Concentrations and Hazards of Polycyclic Aromatic Hydrocarbons in Hawked Baked Ready-to-Eat Foods in Nigeria

The total concentrations of the Ʃ16 polycyclic aromatic hydrocarbons (PAHs) were examined in some samples of baked ready-to-eat foods (cake, sausage roll, meat pie, burger, and bread) with a view to provide information on the hazards associated with the consumption of these hawked street foods. The measurements were performed by using a gas chromatograph-mass spectrometer (GC-MS) after hexane/dichloromethane extraction and clean-up. The total concentrations of the PAHs in these samples of ready-to-eat baked foods ranged from 427.4 to 1224 μg kg–1, 289.9 to 853.7 μg kg–1, 574.4 to 2333 μg kg–1, 364.6 to 2906 μg kg–1, and 15.7 to 213.1 μg kg–1 for cake, sausage roll, meat pie, burger, and bread, respectively. The results indicated that these baked ready-to-eat foods were mainly contaminated with 2-, 3-, and 4-ring PAHs. The concentrations of benzo(a)pyrene were less than 0.1 μg kg–1 in nineteen out of the twenty samples examined

Concentrations and Hazards of Polycyclic Aromatic Hydrocarbons in Hawked Baked Ready-to-Eat Foods in Nigeria

The total concentrations of the Ʃ16 polycyclic aromatic hydrocarbons (PAHs) were examined in some samples of baked ready-to-eat foods (cake, sausage roll, meat pie, burger, and bread) with a view to provide information on the hazards associated with the consumption of these hawked street foods. The measurements were performed by using a gas chromatograph-mass spectrometer (GC-MS) after hexane/dichloromethane extraction and clean-up. The total concentrations of the PAHs in these samples of ready-to-eat baked foods ranged from 427.4 to 1224 μg kg–1, 289.9 to 853.7 μg kg–1, 574.4 to 2333 μg kg–1, 364.6 to 2906 μg kg–1, and 15.7 to 213.1 μg kg–1 for cake, sausage roll, meat pie, burger, and bread, respectively. The results indicated that these baked ready-to-eat foods were mainly contaminated with 2-, 3-, and 4-ring PAHs. The concentrations of benzo(a)pyrene were less than 0.1 μg kg–1 in nineteen out of the twenty samples examined

Mineralization of Nitrogen in Hydromorphic Soils Amended with Organic Wastes

This paper present the results of nitrogen mineralization in hydromorphic (wetland) soils of the Niger Delta amended with organic wastes. The organic wastes amended soil generally showed a decrease in total inorganic (NO3-N+NH3-N) released within first 14 days, which increased thereafter. The nitrogen mineralized during 58 day of incubation ranged from 82.15 mg kg-1 to 281.60 mg kg-1 for fadamal soil, 54.50 mg kg-1 to 197.30 mg kg-1for meander belt soil and 98.50 mg kg-1 to 320.00 mg kg-1 for Mangrove soil (mangal acid sulphate soils). The order of cumulative nitrogen released in the waste amended soil followed the order: sewage sludge>kitchen waste> poultry manure> oil palm waste> cow manure. Total mineralized N indicated negative correlation with total organic N and C:N rati

Fractionation, characterization and speciation of heavy metals in composts and compost-amended soils

Speciation of heavy metals in soils determines the availability for metals for plant uptake and potential for contamination of groundwater following application of composts to agricultural lands. Methodsused to characterize heavy metals in solid phase of composts and compost amended soils include physical fractionation and chemical extraction. Chemical extraction schemes are most frequently usedapproach to fractionate trace metals in soils, sewage sludge and composts. Several variations exist in the sequential extraction procedures. These variations include reagent types, strength, volume and extraction time. A main drawback shared by all sequential extraction schemes is that the procedures themselves are complex and time consuming. This setback has been overcome by the use ofultrasound accelerated extraction which reduce the extraction time for the entire extraction steps to about 90 minutes allowing composting process to be monitored more frequently which help to providedetailed understanding of the partitioning behaviour of heavy metals. Inspite of the variability the sequential extraction schemes, they all aimed at correlating each fraction with the mobility and plantavailability of each metal. Several studies have shown that phase association of heavy metal in composts include water-soluble, exchangeable, precipitated as discrete phases, co-precipitate in metaloxides and adsorbed or complexed by organic ligands and residual forms. The phase association and solubility of metals changes over composting time thereby altering metal availability. It is apparent thatthe positive effects of resulting from compost application far outweigh the negative effect, but more research is needed on a wide range of municipal solid waste compost with more precise determinationof the fate of municipal solid waste compost applied trace metals in the environment

Assessment of Heavy Metal Contamination in Soils around Cassava Processing Mills in Sub- Urban Areas of Delta State, Southern Nigeria

The concentrations, contamination/pollution index, anthropogenic input and enrichment factors for metals in soil in the vicinity of cassava processing mills in sub-urban areas of Delta State of Nigeria were examined. The concentrations of metals in all sites and depths ranged from 0.1 to 383.2 mg kg-1 for Mn, 4.0 to 11.3 mg kg-1 for Ni, 1746.4 to 2839.6 mg kg-1 for Fe, 0.01 to 3.70 mg kg-1 for Cr, 3.7 to 29.5 mg kg-1 for Cu, 21.9 to 97.3 mg kg-1 for Zn, 0.01 to 1.60 mg kg-1 for Cd and <0.01 to <0.01 mg kg-1 for Pb. The concentrations of metals at these sites were below the Department of Petroleum Resources target values for metals in soils except for Cd in some sites. A significant fraction of these metals aroses from anthropogenic sources. The percent anthropogenic fraction of metals in the soil follow the order Cd > Zn > Ni > Cu > Fe > Cr > Pb.Keywords: Anthropogenic input, cassava, heavy metals, pollution inde

Sadržaj teških metala u jetrima i bubrezima goveda iz južne Nigerije.

Results are presented for the levels of cadmium, chromium, copper, lead, iron, manganese and nickel as determined by atomic absorption spectrophotometry, in the livers and kidneys of 88 cattle from seven different locations in southern Nigeria. The mean and range for each metal in mg.kg-1, in livers and kidneys were as follows; cadmium 0.08 (0.01-0.23) and 0.14 (0.01-0.46); chromium 3.62 (0.98-6.33) and 3.63 (1.08-5.87); copper 1.99 (0.11-8.99) and 3.27 (0.22-7.49); 0.8 (n.d-0.23) and 0.04 (n.d-0.95); iron 37.75 (2.64-85.60) and 32.26 (0.10-78.65); Ni 0.12 (0.01-0.55) and 0.20 (0.02-0.46). Significant differences were observed in the heavy metal levels in livers and kidneys from the different locations and between the heavy metal levels in livers and kidneys from the same location. The levels of the various metals were generally low, and within international statutory safe limits.Predočeni su rezultati istraživanja razina kadmija, kroma, bakra, olova, željeza, mangana i nikla ustanovljenih atomskom apsorpcijskom spektrofotometrijom u jetrima i bubrezima podrijetlom od 88 goveda sa sedam različitih područja u južnoj Nigeriji. Srednje vrijednosti razine te razmak od najmanje do najveće vrijednosti u mg.kg-1 u jetrima i bubrezima bile su sljedeće: za kadmij 0,08 (0,01-0,23) u jetrima te 0,14 (0,01- 0,46) u bubrezima; za krom 3,62 (0,98-6,33) u jetrima te 3,63 (1,08-5,87) u bubrezima; za bakar 1,99 (0,11- 8,99) i 3,27 (0,22-7,49); za olovo 0,8 (0,23) te 0,04 (do 0,95); za željezo 37,75 (2,64-85,60) i 32,26 (0,10-78,65); za nikal 0,12 (0,01-0,55) i 0,20 (0,02-0,46). Značajne razlike u razini teških metala ustanovljene su ovisno o pretraženom organu te o području na kojem su obitavale pretražene životinje. Razine različitih metala bile su općenito niske i unutar međunarodno propisanih vrijednosti

Heavy Metals in Soils and Tomatoes Grown in Urban Fringe Environment in Asaba, Delta State, Nigeria

Pb, Cu, Ni, Zn, Cr, Mn and Fe in soils and tomato leaves and fruits from peri-urban environments in Asaba, Delta State were determined after acid digestion by using atomic absorption spectrophotometry (AAS). The concentrations of metals in the soil samples were 10.14, 2.28, 3.96, 7.88, 0.15, 14.53 and 66.00 mg/kg site A; 7.01, 2.01, 2.03, 5.53, 0.16, 12.15, and 70.12 mg/kg site B, and 9.12, 2.24, 3.01, 4.35, 0.01, 11.52, and 61.22 mg/kg site C for Pb, Cu, Ni, Zn, Cr, Mn and Fe respectively. The concentrations of metals in the tomato leaves samples were 4.01, 1.91, 1.83, 4.89, 0.16, 4.51 and 7.13 mg/kg in site A; 3.84, 1.56, 2.07, 4.00, 0.41, 4.48 and 8.15mg/kg in site B, and 4.03, 1.75, 2.01, 4.52, 0.01, 4.42 and 8.11 mg/kg in site C for Pb, Cu, Ni, Zn, Cr, Mn and Fe respectively while in the tomato fruits, the concentrations of metals in mg/kg were 2.96, 0.41, 1.35, 3.33, 0.01, 3.83 and 6.38 mg/kg in site A; 3.01, 1.35, 1.88, 2.98, 0.15, 3.01 and 5.09 mg/kg in site B, and 3.92, 1.44, 1.82, 3.73, 0.01, 3.05 and 6.00 mg/kg in site C for Pb, Cu, Ni, Zn, Cr, Mn and Fe respectively. These values obtained in the soils for all sites were below the given values for naturally occurring metals in soil and Department of Petroleum Resources target and intervention values for metals in soil while the values recorded for tomatoes leaves and fruit are below the levels recommended by WHO/FAO and NAFDAC for metals in foods and vegetables but are within the normal range of metals in plants. There was positive correlation among metals except Pb/Cr, Cr/Mn and Cr/Fe. The values of transfer factor (tf) obtained for all the metals except Fe in leaves and fruits for all the sites were above 0.2 indicating anthropogenic contamination of the sites and also high take up and accumulation of the metals from the soil by the tomatoes thus the need for environmental monitoring of the area.Key words: Heavy metals, tomato, anthropogenic, contamination, pollutio

Trace Elements Concentrations in Water and Aquatic Biota from Ase Creek in Niger Delta

Water, Tilapia zilli , Synodontis nigrita , Clarias angillaris , Ipomoe cearri and Eichornnia natans samples collected from Ase-creek for a period covering ten months (January \u2013 October, 2006). The aforementioned samples were analysed for heavy metals such as selenium, arsenic, chromium, lead, molybdenum, bismuth and cadmium using atomic absorption spectrophotometry (AAS) of model Pye Unicam 2900. The results obtained revealed that there were metal variations and elevated concentrations were obtained except for arsenic which was below detection limit in fish samples. These elevated metal concentrations determined indicate a deep pollution of the Ase-creek. Metal concentrations in the fish species and aquatic plants in this study are good indicators for environmental monitoring in Nigerian rivers. Oil explorations, industries and anthropogenic wastes were traceable to the elevated metal concentrations in the Ase-creek

Mineralization of Nitrogen in Hydromorphic Soils Amended with Organic Wastes

This paper present the results of nitrogen mineralization in hydromorphic (wetland) soils of the Niger Delta amended with organic wastes. The organic wastes amended soil generally showed a decrease in total inorganic (NO3-N+NH3-N) released within first 14 days, which increased thereafter. The nitrogen mineralized during 58 day of incubation ranged from 82.15 mg kg-1 to 281.60 mg kg-1 for fadamal soil, 54.50 mg kg-1 to 197.30 mg kg-1 for meander belt soil and 98.50 mg kg-1 to 320.00 mg kg-1 for Mangrove soil (mangal acid sulphate soils). The order of cumulative nitrogen released in the waste amended soil followed the order: sewage sludge>kitchen waste> poultry manure> oil palm waste> cow manure. Total mineralized N indicated negative correlation with total organic N and C: N ratio

Temperature Effect on Water Extractability of Cadmium, Copper, Lead and Zinc from Composted Organic Solid Wastes of South-West Nigeria

The effect of temperature changes (10 to 80 °C) on water-extractable metal (Zn, Cu, Cd and Pb) concentrations of composted wastes of Nigerian origin was investigated in batch extraction experiments. Metal concentrations were measured using a calibrated atomic absorption spectrophometer after acid digestions. Results showed that the water-extractable metal fractions (I) did not exceed 10% of total metal concentrations of the bulk composts, which corresponded to 0.30 to 6.63% for Zn, 0.09 to 7.51% for Pb, 1.83 to 9.29% for Cu and 0.67 to 9.23% for Cd. Water extractable metal fraction showed positive correlations (r = 0.137 to 0.917*; p* < 0.01) for Cu, Cd and Pb in most cases but negative for Zn (−0.067 to −0.445). Simulations revealed that a steady temperature rise from 0.1 to 1.5 °C might increase I by 0.13 to 168% for all the metals, although stability to gradual temperature rise was demonstrated in some instances. The study revealed that the degree of temperature effect on water extractability of heavy metals from the bulk composts was dependent on metal type, compost formulation and waste type