Assessment of Heavy Metals in Waterleaf from Various Sources in Ota, Nigeria

This study assessed the levels of heavy metals present in waterleaf (Talinum triangulare) from various sources in Ota, Ogun State. Eighty (80) samples of waterleaf were obtained from 5 domestic (non-hazardous) dumpsites, 5 non-dumpsites, 5 markets and 5 streets in Ota. The non-dumpsites were locations in industrial areas. Also, over 500 questionnaires were randomly administered to residents in Ota to assess the extent of consumption of waterleaf. Standard method was followed for sample treatment, digestion, and analysis of selected heavy metals: lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni) and cobalt (Co) using Atomic Absorption Spectrometer. The results showed that in waterleaf from domestic dumpsites the concentration (mg/kg) of heavy metals were: Pb (14.50-20.10), Cd (0.05-0.60), Cr (0.19-2.48), Ni (2.75-7.30) and Co (3.40-6.05); from non-dumpsites: Pb (12.20-24.45), Cd (ND- 0.60), Cr (ND-2.79), Ni (ND-24.00), Co (3.75-5.75); from markets: Pb (0.35-3.85), Cd (ND), Cr (ND-7.11), Ni (ND- 5.10), Co (1.05-2.45); and from streets: Pb (ND-5.00), Cd (ND), Cr (ND), Ni (3.50-7.25), Co (1.50-2.50). Generally, all the heavy metals were highest in waterleaf from domestic dumpsites and non-dumpsites. There were 502 respondents to the questionnaire; of which 82% consumed waterleaf. Out of those who consumed waterleaf, 41% consumed it daily, 32% at least once in a week, and 19% at least once in two weeks. It may be concluded that there is the high tendency of exposure to heavy metals by those who consume waterleaf in the studied locations since the levels in waterleaf from all sources studied generally exceeded the FAO/WHO limits.Keywords: Waterleaf, Talinum triangulare, vegetable, heavy metals, pollution, Ot

Variations in the mineral composition and heavy metals content of Moringa oleifera

The parts of Moringa oleifera were assessed for mineral composition and some heavy metal contents in this study, which included Ca, Mg, K, Na, Mn, Fe, Zn, Co, Se, Pb and Cd. Parts of the plant were obtained from Badagry in Lagos State, Nigeria. The samples were digested with HNO3 and analysed for the mineral element content using atomic absorption spectrophotometer. The observed mean concentrations of the mineral elements were 26000, 643, 8210, 2980, 69.9, 169 and 15.3 mg/kg for Ca, Mg, K, Na, Mn, Fe and Zn, respectively. Co and Se, and the heavy metals Pb and Cd were not detected. There seemed to be no significant differences in the overall levels of the mineral elements in the different parts (P > 0.05). However, the observations showed that there were strong correlations between the levels of the elements in stem bark and root bark, stem bark and leaf, stem wood and pod, stem wood and seed, root bark and leaf, and pod and seed (P < 0.01); and between stem bark androot wood, root wood and root bark, and root wood and leaf (P < 0.05).Key words: Moringa oleifera, mineral composition, heavy metals

Heavy Metals Level in Clarias gariepinus (Catfish), Oreochromis niloticus (Tilapia) and Chrysichthys nigroditatus (Bagrid catfish) collected from Ogun River, Ogun State, Nigeria

Aquatic organisms such as fish are prone to contamination by water pollutants such as heavy metals. This study aims at assessing the levels of heavy metals in the fillet tissues of 75 fish samples comprising Clarias gariepinus (Catfish), Oreochromis niloticus (Tilapia) and Chrysichthys nigroditatus (Bagrid catfish) from five (5) different fishing locations along the Ogun River, Ogun State. The fillet tissues of the fish samples were digested and analysed for Zn, Pb, Fe, Cr and Cd using a Perkin Elmer, AAnalyst \u2013 200 Atomic Absorption Spectrometer. The concentration of Zn in Clarias gariepinus, Oreochromis niloticus and Chrysichthys nigroditatus were 5.37\ub12.558, 6.58\ub12.35 and 5.11\ub11.55 respectively; while the levels of Pb in the species were Clarias gariepinus (1.30\ub13.099), Oreochromis niloticus (1.01\ub10.95) and Chrysichthys nigroditatus (0.35\ub10.59). Concentrations of Fe, Cr and Cd in the species were Clarias gariepinus (8.87\ub13.547, 0.08\ub10.098 and 0.09\ub10.100), Oreochromis niloticus (8.96\ub12.21, 0.12\ub10.11 and 0.11\ub10.11) and Chrysichthys nigroditatus (8.16\ub13.88, 0.11\ub10.11 and 0.11\ub10.11). The data revealed that most of these values were lower than FAO/WHO permissible except Pb and Cr. Some of the fish sampled may pose health hazards to the consumers. There is a need for constant monitoring of pollutants in Ogun River

Levels of Heavy Metals in Commonly Consumed Vegetables Obtained from Some Markets in Ota, Nigeria

Background: As a result of increasing environmental pollution in developing countries, Nigeria in particular, assessment of food contamination is necessary. Objectives: This study aimed at assessing the concentrations of heavy metals in vegetables available in selected markets at Ota, Ogun State. Method: A total of 75 samples of three edible leafy vegetables: fluted pumpkin leaves (Telfairia occidentalis), Lagos spinach, "Green" (Amaranthus hybridus) and Jute Mallow (Corchorus olitorius) were obtained from Iyana Iyesi, Ota, Oju-Ore, Sango-Ota and Toll-gate markets in Ado-Odo/Ota local government, Ogun State, Nigeria. The samples were digested and analyzed for heavy metals using Atomic Absorption Spectrophotometer (AAS) following a standard method. Results: The results showed that all the metals detected were above the WHO/FAO permissible limits. Lead (Pb) was detected in all the vegetables except Jute Mallow from Sango and Fluted Pumpkin in Toll gate. The Pb content in all the vegetables ranged from 0.269±0.36 to 12.601±1.80 mg/kg. Cadmium was also detected in all the vegetables except Lagos Spinach (obtained from Sango Ota) and Fluted Pumpkin (obtained from Iyana Iyesi). The Cd content in all the vegetables ranged from 0.156±0.04 to 0.832±0.03 mg/kg. Chromium (Cr) was not detected in all the vegetables sold at Sango and also in Fluted pumpkin from Iyana Iyesi Market. The Cr content in all the vegetables ranged from 0.508±1.09 to 1.799±1.19 mg/kg. Conclusion: With regards to the locations or markets, the differences in concentrations were significant (P<0.05), while with regards to the metals, the differences in the concentrations were not significant. With significant values of Lead, Cadmium and Chromium observed in samples, vegetable consumers must be wary of vegetables to buy and the source. Keywords: Heavy metals, vegetables, Telfairia occidentalis, Amaranthus hybridus, Corchorus olitorius, Ado-Odo/Ot

Assessment of Heavy Metals in Waterleaf from Various Sources in Ota, Nigeria

This study assessed the levels of heavy metals present in waterleaf (Talinum triangulare) from various sources in Ota, Ogun State. Eighty (80) samples of waterleaf were obtained from 5 domestic (non-hazardous) dumpsites, 5 non-dumpsites, 5 markets and 5 streets in Ota. The non-dumpsites were locations in industrial areas. Also, over 500 questionnaires were randomly administered to residents in Ota to assess the extent of consumption of waterleaf. Standard method was followed for sample treatment, digestion, and analysis of selected heavy metals: lead (Pb), cadmium (Cd), chromium (Cr), nickel (Ni) and cobalt (Co) using Atomic Absorption Spectrometer. The results showed that in waterleaf from domestic dumpsites the concentration (mg/kg) of heavy metals were: Pb (14.50-20.10), Cd (0.05-0.60), Cr (0.19-2.48), Ni (2.75-7.30) and Co (3.40-6.05); from non-dumpsites: Pb (12.20-24.45), Cd (ND- 0.60), Cr (ND-2.79), Ni (ND-24.00), Co (3.75-5.75); from markets: Pb (0.35-3.85), Cd (ND), Cr (ND-7.11), Ni (ND- 5.10), Co (1.05-2.45); and from streets: Pb (ND-5.00), Cd (ND), Cr (ND), Ni (3.50-7.25), Co (1.50-2.50). Generally, all the heavy metals were highest in waterleaf from domestic dumpsites and non-dumpsites. There were 502 respondents to the questionnaire; of which 82% consumed waterleaf. Out of those who consumed waterleaf, 41% consumed it daily, 32% at least once in a week, and 19% at least once in two weeks. It may be concluded that there is the high tendency of exposure to heavy metals by those who consume waterleaf in the studied locations since the levels in waterleaf from all sources studied generally exceeded the FAO/WHO limits.Keywords: Waterleaf, Talinum triangulare, vegetable, heavy metals, pollution, Ot