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 .
Heavy Metal Contamination of Selected Vegetables from Crude Oil and Non Crude Oil-Producing States in Nigeria: A Comparative Study
The aim of this study was to investigate and compare the heavy metal (HM) concentrations of selected vegetables harvested from crude oil-producing Rivers State and non-oil-producing Enugu State in Nigeria. Four vegetables;Telfaria occidentialis, Talinum triangulare, Ocimium gratissimum, and Murraya koenigii,were obtained from local farms in local government areas (LGAs) selected, each from the 3 senatorial zones in each state.The chemical analysis in mg/100g of the heavy metals (HMs) was conducted using standard methods. There mean values varied in the order: lead (Pb) > cadmium (Cd) > mercury (Hg) in mg/100g. Vegetable samples harvested from Rivers State had the highest toxicity level for both Pb (0.19 to 0.34) and Hg (0.01 to 0.03), while samples harvested from Enugu State had the highest toxicity level for Cd (0.07 to 0.25). The mean Pb contents forOcimium gratissimum(0.27) andTalinum triangulare(0.26), harvested from Rivers States were significantly (p < 0.05) higher than their counterparts harvested from Enugu State (0.19 and 0.21, respectively). Mercury had the least mean value than Pb and Cd in all the locations. All the vegetables from all the localities in this study had toxic levels of HM much above the FAO/WHO acceptable limits; 0.03 mg/100g for Pb, and 0.02 mg/100g for Cd in foods and 0.0001 mg/100g for Hg in mineral water. It can therefore be said that the public health importance for increased consumption of fruits and vegetables may equally mean increased HM consumption and bioaccumulation for the population in Rivers and Enugu States.
Heavy metals in edible green vegetables grown along the sites of the Sinza and Msimbazi rivers in Dar es Salaam, Tanzania
Abstract Four heavy metals (cadmium, copper, lead and zinc) were determined in some green vegetables cultivated along the sites of the Sinza and Msimbazi rivers. Atomic absorption spectrophotometry was used to estimate and evaluate the levels of these metals in the vegetables. The contributions of the vegetables to the daily intake of the heavy metals from the vegetables were determined. The results showed the following ranges (mg/100 g): 0.01–0.06, 0.25–1.60, 0.19–0.66, and 1.48–4.93 for cadmium, copper, lead and zinc, respectively. Some vegetables contained high levels beyond the permissible levels given by FAO and WHO for human consumption. When the mean levels of cadmium, copper, lead and zinc (0.20, 7.95, 3.95 and 33.75 mg per kg, respectively) were taken into account, the daily intake contribution of these metals was found to be 21.60 μg, 858.60 μg, 426.60 μg and 3.65 mg for cadmium, copper, lead and zinc, respectively.