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International audience; The consequences of indoor and outdoor air pollution on human health are of great concern nowadays. In this study, we firstly evaluated indoor and outdoor air pollution levels (CO, CO2, NO, NO2, PM10) at an urban site in Dakar city center and at a rural site. Then, the individual exposure levels to selected pollutants and the variations in the levels of biomarkers of exposure were investigated in different groups of persons (bus drivers, traders working along the main roads and housemaids). Benzene exposure levels were higher for housemaids than for bus drivers and traders. High indoor exposure to benzene is probably due to cooking habits (cooking with charcoal), local practices (burning of incense), the use of cleaning products or solvent products which are important emitters of this compound. These results are confirmed by the values of S-PMA, which were higher in housemaids group compared to the others. Urinary 1-HOP levels were significantly higher for urban site housemaids compared to semirural district ones. Moreover, urinary levels of DNA oxidative stress damage (8-OHdG) and inflammatory (interleukin-6 and -8) biomarkers were higher in urban subjects in comparison to rural ones. The air quality measurement campaign showed that the bus interior was more polluted with PM10, CO, CO2 and NO than the market and urban or rural households. However, the interior of households showed higher concentration of VOCs than outdoor sites confirming previous observations of higher indoor individual exposure level to specific classes of pollutants.

Exposure to atmospheric pollutants has been recognized as a major risk factor of respiratory and cardiovascular diseases. Fine particles (PM2.5) and a coarser fraction (PM>2.5) sampled at an urban site in Dakar (HLM), characterized by high road traffic emissions, were compared with particles sampled at a rural area, Toubab Dialaw located about 40 km from Dakar. The physicochemical characteristics of samples revealed that PMs differ for their physical (surface area) and chemical properties (in terms of CHN, metals, ions, paraffins, VOCs and PAHs) that were 65–75% higher in urban samples. Moreover the fine PMs contain higher amounts of anthropogenic related pollutants than the PM>2.5 one. These differences are sustained by the ratios reported for the analysed PAHs which suggest as predominant primary emission sources vehicle exhausts at urban site and biomass combustion at the rural site. The inflammatory response and the oxidative damages were evaluated in BEAS-2B cells by the quantification of 4 selected inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8) and of total carbonylated proteins and the oxidative DNA adduct 8-OHdG after 8 or 24 h exposure. In accordance with the different sources and different physical and chemical properties, the inflammatory response and the oxidative damages were found higher in bronchial cells exposed to urban PMs. These data confirm the importance, also for West African countries, to evaluate the correlation between PM physico-chemical properties and potential biological impacts. Dakar air pollution, influenced by anthropogenic activities, causes inflammatory responses and oxidative damages in vitro.

In Senegal as everywhere in Africa, apiculture is a branch of agriculture that can help people from rural and remote villages to diversify their activities and generate incomes. Honeybees are also involved in the pollination services process in agriculture and a good indicator to environmental degradation. The aim of this cross-sectional study was to diagnose problems encountered by beekeepers in four production basins in Senegal, to guide policy makers and attract investment in the sector. A questionnaire and an interview guide were designed together and distributed to 138 single beekeepers and 32 groups of beekeepers between September 2014 and January 2016. Beekeepers (93.75%) were men aged more than 50 years and (74.7%) didn’t have any knowledge about bee diseases. Modern beekeeping was unequally observed in the four basins. Honey was the most significant preferred commodities followed by the bee’s wax. Lack of beekeeping modern equipment, climate change (environment), and funding were identified and listed as major weaknesses respectively. Nevertheless, beekeepers in the Thies region were (100%) modern, compared with those to Fatick and Velingara who were still doing traditional beekeeping at 9.7% and 91% respectively. However, our study areas with the rich and diversified natural resources remain conducive to beekeeping. Keywords : Beekeeping, diagnostic, deficiency, strengths, Senegal.

The purpose of the study was to determine Pb and Cd concentrations in humans and to assess the effect of co-exposure to these metals on biomarkers of oxidative stress and nephrotoxicity. Blood and urine levels of Pb and Cd, oxidative stress and urinary renal biomarkers were measured in 77 subjects neighboring a discharge and 52 in the control site. Exposed subjects showed significantly higher levels of lead and cadmium in blood and urine than the controls. Excessive production of reactive oxygen species induced by these metals in exposed subjects conducted to a decrease in antioxidant defense system (GPx, Selenium, GSH) and an increase in lipid peroxidation (MDA). Moreover, changes in markers of nephrotoxicity (high urinary concentrations of total protein, RBP and CC16, as well as GSTα and LDH increased activities) suggested the occurrence of discrete and early signs of impaired renal function for the discharge neighboring population.

Isoniazid (INH), recommended by WHO (World Health Organization) in the treatment of tuberculosis (TB), is metabolized primarily by the genetically polymorphic N-acetyltransferase 2 (NAT2) enzyme. The human population is divided into three different phenotypic groups according to acetylation rate: slow, intermediate, and fast acetylators. The objective of this study was to explore the relationship between NAT2 genotypes and the serum concentrations of INH. Blood samples from 96 patients with TB were taken for the analysis. NAT2 polymorphisms on coding region were examined by polymerase chain reaction (PCR) direct sequencing; the acetylation status was obtained by measuring isoniazid (INH) and its metabolite, acetylisoniazid (AcINH) in plasma was obtained by using the liquid chromatography coupled to mass spectrometry. TB patients were distributed into two groups of fast and slow acetylators according to the acetylation index calculated based on the plasma concentration of INH in the 3rd hour (T3) after an oral dose. Our PCR analysis identified several alleles, where NAT2*4, NAT2*5A, NAT2*6A, and NAT2*13A were the most important. The concentrations of INH varied between 1.10 mg/L and 13.10 mg/L at the 3rd hour and between 0.1 and 9.5 mg/L at the 6th hour. The use of the acetylating index I3 allowed the classification of tested patients into two phenotypic groups: slow acetylators (44.3% of TB patients), and rapid acetylators (55.7%). Patient’s acetylation profile provides valuable information on their therapeutic, pharmacological, and toxicological responses. Keywords: NAT2, Genotyping, Isoniazid, Acetylation, Toxicity

International audience; Concentrations of 11 elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se,V and Zn) were quantified in liver and muscle from two commercially important fish species from the Senegalese coast. The fish, a small pelagic species (the round sardinella) and a benthic species (the Senegalese sole) were collected from five sites during the dry and wet seasons in 2013. For both species, elements were more concentrated in liver than in muscle. There was no clear seasonal pattern in concentration of elements, however inter-site differences were observed. We found significant differences in element concentrations between the two studied species, likely associated with their behavior, feeding and habitat use. The concentrations of Cd, Fe, and Pb were significantly higher in sardinella whereas concentration of As, Cu, Cr, Mn and Se were highest in sole. The concentration of cadmium was particularly high in the liver of sardinella (from 0.9 to 56 mg kg−1, with a mean ± sd of 17.2 ± 11.5 mg kg−1) and may be related to anthropogenic pressure such as the phosphate industry but also to the upwelling current which brings dissolved elements to the surface that are taken up by plankton. The results showed that concentrations of Cd and Pb were below the limit values established by the European Community and pose no threat to public health.

The massive increase in emissions of air pollutants due to economic and industrial growth in developing countries has made air quality a crucial health problem in this continent. Hence, it is somewhat critical to have a better knowledge on the air pollution in Sub-Saharan Africa countries. Three air pollution PM2.5 samples were also collected in two urban sites (i.e., Fann and Faidherbe) in Dakar (Senegal) and in a rural site near Dakar (i.e., Ngaparu). The two urban sites mainly differ in the type of used vehicles: in Fann, most of the traffic is made of buses, which are absent, in Faidherbe. The physicochemical characteristics of the three PM2.5 samples revealed their high heterogeneities and complexities, related to the multiple natural and anthropogenic emission sources. Results from 5-bromodeoxyuridine incorporation into DNA, mitochondrial dehydrogenase activity, and extracellular lactate dehydrogenase activity in PM2.5-exposed BEAS-2B cells suggested the exposure conditions (i.e., 3 and 12 μg PM/cm² during 24, 48, and 72 h) to further consider. The organic fractions (i.e., mainly PAHs) of the PM(2.5) samples were able to induce a time and/or concentration-dependent gene expression of CYP1A1 and CYP1B1, and, to a lesser extent, NQO1. There was a time and/or dose-dependent increase of both the gene expression and/or protein secretion of inflammatory mediators (i.e., TNF-α, IL-1β, IL-6, and/or IL-8) in PM(2.5)-exposed BEAS-2B cells. In agreement with the physicochemical characterization, urban PM(2.5) samples caused greater biological responses in BEAS-2B cells than the rural one. Variable concentrations of transition metals (i.e., Fe, Al, Pb, Mn, Zn) and organic compounds (i.e., PAHs) founded in the three PM2.5 samples might be firmly involved in a time- and/or dose-dependent toxicity, relying on inflammatory processes.

Introduction : L’isoniazide (INH) est metabolisee par une N-acetyltransferase (NAT), la NAT2. Il existe de nombreux polymorphismes de la NAT2 qui peuvent etre associes a des toxicites ou a des echecs therapeutiques au cours d’un traitement par INH. Objectif : L’objectif de ce travail est de determiner l’indice d’acetylation de la NAT2 dans la population senegalaise afin de les repartir en acetyleurs lents et rapides. Methodes : L’etude du profil d’acetylation a ete effectuee sur des urines de 247 sujets en utilisant la cafeine comme marqueur. La proportion molaire du 5-acetamino-6-formylamine-3-methyluracile (AFMU) sur le 1-methylxanthine (1X) a ete determinee. La repartition de la population etudiee en phenotype lent ou rapide a ete realisee en se basant sur l’antimode = 0,55. Les sujets possedant un rapport ([AFMU]/[1X]) inferieur a 0,55 sont consideres comme des acetyleurs lents et ceux dont le rapport est >0,55 sont des acetyleurs rapides. Resultats : Les resultats obtenus ont montre une segregation en deux modes apparents de capacite d’acetylation dans la population senegalaise testee avec 63,8 % et 36,2 % d’acetyleurs lents et rapides respectivement. Conclusion : La reponse au traitement de maladies comme la tuberculose depend du polymorphisme d’acetylation de la NAT2, il est donc important de connaitre le phenotype de la NAT2 chez les sujets atteints de tuberculose pour eviter des effets indesirables tels que l’hepatotoxicite ou la neurotoxicite.

Objectif : Cette etude avait pour objectif d’etudier l’impact du recyclage des batteries sur la sante des femmes de Colobane et des mecaniciens de Medina (Dakar, Senegal). Methodes : Differents indicateurs biologiques d’impregnation au plomb ont ete determines aussi bien chez des sujets exposes que chez des sujets temoins. Ainsi, la plombemie a ete evaluee par spectrophotometrie d’absorption atomique (SAA), les taux de protoporphyrine zinc erythrocytaire (PPZ) et d’acide δ aminolevulinique urinaire (AlaU) ont respectivement ete determines par fluorimetrie et par spectrophotometrie. Le fer serique et l’hemoglobine ont egalement ete mesures par spectrophotometrie. Des echantillons d’air et de sol ont ete preleves pour un dosage de plomb par ICP/MS. Resultats : Les teneurs atmospheriques de plomb a Colobane, site plus contamine que le site de Medina, sont de 10,3 µg/m3 et celles du sol de 115 792 mg/kg de sol. Les resultats biologiques obtenus ont revele une plombemie moyenne de 131,08 ± 32,87 µg/L chez les non exposes et de 546,55 ± 185,24 µg/L chez les exposes, sujets pour lesquels la valeur depasse nettement la norme de 300 µg/L fixee pour les professionnels. Les taux de PPZ (12,28 ± 7,09 µg/g Hb) et d’Ala urinaire (9,12 ± 7,52 mg/g de creatinine) ont mis en evidence le degre d’impregnation des mecaniciens et des femmes recuperatrices de plomb. Conclusion : Dans le cadre de la lutte contre le saturnisme, qui touche souvent une population socialement defavorisee, une politique d'eradication ou de gestion du risque saturnin devrait etre mise en œuvre, en conformite avec les textes en vigueur au niveau international.

Objectif : La pollution atmospherique constitue un facteur de risque majeur pour la sante de l’homme. De nombreuses etudes epidemiologiques ont etabli une correlation entre l’exposition aux particules fines de diametre aerodynamique inferieur a 2,5 μm (PM2,5 ) et l’apparition de pathologies respiratoires, notamment de cancers pulmonaires. Notre travail a consiste a collecter des particules sur deux sites (P1 et P2 ) de la ville de Dakar caracterises par un trafic automobile dense. Methode : La collecte des particules a ete effectuee par un impacteur en cascade. Les analyses physico-chimiques effectuees sont : la granulometrie par microscopie electronique a balayage associee a une analyse par rayons X (MEB-EDX); la determination des fractions inorganique par spectrometrie d’emission atomique couplee a un plasma inductif (ICP-AES); organiques (hydrocarbures aromatiques polycycliques et composes organiques volatils) par chromatographie en phase gazeuse couplee a un spectrometre de masse (GC-MS); enfin, ioniques par chromatographie ionique (CI). Resultats : L’exposition de cellules A549 a des concentrations croissantes de particules P1 et P2 provoque une diminution significative de l’incorporation de la bromodesoxyuridine, de l’activite de la deshydrogenase mitochondriale et une augmentation de l’activite de la lactate deshydrogenase extra-cellulaire. Ces tests ont permis de determiner les concentrations letales pour P1 (CL10 = 5,11 μg/cm2 et CL50 = 25,56 μg/cm2 ) et P2 (CL10 = 5,59 μg/cm2 et CL50 = 27,97 μg/cm2 ). La toxicite la plus importante est observee dans les cellules exposees a la concentration maximale des particules P1 (48 μg/cm2 ). Conclusion : Ces resultats pourraient s’expliquer par les effets deleteres synergiques engendres par les fractions inorganique et organique, sources d’especes reactives de l’oxygene potentiellement toxiques.

Trace metals have the potential to associate with sediments that have been recognised as significant source of contamination for the benthic environment. The current study aims assessing the trace metals contamination level in sediments from Dakar coast and Saint Louis estuary, and to examine their bioavailability to predict potential toxicity of sediments. Surface sediment samples were collected between June 2012 and January 2013 in three sampling periods from eight stations. Trace metals were analysed using inductively coupled plasma-optical emission spectrometer. Geoaccumulation indexes (Igeo) showed strong pollution by Cd, Cr, Cu and Pb confirmed by enrichment factor (EF) suggesting that these metals derived from anthropogenic sources. Toxicity indexes exceeded one in several sites suggesting the potential effects on sediment-dwelling organisms, which may constitute a risk to populations' health. However, seasonal variability of metal bioavailability was noted, revealing the best period to monitor metal contamination. From an ecotoxicological point of view, concentrations of Cd, Cr, Cu and Pb were above the effects range low threshold limit of the sediment quality guidelines for adverse biological effects. In addition, with Pb concentrations above the effect range medium values in some sites, biological effects may occur.

L’objectif de cette etude est de quantifier les concentrations en metaux lourds et de rechercher la presence de residus de molecules medicamenteuses des effluents de trois hopitaux de Dakar (Senegal). C’est ainsi que la collecte des effluents a ete realisee chaque jour sur une periode de trois semaines a l’entree du deversoir des services de radiologie, de medecine interne et d’odontologie. Ensuite, des echantillons composites par semaine ont ete constitues pour rechercher leur composition en metaux lourds et en residus medicamenteux. Le transport a ete effectue a +4 °C et a l'obscurite pour assurer une conservation satisfaisante. Les metaux lourds ont ete doses par ICP-MS et les residus de medicaments ont ete recherches par UPLCMS/ MS. Les medicaments identifies dans les effluents sont essentiellement des analgesiques et des psychotropes. La concentration en metaux lourds des effluents des trois hopitaux est inferieure aux normes senegalaises et de celles de L’OMS fixant les conditions de rejet de metaux dans les eaux usees. Cependant, bien que les taux retrouves soient tolerables, leur introduction continuelle en milieu aquatique pourrait etre a l’origine d’effets nefastes sur les organismes marins par des phenomenes de bioaccumulation et de biomagnification. D’ou l’importance et la necessite des stations d’epuration pour une bonne gestion et une reduction des risques ecotoxicologiques lies aux effluents liquides hospitaliers. Mots cles : Effluents hospitaliers, metaux lourds, residus medicamenteux, toxicite.

Les etudes epidemiologiques associent la pollution atmospherique, notamment particulaire, a l’augmentation de la morbidite et de la mortalite d’origine respiratoire et cardio-vasculaire. L’Afrique, qui possede un taux d’urbanisation parmi les plus eleves du monde, y est particulierement exposee. L’« Initiative sur la qualite de l’air en Afrique subsaharienne » a montre l’importance des concentrations atmospheriques de certains polluants tels que les oxydes d’azote, le dioxyde de soufre et les particules en suspension dans l’air de diametre inferieur ou egal a 10 μm (PM10). A l’instar des grandes capitales africaines, Abidjan, capitale economique et ville la plus industrialisee de la Cote-d’Ivoire, est confrontee a une pollution atmospherique d’origine industrialo-urbaine et a ses consequences sanitaires pour sa population de pres de 6 millions d’habitants.Afin de mieux connaitre les mecanismes d’action pulmonaires consecutifs a l’exposition aux particules atmospheriques, nous nous sommes proposes de : (i) prelever par impaction en cascade dans le District d’Abidjan des particules atmospheriques (PM2,5) sous trois influences (rurale, urbaine ou industrielle) ; (ii) determiner leurs principales caracteristiques physico-chimiques ; (iii) evaluer leur cytotoxicite et leur role dans l’induction de lesions oxydatives dans un modele de cellules pulmonaires humaines (A549) en culture.L’analyse de la composition chimique des particules a montre leur heterogeneite. De nombreux elements inorganiques (Al, Ca, Fe, Mn, Zn, Ni, Cr, Cu, Pb, Mg) et composes organiques (paraffines) ont pu etre quantifies sous les differentes influences. Leurs Concentrations d’Effets (CE) a 10 % et 50 % sur les cellules A549 etaient les suivantes : influence rurale : CE10 = 5,91 μg/cm2 et CE50 = 29,55 μg/cm2, influence urbaine : CE10 = 5,45 μg/cm2 et CE50 = 27,23 μg/cm2, et influence industrielle : CE10 = 6,86 μg/cm2 et CE50 = 34,29 μg/cm2. L’exposition des cellules A549 pendant 24, 48 ou 72 h a ces particules atmospheriques a leurs CE10 ou CE50 a induit des dommages oxydatifs, comme l’ont montre la formation de malondialdehyde, les variations de l’activite enzymatique du superoxyde dismutase et l’alteration du statut en glutathion.

Background and objectives Between November 2007 and March 2008, 18 children died from a rapidly progressive central nervous system disease of unexplained origin in a community involved in the recycling of used lead-acid batteries (ULAB) in the suburbs of Dakar, Senegal. We investigated the cause of these deaths. Methods Because autopsies were not possible, the investigation centered on clinical and laboratory assessments performed on 32 siblings of deceased children and 23 mothers and on 18 children and 8 adults living in the same area, complemented by environmental health investigations. Results All 81 individuals investigated were poisoned with lead, some of them severely. The blood lead level of the 50 children tested ranged from 39.8 to 613.9 μg/dL with a mean of 129.5 μg/dL. Seventeen children showed severe neurologic features of toxicity. Homes and soil in surrounding areas were heavily contaminated with lead (indoors, up to 14,000 mg/kg; outdoors, up to 302,000 mg/kg) as a result of informal ULAB recycling. Conclusions Our investigations revealed a mass lead intoxication that occurred through inhalation and ingestion of soil and dust heavily contaminated with lead as a result of informal and unsafe ULAB recycling. Circumstantial evidence suggested that most or all of the 18 deaths were due to encephalopathy resulting from severe lead intoxication. Findings also suggest that most habitants of the contaminated area, estimated at 950, are also likely to be poisoned. This highlights the severe health risks posed by informal ULAB recycling, in particular in developing countries, and emphasizes the need to strengthen national and international efforts to address this global public health problem.

Background Artesunate plus amodiaquine is a coblistered ACT, given as a single daily intake. It has been suggested that, in view of the number of tablets to be taken (particularly in adults), it may be possible to improve compliance by allowing patients to divide the daily dose. The objectives of this randomized, comparative, open-label, multicentre study, conducted in Senegal and in Cameroon in 2005, was to demonstrate the non-inferiority and to compare the safety of artesunate plus amodiaquine, as a single daily intake versus two daily intakes. Methods A three-day treatment period and 14-day follow-up period was performed in any subject weighting more than 10 kg, presenting with a malaria paroxysm confirmed by parasitaemia ≥ 1,000/μl, after informed consent. Patients were randomly allocated into one of the two regimens, with dosage according to bodyweight range. All products were administered by an authorized person, blinded to both the investigating physician and the biologist. The primary endpoint was an adequate response to treatment on D14 (WHO definition). The two-sided 90% confidence interval of the difference was calculated on intent to treat (ITT) population; the acceptance limit for non-inferiority was 3%. The safety was evaluated by incidence of adverse events. Results Three-hundred and sixteen patients were included in the study. The two patient groups were strictly comparable on D0. The adequate responses to treatment were similar for the two treatment regimens on D14, PCR-corrected (99,4% in the one-daily intake group versus 99,3% in the comparative group). The statistical analyses demonstrated the non-inferiority of administering artesunate/amodiaquine as two intakes. The drug was well tolerated. The main adverse events were gastrointestinal disorders (2.5%) and pruritus (2.5%); safety profiles were similar in the two groups. Conclusion This pilot study confirms the efficacy and good tolerability of artesunate plus amodiaquine, administrated either in one or in two daily intakes.

Les écosystèmes marins côtiers sont des milieux de plus en plus affectés par l’activité humaine à cause des rejets urbains et l’utilisation de l’océan comme dépotoir pouvant mener à de hauts niveaux de pollution. L’objectif de cette étude était de déterminer les profils de concentration en éléments traces métalliques (Cd, Cr, Cu, Co, Ni, Pb et Zn) des sédiments dans des zones présumées être contaminées par les rejets des eaux usées à Dakar et d’évaluer leur qualité. Pour ce faire, des échantillons de sédiments ont été prélevés au niveau de cinq points d’évacuation des eaux usées vers la mer à Dakar (Sénégal). Les résultats montrent des caractéristiques géochimiques (granulométrie, alcalinité, teneur en carbone organique et en soufre) comparables. L’évaluation de la qualité des sédiments a été effectuée par le calcul de divers indices. Un enrichissement important des sédiments en cadmium et en plomb a surtout été noté. L’Indice de Pollution Sédimentaire (IPS), qui estime le degré de contamination d’un site en fonction de la toxicité relative de chaque métal considéré, fait état d’une forte pollution, voire même d’une dangerosité des sédiments étudiés. En effet, le cadmium et le plomb, présents en fortes teneurs dans les sites, contribuent respectivement à l’ordre de 94 % et 5 % à la dangerosité potentielle des sédiments (selon le classement de l’indice de pollution sédimentaire) alors que le zinc, le cuivre, le nickel et le chrome, également présents en fortes concentrations, ne représentent que 1 % de la pollution globale. Des corrélations positives élevées et modérées sont observées entre Pb/Cd, Pb/Co, Cr/Cu, Cr/Zn, Cr/Fe, Cr/Mn, Cu/Ni, Cu/Fe, Cu/Mn et Zn/Mn, indiquant leurs sources communes possibles à partir des activités industrielles et/ou urbaines ainsi que des comportements comparables dans le sédiment., Coastal marine environments are increasingly affected by human activity because of urban waste, and use of the ocean as a dumping ground could lead to high levels of pollution. The objective of this study was to determine the concentration profiles of trace metals (Cd, Cr, Cu, Co, Ni, Pb and Zn) in sediments in areas suspected to be contaminated by discharges of wastewater from Dakar, and to evaluate the quality of the sediments. To do this, sediment samples were collected at five points of sewage discharge into the sea near Dakar (Senegal). The results show comparable geochemical characteristics (size, alkalinity, organic carbon content and sulfur content) at the different sites. The assessment of sediment quality was performed by calculating various indices. A substantial enrichment of sediment cadmium and lead was especially noted. The Sediment Pollution Index (SPI), which estimates the degree of contamination of a site based on the relative toxicity of each metal in question, indicated a high degree of pollution or even an environmental hazard for the sediments studied. Indeed, cadmium and lead are present at high concentrations at the sites, each contributing about 94% and 5% to the potential hazard of the sediments (ranked by the SPI index), whereas zinc, copper, nickel and chromium, also present at high concentrations, contribute only about 1% to the overall pollution. High and moderate positive correlations are observed between Pb/Cd, Pb/Co, Cr/Cu, Cr/Zn, Cr/Fe, Cr/Mn, Cu/Ni, Cu/Fe, Cu/Mn and Zn/Mn, indicating their possible common origin from industrial and/or urban sources, and their comparable behavior in the sediment.

Airborne Particulate Matter (PM) is an important risk factor for human health. In spite of the numerous studies that have been carried out, the underlying mechanisms of action involved in particulate matter physiopathological effects are still unclear. In this work, PM samples were collected in two urban sites (Fann and Faidherbe) in Dakar (Senegal) and in a rural site (Ngaparou). The two urban sites mainly differ in the type of motor vehicles circulating in the area : most of the traffic is made of buses in Fann, whereas they are absent from Faidherbe. The physical characterization of the three samples showed their fine size distribution (96% < 2,5 μm), with surface areas ranging from 8 to 13m²/g. Collected PM were then able to reach deep lung, and to adsorb potentially toxic substances. Their chemical composition, rich in inorganic and organic compounds demonstrated the diversity of emission sources. After assessing their cytotoxicity in human epithelial bronchial cells (BEAS-2B), we showed that these PM could induce gene expression of metabolizing enzymes CYP1A1, 1B1 and NQO1, and therefore the metabolic activation of their organic fraction. No significant response to oxidative damage through lipid peroxidation (MDA) or glutathione status modification (GSSG/GSH) was observed after cells exposure to particulate matter. However, this exposure induced an inflammatory response by a significant increase in expression and secretion of cytokines TNF-α, IL-1β, IL-6 and IL-8., La pollution atmosphérique particulaire constitue un facteur de risque majeur pour la santé humaine. En dépit des nombreuses études réalisées, les mécanismes d'action sous-jacents à l'exposition aux particules et responsables des effets physiopathologiques observés restent encore mal connus. Notre travail a consisté en la collecte d'aérosols particulaires sur 2 sites urbains (Fann et Faidherbe) dans la ville de Dakar (Sénégal) et un site rural (Ngaparou). Les sites urbains sont caractérisés par un trafic automobile dense avec le site de Fann présentant une circulation majoritaire de véhicules de transport en commun alors qu'à Faidherbe le trafic est constitué en majorité de véhicules particuliers. la caractérisation physico-chimique des trois échantillons particulaires a montré une granulométrie fine (96% < 2,5 μm), donc capables de pénétrer profondément dans les poumons, des surfaces spécifiques comprises entre 8 et 13m²/g pouvant adsorber à leur surfaces des substances potentiellement toxiques. Leur composition chimique, riche en éléments inorganiques et organiques, démontre la diversité de leur sources (naturelle et anthropique). Après évaluation de leur cytotoxicité dans les cellules épithéliales bronchiques humaines (BEAS-2B), nous avons montré la capacité de ces aérosols particulaires à induire l'activation métabolique de leur fraction organique par l'induction de l'expression génique des enzymes de métabolisation CYP1A1, 1B1 et NQO1. Nous n'avons pas observé de réponse significative dans le processus d'altération oxydative via la péroxydation lipidique (MDA) et le statut du glutathion (GSSG/GSH). En revanche nous avons montré l'implication de ces aérosols particulaires dans le développement de la réponse inflammatoire par l'expression et la sécrétion significative de cytokines TNF-α, IL-1β, IL-6 et IL-8.