The determination of Cd, Cr, Cu, Pb and Zn in the exchangeable, carbonate, Fe-Mn-oxides, organic matter and residual sediment chemical fractions of Kubanni Dam during dry and raining seasons was carried out using the spectrophotometric method after Tessiers' sequential scheme for speciation had been carried out. The pH and Total Organic Carbon (TOC) of the sediment samples were also determined to study their effects on the distribution of metals. The results indicate that pH influenced the release or adsorption of each metal in the different sediment fractions. At low average pH of 5.21 recorded during dry season, desorption of metals from the reducible sediment fraction into the water column occurred, which may have effect on aquatic organisms. Due to increased metal complexation at high pH, total extractable fractions of metals generally increased. Higher TOC levels during the rainy season indicated larger adsorption surfaces for Cr (19.92%) Pb (19.97%) and Zn (21.14%) on the organic matter fraction, which, under oxidizing condition, these metals may be remobilized into the aquatic environment. Cu correlated positively with the organic carbon content of the sediment samples. The positive correlation of Pb, Cd and Cr with sediment pH may reflect the tendency of cation adsorption to increase at high pH.

SummaryAn aqueous extract of defatted leaves of Azadirachta indica was found to possess trypanocidal activity against Trypanosoma brucei brucei. Column chromatography of the crude extract gave three fractions, I, II, and III, that eluted with ethylacetate/methanol, benzene/ methanol, and acetic acid/methanol, respectively. Of these extracts, only fraction III retained trypanocidal properties and cured mice chronically infected with Trypanosoma brucei brucei. Histopathological studies of the brains, livers, hearts, and spleens of the treated mice showed no cellular infiltrations. These findings are discussed in relation to trypanosome chemotherapy.

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This study was initiated as a follow-up information on some impounded products chocolates and candies (Samples A, B, C and D) imported from overseas, and sold in Nigeria markets. This result as their failure to meets Nation Agency for food drug administration and control (NAFDAC) regulatory standard. Samples of these products were collected in five markets of each six states each from the six geographical zones: North-West (Bauchi), North-East (Kano), North-Central (Kogi), South-West (Lagos), South-East (Abia), and South-South (Rivers) of the country. In order to evaluate the quality of the products, the levels of some heavy metals (Cu, Mn, Fe, Ni, Zn, Ti and Cr) were evaluated in the samples using X-ray fluorescence (XRF). Concentrations of metals in both chocolates and candies ranged 3.0 -4.2 mg/g for Cu, 40.0 -55.7 mg/g for Mn, ND -102.5 mg/g for Fe, ND -305.0 mg/g for Ni, ND -42.5 mg/g for Zn, ND -23.8 mg/g for Ti, and ND -10.8 mg/g for Cr. The results showed that that these metals are at higher levels in Samples A, B, C and D compared to other studies in candies and chocolates in Nigeria. Correlation analysis among metals revealed positive correlations, which indicates similar sources of these metals. Also, evaluation of dietary intake of these products daily revealed that Samples A (except for Cu), B and C are above the daily dietary recommended limit for all the studied metals in food. Thus a frequent intake of these contaminated products is likely to induce health effects arising largely from Cu, Mn, Fe, Ni and Zn.

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