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 levels in vegetables from selected markets in Lagos, Nigeria.
This study was conducted to analyze the heavy metal in a selected vegetable in Lagos, Nigeria. Recently matured leafy vegetable (fluted-pumpkin) from ten (10) different markets were sampled, digested using 98% nitric acid (HN03) and analyzed with the aid of Atomic Absorption Spectrophotometer(AAS) to determine heavy metals. The mean concentration for each heavy metal in the samples gotten from each market were calculated and the comparison of these data was done amongst the ten markets, and compared with the permissible levels set by the FAO and WHO. Results showed that the levels of Cadmium and Zinc for the leafy vegetables ranged from 0.028±0.003 to 0.091±0.103 and from 0.348±0.317 to 0.77±0.38mg/kg dry weight respectively. Lead was not detected in all the samples . When compared with standards, heavy metal levels were found to be within safe limit.
Heavy Metal Contamination of Soil and Vegetation in the Vicinity of Industries in Bangladesh
A study was conducted to investigate the heavy metal contamination of soil and vegetation in the vicinity of industries around Dhaka city in Bangladesh. Categorically soils, grass (Cynoden doctylon L), water hyacinth (Eichhornia crassipes L), rice (Oryza sative L), and arum (Alocasia esculenta L) were collected from tannery, ceramic, textile dying and sulphuric acid producing industrial sites. The concentrations of total Cd, Cu, Mn, Ni, Pb and Zn ranged from 0.1–1.8, 28–217, 106–577, 25–112, 17–99 and 53–477 mg kg−1 soil, respectively among the industrial sites. The concentrations of some heavy metals ranged from background levels to levels in excess of tolerable limits in agricultural soils. The concentrations of total Cu, Mn, Ni, Pb and Zn decreased with increasing distance from the disposal points of the tannery and the textile dying industries. Cadmium, Cu, Mn, Ni, Pb and Zn showed highly significant (p < 0.01) positive correlations with their total and DTPA-extractable contents in soils. The concentrations of most heavy metals were also higher in the vegetation samples of tannery area and the content of Pb (13–45 mg kg−1) in grass samples exceeded the toxic limit. In correlation matrix, plant concentrations of Cu, Mn, Pb and Zn were significantly correlated with their total and extractable contents in soils.