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Lake Nokoué and Cotonou Lagoon are the most important and most productive continental freshwaters in Bénin, with an estimated fish production of over 2 tonnes per hectare in Lake Nokoué. Organochlorine pesticides are used in agriculture and to repel tsetse flies, malaria mosquitoes and other diseases raised. Sediment, fish, shrimp and oyster species were collected in Lake Nokoué and Cotonou Lagoon for pesticide residues analysis. The main pesticides identified in sediment were pp'-DDT and its metabolites pp-DDE and pp'-DDD, with residue levels between the detection limit and 24.4 μg/kg dry weight. Fish species commonly consumed such as Elops lacerta, Podamasys jubelini, Gobbienellus occidentalis, Ethmalosa fimbriata, Mugil cephalus and Hemichromis fasciatus were contaminated with residues of seven to nine pesticides, including pp-DDE, op'-DDD, pp'-DDD, op'-DDT, pp'-DDT, α-endosulfan, aldrin, dieldrin and γ-hexachlorocyclohexane. The levels ranged from detection limit to 289 ng/g lipid. The same pesticides were also detected in other aquatic species, such as shrimp and oysters. A summed risk assessment, comparing pesticide intake levels through fish consumption with tolerable daily intake levels proposed by the World Health Organization, showed in all cases a low risk for human health.

To evaluate lead and cadmium contamination in Moringa oleifera leaves powders marketed in Cotonou and health risks associated with its consumption, cross-sectional and analytical study were done from October 23 th , 2012 to June 20 th , 2013. Samples of Moringa powders were purchased at different outlets (health centers, supermarkets, pharmacy, etc.). Assays were performed by atomic absorption spectrophotometry after digestion according calcination method. Pb and Cd levels were compared with Codex Alimentarius standards, using the Student t test. Daily Exposure Doses (DDE) and Hazard Quotients (HQ) specific to each contaminant were calculated using a conventional method. Results revealed that the mean concentration of lead for all samples (1.526 mg/kg) exceeded of about 5.08 times the maximum allowable limit whereas cadmium levels (0.246 mg/kg) was not statistically higher than the standard. The highest concentrations of Pb and Cd are respectively 4.263 mg/kg and 0.354 mg/kg. Children are 2.3 to 3.8 times in greater danger * Corresponding author. A. K. Aissi et al. 771than adults although all QD calculated are less than 1, reflecting that there is a low risk to consumers in general. For both metals, DJE specifically linked to the consumption of Moringa was less than 2% compared to other kinds of food intake. In conclusion, the current level of contamination (with lead and cadmium) of Moringa leaves powders marketed in Cotonou is not yet an alarming threat to consumers' health. However, care must be taken to reduce chemical pollution especially soils where these plants grow.

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To determine possible human and environmental health risks, organochlorine pesticide residues were determined in vegetables grown in floodplains along the Ouémé River near Lowé in Bénin. Testing of vegetables found 13 pesticides with ΣDDT, α-endosulfan, Σdrin, and lindane being most important. The same pesticides were also detected in plants eaten by bovine cattle, sheep, and herbivorous fish. Human pesticide intake by vegetable consumption was compared with tolerable daily intake (TDI) values reported by the World Health Organization. Pesticide intake by fish consumption was estimated from residue levels in whole fish collected from the Ouémé River in 2004 and reported earlier. Fish consumption does not pose a risk for human health, but consuming vegetables that contain pesticide residues may lead to exceedance of TDI values. Based on these findings, concerns are warranted, and more work is needed to understand the full exposure profile for the local population.

Le maraîchage dans les villes et les localités périurbaines ne sont pas sans conséquence sur la qualité des produits maraîchers qui y sont cultivés. La présente étude vise à évaluer la qualité des produits maraîchers consommés au Bénin afin de mieux appréhender les risques pour la santé humaine. Les métaux lourds (Pb, Cu et Zn) ont été dosés par la spectrophotométrie d’absorption atomique dans le sol et les cultures maraîchères fraîches et cuites. Il ressort de l’étude que le sol des différentes cultures maraîchères est contaminé par les métaux lourds (Pb : 0,028 à 2,235 mg/kg, Cu : 0,037 mg/kg à 0,264 mg/kg, Zn : 0,613 à 3,234 mg/kg) ainsi que le compost utilisé pour son amendement (Pb : 0,224 mg/kg, Cu : 0,419 mg/kg et Zn : 1,717 mg/kg). Les cultures maraîchères analysées sont aussi contaminés par les métaux lourds (Pb : 0,009 à 4,124 mg/kg, Cu : 0,073 mg/kg à 2,146 mg/kg, Zn : 0,573 à 14,12 mg/kg) avec des facteurs de bioconcentration allant à plus de 4 pour le Brassica oleracea et 8 pour le Vernonia amygdalina qui sont les plus contaminés. Toutefois, la cuisson a entraîné une réduction considérable des teneurs en métaux lourds, ce qui réduit le risque sanitaire pour le consommateur. Une vigilance de la population et une variation de l’alimentation sont alors importantes pour garantir une meilleure santé. Il est prévu de continuer les travaux de recherche sur d’autres spéculations maraîchères et polluants chimiques.Mots clés: Éléments métalliques, spéculations maraîchères, influence modes de cuisson. English Title: Determination of heavy metals in soil and vegetable products in BeninMarket gardening in towns and peri-urban localities is not without consequence on the quality of the market garden products which are cultivated there. This study aims to evaluate the quality of market garden produce consumed in Benin in order to better understand the risks to human health. Heavy metals (Pb, Cu and Zn) were determined by atomic absorption spectrophotometry in soil and fresh and cooked vegetable crops. The study showed that the soil of the various vegetable crops is contaminated by heavy metals (Pb: 0.028 to 2.235 mg/kg, Cu: 0.037 mg/kg to 0.264 mg/kg, Zn: 0.613 to 3.234 mg/kg) and the compost used for its amendment too (Pb: 0.224 mg/kg, Cu: 0.419 mg/kg and Zn: 1.717 mg/kg). The vegetable crops analyzed are also contaminated by heavy metals (Pb: 0.009 to 4.124 mg/kg, Cu: 0.073 mg/kg to 2.146 mg/kg, Zn: 0.573 to 14.12 mg/kg) with bioconcentration factors ranging from more than 4 for Brassica oleracea and 8 for Vernonia amygdalina which are the most contaminated. However, cooking has resulted in a significant reduction in heavy metal contents, which reduces the health risk for the consumer. A vigilance of the population and a variation of the food are then important to guarantee a better health. It is planned to continue research on other vegetable crops and chemical pollutantsKeywords: Metallic elements, vegetables crops, cooking methods influence.  

In Bénin different techniques are used for large-scale commercial fishing, Acadjas (enclosures constructed in the river) and Whédos (holes made in the river banks). This study aimed at assessing the extent of contamination related to these fishing techniques. Fish contained residues of DDT and its metabolites, α-endosulfan, dieldrin, aldrin, endrin and lindane. Pesticide levels were similar in fish from Acadjas and Whédos, except for higher α-endosulfan levels in fish from the Whédos. Comparing pesticide intake levels through fish consumption with tolerable daily intake levels showed that in all cases risk for human health is low.

Les escargots de la famille des Achatinidae, très appréciés par les populations béninoises, sont des espèces qui ont la capacité d'absorber et de concentrer dans leur organisme certaines substances chimiques toxiques comme les métaux lourds. La présente étude a pour objectif de déterminer la concentration des métaux lourds (Pb et Cd) dans deux espèces d'escargots bouillis et frits de la vallée de l'Ouémé et d'évaluer les risques sanitaires encourus par les populations. La méthode d'analyse utilisée pour le dosage des métaux lourds dans les échantillons des espèces Archachatina marginata et Limicolaria spp collectés est la voltampérométrie inverse. Il ressort des résultats que dans les escargots bouillis, les concentrations moyennes du cadmium et du plomb varient respectivement entre 0 et 0,046 mg/kg puis entre 0,035 et 0,096 mg/kg pour Archachatina marginata et entre 0 et 0,422 mg/kg puis entre 0,016 et 1,024 mg/kg pour Limicolaria spp. Dans les escargots frits, les concentrations moyennes du cadmium et du plomb varient respectivement entre 0,003 et 0,067 mg/kg puis entre 0,023 et 0,062 mg/kg pour l'Archachatina marginata et entre 0 et 0,769 mg/kg puis entre 0 et 0,275 mg/kg pour Limicolaria spp. L'évaluation des risques sanitaires a révélé que le quotient de danger du cadmium est supérieur à 1 pour les adultes et les enfants dans les deux espèces d'escargots bouillis et frits dans plusieurs localités. La consommation des escargots provenant de ces localités présenterait donc un danger pour la santé des adultes et encore plus des enfants à cause de l'accumulation du cadmium dans la viande des escargots malgré les méthodes de cuisson. Il urge donc que les populations réduisent la quantité d'escargots consommés par repas ainsi que la fréquence.