Determination of Mercury Level in Rana esculenta (Frog), Sediment and Water from River Guma, Benue State Nigeria

The level of mercury was determined in R. esculenta (edible frog), sediment and water from river Guma, Benue State, for three (3) consecutive months using hydride generation atomic absorption spectrophotometer (HG-AAS) technique. The mean   concentrations of mercury in the R. esculenta, water and sediment were 0.027mg/kg, 0.00mg/kg and 0.001mg/kg, respectively. The absence of mercury in the water signifies its affinity to adsorbed to any surface in the river. Mercury builds up in the tissues of R. esculenta and its levels in tissues increase as we go up the food chain. The result of the analysis shows that the level of mercury is always higher in the liver (0.014mg/kg) compared to intestine (0.010mg/kg) and muscle (0.003mg/kg). The mean concentration of mercury obtained in R. esculenta (0.027mg/kg) was below the International Atomic Energy Agency recommendation value (IAEA – 433) of 0.168mg/kg. Keywords: Mercury, Edible Frog, Sediment, Guma, HG-AAS

Synthesis and Characterization of 2-Ethoxy Isobutryl Acid Hydrazide and 2-Ethoxy Isobutryl Aceto Hydrazone and Its Metal Complexes with Co(II), Ni(II) and Cu(II)

Complexes of Co(II), Ni(II) and Cu(II) derived from 2-ethoxy isobutryl acid hydrazide (EIAH1) and 2-ethoxy isobutryl aceto hydrazone (EIAH2) have been synthesized and characterized by elemental analysis, FT-IR, molar conductance, UV – visible spectra, ESR, thermal analysis and magnetic susceptibility. The complexes are coloured, stable in air and exhibit coordination number of 4 or 6. Analytical data showed that all the complexes exhibited 1:2 (metal:ligand) ratio. The changes observed between the FT-IR and UV – visible spectra of the ligands and of the complexes allowed us to establish the coordination mode of the metal in complexes. Presence of coordinated water molecules in Co (II) and Ni (II) complexes is confirmed by TGA studies. The conductivity data show that all these complexes are non electrolytes. The solubility test on the ligands and its metal(II) complexes revealed their solubility in dimethylsulphoxide (DMSO). The ligands and metal complexes show a good activity against the bacteria; B. Subtilis, E.coli and S.aureus and fungi A.niger, A.flavus and C.albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the ligands. Keywords: Synthesis, hydrazine, hydrazone, metal complexes, characterizatio

Analysis of Heavy Metals Content of Fluted Pumpkin (Telfairia occidentalis) Leaves Cultivated on the South Bank of River Benue, Nigeria

Assessment of heavy metals (Fe, Mn, Zn, Cu, Cd, Cr, and Pb) content of fluted pumpkin leaves (Telfairia occidentalis) cultivated along the bank of river Benue at Makurdi, Central Nigeria was done using atomic absorption spectrophotometery (AAS). The concentration of these metals was also determined in the soil and river Benue water samples. The results show the mean concentration of heavy metals in T. occidentalis leaves samples as: Fe (54.7±21.9 mg/kg), Mn (278± 156 mg/kg), Zn (50.4± 9.2 mg/kg), Cu (5.03± 1.1 mg/kg), Cd (0.760± 0.2 mg/kg), Cr (3.78± 2.9 mg/kg) and Pb (44.05± 22.6 mg/kg). The load of heavy metals in fluted pumpkin leaves' samples increased in the order Cd<Cr<Cu<Pb<Zn<Fe<Mn. This correlates with the trend of observed heavy metals content in the order Cd<Cu<Cr<Pb<Zn<Mn<Fe for the analysed soil and water samples. The concentrations of Fe, Mn, Zn, and Cu in the vegetable were below Codex Alimentarius limits while Cd, Cr and Pb values exceeded their permissible limits in vegetable samples set by Codex Alimentarius Commission. Thus, there is a need to continuously monitor the heavy metal content of food crops cultivated along the banks of river Benue and other such places. Keywords: Atomic absorption spectrophotometry, Fluted pumpkin (Telfairia occidentalis), Heavy metals, River Benu

Bioaccumulation of Heavy Metals in Fish (Tilapia Zilli and Clarias Gariepinus) Organs from River Benue, North – Central Nigeria

Heavy metals concentrations were determined in fish organs of Tilapia zilli and Clarias gariepinus from River Benue along Makurdi metropolis using atomic absorption spectrophotometer. The results indicated that Tilapia zilli gills contained the highest concentration (52.2%) of all the detected heavy metals, followed by the intestine (26.3%), while the muscle tissues appeared to be the least preferred site for the bioaccumulation of metals as the lowest metal concentration (21.5%) were detected in this tissue. Similarly, the Clarias gariepinus gills contained the highest concentration (40.3%) of all the detected heavy metals, followed by the intestine (31.6%), while the muscle tissue (28.1%) was the lowest. The trend of heavy metals concentration can be represented as: Cr > Zn > Cu > Fe > Mn > Cd > Pb for Tilapia zilli, while that of Clarias gariepinus was Cr > Zn > Fe > Cu > Mn > Cd > Pb. Tilapia zilli showed high bioaccumulation factors of 244, 229 and 178 for Cr, Zn and Cu, respectively. Claria gariepinus showed 232, 226 and 151 for Cr, Zn and Fe, respectively. This suggests that the fish samples could be used to monitor Cr and Zn pollution levels in the River Benue