Bioaccumulation of heavy metals in frequently consumed leafy vegetable grown along Nigeria-Benin Seme Border, West Africa

Vegetable growing along major highways with heavy vehicular movement has been a serious concern to food safety specialist in large cities. The contributions of heavy metals in selected vegetables through atmospheric deposition were quantified using atomic absorption spectrophotometer. The level of some heavy metal (.Pb, Cu, Fe, and Cr) were examined in the edible portion of Telfciria occidentals, Corchorus olitorius, Celocia argentea, and Thymus Vulgaries, grown along Nigeria-Republic of Benin border Seme. The results showed that the levels of heavy metal ranged from 21.69 ± 7.36 μg/g Cu to172.87 ±62.05 μg/g Fe in Telfaria occidentalis, 21.74±13.00 μg/g Pb to 304.50±72.77 μg/g Fe in Corchorus olitorius, 16.75±10.54 μg/g Pb to 260.74±215.37 μg/g Fe in Celocia argentea and 23.53±3.52 μg/g Cu to 406.33±225.06 μg/g Fe in Thymus Vulgaries were recorded in site A. The value heavy metal contamination obtained from site B ranged from 18.91±11.98 μg/g Pb to 166.49 ± 86.22 μg/g Fe in Telfaria occidentalis, 16.57± 9.22 μg/g Pb to 292.36±196.33 μg/g Fe in Corchorus olitorius, 19.99±8.54 μg/g Pb to 354.03±302.80 Fe in Celocia argentea and 21.73±8.44 μg/g Pb to 388.20±226.39 μg/g Fe in Thymus Vulgaries. The order of contamination in the vegetable sample was Fe > Cr > Cu > Pb. The data were analyzed with t-test and ANOVA. There were no significant different between the (p< .05) between the level of heavy metal in vegetable at each sampling site. The high levels of metal in the sampled vegetable may be attributed to excessive application of fertilizers and other agro chemical, as well the use of use of waste water for washing the vegetables. The obtained results were higher than the threshold value of WHO, FEPA and China stipulated standards for mature plant tissue except for copper in all the analyzed vegetable. Therefore, the consumption of these vegetables as food may pose possible health hazards to human

MICELLIZATION OF QUARTERNARY BASED CATIONIC SURFACTANTS IN TRIETHANOLAMINE-WATER MEDIA: A CONDUCTOMETRY STUDY

The effect of polar organic solvent, triethanolamine (TEA) on the micellization of a mixture of dodecyltrimethylammonium bromide (DETABr) and hexadecyltrimethylammonium bromide (HATABr) has been studied by conductance measurements at temperature range of 298.1 to 313.1K in steps of 5.1K. The values of the critical micelle concentration (CMC*) and the extent of counter-ion binding were obtained by fittings of the specific conductivity-concentration curve to the integrated form of the Boltzmann-Sigmoid equations. The values of CMC* was found to decrease with increase in the percentage composition of TEA. The degree of counter-ion binding of the mixed micelles (β) was determined from the ratio of the slopes corresponding to the post (A2) and pre-mixed micellar regions (A1). The thermodynamic quantities ( and ) was evaluated with the aid of the equilibrium model of mixed micelle formation. The negative deviation of the CMC* from the ideal system, the spontaneity, and the increased degree of randomness of the system were discussed on the basis of hydrophobic-solvophobic interactions of the monomers at elevated temperature

Assessment of Pollution Trend of Oke Afa Canal Lagos, Nigeria

The physiochemical properties of Oke Afa water body were investigated. The parameters were compared with established international standard (APCELS). The canal water contained very high concentration of BOD (64.8±11.3 mg/L) and COD (107.8±22.3 mg/L) which would suggest the presence of a high level of organic load that result in the pollution of the canals. Significant concentration of TSS ranging from (92±100 mg/L), SO42- (9.84±5.59 mg/L), PO43- (0.66±0.33 mg/L), Cl (37±2.84 mg/L), NO3- (2.63±0.6 mg/L) and DO (0.96±0.15 mg/L) were observed. Low concentration of zinc and copper were observed except lead that has a higher concentration above the allowed permissible level at a point B of the sampling sites. Some heavy metals were not detected at all in all the sampled points of the canal. The pH and temperature were fairly constant and the values of conductivity reveal a slight decline in the ability of the water to conduct electricity down the canal. All the detected parameters fell within limits except Lead

Determination of Heavy Metals in Crab and Prawn in Ojo Rivers Lagos, Nigeria

The level of heavy metals in crabs and prawns was investigated using Atomic Absorption Spectrophotometer. The mean concentration of copper in the crab was 1.56±0.87 µg/g; the mean concentration of zinc in the crab was also 0.64±1.96 ܖg/g. Chromium had the highest mean concentration of 8.936±35.4 µg/g while cadmium had the lowest mean of 1.66±1.82 µg/g lead was not detected. The mean concentration of heavy metals in prawn samples were follows: copper: 1.04±0.6 µg/g, cadmium: 0.07±0.08 µg/g, chromium: 4.06±7.00 µg/g and Zn 0.64±0.45 µg/g. Lead was not detected in prawn. The mean concentration of copper, cadmium and zinc in prawn was observed to be within the range NAFDAC standard for water and aquatic foods while crabs have higher mean concentration of heavy metals with the exception of zinc and copper are within the limit