Le site d’étude choisi est le bassin versant de la Méfou, qui draine la capitale du Cameroun, Yaoundé. Dans un premier temps, le site est caractérisé par ses spécificités environnementales (relief, occupation des sols) et sociodémographiques afin d’identifier les pressions anthropiques. Les pratiques d’agriculture urbaine, et en particulier le maraîchage intensif dans les bas-fonds entraîneraient l’utilisation massive de pesticides. L’absence d’assainissement efficace et les multiples latrines, drains et fosses septiques constitunt autant de sources diffuses de contamination par les résidus de médicaments. En prenant le cas des pesticides, une méthode cartographique a permis de confirmer l’hypothèse selon laquelle les parcelles agricoles pourraient être identifiées comme des sources de pollution diffuses de pesticides via le ruissellement. La méthode multicritère SIRIS-Pesticides de l’INERIS (Institut National de l’Environnement Industriel et des Risques) appliquée sur deux scénarios de pratiques agricoles indique un potentiel transfert des pesticides ciblés vers les eaux de surface. Afin de conforter ces hypothèses, deux diagnostics de pollution ont été réalisés entre 2015 et 2018 en saisons pluvieuses, couplant des méthodes d’échantillonnages ponctuels et passifs. Une liste de 32 pesticides et de 24 résidus pharmaceutiques a été recherchée dans les eaux de surface et les eaux souterraines du bassin de la Méfou. Les résultats généraux indiquent (i) de fortes concentrations en herbicides et en anti-inflammatoires non stéroïdiens ainsi que la détection et la quantification d’une large gamme de composés recherchés, (ii) une contamination bien plus marquée en milieu urbain qu’en milieu péri-urbain, (iii) un risque environnemental à ces concentrations pour deux herbicides (diuron et atrazine) et (iv) la contamination de certains points d’eau souterraine (forages, puits, sources) par les résidus pharmaceutiques. Une enquête sociologique réalisée autour des points d’eau de prélèvement a permis d’identifier les enjeux liés à l’utilisation de cette ressource en eau. La contamination des eaux souterraines pourrait entraîner une exposition potentielle des populations aux résidus pharmaceutiques présents dans leur eau de boisson. Les résultats principaux constituent donc une base d’information sur les pressions anthropiques, les niveaux de contamination et les enjeux liés à l’eau à Yaoundé. Ils soulèvent des questionnements sur (i) les transferts des pesticides et des résidus médicamenteux dans l’hydrosystème de la Méfou, et (ii) à propos de l’exposition et des risques sanitaires potentiels posés par leur occurrence et leurs niveaux de contamination dans la ressource en eau
Demographic growth and urbanization create pressure on water resources. Among urban contaminants, pesticides and pharmaceuticals can be discharged into the aquatic environment through agricultural activities and untreated waste waters. Their presence is also reported in global water bodies. Measured contamination levels can have ecotoxicological effects on aquatic organisms as well as on human populations. In Sub-Saharan Africa, these problems are beginning to be highlighted. Local agricultural practices and consumption of pharmaceuticals lead to specific concerns.The aim of this thesis is to identify and characterize the impacts of human activity on the quality of the water resource in urban Sub-Saharan Africa, by analyzing pesticide and pharmaceutical contamination. The study area was the Méfou watershed that drains the political capital of Cameroon, Yaoundé (Center Region).First, the study area was characterized by its environmental (reliefs, land use) and socio-demographic specificities to identify anthropogenic pressures. Urban agricultural practices and in particular the intensive market gardening in the humid lowlands involves the use of massive amounts of pesticides. The absence of a sewage system and the numerous pit-latrines, drains and septic tanks are the sources of diffuse pharmaceutical contamination.Using the example of pesticides, a contaminated runoff mapping method based on susceptibility maps (from the IRIP method) confirmed that some treated plots located in situations that favor runoff were sources of diffuse pesticide contamination. Several areas in the study basin can accumulate this polluted runoff. Next, the multi-criteria SIRIS-Pesticides method from INERIS was applied based on two agricultural scenarios constructed with data sources from the literature. Results pointed to the potential transfer of pesticides from crops to both surface and groundwater.To reinforce these hypotheses, two water quality surveys were conducted in the rainy season between 2015 and 2018, combining grab and passive sampling. Thirty-two pesticides and twenty-four pharmaceuticals were searched for in surface and groundwater in the Méfou watershed. The main results indicate that (i) high concentrations of herbicides and analgesics were detected and quantified in the water samples along with a wide range of targeted compounds; (ii) the contamination pattern showed that the urban area is more polluted than the peri-urban area of Yaoundé; (iii) the measured concentrations pose an environmental risk, in particular the herbicides atrazine and diuron; and (iv) some groundwater sampling points used for drinking water were contaminated by the targeted pharmaceuticals.A social survey conducted in March 2018 around the sampling points identified the risks related to water use. The lack of a sewage system and the discharge of untreated waste water into the immediate surroundings facilitate contamination of the sampling sites. As groundwater is used as an alternative to the tap water network in Yaoundé, the population is also exposed to the risk of pharmaceutically contaminated drinking water.The main results provide baseline information about anthropogenic pressures, contamination levels and related issues in Yaoundé. They raise questions about (i) the transfer of contaminants in the Méfou hydrosystem and (ii) population exposure and potential health risks due to their presence and to the levels of contamination of the water resources

Résumé : Cette thèse porte sur le rôle de deux expositions environnementales encore peu étudiées et pouvant influer sur l’incidence des hémopathies malignes (HME) de l’enfant : les rayons ultraviolets (UV) et les pesticides liés aux activités agricoles.Les leucémies (LA) et lymphomes de l’enfant sont les deux types principaux de HME et représentent respectivement environ 470 et 200 nouveaux cas par an en France. Leur prise en charge thérapeutique et leur survie ont fait d’immenses progrès, cependant la connaissance de leurs facteurs de risque est encore très partielle.Les études sur les effets des UV dans les cancers de l’enfant sont peu développées. Plusieurs méta-analyses récentes concluent à une augmentation du risque de LA chez l’enfant lors d’une exposition professionnelle ou domestique de la mère aux pesticides pendant la grossesse. L’exposition aux pesticides d’origine agricole a été moins étudiée, et les résultats sont hétérogènes.La première partie, écologique, de ce travail s’intéresse à l’exposition résidentielle aux UV. Une étude a été réalisée à partir des observations du Registre National des Hémopathies malignes de l’Enfant (RNHE) faites sur une longue période, entre 1990-2009 et sur l’ensemble de la France métropolitaine (9 082 cas de LA et 3 563 cas de lymphomes). Les données de l’exposition aux UV résidentiels étaient issues de la base EUROSUN. Une moyenne quotidienne d’exposition aux UV résidentiels sur l’ensemble de la période 1988-2007 à l’échelle communale a été considérée. Une augmentation significative de l’incidence des leucémies aiguës lymphoblastiques à précurseurs B (LAL-Pré B) chez les moins de 5 ans a été observée avec l’exposition aux UV résidentiels au moment du diagnostic. L’association n’était pas modifiée après une stratification par périodes ; par tranches d’unités urbaines ; par grandes régions, et par un indice de défaveur français. Une deuxième étude, individuelle, sur les UV ne trouvait pas de modification de l’association en prenant en compte le rôle de facteurs individuels soupçonnés d’être associés aux LAL et en regardant l’exposition à la naissance. Les données individuelles de ces facteurs provenaient de deux études cas-témoins en population générale, l’enquête ESCALE (2003-2004) et l’enquête ESTELLE (2010-2011).La dernière partie de la thèse se penche sur l’exposition résidentielle aux pesticides liés aux activités agricoles. Cette étude s’appuie sur les données du RNHE, recueillant 10 994 cas de LA et 4 301 cas de lymphomes sur la période 1990-2013. L’intensité de l’activité agricole dans le canton de résidence au moment du diagnostic a été choisie comme proxy de l’exposition aux pesticides. Cette intensité a été à partir des données cantonales du Recensement général Agricole de 2000. Dans cette première approche aucune association n’a été mise en évidence entre les HME et la part de Surface Agricole Utile (SAU) totale. Les analyses par grands types de cultures montrent, dans cette première approche, une association positive et significative entre l’intensité de cultures en oléagineux et l’incidence des LAL Pré-B et des lymphomes de Burkitt. Des analyses de sensibilité montraient des résultats hétérogènes par période d’étude
Abstract: This thesis deals with the role of two environmental exposures not much studied and that could have an impact on the incidence of childhood hematological malignancies (CHM): ultraviolet radiation (UV) and agricultural pesticides.The two major diagnostic groups are acute leukemia (AL) and lymphomas and represent respectively around 470 and 200 new cases per year in France. Despite the progress made in improving therapeutic caring and survival, the etiology of these cancers remains largely unknown.There are very few studies on the association between UV and these cancers. Meta-analyses found a coherent association between childhood AL and parental professional or domestic pesticides exposure during pregnancy. However the association with residential exposure to agricultural pesticides has been less studied and results are heterogeneous.The first, ecological, part of the thesis addressed the associations between residential UV exposure at diagnosis and the incidence of types and subtypes of CHM in France. The 9,082 cases of acute leukemia (AL) and 3,563 cases of lymphoma diagnosed before the age of 15 years from 1990 to 2009 were provided by the French National Registry of Childhood Hematological Malignancies. UV data from 1988 to 2007 were extracted from the EUROSUN database. The annual daily average UV exposure of the children estimated at the municipalities of residence was considered. There was a significant increase in precursor B-cell acute lymphoblastic leukemia (PBC-ALL) in children aged less than 5 years with residential exposure to UV. The results remained stable in analyses stratifying by deprivation index or degree of urbanization of the municipalities.A second, individual, study found no change in the association between UV and PBC-ALL after taking into account the influence of suspected individual risk factors for ALL, and evaluated this association at birth. Individual data were collected by interviews in the ESCALE (2003-2004) and ESTELLE (2010-2011) nationwide case-control studies.The last part of this work focused on the residential exposure to agricultural pesticides. The 10,994 cases of AL and the 4,301 cases of lymphomas diagnosed among children less than 15 years old were obtained from the French National Registry of Childhood Hematological Malignancies over the period 1990-2013. Intensity of agricultural activities by Canton was used as a proxy of residential agricultural pesticides exposure. This proxy was estimated from the 2000 French agricultural census data. At this first step of the analysis, no associations were found between total agricultural area and incidence of CHM. Analyses by types of crops showed, at this first step, a significant association between oilseeds and PBC-ALL and Burkitt lymphoma. Sensitivity analyses evidenced heterogeneous results by time period

Phan Me is a midland-mountainous commune of Phu Luong district, Thai Nguyen province, Vietnam where the agricultural activities are predominant occupation. The investigation on the use of plant protection products in here showed that chemical pesticides have been commonly used in agricultural activities. Although some local people have a good attitude in using plant protection products, the status of using chemical pesticides that were not recommended (like Vofatox) has been quite popular due to the old cultivation customs. The local people have not applied any measures for wastewater treatment, or plant protection product package treatment. Besides, the use of plant protection products in higher concentration than recommendation for vegetables or crops caused the residues of toxics in agricultural products as well as in cultivation soil. The accumulation of toxic residues in the environment is a serious matter of concern because of their significant impact on the environment, agricultural ecosystem and human health.
Phấn Mễ là một xã trung du miền núi của huyện Phú Lương, tỉnh Thái Nguyên, Việt Nam với hoạt động sản xuất nông nghiệp là chủ yếu. Qua thực tế điều tra tình hình sử dụng thuốc bảo vệ thực vật (BVTV) tại đây cho thấy hầu hết các loại hình sản xuất nông nghiệp đều sử dụng thuốc BVTV. Một số người dân đã có ý thức trong việc sử dụng thuốc BVTV tuy nhiên do tập quán canh tác từ lâu đời nên việc sử dụng các loại thuốc bị khuyến cáo, chẳng hạn như Vofatox, vẫn còn khá phổ biến. Người dân chưa tiến hành các biện pháp để xử lý nước thải, bao bì, vỏ chai thuốc BVTV sau khi sử dụng. Bên canh đó, họ còn sử dụng thuốc BVTV không đúng liều lượng cho một số loại cây rau để lại dư lượng thuốc trên nông sản cũng như đất canh tác. Sự tích lũy dư lượng của những chất độc hại này trong môi trường là vấn đề đáng lo ngại do sự ảnh hưởng nghiêm trọng của chúng đối với môi trường sống, hệ sinh thái nông nghiệp và sức khỏe con người.

L?utilisation de produits phytosanitaires est à l?origine d?un problème majeur à l?interface de l?agriculture et de la préservation des ressources en eau. Dans ce contexte, les effets de différents métaux (Cu, Zn), métalloïdes (As) et pesticides (Azimsulfuron, Oxadiazon, Prétilachlore, Fipronil et Alphacyperméthrine) ont été étudiés en terme de biodisponibilité voire de toxicité sur des algues d?eaux douces (Pseudokirchneriella subcapitata et Chlorella sp.) sensibles aux pollutions diffuses d?origine agricole, en prenant en compte l?influence des ligands naturels et l?impact d?une multipollution. L?étude de la relation potentielle entre spéciation, biodisponibilité et toxicité a été menée, sur trois sites d?étude associés à une pollution d'origine agricole. Des échantillons d'eaux, collectés dans des canaux de drainage et des rizières (pollution organique), de drainage prélevés sur des parcelles soumises ou non à des épandages de lisiers de porcs (Cu, Zn) et de ruissellement issus de parcelles viticoles (multipollution) ont été caractérisés et analysés. Les résultats de toxicité ont été confrontés avec ceux mesurés sur des solutions standards en conditions contrôlées et les résultats analytiques ; dosage de résidus de pesticides et des métaux et métalloïdes traces. L?analyse d?échantillons non toxiques menée conjointement, après additions de Cu, par biotests et DPASV a permis d?approfondir les relations entre la toxicité et les espèces électrochimiquement labiles détectées. Elle a souligné la présence de complexes labiles du cuivre (CuL), responsables de la toxicité. Les études de laboratoire et de terrain illustrent de la complexité de l'évaluation de l'exposition dans des contextes de multipollution, chaque molécule nécessitant une évaluation spécifique de son comportement et de ses effets dans un milieu donné. Par ailleurs, les divers produits phytosanitaires présents sont susceptibles d'interagir entre-eux (toxicité de mélanges complexes) et avec les ligands naturels (complexation).

La diminution de la pollution des eaux par les pesticides constitue l'enjeux environnemental majeur de la Martinique au début du 20ème siècle. Dans ce cadre est proposée l'analyse de l'organisation spatiale des activités agricoles à l'origine de la variabilité spatiale de la charge polluante. L'appréhension de plusieurs niveaux d'organisation spatiale, selon trois points de vue sur l’espace, apporte une connaissance de la complexité du système rural. Cette approche conceptuelle se concrétise par l’utilisation de trois outils : les Systèmes d’Informations Géographiques (SIG), la modélisation graphique (chorèmes) et les Systèmes multi - agents (SMA), au moyen desquels sont exploitées les données issues d’enquêtes auprès des exploitants. Cette démarche est appliquée sur un territoire rural de 1200 hectares situés sur la rive gauche de la Capot, caractérisée par l'exclusivité des activités agricoles et la présence de 46 exploitations. Plusieurs points sont -soulignés : la construction historique- de l'espace martiniquais ; la répartition de logiques de gestion de l'espace ; la distribution des orientations culturales et des systèmes de cultures calqués en partie sur celle de types de fonctionnement spatial d’exploitations. Les conséquences environnementales sont évaluées à travers un indicateur de contribution des parcelles à la pression polluante : systèmes de culture et orientation culturales constituent les principaux critères de différenciation spatiale. Des simulations multi - agents confirment par ailleurs I hypothèse du rôle majeur de l'aménagement foncier dans la mise en œuvre de pratiques minimisant les épandages de pesticides
This study shows how the spatial organization of agricultural activities is at the origin of polluting loads distribution. In order to understand the complexity of the rural system in which the various activities take place, an approach was necessary which would consider several levels of space organization, according to three points of view on space: As a result, three tools have been used at once : geographic information systems (GIS), graphic modeling (chorèmes) and-multi-agents systems (MAS) used to analyse data resulting from farmer's interviews. These tools are applied to a rural territory of 1200 hectares located on the Pelée mountain, characterized by the exclusiveness of agricultural activities-and the presence of 46 exploitations. Several conclusions can be drawn from this study: historical construction of space at several levels of organization; distribution of logics of space management according to units of constraints; distribution of farming orientations and crop systems depending on distribution of- logics of space management. The environmental consequences have been evaluated by identifying plant health practices, formalized by an indicator of contribution of the plots to the polluting pressure: crops systems and farming orientation appears to be the principal criteria of space differentiation. Multi agents simulations helped to identify the ownership question as being at the basis for setting practices while minimizing spreadings of pesticides. At last, the study shows the need to take into account the various sides of rural development and the new functions of agriculture in order to solve environmental problems

L’utilisation de microorganismes ou de substances naturelles d’origine microbienne est une des solutions alternatives actuellement envisagées pour remplacer partiellement ou totalement les pesticides conventionnels. Dans ce contexte, l’objectif de ce travail de thèse a été d’évaluer le potentiel de biocontrôle des souches de P. syringae. Une étude des lipopeptides produits par les souches du complexe P. syringae a d’abord été réalisée car ces molécules sont connues pour leurs activités antimicrobiennes puis l’activité antifongique des bactéries a été analysée. Pour y parvenir, une collection de 709 souches, représentative de la diversité phylogénétique du complexe P. syringae, a été explorée. Grâce à une stratégie faisant intervenir des approches complémentaires de spectrométrie de masse et de bioinformatique, il a été possible de révéler une forte diversité structurale de lipopeptides : 61 lipopeptides dont 38 nouveaux, répartis dans les 5 familles décrites chez P. syringae (syringafactine, syringomycine, corpeptine, syringopeptines 22 et 25) ont été identifiés. Ces lipopeptides sont produits par 81,1% des souches de la collection étudiée, réparties dans 8 des 13 phylogroupes référencés au sein du complexe P. syringae. Concernant leurs activités, 22,3% des souches ont montré une activité antifongique in vitro. Les lipopeptides, produits par 97,3% des souches antifongiques et retrouvés dans des surnageants de culture bruts et semi-purifiés, sont certainement responsables de ces activités. Enfin, deux souches ont montré, in planta, un potentiel intéressant de biocontrôle de la septoriose du blé, causée par le champignon phytopathogène Zymoseptoria tritici. Leurs surnageants de culture bruts et ultrafiltrés, ont montré des niveaux de protection du blé allant jusqu’à 62% par rapport au témoin d’infection
The use of microorganisms or natural substances of microbial origin is one of the identified alternatives to partially or totally replace conventional pesticides. In this context, the aim of this thesis was to evaluate the biocontrol potential of strains belonging to the P. syringae complex. First, the lipopeptides produced by strains of this bacterial complex have been studied because these molecules are known for their antimicrobial activities. Then, the antifungal activity of these bacteria was analysed. To reach this goal, a collection of 709 strains, representative of the phylogenetic diversity of the P. syringae complex, was explored. Through a strategy involving complementary approaches of mass spectrometry and bioinformatics, it has been possible to reveal a huge lipopeptide structural diversity: in total, 61 lipopeptides, including 38 new, distributed into the 5 families described in the P. syringae complex (syringafactin, syringomycin, corpeptin, syringopeptins 22 and 25) have been identified. Lipopeptides producing strains, which represent 81.1% of the collection studied, belong to 8 of the 13 phylogroups referenced in the P. syringae complex. Concerning their activities, 22.3% of the strains have shown an antifungal activity in vitro. Lipopeptides, which are produced by 97,3% of the antifungal strains and are also found in crude and ultra-filtered cell free supernatants, are certainly responsible for these activities. Finally, two strains have shown, in planta, an interesting potential for the biocontrol of Septoria tritici blotch of wheat caused by the fungus Zymoseptoria tritici. Their crude and ultra-filtered cell free supernatants have shown different wheat protection levels up to 62% compared to the infection control

Molte attività antropiche danno origine a problemi ambientali per i quali è necessario trovare soluzioni. La presenza di sostanze indesiderabili nell'acqua, infatti, può rappresentare un rischio per la salute e l'igiene sia degli uomini che degli animali. È quindi fondamentale trovare metodi per evitare gli inquinanti di queste matrici, in modo da renderli compatibili con il mantenimento di condizioni ambientali adeguate e salutari. Questa tesi si propone di valutare la qualità delle acque sotterranee di un'area in cui la qualità dell'acqua non è mai stata studiata, in particolare indagando la presenza di pesticidi e nitrati al fine di comprendere l’impatto della viticoltura sull'inquinamento delle acque sotterranee. Questo studio nasce dalla necessità di migliorare la governance delle acque e di implementare le migliori pratiche di gestione e misure di mitigazione per prevenire l'inquinamento delle acque e quello ambientale. I risultati degli studi di monitoraggio hanno mostrato una contaminazione delle acque sotterranee da parte di pesticidi e nitrati e quindi è stata effettuata una valutazione della fonte di contaminazione da pesticidi e nitrati attraverso studi isotopici di N e O di NO3-, e attraverso analisi idrologiche utilizzando il modello CRITERIA 3D. Come una delle principali conclusioni del lavoro si può affermare che la presenza di pesticidi nelle acque sotterranee in un’area ad attività vitivinicola intensa, non può essere correlata solo alle proprietà e al destino chimico-ambientale delle sostanze o alle condizioni pedoclimatiche, ma anche al comportamento dell'utilizzatore finale. In effetti, la fonte di contaminazione valutata, è risultata essere dovuta sia a una contaminazione diffusa che a una contaminazione puntiforme. Per quanto riguarda l'influenza della fertilizzazione a base di azoto sulla presenza di nitrati nelle acque sotterranee, i risultati hanno mostrato un'elevata vulnerabilità dell'acquifero ai cambiamenti esterni. Dalle indagini isotopiche è emerso che la maggior parte dell'NO3- rilevato nelle acque sotterranee, deriva dall'utilizzo di fertilizzanti azotati inorganici, in accordo con le pratiche di uso del suolo e di viticoltura dichiarate dagli agricoltori della zona. Il risultato più importante dello studio, tuttavia, è stato che alla fine del processo, l'approccio multi-actor e la strategia di coinvolgimento adottati, hanno avuto successo nel migliorare gli atteggiamenti verso pratiche più sostenibili.
Many anthropic activities give rise to environmental problems for which it is necessary to find solutions. The presence of undesirable substances in water, indeed, can pose a risk to the health and hygiene of both men and animals. It is, therefore, essential to find methods in order to avoid pollutants from these matrices, so as to make them compatible with the maintenance of healthy environmental conditions. This thesis aims to assessing the groundwater quality of an area in which the quality of water was never studied, particularly investigating the occurrence of pesticides and nitrate in order to understand the grant of viticulture on water pollution. This study derives from the necessity to improve the water governance and to implement the best management practices and mitigation measures to prevent groundwater and environmental pollution. The results of monitoring studies showed a contamination of groundwater by pesticides and nitrate and thus an evaluation of PPPs and nitrates source contamination was carried out through isotopic studies of N and O of NO3- , and through hydrologic analysis by use of the model CRITERIA 3D. As one of the main conclusions of the work, the occurrence of PPPs in groundwater in areas with intensive viticultural activities cannot be related just to chemical environmental fate properties or pedoclimatic conditions, but also to end-user behavior. In fact, the contamination source evaluated, resulted to be due to both diffuse and point-source contamination. For what concerns the influence of nitrogen-based fertilization on nitrate occurrence in groundwater, the results showed a high vulnerability of the aquifer to external changes. Isotopic investigations showed that most of the NO3- detected in the groundwater, derived from the use of inorganic nitrogen fertilizers, in agreement with the land use and viticulture practices declared by the farmers. The most important result of the study, however, was that at the end of the overall process, the multi-actor approach and engagement strategy adopted were successful in improving attitudes to more sustainable practices.

Molte attività antropiche danno origine a problemi ambientali per i quali è necessario trovare soluzioni. La presenza di sostanze indesiderabili nell'acqua, infatti, può rappresentare un rischio per la salute e l'igiene sia degli uomini che degli animali. È quindi fondamentale trovare metodi per evitare gli inquinanti di queste matrici, in modo da renderli compatibili con il mantenimento di condizioni ambientali adeguate e salutari. Questa tesi si propone di valutare la qualità delle acque sotterranee di un'area in cui la qualità dell'acqua non è mai stata studiata, in particolare indagando la presenza di pesticidi e nitrati al fine di comprendere l’impatto della viticoltura sull'inquinamento delle acque sotterranee. Questo studio nasce dalla necessità di migliorare la governance delle acque e di implementare le migliori pratiche di gestione e misure di mitigazione per prevenire l'inquinamento delle acque e quello ambientale. I risultati degli studi di monitoraggio hanno mostrato una contaminazione delle acque sotterranee da parte di pesticidi e nitrati e quindi è stata effettuata una valutazione della fonte di contaminazione da pesticidi e nitrati attraverso studi isotopici di N e O di NO3-, e attraverso analisi idrologiche utilizzando il modello CRITERIA 3D. Come una delle principali conclusioni del lavoro si può affermare che la presenza di pesticidi nelle acque sotterranee in un’area ad attività vitivinicola intensa, non può essere correlata solo alle proprietà e al destino chimico-ambientale delle sostanze o alle condizioni pedoclimatiche, ma anche al comportamento dell'utilizzatore finale. In effetti, la fonte di contaminazione valutata, è risultata essere dovuta sia a una contaminazione diffusa che a una contaminazione puntiforme. Per quanto riguarda l'influenza della fertilizzazione a base di azoto sulla presenza di nitrati nelle acque sotterranee, i risultati hanno mostrato un'elevata vulnerabilità dell'acquifero ai cambiamenti esterni. Dalle indagini isotopiche è emerso che la maggior parte dell'NO3- rilevato nelle acque sotterranee, deriva dall'utilizzo di fertilizzanti azotati inorganici, in accordo con le pratiche di uso del suolo e di viticoltura dichiarate dagli agricoltori della zona. Il risultato più importante dello studio, tuttavia, è stato che alla fine del processo, l'approccio multi-actor e la strategia di coinvolgimento adottati, hanno avuto successo nel migliorare gli atteggiamenti verso pratiche più sostenibili.
Many anthropic activities give rise to environmental problems for which it is necessary to find solutions. The presence of undesirable substances in water, indeed, can pose a risk to the health and hygiene of both men and animals. It is, therefore, essential to find methods in order to avoid pollutants from these matrices, so as to make them compatible with the maintenance of healthy environmental conditions. This thesis aims to assessing the groundwater quality of an area in which the quality of water was never studied, particularly investigating the occurrence of pesticides and nitrate in order to understand the grant of viticulture on water pollution. This study derives from the necessity to improve the water governance and to implement the best management practices and mitigation measures to prevent groundwater and environmental pollution. The results of monitoring studies showed a contamination of groundwater by pesticides and nitrate and thus an evaluation of PPPs and nitrates source contamination was carried out through isotopic studies of N and O of NO3- , and through hydrologic analysis by use of the model CRITERIA 3D. As one of the main conclusions of the work, the occurrence of PPPs in groundwater in areas with intensive viticultural activities cannot be related just to chemical environmental fate properties or pedoclimatic conditions, but also to end-user behavior. In fact, the contamination source evaluated, resulted to be due to both diffuse and point-source contamination. For what concerns the influence of nitrogen-based fertilization on nitrate occurrence in groundwater, the results showed a high vulnerability of the aquifer to external changes. Isotopic investigations showed that most of the NO3- detected in the groundwater, derived from the use of inorganic nitrogen fertilizers, in agreement with the land use and viticulture practices declared by the farmers. The most important result of the study, however, was that at the end of the overall process, the multi-actor approach and engagement strategy adopted were successful in improving attitudes to more sustainable practices.

Cette thèse porte sur la régulation des innovations en Europe. Elle examine en particulier l'impact économique des procédures d'Autorisation de Mise sur le Marché (AMM) sur les comportements des acteurs économiques à savoir les firmes innovantes. Il s'agit d'un travail appliqué au secteur de la santé des plantes dans lequel l'AMM joue un rôle central. En effet, dans ce secteur, la mise sur le marché des pesticides est subordonnée à une autorisation officielle. Les procédures d'autorisation de mise sur le marché (AMM) des nouveaux produits consistent à vérifier qu'ils n'ont pas d'effets toxiques inacceptables sur la santé et l'environnement et à définir des conditions d'utilisation dans lesquelles ces produits sont réputés efficaces. En Europe, ces procédures sont instruites par des autorités européennes ou nationales. Dans le cas des pesticides, les matières actives sont autorisées à l'échelle européenne, les spécialités commerciales le sont à l'échelle nationale, par reconnaissance mutuelle au sein d'une zone géographique. Au cours des dernières décennies, les exigences dans le domaine des risques sanitaires ont conduit à un renforcement des contraintes imposées pour la mise en marché des produits phytosanitaires. Ces exigences renforcées ont conduit à une réduction du nombre de molécules autorisées en rapport au nombre de molécules potentiellement efficaces. Par exemple, le nombre de molécules pesticides autorisées a été réduit de moitié (de 800 à 400) au cours des dix dernières années. C'est pourquoi, l'objet principal de cette recherche est d'étudier les effets des procédures d'AMM sur le comportement des firmes agrochimiques. Cette recherche s'articule autour de trois chapitres. Le premier chapitre est théorique. Il analyse les interactions stratégiques entre les agences de régulation des pesticides dans un contexte d'autorisation de mise sur le marché par reconnaissance mutuelle. Le chapitre 2 est à la fois théorique et empirique et porte sur les délais de mise sur le marché des substances actives phytosanitaires. Dans le chapitre 3, nous examinons, à l'aide d'un modèle théorique, l'impact de la régulation des pesticides sur les incitations des firmes agrochimiques à investir en R&D
This thesis focuses on the regulation of innovations in Europe. In particular, it analyses the economic impact of the market approval procedures on the behavior of economic actors such as innovative firms. This is an applied work in the health sector of plants in which the market approval procedures play a central role. Indeed, in this area, the introduction on the market of pesticides is subject to an official approval. The market approval procedures for new products are to ensure that they do not have unacceptable toxic effects on human health and the environment and to define the conditions of use in which these products were efficient. In Europe, these procedures are investigated by European or national authorities. In the case of pesticides, the active substances are approved at EU level and the pesticides formulation at the national level through mutual recognition within a geographic area. In recent decades, the requirements in the field of health risks have led to a strengthening of the constraints imposed on the approval of pesticides. These stringent requirements have led to a reduction in the number of approved molecules relative to the number of molecules potentially efficient. For example, the number of approved actives substances was reduced by half (800 to 400) over the last ten years. Therefore, the main purpose of this research is to study the effects of market approval procedures on the behavior of agrochemical companies. This research is based on three chapters. The first chapter is theoretical. It analyses the strategic interactions between pesticide regulatory agencies in the context of market approval through the mutual recognition system. The chapter 2 is both a theoretical and an empirical work. It examines the examination delays of plant protection active substances. In Chapter 3, we examine, using a theoretical model, the impact of the regulation of pesticides on the incentives of agrochemical companies to invest in R & D

Le travail presente dans ce memoire concerne une etude du devenir d'un herbicide du mais, l'atrazine en condition de plein-champ: bilan et modes de dissipation. Des experimentations de laboratoire mettant en jeu des methodes diverses (suivi de l'atrazine #1#4c, couches minces et colonnes de terre, lysimetre non remanie) permettent d'etayer les resultats obtenus sur la parcelle experimentale du site observatoire des pollutions diffuses du lycee agricole de la cote saint andre (isere, france) ou a ete suivie pendant 3 ans la composition en herbicide et metabolites du sol sur 1 metre de profondeur et celle de l'eau interstitielle prelevee par bougies filtrantes. La matiere active (1 kg/ha) apportee annuellement fin avril se dissipe selon cinq voies d'importances tres inegales: volatilisation (15%), absorption par la culture (10%), adsorption sur le complexe argilo-humique et metabolisation (40-50%), entrainement vers les eaux profondes (30-40%). Dans la situation etudiee, les deux voies principales sont la metabolisation par la microflore du sol et l'entrainement lors des episodes pluvieux precoces. Apres un an de culture, la teneur en atrazine et derives au sein du premier metre de sol est voisine de 400 g/ha ce qui indique que l'evacuation de la matiere active n'est pas complete. Notre etude de terrain completee par une experimentation de laboratoire, conduit a mettre en evidence la possibilite de pertes precoces importantes de matiere active durant les deux premiers mois de culture. Trois concepts importants relatifs a l'efficacite d'un herbicide de prelevee emergent de notre etude: la concentration critique dans l'eau du sol, la duree critique durant laquelle cette concentration doit etre maintenue pour assurer l'effet herbicide, la profondeur critique qui represente la couche de sol dans laquelle doit jouer l'effet herbicide. Pour l'atrazine en culture de mais, dans nos conditions, ces criteres ont ete mesures: concentration critique: entre 50 et 200 micromoles ; duree critique: deux mois ; profondeur critique: 10 cm. Avec 1 kg/ha d'atrazine sous forme de suspension concentree, les trois criteres d'efficacite sont remplis malgre d'importantes pertes par drainage lors des episodes pluvieux precoces. Des modifications de formulation ayant pour consequence un relargage progressif devrait permettre l'economie d'une part importante de matiere active. La derniere partie de ce travail concerne une approche de mise en place de solutions alternatives de traitements herbicides en culture de mais