The capacity of four mineral sorbents to retain arsenic under simulated mature landfill conditions was tested using semi-batch and continuous flow columns. The sorbents tested were Fe-, Ti-, La-, and Zr- based oxi(hydroxides). The Fe sorbent was included as a positive control to compare the release of As from a substrate subject to reduction to those of the, non-sensitive to reduction under typical mature landfill conditions, Ti, La, and Zr media. It has been proved that under mature landfill conditions, As(V) preloaded on ferric sorbents is prompt to be released at high levels. Our results indicate that Ti, La, and Zr sorbents can release As at a similar or higher degree than a ferric sorbent. In a second phase, the capacity of the same sorbents to retain As was evaluated after being subject to polymeric encapsulation in an epoxic resin. Landfill conditions were simulated by use of semi-batch column systems packed with compost and fed with actual landfill leachate. Results obtained indicated that encapsulation highly enhanced As retention of the media under simulated landfill conditions. In our research regarding soil contamination by atmospheric transport from mine tailings, a previously developed deposition forecasting model (DFM) that is designed to model the transport of particulate As and Pb from mine tailing impoundments is verified using dust collection and topsoil measurements. The forecast deposition patterns are compared to dust collected by inverted-disc samplers through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. Finally, the bioaccessibility of As and Pb were on samples collected at Iron King Mine Tailing was evaluated through chemical extractions using simulated the gastric and the lung fluids of the human body. Results obtained indicate that extractions using simulated gastric fluid lead to As concentrations one order of magnitude higher to those obtained with lung fluid. For Pb concentration the difference was greater than 2 orders of magnitude.

The purpose of this work was to estimate metals bioaccessibility in soil samples from 15 city parks in Toronto, Ontario, Canada. Total metals concentrations were analyzed to identify contaminants that exceeded the Canadian Council of Ministers of the Environment (CCME) guidelines for residential/parkland use. Arsenic, barium, cadmium, cobalt, copper, lead, nickel and zinc were of particular interest as they have been known to have major effects on human health. Metal concentrations were below the CCME guidelines except for lead at three of the parks. Lead, copper and cadmium bioaccessibility in the soil samples as determined by an in-vitro physiologically based extraction test (PBET) were relatively high. Based on linear regression analyses there were no significant relationships between total metals and soil properties such as pH and total organic carbon (TOC). Generally there was negative correlation between metal bioaccessibility and TOC and positive correlation between bioaccessibility and soil pH.

A better understanding of how dietary fibres impact the bioavailability of fat-soluble nutrients and nutraceuticals is required. The purpose of this research was to determine the influence of guar gum (GG) on the transfer processes impacting beta-carotene (BC) bioaccessibility (transfer to the aqueous phase) from an oil-in-water emulsion using an in vitro model simulating gastric and duodenal digestion. Canola oil emulsions (1.5 % soy protein isolate, 10 % canola oil and 0.1 % all trans BC, D4,3~160 nm) were prepared by microfluidization (40 MPa, 4 passes) and exposed, in the presence of 0.0, 1.0, 1.5, 2.0, or 4.0 % GG, to conditions representative of the stomach and duodenum in the fed state. Lipolysis, BC bioaccessibility, digestate apparent viscosities, droplet size, and bile acid (BA) binding were studied. With increasing concentration of GG, digestate viscosity was increased and lipolysis and bioaccessibility were decreased (P<0.05). Peak lipolysis was 56.2% vs. 21.6% for emulsions containing 0.0 % vs. 4.0 % GG, respectively. BC bioaccessibility was also lower in the presence of GG (i.e. 29.7 vs. 6.98 % for 0.0 vs. 4.0 % GG respectively). Thus, the presence of GG impacted digestive processes central to BC absorption. The impact of GG may be related to increased digestate viscosity entrapping mixed micelles or BAs and decreasing diffusion leading to decreased lipolysis and BC bioaccessibility. / NSERC, CFI

This thesis examines the air-soil and air-water gas exchange of persistent organic pollutants (POPs) with emphasis on organochlorine pesticides (OCPs). The current status of net exchange, factors which influence the exchange process, and different approaches used to estimate the surface exchange were explored. The net exchange of chemicals was evaluated using the fugacity approach, with the aid of chemical tracers (congener profiles of complex mixtures and enantiomer proportions of chiral chemicals) to infer current use vs. legacy sources to the atmosphere. DDT in southern Mexico was undergoing net deposition from air to soil. Occurrence of fresher DDT residues in the south was indicated by a higher proportion of p,p’-DDT relative to p,p’-DDE and racemic o,p’-DDT in air and soils. Congener profiles of toxaphene suggested soil emissions as the source to air. The influence of chemical aging on soil-air exchange and bioaccessibility was studied in a high organic soil. The use of nonexhaustive extraction with hydroxypropyl-beta-cyclodextrin (HPCD) to predict bioaccessibility was optimized for OCPs and polychlorinated biphenyls (PCBs). Reduced volatility of spiked chemicals correlated with reduced HPCD extractability for soil that had been aged under indoor and outdoor conditions for 730 d and infers volatility could be used as a surrogate for bioaccessibility. Measured soil-air partition coefficients (Ksa) were lower than those predicted from the Karickhoff relationship, which considers octanol as a surrogate for soil organic matter. The role of soil moisture, organic carbon, temperature, depth of soil surface horizon and dissolved organic carbon in the fate of organic contaminants in soil were assessed using chemical partitioning space maps. These maps allow instant visual prediction of the phase distribution and transport process of a chemical among the three major phases in soil; i.e., air, water and solid. Net volatilization of alpha-hexachlorocyclohexane from water to air was found in the southern Beaufort Sea using fugacity calculations and flux measurements. The influence of ice cover on volatilization was indicated by a winter-summer shift from racemic to nonracemic alpha-HCH in boundary layer air.

This thesis examines the air-soil and air-water gas exchange of persistent organic pollutants (POPs) with emphasis on organochlorine pesticides (OCPs). The current status of net exchange, factors which influence the exchange process, and different approaches used to estimate the surface exchange were explored. The net exchange of chemicals was evaluated using the fugacity approach, with the aid of chemical tracers (congener profiles of complex mixtures and enantiomer proportions of chiral chemicals) to infer current use vs. legacy sources to the atmosphere. DDT in southern Mexico was undergoing net deposition from air to soil. Occurrence of fresher DDT residues in the south was indicated by a higher proportion of p,p’-DDT relative to p,p’-DDE and racemic o,p’-DDT in air and soils. Congener profiles of toxaphene suggested soil emissions as the source to air. The influence of chemical aging on soil-air exchange and bioaccessibility was studied in a high organic soil. The use of nonexhaustive extraction with hydroxypropyl-beta-cyclodextrin (HPCD) to predict bioaccessibility was optimized for OCPs and polychlorinated biphenyls (PCBs). Reduced volatility of spiked chemicals correlated with reduced HPCD extractability for soil that had been aged under indoor and outdoor conditions for 730 d and infers volatility could be used as a surrogate for bioaccessibility. Measured soil-air partition coefficients (Ksa) were lower than those predicted from the Karickhoff relationship, which considers octanol as a surrogate for soil organic matter. The role of soil moisture, organic carbon, temperature, depth of soil surface horizon and dissolved organic carbon in the fate of organic contaminants in soil were assessed using chemical partitioning space maps. These maps allow instant visual prediction of the phase distribution and transport process of a chemical among the three major phases in soil; i.e., air, water and solid. Net volatilization of alpha-hexachlorocyclohexane from water to air was found in the southern Beaufort Sea using fugacity calculations and flux measurements. The influence of ice cover on volatilization was indicated by a winter-summer shift from racemic to nonracemic alpha-HCH in boundary layer air.

No description available.

La carence en vitamine A est un problème de santé publique dans de nombreux pays et elle touche particulièrement les groupes vulnérables. Un régime alimentaire varié permet de lutter durablement contre cette carence. Les fruits et légumes ont un rôle important dans ce contexte. Certains caroténoïdes provitaminiques peuvent participer à la couverture des besoins en vitamine A. Leur faible absorption intestinale et conversion en vitamine A est un facteur limitant. Cette thèse avait pour objectif, tout d’abord, d’identifier les déterminants de la bioaccessibilité des caroténoïdes (β-carotène et lutéine) et de l’α-tocophérol dans 8 légumes feuilles frais consommés en Asie du Sud Est. Le profil nutritionnel de ces aliments, ainsi, que leurs capacités à libérer les micronutriments d’intérêt pendant des digestions in vitro ont été évalués. Des corrélations statistiques ont été recherchées entre les différentes variables pour identifier quels facteurs favorisent ou limitent la bioaccessibilité des composés. Dans un deuxième temps, deux études poussées ont été menées sur les feuilles de moringa et brèdes chouchou afin d’évaluer l’influence des traitements culinaires et procédés de conservation sur la bioaccessibilité des micronutriments lipophiles. Une approche microscopique a été mise en œuvre pour suivre le changement de structure des feuilles à l’échelle cellulaire. Enfin, une méthode de purification et quantification des pectines et tanins ayant diffusés dans les milieux digestifs a été développée afin de voir si ces polymères étaient impliqués dans la modulation de la bioaccessibilité des caroténoïdes et tocophérols selon les variétés. Les légumes feuilles sont composés de trois tissus distincts (épiderme, mésophylle et tissu vasculaire). Les teneurs en pectines des légumes feuilles ont été le seul déterminant identifié dans la faible micellisation des caroténoïdes. L’analyse de la teneur en pectines des milieux digestifs n’a pas permis de confirmer cette hypothèse. Les tanins condensés, quant à eux, auraient un effet protecteur probablement liés à leurs propriétés antioxydantes. Parmi les opérations culinaires, la cuisson à la vapeur est celle qui augmente le plus la bioaccessibilité des caroténoïdes et de l’α-tocophérol des feuilles en déstructurant légèrement les tissus et en induisant peu de reactions de dégradations. En revanche, la friture détruit l’épiderme, ouvre les cellules palissadiques et dégrade les vitamines par réaction à hautes températures. Le séchage doux (60°C) couplé au broyage permet d’obtenir des poudres dont les composés sont libérés plus aisément pendant la digestion ; les cellules sont alors en partie ouvertes par le traitement. En conclusion, les légumes feuilles frais et transformés ont un profil nutritionnel intéressant et les procédés (séchage/broyage, cuisson à la vapeur, stérilisation) améliorent la capacité des aliments à relarguer les micronutriments pendant la digestion. L’ouverture des cellules est un élément important dans la bioaccessibilité des composés mais la composition des légumes elle même influence le devenir digestif (stabilité, micellisation). La stabilisation par abaissement de la teneur en eau et broyage, permet de disposer sur l’année de légumes sous forme de poudre « fonctionnalisée ». Le Moringa a un profil nutritionnel comparable aux autres légumes feuilles à l’exception des composés phénoliques qu’il contient. Diversifier les modes de consommation de légumes sous forme fraiche ou transformée pourrait améliorer le statut nutritionnel des populations. / The vitamin A deficiency is a major public health problem in numerous countries and affects specifically vulnerable groups. A diversified diet allows decreasing the vitamin A deficiency in a sustainable way. Fruits and vegetables have an important role to play in this context. Some of provitamin A carotenoids can fulfil human vitamin A requirements. Their poor intestinal absorption and bioconversion into vitamin A is a limiting factor. This thesis aim at, firstly, identify the key determinants of carotenoid (β-carotene and lutein) and α-tocopherol bioaccessibility in 8 fresh leafy vegetables consumed in South East Asia. Their nutritional profile and capacity to liberate micronutrient throughout in vitro digestion were assessed. Statistical correlations were determined among the variables to identify which factor promotes or impairs the micronutrient bioaccessibility. In a second step, two studies were leaded on chayote and moringa leaves to evaluate the influence of culinary treatments and preservation methods on the compound bioaccessibility. A microscopical approach was used to assess the structural changes of the food at the cellular scale. Finally, a quantification method of pectins and tannins in the digestive medium was developed to highlight their role in the carotenoid micellarisation. Leafy vegetables are constituted of tree distinct tissues (epidermis, mesophylle and vascular bundles). The pectin contents in leafy vegetable were the only key factor statically involved in the carotenoid micellarisation. The analysis of the pectin contents of the digestive medium of leafy vegetable did not confirm this hypothesis. The condensed tannins had rather a protective role probably related to their antioxidant properties. Among the culinary treatments, steaming increased greatly the carotenoid and α-tocopherol bioaccessibility with concomitant tissue disorganization and low degradation reactions. On the contrary, frying destroys the epidermis layer, opens some palissadic cells with a high level of destruction of vitamins with the high temperature used. Drying at moderate temperature (60°C) plus grinding produce powders with high release of compounds during in vitro digestion. In conclusion, fresh and processed vegetables have an interesting nutritional profile and processing (drying/grinding, steaming, sterilization) improves the digestive release of micronutrients. Cell opening is an important factor as well as the biochemical composition of the leaves which determine the digestive behaviour (stability, micellarisation). Stabilisation of leaves by drying and grinding allow delivering functionalised powder during the year. Moringa has a nutritional profile comparable to others leafy vegetables except for its phenolic contents. The consumption of diversified products based on leafy vegetables in fresh or processed state should improve the nutritional status of populations.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / For the proper functioning of the human body are essential various nutrients, among these are the macro and micro. The minerals are important in the physiological and biochemical functions of the human body. Insufficient intake can cause deficiencies, on the other hand excessive intake may be toxic. For the recommended doses of each mineral we need to consume fruits, vegetables, grains and vegetables. The food supplement is useful when selecting foods in a diet has some nutrient deficiencies. However, not all nutrient contained in a food supplement can be made available to be absorbed by the body, ie bioaccessible. Thus, the study of mineral bioaccessibility in this array is necessary. Thus, the aim of this study was to evaluate the in vitro bioaccessibility of macro and micro minerals in samples of amaranth, and quinoa multimixture, used as a food supplement. To determine the total content of minerals, samples were digested in oven with microwave cavity and the content of mineral measured by ICP OES. To evaluate the bioaccessibility, the samples were subjected to in vitro gastrointestinal digestion. The bioaccessible fraction was digested in the digester block prior to analysis by ICP OES. The three studied food supplements, as the total contents, are rich in Cu, Fe, Mg, Mn and P, and only multimixture is a source of Ca and Zn, with respective contributions of 19.1% and 20.1%, considering : source (15-29% of RDA) and rich (at least 30% of RDA). However, the amount of Cu and Mn amaranth and quinoa multimixture exceeded the UL (upper tolerable limit intake). After in vitro digestion, there was a marked reduction in the contribution to the RDA of all the three minerals and food supplements. The bioaccessibility study results show that the amaranth is a source of Fe, Mg and Mn-rich P and Cu; multimixture is the source of Fe, Mn and high in P and quinoa source of Mn and high in P and Cu. The application of PCA (principal component analysis) showed that multimixture has higher content of K, Cu, Mg, Zn, Fe and Ca and amaranth Mg and P (total contents) and the bioaccessibility, amaranth was more bioaccessible of Ca, Fe and Mg; multimixture K and Zn; and amaranth and quinoa, similarly, Cu, Mn and P. Regarding the content of phytic acid in the samples was observed that the greater the anti-nutritional content of such lower bioaccessibility of Ca, Cu, Fe and Mn. This work shows that the study of bioaccessibility and anti-nutritional factors performed to amaranth, and quinoa multimixture were relevant, since they can be inserted more precise information on the absorption of minerals in nutritional composition tables of these foods / Para o bom funcionamento do corpo humano sÃo essenciais vÃrios nutrientes, dentre estes estÃo os macro e microminerais. Os minerais sÃo importantes nas funÃÃes fisiolÃgicas e bioquÃmicas do corpo humano. A ingestÃo insuficiente pode causar deficiÃncias, por outro lado a ingestÃo excessiva pode ser tÃxica. Para obter as doses recomendadas de cada mineral à preciso consumir frutas, verduras, cereais e hortaliÃas. A complementaÃÃo alimentar à Ãtil quando a seleÃÃo de alimentos em uma dieta possui carÃncias de algum nutriente. Contudo, nem todo nutriente contido em um complemento alimentar pode estar disponÃvel para ser absorvido pelo organismo, ou seja, bioacessÃvel. Logo, o estudo da bioacessibilidade de minerais nessa matriz faz-se necessÃrio. Desse modo, o objetivo deste trabalho foi avaliar a bioacessibilidade in vitro de macro e microminerais em amostras de amaranto, multimistura e quinoa, usadas como complemento alimentar. Para a determinaÃÃo dos teores totais dos minerais, as amostras foram digeridas em forno de micro-ondas com cavidade e o teor dos minerais medidos por ICP OES. Para avaliaÃÃo da bioacessibilidade, as amostras foram submetidas à digestÃo gastrointestinal in vitro. A fraÃÃo bioacessÃvel foi digerida em bloco digestor antes das anÃlises por ICP OES. Os trÃs complementos alimentares estudados, quanto aos teores totais, sÃo ricos em Cu, Fe, Mg, Mn e P, e apenas a multimistura à fonte de Ca e Zn, com respectivas contribuiÃÃes de 19,1% e 20,1%, considerando: fonte (15-29% da RDA) e rico (no mÃnimo 30% da RDA). No entanto, a quantidade de Cu e Mn no amaranto, multimistura e quinoa excedeu a UL (Limite superior tolerÃvel de ingestÃo). ApÃs digestÃo in vitro, houve uma reduÃÃo acentuada na contribuiÃÃo para a RDA de todos os minerais e nos trÃs complementos alimentares. Os resultados do estudo de bioacessibilidade mostram que o amaranto à fonte de Fe, Mg e Mn e rico em P e Cu; a multimistura à fonte de Fe, Mn e rica em P e a quinoa fonte de Mn e rica em P e Cu. A aplicaÃÃo da PCA (anÃlise de componentes principais) mostrou que a multimistura possui maior teor de K, Cu, Mg, Zn, Fe e Ca e o amaranto de Mg e P (teores totais) e com a bioacessibilidade, o amaranto foi mais bioacessÃvel em Ca, Fe e Mg; a multimistura em K e Zn; e o amaranto e a quinoa, de forma similar, em Cu, Mn e P. Quanto aos teores de Ãcido fÃtico nas amostras observou-se que quanto maior à o teor desse antinutricional menor a bioacessibilidade de Ca, Cu, Fe e Mn. Este trabalho mostra que o estudo de bioacessibilidade e dos fatores antinutricionais realizados para amaranto, multimistura e quinoa foram pertinentes, uma vez que podem ser inseridas informaÃÃes mais precisas quanto à absorÃÃo de minerais em tabelas de composiÃÃo nutricionais desses alimentos.

Le syndrome métabolique (MS), une association des plus dangereux facteurs de risque pour les maladies cardiovasculaires et le diabète de type 2, est devenu l'un des principaux défis cliniques et de santé publique dans le monde. Un nombre croissant d’évidences s’est accumulé au cours de la dernière décennie, démontrant l'efficacité de certains composés bioactifs alimentaires pour le traitement et la prévention du MS. Néanmoins, la plupart des études d'intervention administre les composés bioactifs sous forme de composés purs, sans considérer que l'interaction entre les bioactifs ajoutés et l'ensemble de la matrice alimentaire peut impacter la bioaccessibilité, la biodisponibilité et, par conséquent, l’efficacité de ces molécules bioactives.L'objectif principal de cette thèse, intégrée dans le projet européen PATHWAY-27, était de formuler des aliments enrichis en composés bioactifs potentiellement efficaces contre le MS, et d'étudier l'effet de la matrice alimentaire sur la bioaccessibilité et la biodisponibilité de ces bioactifs. Cette étude a mis l'accent sur l'utilisation des anthocyanes, de l’acide docosahexaénoïque et, dans une moindre mesure, des bêta-glucanes comme ingrédients bioactifs pour enrichir des produits laitiers et des produits à base d'œuf. Une combinaison des modèles de digestion in vitro et in vivo (chez le porc) a été utilisée.La composition et la structure des matrices alimentaires ont impacté la libération et la solubilisation de substances bioactives au cours de la digestion (bioaccessibilité), tel que démontré in vitro et in vivo. La structure de / Metabolic Syndrome (MS), a constellation of the most dangerous cardiovascular disease and type 2 diabetes mellitus risk factors, has become one of the major clinical and public health challenges worldwide. During the last decade, many bioactives have been proposed as effective for the treatment and prevention of MS. However, most intervention studies administer bioactives as pure compounds, without consider that bioactive-food matrix interactions could deeply impact on the bioaccessibility, bioavailability and hence on the effectiveness of bioactives.The main objective of this thesis, included within the European project PATHWAY-27, was to formulate potential effective bioactive-enriched foods against MS and to investigate the effect of the food matrix on the bioaccessibility and bioavailability of dietary bioactives.In particular, this study focused in the use of dairy and egg-based products as matrices and in the addition of anthocyanins, docosahexaenoic acid and, to a lesser extent, beta glucan as bioactives. A combination of in vitro and in vivo (pig) digestion models was used.Both the structure and the composition of the food matrices impacted the release and the solubilisation of bioactives during digestion (bioaccessibility), as demonstrated in vitro and in vivo. In addition, the structure of the food matrix modulated the final amount of DHA into the systemic circulation of pigs (bioavailability). This study proves that understanding how dietary bioactives interact with the matrix in which they are included in is the basis for the production of effective bioact

Dans son rôle « géo-accumulateur », le sol peut constituer un réservoir de Polluants Organiques Persistants (PoP). Les animaux élevés en plein air comme les ruminants laitiers peuvent alors être exposés aux PoP via l’ingestion involontaire de sol, un bovin adulte pouvant ingérer jusqu’à 800 g de sol par jour. Cependant, le mécanisme de sorption des PoP sur les particules du sol se caractérise par la formation de liaisons fortes susceptibles d’atténuer leur biodisponibilité. Afin de préciser le transfert des PoP du sol vers le ruminant, nous avons développé différentes approches permettant d’évaluer la biodisponibilité de ces contaminants. La chèvre en lactation a été choisie comme modèle de ruminant laitier.Les travaux se sont focalisés sur deux familles de composés : les Hydrocarbures Aromatiques Polycycliques (HAP) qui sont des molécules sensibles au métabolisme, et les PolyChloroBiphenyles (PCB), peu sensibles au métabolisme. Pour les PCB, la biodisponibilité relative a été obtenue en comparant les coefficients de transfert ou « Carry-Over Rate » obtenus à la suite de l’ingestion de sol avec ceux trouvés dans la littérature impliquant des matrices alimentaires telles que le foin. Cette valeur, obtenue à l’équilibre, désigne la part fixe du contaminant atteignant le lait. La seconde expérience a été élaborée afin de calculer la biodisponibilité relative des HAP liés au sol. Cette démarche s’est basée sur la comparaison des pentes des courbes doses-réponses obtenues entre l’ingestion de la matrice sol ou de la matrice de référence (l’huile) et l’excrétion des métabolites de HAP hydroxylés majoritaires dans les urines. La dernière étude a consisté en une collecte de données de la littérature, dans le but de déterminer globalement le rôle de la matière organique (carbone organique) du sol sur la bioaccessibilité des HAP dans le tractus gastro-intestinal. Les résultats des études que nous avons menées démontrent que le sol a un impact limité sur la biodisponibilité orale de l’ensemble des PoP chez le ruminant. Cependant, la lipophilicité des PoP semble jouer un rôle dans la régulation de leur biodisponibilité. En effet, l’impact du sol sur la biodisponibilité du Phénanthrène est limité (molécule à trois cycles), tandis que la réduction de la biodisponibilité du Pyrène a été estimée à 50 % (molécule à quatre cycles).Du plus, la bioaccessibilité dans le tractus digestif (une des composantes de la biodisponibilité) a été estimée pour les HAP : elle varierait entre 0,2 et 46%, et serait guidée par la concentration des HAP et la teneur en carbone organique du sol. L’effet géosorbant du sol, qui explique son rôle de réservoir environnemental de PoP, paraît insuffisant dans les conditions du tractus digestif du ruminant laitier, pour éviter une contamination des produits animaux. Une attention particulière doit être portée au sol dans les scénarios d’évaluation du risque / Persistent Organic Pollutants (PoP) can be accumulated through the “memory effect of soil”. Ruminants can therefore be exposed to the PoP through involuntary ingestion of the contaminated soil. On pasture, soil ingested by ruminants can reach 800 g of soil per day. But PoP interact with the soil particles, leading to the formation of strong bonds which can decrease their bioavailability. Therefore, we developed several approaches in order to determine the bioavailability of soil-bound PoP. Indeed, more precision on the impact of soil on the bioavailability of the contaminants is essential to assess the transfer to the animal products. The investigations focused on two PoP families: the Polycyclic Aromatic Hydrocarbons (PAH) which are readily cleared and the PolyChloroBiphenyls (PCB) which are poorly metabolized. For the PCB, the relative bioavailability was estimated by comparing the values of the transfer coefficients or « Carry-Over Rates » obtained after soil ingestion, with that those obtained in the literature with other food matrices such as hay. The second study was conducted in order to calculate the bioavailability of soil-bound PAH. This experimental approach lay in comparing soil matrix with the reference matrix (oil) through the urinary excretion of the major hydroxylated PAH metabolites. The last investigation focused on the statistical combination of the results of several studies that address a set of related research on the role of organic matter (organic carbon) on the bioaccessibility of the PAH in the gastro-intestinal tract. The results of the studies performed show that soil has limited impact on the PoP bioavailability in ruminants. However, the lipophilicity of PoP seems to play a role in regulating their bioavailability. Indeed, soil impact is not significant for Phenanthrene (three-ring molecule), whereas the bioavailability of Pyrene is estimated at 50 % (four-ring molecule). The bioaccessibility in the gastro-intestinal tract is a component of the bioavailability; it was estimated for PAH at between 0.2 and 46%, and seems to be led by the concentration of PAH and the organic carbon content in soil. These results suggest that soil matrix deserves some special focus because its properties of geoaccumulation may increase the risk of transfer of PoP to the ruminant. The geosorbant property of soil, which explains its role as environmental reservoir of PoP, does not appear enough to avoid contamination of animal products, in the conditions of the lactating ruminant digestif tract. Particular attention should be paid to soil in the scenarios of risk assessment