Godswill O. Tesi

Safety evaluation of metal exposure from commonly used moisturizing and skin-lightening creams in Nigeria

The concentrations of ten metals (Cd, Pb, Ni, Cr, Cu, Co, Fe, Mn, Zn and Al) were measured in some commonly used moisturizing and skin-lightening creams in Nigeria with a view to providing information on the risk of exposure to metals from the use of these products. The metal concentrations in these products were measured by atomic absorption spectrometry after acid digestion of the samples. The measured concentrations of metals in the skin moisturizing creams ranged from <0.15 to 6.3 μg/g Cd, <0.02 to 17.5 μg/g Cu, 2.25 to 6.25 μg/g Cr, <0.25 to 124.3 μg/g Al, 0.2 to 7.3 μg/g Pb, <0.03 to 10.7 μg/g Ni, 17.3 to 372.0 μg/g Zn, <0.02 to 1.0 μg/g Co, 17.75 to 28.8 μg/g Mn, <0.1 to 89.8 μg/g Fe while the concentrations of metals in the skin-lightening products ranged from <0.15 to 16.5 μg/g Cd, <0.02 to 10.0 μg/g Cu, 4.25 to 8.0 μg/g Cr, <0.25 to 128.0 μg/g Al, 0.5 to 4.5 μg/g Pb, <0.03 to 1.65 μg/g Ni, 24.7 to 267.5 μg/g Zn, <0.02 to 2.5 μg/g for Co, 19.3 to 31.8 μg/g Mn, 9.5 to 211.63 μg/g Fe. In a significant number (>93%) of the samples investigated the concentrations of Pb, Cd, Ni and Co were below the specified limit, or the maximal limit for impurities in colour additives in cosmetics for external use. However, Cr was found at concentrations above the allergenic limit of 1 μg/g. The results also showed that skin-lightening creams contained higher concentrations of the studied metals than the moisturizing creams, except for Ni, which indicates that persons who uses skin-lightening creams in preference to moisturizing ones, are exposed to higher concentrations of metals.

Polycyclic aromatic hydrocarbon concentrations in commercially available infant formulae in Nigeria: Estimation of dietary intakes and risk assessment

The concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) in commercially available infant formulae and follow-up formulae in Nigeria were determined with a view to providing information on the health risks to children from the consumption of these infant foods. The concentrations of PAHs were measured by means of gas chromatography-mass spectrometry (GC-MS) after extraction by ultrasonication with acetone/dichloromethane and clean-up. The concentrations of the Σ16 PAHs in these infant formulae ranged from 0.102 to 1.98 μg kg(-1), 0.054-1.98 μg kg(-1), 0.081-2.54 μg kg(-1) and 0.51-0.70 μg kg(-1) for infants of ages 0-6 months, 6-12 months, 1-3 years and 0-12 months respectively. The concentrations of benzo(a)pyrene (BaP) in all samples investigated were below the 1 μg kg(-1) European Commission permissible limit for BaP in foods meant for infants. The estimated daily intake of PAHs based on the European Food Safety Authority (EFSA) suggested indicators of occurrence and effects of PAHs in foods were not detected (nd) to 2.67 ng BaP kg(-1) bw day(-1), nd-5.29 ng PAH2 kg(-1) bw day(-1), nd-11.20 ngPAH4 kg(-1) bw day(-1) and nd-34.96 ng PAH8 kg(-1) bw day(-1). The estimated margin of exposure (MOE) values: BaP-MOE, PAH2-MOE, PAH4-MOE and PAH8-MOE values were greater than 10,000 which indicates that there are no health risks from the consumption of these products by infants. The concentrations and dietary exposure to PAHs from these products were similar to values reported in the literature for European Communities.

Concentrations and exposure risks of some metals in facial cosmetics in Nigeria

The concentrations of nine metals (Cd, Pb, Ni, Cr, Co, Cu, Fe, Mn and Zn) were determined in lip sticks, lip glosses, lip balms, eye pencils, eyeliners, eye shadows, blushes, mascaras and face powders. The study was aimed at providing information on the risk associated with human exposure to metals in these facial cosmetic products. The concentrations of metals in the samples were measured by atomic absorption spectrometry after digestion with a mixture of nitric acid, hydrochloric acid and hydrogen peroxide. The mean concentrations of metals in these facial cosmetics ranged from 3.1 to 8.4 μg g−1 Cd, 12–240 μg g−1 Pb, 9.1–44 μg g−1 Cr, 18–288 μg g−1 Ni, 1.6–80 μg g−1 Cu, 7.9–17 μg g−1 Co, 2.3–28 mg g−1 Fe, 12–230 μg g−1 Mn, and from 18 to 320 μg g−1 Zn. The concentrations of Ni, Cr and Co were above the suggested safe limit of 1 μg g−1 for skin protection, while Cd and Pb were above the Canadian specified limits. The systemic exposure dosage (SED) values for these metals obtained from the use of these facial cosmetic products were below their respective provisional tolerable daily intake (PTDI)/or recommended daily intake (RDI) values. The margin of safety values obtained were greater than 100 which indicated that the concentrations of the metals investigated in these facial cosmetics do not present considerable risk to the users except in the case of face powders.

Concentrations and Profiles of Polycyclic Aromatic Hydrocarbons in Some Commercial Brands of Tea-, Coffee-, and Cocoa-Based Food Drinks in Nigeria

Concentrations and profiles of polycyclic aromatic hydrocarbons were determined in some popular commercial brands of tea-, coffee-, and cocoa-based food drinks in Nigeria by gas chromatograph-flame ionization after hexane/dichloromethane extraction and clean up. The concentrations of the ∑16 Polycyclic aromatic hydrocarbons in these products ranged from 5.2–913.1, 38.7–593.1, and 38.0–1406.4 μg kg−1 for tea-, coffee-, and cocoa-based food drinks, respectively. The polycyclic aromatic hydrocarbon profiles indicate the dominance of three and four rings PAHs in these food items. The concentrations of the European Food Safety Authority (EFSA) eight carcinogenic polycyclic aromatic hydrocarbons ranged from nd–218.9, nd–102.9, and nd–1248.5 μg kg−1 for tea-, coffee-, and cocoa-based food drinks, respectively.

Concentrations and profiles of polycyclic aromatic hydrocarbons in some popular fish species in Nigeria.

The concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) in 10 popular fish species in the Nigerian market were determined with a view to providing information on the health hazards associated with the consumption of these fish species. The concentrations of PAHs were measured by gas chromatography-mass spectrometry after extraction by ultrasonication with acetone-dichloromethane and clean up. The concentration ranges of the Σ16 PAHs were 20 to 39.6 μg kg(-1) for Parachanna obscura (African snake head), 6.8 to 532.3 μg kg(-1) for Oreochromis niloticus (tilapia), 7.4 to 91.1 μg kg(-1) for Gymnarchus niloticus (Asa), 13.1 to 34.1 μg kg(-1) for Sebastes fasciatus (red fish), 11.2 to 80.0 μg kg(-1) for Gadus morhua (cod), 23.9 to 34.6 μg kg(-1) for Chrysicthys nigrodigitatus (silver cat fish), 63.4 to 131.4 μg kg(-1) for Sardinella aurita (sardine), 22 to 52.9 μg kg(-1) for Trachurus trachurus (Atlantic horse mackerel), 21.0 to 63.7 μg kg(-1) for Scomber scombrus (mackerel), and 27.7 to 44.5 μg kg(-1) for Pseudotolithus senegalensis (croaker). Benzo[a]pyrene occurred in 23% of these fish samples at concentrations above the European Union permissible limit of 2.0 μg kg(-1). The calculated margins of exposure based on the indicators for occurrence and effects of PAHs were greater than 10,000 indicating no potential risk for the consumers of the species evaluated in this study.

Polycyclic Aromatic Hydrocarbon Profiles of Some Brands of Canned Fish in the Nigerian Market

ABSTRACT Concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) were determined in selected popular brands of canned fish (mackerel, sardine, and tuna) consumed in Nigeria with a view to providing information on the health risk associated with consumption of these products. The concentrations of PAHs were measured by gas chromatography equipped with flame ionization detection (GC-FID) after dichloromethane/hexane extraction and clean-up. The concentrations of Σ16 PAHs in these brands of canned fish varied from 174.6 to 350.8 μg/kg, 187.4 to 592.5 μg/kg, and 204 to 264.6 μg/kg for mackerel, sardine, and tuna, respectively. Benzo(a)pyrene was detected in 48% of the investigated brands at concentrations higher than the maximum tolerable limit of 5 μg/kg. The daily intake of PAHs from the consumption of any brand of these canned fish ranged from not detected (nd) to 54.3 ng BaP/kg bw/day, nd to 56.4 ng PAH2/kg bw/day, nd to 86.4 ng PAH4/kg bw/day, and nd to 153.7 ng PAH8/kg bw/day. The estimated margin of exposure (MOE) values (BaP-MOE, PAH2-MOE, PAH4-MOE, and PAH8-MOE) in a significant proportion of the brands was less than 10,000, which indicates a potential health risk for the consumers of these brands of canned fish.

Chemical fractionation and mobility of metals in floodplain soils of the lower reaches of the River Niger, Nigeria

The chemical fractionation of nine metals, Cd, Pb, Cr, Ni, Cu, Co, Ba, Mn and Zn, in soil profiles of the floodplain of the lower reaches of the River Niger in Nigeria, was investigated with a view to providing information on the forms, bioavailability and mobility of these metals in the soil profiles. The chemical forms of metals in the soil were determined by using the European Community Bureau of Reference (BCR) sequential chemical extraction method and the concentrations were measured by inductively coupled plasma-atomic emission spectrophotometry (ICP-AES). The results indicated that the residual and Fe-Mn oxide/hydroxide phases were the predominant forms of the metals in the soil profiles. The percentage of metals in the readily available and potentially available fractions followed the order: Pb > Ba > Cd > Ni > Co > Zn > Mn > Cu > Cr. Significant proportions of these metals were found in the potentially available phases, which indicate an increase in mobility and availability as a result of changes in the physicochemical characteristics (pH and Eh) of the soil following flooding events.

Concentrations, health risks and sources of polycyclic aromatic hydrocarbons in Nigerian honey

The concentrations of the US EPA 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in honey samples collected from different regions of Nigeria with a view to providing information on the extent of contamination, regional profiles, sources and risks of PAHs in this food type. The concentrations of the PAHs were determined by using gas chromatography-mass spectrometry after extraction by ultra-sonication with n-hexane and dichloromethane. The concentrations of ∑16 PAHs in the honey samples ranged from 169-522 μg kg-1, 97.2-1980 μg kg-1, 180-641 μg kg-1 and 122-357 μg kg-1 for South- East, South-West, Niger Delta, and North Central regions respectively. The compositional patterns of PAHs in the analyzed honey samples followed the order: 5-rings>4-rings>3-rings>6-rings>2-rings. The estimated daily intake values from consumption of these honey samples ranged from not detected (nd) to 1.9 ng kg-1 bw day-1, nd to 5.9 ng kg-1 bw day-1, nd to 18 ng kg-1 bw day-1 and 0.6 to 33 ng kg-1 bw day-1 for BaP, PAH2, PAH4 and PAH8 respectively. The incremental life cancer risk and margin of exposure values for the majority of the samples indicate that there is no risk associated with the consumption of these honey samples. The PAH isomeric ratios and principal component analysis indicated that combustion of fossil fuels, natural gas and biomass, and automobile emissions were the main sources of PAHs in these samples from the different regions of Nigeria.

Lagdo Dam Flood Disaster of 2012: An Assessment of the Concentrations, Sources, and Risks of PAHs in Floodplain Soils of the Lower Reaches of River Niger, Nigeria.

The concentrations of the USEPA 16 priority polycyclic aromatic hydrocarbons (PAHs) in soils of the floodplain of the lower reaches of River Niger, Nigeria, were investigated following the Lagdo Dam flood disaster of 2012. The aim was to provide information on the extent of contamination, sources, and risks of PAHs in these soils. The concentrations of Σ16 PAHs in the floodplain soils ranged from 812 to 10,700 μg kg. The benzo(a)pyrene (BaP) toxic equivalence and incremental lifetime cancer risk (ILCR) factors were used to evaluate the risk of human exposure to PAHs in these soils. The concentrations of benzo(a)pyrene carcinogenic equivalence (BaP) and benzo(a)pyrene mutagenic equivalence (BaP) ranged from not detected to 4090 μg kg and not detected to 4150 μg kg, respectively. The total ILCR for children and adults was calculated as the summation of the individual risks through the three routes of exposure, (ingestion, dermal, and inhalation of vapor or dust). The values obtained indicate that there are 6450 and 4480 chances in one million equally exposed persons to develop the risk of cancer for children and adults, respectively, which were higher than the USEPA acceptable guideline value of one cancer case in one million (10) equally exposed persons. The PAHs source evaluation, using the diagnostic ratios and principal component analysis (PCA), indicated that the major sources of PAHs in these soils were fossil fuel combustion, gas flaring, wood combustion, traffic emissions, and input from petroleum.

Concentrations of polycyclic aromatic hydrocarbons in some commercial brands of candies and chocolates in Nigeria

The concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) were investigated in 29 commercial brands of candies and chocolates commonly consumed in Nigeria with a view to providing information on the risks associated with the consumption of these products. The measurements were performed by means of gas chromatography-mass spectrometry after hexane/dichloromethane extraction and clean-up. The concentrations of the Σ16 PAHs in the candies and chocolates were in the range of 1.09-149.46 μg/kg and 0.95-222.62 μg/kg, respectively. The profiles of PAHs in these brands of candies and chocolates indicate dominance of low molecular weight PAHs (3- and 4-ring) over high molecular weight PAHs (5- and 6-ring). In this study, three samples of chocolate had PAH4 (benzo(a)anthracene + benzo(b) fluoranthene + benzo(a)pyrene + chrysene) concentrations above the 35 μg/kg PAH4 limit in cocoa butter stipulated by European Commission Regulation no. 835/2011.