In southern Benin, where population is growing and water demand for domestic activities is increasing, water balance assessment constitutes a serious concern about sustainability of water resources. Major ions have been employed with statistical methods to identify geochemical processes controlling groundwater quality. Multivariate statistical analysis (principal component analysis "PCA" and hierarchical cluster analysis "HCA") revealed the main sources of groundwater mineralization. According to the hydrochemical data and the methods of treatment, groundwater mineralization in the investigated aquifer is caused by four main processes: 1) mixing with Nokoué lake and Porto-Novo lagoon salt water causing salinity to increase in the southern part of the aquifer; 2) anthropogenic activities; 3) cation exchange process; and 4) soil CO2 diffusion providing a large proportion of bicarbonates.

In this research work, we have studied the physico-chemical characterization and searched for twenty-six metallic elements in the well waters of the sixth neighborhoodofCotonou. Well water was sampled in ten neighborhoods of this neighborhood.Physico-chemical parameters such as pH, temperature, conductivity, total dissolved salts (TDS) and salinity were measured on site while ammonium, phosphate, chloride, nitrite and nitrate ions are determined in the laboratory. Twenty-six metallic elements were measured after acid digestion of the water samples using the inductively coupled plasma source mass spectrometer (ICP-MS). The results showed that groundwater in the sixth neighborhood is in a degradation of its physico-chemical quality. The conductivity values varying between 2.06 and 1270 µS/Cm with an average of 872.41 and a standard deviation of 393.90 show that these waters are highly mineralized (the WHO qualifies waters with a conductivity greater than 200µS/Cm of very highly mineralized water). Ammonium and nitrite ions varying respectively between 0.6 and 7.1 mg/L with an average of 2.21 mg/L and 0.02 and 0.61 mg/L with an average of 0.22 mg/L are at abnormal concentrations in groundwater. The ammonium ion contents are beyond the standard value.As for metallic elements, aluminum, which is a trace element, is strongly present in water with an atypical observation of 5.008 mg/L. This value exceeds more than 25 times the standard defined by the WHO which is 0.2 mg/L. Iron is also present with an abnormal concentration of 2.711 mg/L as maximum value. Even if the values of the trace metals whose toxicities approved are lower than the standards, some atypical values are recorded and significant correlations established between these different chemical elements results from the common origins for the positively correlated metals and different origins for those which are negatively correlated.

Fruit juices have been gaining interest in recent years for their contributions of minerals and other essential vitamins. But, with the development of intensive agriculture massively using pesticides and mineral fertilizers, the risk of contamination of these juices is high along the production chain. In this study, we evaluated the concentrations of arsenic       (As), cadmium (Cd), berrylium (Be), aluminium (Al), strontium (Sr), tin       (Sn), barium (Ba), mercury (Hg), thallium          (Tl), lead   (Pb), thorium (Th), uranium (U) for 92 commercial samples of pineapple juice, cocktail of pineapple and watermelon and pineapple syrup of Benin and France using Inductively Coupled Plasma-Source Mass Spectrometry (ICP-MS). The concentrations vary in the following ranges: As <QL at 39.3 ppb, Cd <QL at 0.7 ppb, Be <QL at 0.59 ppb, Al 26.4 ppb at 30620 ppb, Sr 130 ppb at 4049 ppb, Sn<QL at 43 ppb, Ba 42 ppb at 1582 ppb, Hg <QL at 31.7 ppb, Tl<QL at 21.3 ppb, Pb<QL at 608 ppb, Th<QL at 24.7 ppb ppb and U <QL at 1.04 ppb. Se, Ag and Pt have concentrations below the quantification limit (<QL). The levels of Ba, Hg and Pb exceeded the norms for some samples. The presence of aluminum, arsenic and cadmium in the tested samples of fruit juices can be toxic since they have no nutritional value, and hence may be treated as potential contaminants in these beverages. The classification of concentration levels of metallic contaminants reveals two main groups, the minor and the trace elements. These results make it possible to classify the contaminants in the decreasing order of the concentrations in the following way: Al> Sr> Ba> Pb> Sn> Tl> As> Th> Hg> Cd> Be> U. The average concentrations’ levels of trace elements are generally in accordance with the levels obtained for French pineapple juices chosen as reference, national and international standards for the quality of beverages.

RESUMEL'eau, source potentielle de vie, doit subir diverses analyses physico-chimiques qui définiront sa qualité pour la consommation humaine afin d'éviter les risques de maladies hydriques pour les consommateurs. La présente étude vise à déterminer la qualité physico-chimique de l'eau de boisson des populations de deux villes du Bénin : Dassa-Zoumè et Cotonou. Trois points de prélèvement ont été identifiés dans chacune des deux localités pour un total de six (06) échantillons. Dix-neuf paramètres physico-chimiques ont été évalués sur ces échantillons. Certains paramètres (température, pH, turbidité et conductivité) susceptibles de modification au cours du transport ont été déterminés "in situ". Les résultats obtenus ont montré que l'eau des deux localités que consomment les populations est de bonne qualité sur le plan physico-chimique. Study of the physico-chemical quality of drinking water in two localities ofBenin: Cotonou and Dassa-Zoumè ABSTRACT Water, potential source of life, must undergo various physico-chemical analyzes that will define its quality for human consumption in order to avoid the risk of water-borne diseases to consumers. The present study aims to determine the physico-chemical quality of population's drinking water in two cities of Benin: Cotonou and Dassa-Zoume. Three sampling points were identified in each of the two localities for a total of six (06) samples. Nineteen physico-chemical parameters were evaluated on these samples. Some parameters (temperature, pH, turbidity and conductivity) which may be modified during transport were determined "in V. GBOHAIDA et al. / Int. J. Biol. Chem. Sci. 10(1): 422-434, 2016 423 situ". The results showed that the water consumed by the populations of both localities has a good physicochemical quality. Nevertheless, drinking water of Dassa's populations was more alkaline and harder than that of Cotonou: respectively 390-480 mg/l and 232-260 mg/l for Dassa and then 25-35 mg/l and 15-17 mg/l for Cotonou. This finding may explain the less foaming character and dull taste often noticed in Dassa's water and would be linked to the geological nature of the soils traversed.

Magnesium, calcium and manganese have very high values in Lake Nokoué respectively at Ganvié market station GAN_M (2990 ± 105 mg/L), Ganvié center, station GAN_C (4991 ± 177 mg/L) and Lake middle station MLak4 (10662 ± 17.03 µg/L). On the other hand, iron, aluminum and strontium have very high concentrations in the Cotonou Channel respectively at Agbato station AGB (5236 ± 103 and 8289 ± 519 µg/L) and at the estuary station EST (6118 ± 68 µg/L). The concentrations were compared to wells and cborehole waters in sixth neighborhood of Cotonou. We have used statistical analyzers such as MANOVA which have made it possible to classify the waters and metals in the ecosystems studied compared to groundwater and Well water waters. We use hierarchical clustering on principal components to identify similarities between stations based on metal concentration with R software packages "FactoMineR" and "factoextra". In general, we can conclude that most of the metals have an anthropogenic source except strontium and major elements (Ca and Mg) which could respectively provide from marine waters and geochemical sources.

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In this work, we valorized two wastes of plant origin in activated carbon (AC) by chemical activation, with a view to their use for the elimination of industrial dyes and artisanal dyeing simulated by methylene blue and iodine in the water. These are coconut shells (Coco nucifera) and teak wood chips (Tectona grandis). For the preparation of activated carbon based on coconut residues, the chemical activation was carried out by citric acid extracts of lemon juice (Citrus aurantiifolia) and then compared to that carried out with phosphoric acid and hydroxide of potassium. For the preparation of activated carbon from the teak residue, the activating agent used is potassium hydroxide. The results obtained show that activated carbon based on the coconut are microporous and mesoporous with an iodine number between 338.9 and 487.9 mg/g, a methylene blue number between 369.2 and 447.2 mg/g and a more pronounced post-treatment residual acidity for phosphoric acid than with lemon juice. The test conditions (the impregnation ratio, the duration, and the carbonization temperature) made it possible to prepare six activated carbons from the teak residue. The carbonization time does not have a significant effect on the adsorption efficiency although it does have a considerable effect on the carbonization efficiency. The adsorption kinetics of methylene blue on these materials is second order and the adsorption isotherm is more of the Langmuir type than that of the Freundlich model; this isotherm is characteristic of a wide distribution of microporosity and a well-developed mesoporosity. These activated carbons can therefore be used in the treatment of wastewater, in particular for the removal of industrial dyes and artisanal dyeing.

The extensive development of industries gives birth to many chemicals which brings contaminations towards environment. The present study is to apply QUECHERS extraction coupled with GC/MS for detection of polycyclic aromatic hydrocarbons (PAHs) and organochloride pesticides (OCPs) in Lake Nokoué of Benin Republic. The method was first benchmarked with standard PAHs and OCPs, and limit of detection (2-194 ppb) and limit of quantification (8-645 ppb) were obtained with recovery rate of 91-110%. The method was then applied to the detection of PAHs and OCPs in the lake water, no benzo[a]pyrene, chrysene or pyrene was detected. The main origin of PAH compounds in Nokoué Lagoon are material combustion and fuels for Polycyclic Aromatic hydrocarbons and due to remoteness pollution for organochorid pesticides compounds.