Relation eau de ruissellement et eau des sources et forages artésiens dans la région Zagnanado-Zogbodomey au Bénin : Approche couplée (pollution microbiologique – télédétection)

La région Zagnanado-Zogbodomey constituée de grandes dépressions et de vallée a été retenue pour mieux comprendre l’influence des eaux de ruissellement sur la qualité des eaux souterraines des aquifères continus du Bassin sédimentaire côtier. A partir d’analyses microbiologiques portant sur des échantillons d’eau prélevés à la fois au niveau des sources et forages artésiens, la signature microbienne de chaque système hydrique a été établie. Les sources et forages artésiens sont plus affectés pendant la saison pluvieuse que la saison sèche, par la présence de germes bactériologiques. La présence de coliformes totaux et de coliformes fécaux dans l’eau des échantillons révèle que la contamination provient de la surface. Pour caractériser le seuil topographique qui représente une zone de recharge probable pour les eaux souterraines de la région, une étude des fractures à partir des linéaments observables sur un Modèle Numérique d’Altitude (MNA) détaillé de la région a été effectuée. En appui à la bactériologie, le traitement d’images satellitaires a permis de ressortir le réseau des fractures de notre zone d’étude située sur les formations du Bassin sédimentaire côtier. Les fractures étant en contact avec le réseau hydrographique, celles-ci pourraient jouer un rôle de drain pour les aquifères de la zone d’étude.Mots clés: Linéaments, infiltration, eau de ruissellement, eau souterraine

Evaluation of heavy metals pollution of Nokoue Lake

Toxic metals (cadmium, lead, copper and arsenic) assessment was carried out in water and sediments samples of Nokoue Lake. Except for water, a group of sediment samples was mineralized before the analysis with atomic absorption spectrophotometer. The second group of sediment samples was processed for texture analysis. The results revealed that for the physico-chemical characteristics, the pH is from 6.5 to 8.5. Four kinds of textures were identified: mud, sand, sandy mud and muddy sand. Heavy metals mean concentrations in water rose from 0.01 to 10.1 mg/L for lead and 5.84 to 8.47 for arsenic. In water, copper showed low concentrations in all sites and the values of cadmium were below the detectable limits. The mean concentrations in the sediments were: Cd (0.56 to 22.07 mg/L); Pb (3.2 to 13.94 mg/L); Cu (11.51 to 54.39 mg/L) and As (ND to 436.81 mg/L). Besides, the pattern of trace elements accumulation according to textures revealed that sandy mud and sand sediments recorded high concentrations of arsenic, mud registered high concentrations of cadmium and the sediment combining sand and mud registered high concentrations of copper. Besides, the correlation between heavy metal concentrations and pH except for arsenic.Key words: Nokoue Lake, pollution, heavy metal, texture

Contamination of boreholes water by 76 pesticides molecules in the cotton zone of Kérou

Analysis campaign of underground water was done in 2010 on five boreholes water samples situated in agricultural cotton zone. The obtained results showed the presence of various active matters of at least 76 residues of pesticides, especially insecticides, herbicides and fungicides, with accumulated contents which could average 0.350 or 350 ƒÊg/L per borehole. Indeed, all the prospected boreholes were contaminated. Every molecules of pesticides analyzed were present with at least 1 ƒÊg/L, some molecules concentration such as: aldrine (7 } 0.7 ƒÊg/L), dieldrin (2 } 0.7 ƒÊg/Ls), phorate (7 } 2 ƒÊg/L) and terbufos (7 } 1 ƒÊg/L), highly exceeded maximum residue limits. The most affected zones of the contamination of the underground water by pesticides were those areas where the cotton faming is practiced.Keywords: Kerou, cotton farming, water of boreholes, pesticides

Assessment of groundwater to pollution by the toxic metals in the municipality of Kerou (Benin) in watershed of the Niger

This case study has assessed the vulnerability of boreholes water to pollution by toxic metals in the cotton zone of Kerou, in northern Benin. Toxic metals (lead, copper, cadmium, zinc, nickel and iron) were analyzed by atomic absorption spectrophotometry. The results show high values for lead, nickel and iron, which means that 7 out of 18 boreholes are contaminated. Only the lead level exceeds the standard for the boreholes of Ganbore and Korigourou (0.0613 and 0.098 mg/l against 0.04 mg/l) The level of contamination of Cadmium, zinc and copper is very irregular, but however one must notice that the two aforementioned boreholes are contaminate with the concentration of cadmium above the permitted limit (0.0234 and 0.0244 mg/l against 0.005 mg/l). These findings allow us to say that, apart from the two boreholes of the localities of Ganbore and Korigourou located in cotton farm, most of the boreholes are resistant to pollution. So the responsible factors, of the noticed contamination are defined. It is above all due to the cultivation of cotton in this area. The assays witness of the Mekrou River has revealed high contamination by lead (0.060 mg/l) and the iron (1.4341 mg/l): this result can highlight the ongoing relationship of surface water with groundwater.Keywords: Vulnerability, groundwater, contamination, toxic metals, cotton cultur

Dosage du plomb et du cadmium dans le sperme des sujets consultant pour infertilité masculine dans la ville de Cotonou

La diminution de la concentration des paramètres d’appréciation du sperme a soulevé le problème de la fertilité des hommes. La pollution de l’environnement est incriminée en grande partie dans cette infertilité. Dans la ville de Cotonou (BENIN), nous avons recherché au cours de la présente étude les effets du plomb et du cadmium sur la fertilité masculine. Ces métaux lourds toxiques n’ont aucune utilité pour l’organisme et perturbent le système de reproduction entrainant une infertilité du couple. Dans le cadre de cette étude, nous avons étudié en deux phases le sperme de 27 sujets qui souffrent d’une infertilité masculine dans la ville de Cotonou. La première phase a consisté à faire le bilan de l’infertilité masculine sur le sperme des 27 sujets qui ont fait l’objet de notre étude. Quant à la seconde phase, nous avons dosé par Spectrophotométrie d’Absorption Atomique le plomb et le cadmium dans 10 échantillons de sperme de volume supérieur à 2 g. Les résultats ont montré que 7 des 10 échantillons de sperme ont accumulé le cadmium à des concentrations différentes. Par contre, les teneurs en plomb des échantillons de sperme étaient inférieures à la limite de détection de l’appareil pour le plomb. Mais aucune relation significative n’a pu être démontrée entre les teneurs en cadmium et les anomalies observées. Toutefois, on peut soupçonner que la présence de cadmium dans le sperme, même à un taux infirme, serait responsable des Anomalies observées.Mots clés: Fertilité, Plomb, Cadmium, Spermatozoïde

Assessment of pesticides residues in fish (Tilapia guineensis) in the Couffo River in Djidja (Benin)

In Benin, the main cash crop is the cotton of which the level of production is largely insufficient to satisfy the national and International market. The main food crops (corn, cassava, yam, bean, rice, etc.) permit to cover the food needed globally, but remain again extensively on this side of the potentialities offered by the ecological conditions of the country. In the process to increase the agricultural production, the herbicides, insecticides and the fertilizers are used now in higher quantity that in the past. The aim of this work was to assess the level of contamination of fish (Tilapia guineensis) in the Couffo River in Djidja (Benin) by the pesticides. Nine (09) samples of fish (Tilapia guineensis) have been collected in nine (09) points along the Couffo River. The analysis of these fish has been done by gas chromatography after extraction and purification. In fish, the detected concentrations in average ranged between 0.123 µg/kg and 0.191 µg/kg for the glyphosate, from 0.095 to 0.128 µg/kg for the profenofos, between 0.112 and 0.125 µg/kg for the acetamiprid and 0.127 and 0.139 µg/kg. To assess the risk to public health, pesticides intake by fish consumption was estimated and compared with Estimated Daily Intake (EDI) values reported by the Codex Alimentarius. This comparison showed that fish consumption does not pose a risk for public health

Haematological evaluation of Wistar rats exposed to chronic doses of cadmium, mercury and combined cadmium and mercury

Cadmium and mercury present in the environment, cause blood disorders. This study was conducted to evaluate the influence of cadmium, mercury and their combination on hematological parameters of Wistar rats. For this purpose, two different doses of each metal and their combination were administered orally for 28 days to six groups of five rats each. Two groups (A and B) were respectively exposed to CdCl2 (0.25 and 2.5 mg/kg), two other groups (C and D) respectively received HgCl2 (0.12 and 1.2 mg/kg) and the last two groups (E and F) were respectively treated with the combination of these two metals: (0.25 mg/kg Cd + 0.12 mg/kg Hg) and (2.5 mg/kg Cd + 1.2 mg/kg Hg). The control group (G) received the same volume of distilled water. At the end of exposure, bodies of rats were weighed and the whole blood was collected by retro-orbital sinus method for analysis of hematological parameters. The results of this study show a significant decrease (p<0.05) in white blood cells (WBC) in the lot treated with the combination (0.25 mg/kg Cd + 012 mg/kg Hg) and also indicate a significant decrease (p<0.05) in WBC, red blood cells (RBC), hemoglobin concentration (HGB) and the mean corpuscular hemoglobin concentration (MCHC) with high levels of mercury (2.5 mg/kg) and the combination (2.5 mg/kg Cd + 1.2 mg/kg Hg). An increase in the number of platelet count (PLT) in all intoxicated lots was observed.Keywords: Cadmium, mercury, hematology, blood parameters, ratsAfrican Journal of BiotechnologyVol. 12(23), pp. 3731-373