Assessment of Trace Metal Levels In Commonly Edible Vegetables From Selected Markets In Lagos State, Nigeria
Consumption of food contaminated with heavy metals is a major source of health problems for man and animals. Three commonly edible Leafy vegetables (Amaranthus hybridus, Celosia argentea ,Cochorus olitoris) from Agboju and Iba markets , Lagos Nigeria were sampled, identified, digested and analyzed with the aid of Atomic Absorption Spectrophotometer (AAS) as directed by APHA (American Public Health Association) to determine heavy metals concentration in them with the aim of ascertaining their edibility for human consumption. The mean concentration for each heavy metal in the samples gotten from each market were calculated, the comparison of these data was done amongst the two markets, and compared with the permissible levels set by the FAO and WHO. The results showed that the levels of Lead, Cadmium, Copper, Zinc, Iron, Nickel, Selenium and Chromium present in the vegetable concentrated in the following order Fe>Pb>Zn>Cd>Ni>Cu>Cr>Se. With regards to vegetables in questions, analysis of variance showed that some vegetables accumulated metals more than each other and as such indicated that metals like copper, cadmium, selenium, iron and zinc are significant at P 0.05). With significant values of lead, cadmium and nickel, recorded in both Amaranthus hybridus and Celosia argentea vegetables, vegetables consumers must be weary of vegetables to buy and the market that is save to buy from, especially markets located very close to highways or close to major busy roads .
Nutritional Composition, Physical Characteristics and Sanitary Quality of the Tomato Variety Mongol F1 from Burkina Faso
Tomato (Lycopersicon esculentum Mill) is quantitatively the highest vegetable consumed in Burkina Faso. The objective of this study was to evaluate the physico-chemical, nutritional characteristics, and sanitary quality of the tomato variety Mongal F1 from different production sites. Twenty-eight (28) samples of Mongal F1 fresh tomatoes were collected from 28 producers at three different localities of Ouahigouya, Loumbila and Ouagadougou. The physico-chemical and nutritional characteristics were determined by standardized methods and the traces metallic elements by atomic absorption spectrophotometry. The results revealed a degree brix varying from 4.07° to 5.50° and a pH ranging from 3.71 to 4.08 corresponding to a total acidity of 0.39% to 0.55% citric acid equivalents. The moisture content, the ash content, the total carbohydrates content, the reducing carbohydrates content, the lipids content and the protein content were ranged from 95.09% to 96.17%, 9.25% to 10.60%, 47.00% to 53.43%, 30.03% to 41.21%, 3.04% to 7.71% and 17.09% to 25.03% respectively. The results of the trace metals showed a high accumulation of total cadmium from 0.11 to 0.22 ppm, of total lead of 1.15 to 1.27 ppm and arsenic total of 0.19 to 0.20 ppm. The results proved that environmental conditions influence the quality of the tomato Mongal F1. Detection of trace elements in the tomato fruits suggests that a better production practices are needed.
Determination of trace elements in edible vegetable oils by atomic absorption spectrophotometry
Methods are described for the direct determination of Al, Cr, Cu, Fe, Ni and Pb by atomic absorption spectrophotometry in sunflower oil and olive oils. Metallic contamination after storage under different controlled conditions and in contact with carbon steel, austenitic steel, ferritic steel and aluminum was examined. Additionally, chemical characteristics related to quality (acid value, peroxide value, K270 and oxidative stability) and some physical parameters of interest were evaluated after storage. When the samples were atomized directly off the tube wall, matrix interferences were not observed in the determination of Cr, Cu, Ni and Pb, whereas such interferences were noted when Al and Fe were determined. The results indicated that the L'Vov platform for Al and Fe determinations eliminates the matrix effects. Contamination with Fe was only detected in the olive oil that had been in contact with carbon steel, Fe concentration increased from 120±12 to 3,520±157 ppb. The physicochemical characteristics were affected only by the storage conditions, regardless of the metal sheets with which they were in contact. Virgin olive oil showed lowered stability after storage in contact with a carbon-steel sheet than when stored in absence of metal.