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Papers by Chukwujindu Iwegbue

Environmental Science: Processes & Impacts

This study investigates the concentrations, sources, ecological and human health risks resulting ... more This study investigates the concentrations, sources, ecological and human health risks resulting from human exposure to polycyclic aromatic hydrocarbons (PAHs) in soils of rural communities around gas flare points in...

Turkish Journal of Agriculture: Food Science and Technology, Dec 4, 2013

Concentrations of selected metals (Cu, Cd, Ni, Pb, Mn, Fe, Zn, Cr and Co) in some ready-to-eat-fo... more Concentrations of selected metals (Cu, Cd, Ni, Pb, Mn, Fe, Zn, Cr and Co) in some ready-to-eat-foods consumed in southern Nigeria were investigated with a view to providing information on the risk associated with the consumption of these products. The concentrations of metals (mg kg-1) in these ready-to-eat-foods are in the ranges of 2.4-5.2 for Cu; 0.1-0.8 for Cd; 0.7-4.0 for Ni; 8.1-53.7 for Fe; 8.9-20.0 for Zn; 0.1-3.8 for Pb; 5.1-14.4 for Mn; 0.83-21.4 for Cr and 0.20-1.32 for Co. The concentrations and estimated intakes of Cd, Ni and Pb in some of these food types exceeded the permissible limits and tolerable daily intake respectively. The target hazard quotients (THQ) for the individual metals indicate levels of concern for Ni, Cd, and Co in some of the ready-to-eat-foods. The combined THQ values for the metals in the examined samples ranged from 1.7 to 10 with significant contributions from Cd, Ni and Co.

Applied Water Science

In this study, some physicochemical properties, concentrations of metals (Pb, Cd, Cu, Zn, Fe, and... more In this study, some physicochemical properties, concentrations of metals (Pb, Cd, Cu, Zn, Fe, and Mn), and the overall water quality from Bomadi Creek in the Niger Delta of Nigeria were assessed over two seasons. Water samples were collected from designated areas along the course of the river and were prepared for analysis by standard procedures. The ranges of the mean values for some water quality indicators were found to be as follows: pH: 7.40–8.17, turbidity (NTU): 20.5–42.3, total dissolved solids (mg L−1): 27.5–44.7, total suspended solids (mg L−1): 34.1–61.7, dissolved oxygen (mg L−1): 3.07–6.53, biochemical oxygen demand (mg L−1): 0.13–2.77, total hardness (mg L−1): 28.3–60.0, and nitrate (mg L−1): 0.37–0.92. Only the turbidity values exceeded the permissible limit of 5 NTU. The concentration ranges (mg L−1) for the six metal ions determined were: Pb: 0.01–0.02, Cd: 0.01–0.03, Zn: 0.1–0.3, Cu: 0.03–0.07, Fe: 0.6–0.9, and Mn: 0.01–0.05. There were no significant variations in...

Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences, 2013

Dust samples were collected from 30 sites within Benin city, Nigeria, during the month of Decembe... more Dust samples were collected from 30 sites within Benin city, Nigeria, during the month of December, 2006-March 2007 and analysed for Cu, Cr, Ni, Cd and Pb using atomic absorption spectrophotometry. The samples were divided into 3 categories, including a control. Results showed that the dust samples contained significant levels of the metals studied compared to the control site. The mean values for Cu, Cr, Ni, Cd and Pb were 16.83 mg/kg, 55.40 mg/kg, 5.91 mg/kg, 3.17 mg/kg, and 182 mg/ kg, respectively, for the high traffic density. The mean concentrations of Cu, Cr, Ni, Cd and Pb were 11.98 mg/kg, 52.21 mg/kg, 6.89 mg/kg, 3.92 mg/kg and 167.34 mg/kg, respectively, for the medium traffic areas, while mean concentrations of Cu, Cr, Ni, Cd and Pb in the low traffic areas were 10.46 mg/kg, 58.7 mg/kg, 8.06 mg/kg, 3.49 mg/kg and 142.53 mg/kg, respectively. These values suggest that motor vehicles and electricity generating sets formed the major sources of these metals in the dust samples. The values of metals in the dust samples in these areas were compared with the results of investigations in other countries and these values at various zones of Benin city were found similar, which indicates that Benin city can be considered as one big urban centre with high population and traffic density.

Journal of Applied Sciences and Environmental Management, 2012

Sediment samples were collected from selected gutters and Lagos bar beach for the investigation o... more Sediment samples were collected from selected gutters and Lagos bar beach for the investigation of trace element concentrations. The metals investigated were chromium, lead, arsenic, selenium, cadmium and barium using the atomic absorption spectrophotometry. The results obtained further revealed elevated concentrations metals from both selected gutters and the Lagos bar beach. It was also observed that the Lagos bar beach is the receiving end of all the pollution loads arising from the channeled gutters. These elevated trace element concentrations obtained in sediment in this study were compared with other similar studies. The sediment contaminations by metals were traceable to industries and anthropogenic substances in Lagos metropolis. Keywords: Lagos bar beach, gutter sediments, trace elements, industries and anthropogenic substances J. Appl. Sci. Environ. Manage . Sept., 2012, Vol. 16 (3) 253 - 255

Archives of Environmental Contamination and Toxicology, 2021

This study provides data on the characteristic levels, spatial patterns, sources, and risk of n-a... more This study provides data on the characteristic levels, spatial patterns, sources, and risk of n-alkanes (AHs) [octane, n-C8, to tetracontane, n-C40] and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments from the Escravos River Basin (ERB), Nigeria. The n-alkane and PAH concentrations in sediments were quantified by chromatographic methods. The concentrations of AHs and PAHs in the ERB sediments varied from 95 to 3430 µg g−1 and from 0.75 to 213 µg g−1, respectively. Both the concentrations of AHs and PAHs in ERB sediments exceeded their respective guideline values. The carbon preference index and other AH markers provide evidence that the AHs in the ERB sediments originated from petroleum sources. Ecological risk assessment indicated that the ecological risk relating to an organism’s contact with PAHs in the ERB sediments was high. The possible carcinogenic risk arising from human exposure with PAHs in surface sediments through accidental oral ingestion and skin contact exceeded the safe level of 10–6, indicating a considerable probable cancer risk for fishermen and other inhabitants of the ERB. PAH isomer ratios and multivariate statistics suggested that the PAHs in sediments from the ERB originated from gas flaring inputs, discharges from oil drilling platforms, diesel engines, ships, and speed boats, and combustion of wood and other biomass.

International Journal of Recycling of Organic Waste in Agriculture, 2019

In the original publication of the article, the author’s name Reuben N. Okparanma was misspelled.

International Journal of Recycling of Organic Waste in Agriculture, 2019

Purpose This study sought to investigate the effects of organic amendments on the degradation of ... more Purpose This study sought to investigate the effects of organic amendments on the degradation of hydrocarbons and vegetative properties of Zea mays grown in crude oil-contaminated wetland soils of the Niger Delta, Nigeria. Methods Two soil types were investigated, namely, fadama soil (oxisol) and swamp forest soil (utisol). For each soil type, 48 treatment cells and 1 control containing 1 kg of soil each were spiked with crude oil at concentrations ranging from 50 to 200 g kg−1, representing 5–20% (m/m) contamination levels, respectively. Then, 5 days after the contamination, the soils were amended with cow dung (CD), poultry waste (PW), and palm oil waste (POW). The ratios of soil to organic amendments used were 1:1 and 2:1. The soils were tilled and irrigated regularly, and monitored for a total period of 112 days. The same conditions were used to investigate the vegetative properties of Z. mays in these oil-contaminated soils with organic amendments. Results The total organic car...

Polycyclic Aromatic Compounds, 2019

The present study presents the results for the determination of the concentrations of the 16 USEP... more The present study presents the results for the determination of the concentrations of the 16 USEPA polycyclic aromatic hydrocarbons (PAHs) in 30 samples of different types of vegetable oil (palm, groundnut, palm olein, soybean, cotton and castor seed oils) and shea butter in Nigeria. In addition, information is provided on the compositional patterns and sources of PAHs, as well as possible risks through consumption of contaminated products. Detection and quantification of the PAHs was carried out by means of gas chromatography-mass spectrometry (GC-MS). The PAH concentrations in the samples varied from 126 to 865 mg kg À1. The compositional patterns of the PAHs in the oil samples followed the order: 4R > 3R > 5R > 6R > 2R. The majority of the samples had individual PAH concentrations above the 2 mg kg À1 limit and all the samples surpassed the German Society for Fat Science limit of 25 mg kg À1 for the total PAHs. The estimated dietary intakes based on a 11.1 kg per capita consumption rate ranged from not detected to 133 ng BaP kg À1 bw day À1 , 3.0 to 154 ng PAH2 kg À1 bw day À1 , 11.7 to 178 ng PAH4 kg À1 bw day À1 and 13.2 to 234 ng PAH8 kg À1 bw day À1. The results indicate 5 to 669 chances in a million population of the risk of developing cancer. Source apportionment, as derived from PAH isomeric ratios, suggests that combustion processes, contamination by petroleum from transport trucks, as well as pyrolysis of fats, are the main sources of PAHs in these vegetable oils and shea butter.

Environmental Earth Sciences, 2018

The concentrations of eleven metals (Cd, Pb, Cr, Ni, Cu, Co, Ba, Mn, Zn, Fe and Al) were measured... more The concentrations of eleven metals (Cd, Pb, Cr, Ni, Cu, Co, Ba, Mn, Zn, Fe and Al) were measured in surficial sediments of the Forcados River and its estuary situated in the Niger Delta, Nigeria. The aim of the study was to provide information on the influence of seasonal changes on the distribution patterns and sources of these metals and the ecological risks associated with exposure to metals in the river sediment system. Samples from nine locations were collected monthly for a period of 6 months covering both the wet and dry seasons. The sediment samples were digested with aqua regia, and the metal concentrations in the digests were quantified by means of inductively coupled plasma-atomic emission spectrometry (ICP-AES). The concentration ranges of metals in the sediments were:

Toxicology and Environmental Health Sciences, 2016

The concentrations and compositional patterns of the United States Environmental Protection Agenc... more The concentrations and compositional patterns of the United States Environmental Protection Agency (US EPA) 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined in surface soils of an urban environment in the Niger Delta of Nigeria with a view to providing information on the sources, extent of contamination and human health risks of PAHs in these soils. The analyses were performed by means of gas chromatography-mass spectrometry (GC-MS) after extraction of the soils with hexane/dichloromethane and clean-up of the extracts. The concentration of ∑16 PAHs in the urban soils ranged from 188 to 684 μg kg-1 , while the ∑PAH 7c (carcinogenic PAHs) ranged from 28.5 and 571 μg kg-1. The estimated carcinogenic and mutagenic potency factors for these sites ranged from 2.34 to 197 and 9.66 to 195 μg kg-1 respectively. The composition of PAHs in these soils follows the order: 5-rings>4-rings>3-rings>6-rings>2-rings, and higher molecular weight PAHs accounted for a significant proportion of the ∑16 PAH concentration in this study. The results indicated that there is a high potential risk of cancer development as a result of exposure of PAHs via ingestion, dermal contact and inhalation. The diagnostic ratios indicate that the PAHs in these soils originated mainly from pyrogenic processes, such as combustion of petroleum, fossil fuels and biomass such as woods, charcoal straw and grasses. The results of this study provided information on the concentrations and compositional patterns of PAHs, which is useful in understanding the effects, sources, fate and transport of PAHs in soils, as well as environmental quality management and environmental forensic studies.

Toxicology and Environmental Health Sciences, 2016

The concentrations of the US EPA 16 priority polycyclic aromatic hydrocarbons (PAHs) were measure... more 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.

International Journal of Environmental Studies, 2016

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in nine popular smo... more The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in nine popular smoked fish species, (Clarias gariepinus, Parachana obscura, Heterotis niloticus, Pseudotolithus senegalensis, Gymnarchus niloticus, Ethmalosa fimbriata, Sardinella aurita, Scromber scrombus and Trachurus trachurus), in the Nigerian market by using gas chromatography-mass spectrometry after extraction by ultrasonication with hexane/dichloromethane. The mean concentrations of ∑16 PAHs in these species ranged from 52.4 μg kg−1 to 1230 μg kg−1. The estimated margins of exposure (MOE values) were less than 10,000 for C. gariepinus, G. niloticus and E. fimbriata indicating serious concern for the consumers’ health. The estimated excess cancer risk factors for these fish species investigated indicate that approximately 1 to 65 out of 106 equally exposed adults may suffer from cancer and cancer-related diseases during their lifetime through the ingestion of carcinogenic PAHs from smoked fish in their diet.

Environmental Forensics, 2015

ABSTRACT The spatial and seasonal changes in the distribution, composition, and concentrations of... more ABSTRACT The spatial and seasonal changes in the distribution, composition, and concentrations of aliphatic hydrocarbons were investigated in sediment cores of Ubeji, Ifie, and Egbokodo Creeks in the Niger Delta, Nigeria. A total of 222 sediment core samples were collected during the wet season (August 2010) and the dry season (January 2011). The samples were dried, soxhlet extracted, fractionated and analyzed for aliphatic hydrocarbons by using a gas chromatograph with flame ionization detector (GC-FID). The concentrations of aliphatic hydrocarbons ranged from 37 to 286,894 μg/kg (wet season) and from 30 to 11,773 μg/kg (dry season). The concentrations of n-alkanes for a number of stations in this study are comparable to sites with high anthropogenic activities in the Niger Delta. The carbon preference index (CPI) and the pristane/phytane ratios showed that the major source of hydrocarbon pollution in the sediment core was from petrogenic origin.

International Journal of Biological and Chemical Sciences, 2011

Analytical results are presented for the determination of Cd, Pb, Cu, Cr, Ni, Fe and Zn contents ... more Analytical results are presented for the determination of Cd, Pb, Cu, Cr, Ni, Fe and Zn contents in some species of fresh vegetables and spices (

Folia Malacologica, 2009

Zn; Cr was below the limit of detection. Concentrations of Pb, Fe, Ni, Cu, Co, Cd and Zn in the s... more Zn; Cr was below the limit of detection. Concentrations of Pb, Fe, Ni, Cu, Co, Cd and Zn in the snail tissue varied significantly (95% confidence limit) between the localities. No significant variation was observed in the concentrations of Cr and Mn. Pb and Cd concentration exceeded the statutory safety limits for these elements in meat. The results indicate a heavy metal pollution of the habitats.

Journal of Applied Sciences and Environmental Management, 2011

This paper present the results of nitrogen mineralization in hydromorphic (wetland) soils of the ... more 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. @JASEM

Soil and Sediment Contamination: An International Journal, 2009

This study assessed and modelled the accumulation of heavy metals in the seeds of Zea mays L. (ma... more This study assessed and modelled the accumulation of heavy metals in the seeds of Zea mays L. (maize) planted in a crude oil impacted soil. A total of thirteen soil samples were randomly collected. Five samples each were obtained from plot A (PA)and plot B (PB); the crude oil impacted plots. Three samples were obtained from plot C (PC); the control plot which was about 200 m away from the spill impacted area. All samples were analysed for Total Petroleum Hydrocarbon (TPH) and Heavy Metals [iron (Fe), lead (Pb), zinc (Zn), chromium (Cr) and vanadium (V)]. Maize was planted on each of the thirteen plots and the seeds upon harvest was analysed for heavy metals (Fe, Pb, Zn, Cr and V). The seed accumulation factors for each heavy metal was modelled using TPH as the independent variable. Aside the Zn regression model with R 2 value of 0.399, other models performed well with R 2 values of 0.994, 0.942, 0.974 and 0.964 for Fe, Pb, Cr and V respectively. TPH was able to model the seed parameters with relatively high model performance except for Zinc. This suggests that accumulation of some heavy metals in the seed of the Zea mays L. planted is dependent on TPH. These models can be useful in predicting accumulation of heavy metals in the seeds of Maize planted in a crude oil polluted soil.

International Journal of Environmental Science & Technology, 2006

This communication presents the results of preliminary investigation of the characteristic levels... more This communication presents the results of preliminary investigation of the characteristic levels of heavy metals in surface soils of an oilfield in the Niger Delta. The results indicate higher concentration of the following metals: Cd, Pb, Cu; Ni, Zn, Cr, Mn and Hg in soils around the gas plant than the pipeline areas. There is a significant temporal and spatial variation in the concentrations of the heavy metals. Samples collected during the wet season showed lower concentrations of heavy metals. The distribution pattern of heavy metals follows the following order Fe> Mn> Zn> V> Cr> Pb> Cu> Ni> Cd> Hg> As. The soils around the oilfield could be considered unpolluted since the concentrations of the metals fit into background levels and concentrations found in natural and agricultural soils. Since metal build up is a gradual process, farmland, fishing ponds and water bodies closer to these facilities will be at risk of heavy metal pollution over time.

Vet Arch, 2008

Results are presented for the levels of cadmium, chromium, copper, lead, iron, manganese and nick... more 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 ...

Environmental Science: Processes & Impacts

This study investigates the concentrations, sources, ecological and human health risks resulting ... more This study investigates the concentrations, sources, ecological and human health risks resulting from human exposure to polycyclic aromatic hydrocarbons (PAHs) in soils of rural communities around gas flare points in...

Turkish Journal of Agriculture: Food Science and Technology, Dec 4, 2013

Concentrations of selected metals (Cu, Cd, Ni, Pb, Mn, Fe, Zn, Cr and Co) in some ready-to-eat-fo... more Concentrations of selected metals (Cu, Cd, Ni, Pb, Mn, Fe, Zn, Cr and Co) in some ready-to-eat-foods consumed in southern Nigeria were investigated with a view to providing information on the risk associated with the consumption of these products. The concentrations of metals (mg kg-1) in these ready-to-eat-foods are in the ranges of 2.4-5.2 for Cu; 0.1-0.8 for Cd; 0.7-4.0 for Ni; 8.1-53.7 for Fe; 8.9-20.0 for Zn; 0.1-3.8 for Pb; 5.1-14.4 for Mn; 0.83-21.4 for Cr and 0.20-1.32 for Co. The concentrations and estimated intakes of Cd, Ni and Pb in some of these food types exceeded the permissible limits and tolerable daily intake respectively. The target hazard quotients (THQ) for the individual metals indicate levels of concern for Ni, Cd, and Co in some of the ready-to-eat-foods. The combined THQ values for the metals in the examined samples ranged from 1.7 to 10 with significant contributions from Cd, Ni and Co.

Applied Water Science

In this study, some physicochemical properties, concentrations of metals (Pb, Cd, Cu, Zn, Fe, and... more In this study, some physicochemical properties, concentrations of metals (Pb, Cd, Cu, Zn, Fe, and Mn), and the overall water quality from Bomadi Creek in the Niger Delta of Nigeria were assessed over two seasons. Water samples were collected from designated areas along the course of the river and were prepared for analysis by standard procedures. The ranges of the mean values for some water quality indicators were found to be as follows: pH: 7.40–8.17, turbidity (NTU): 20.5–42.3, total dissolved solids (mg L−1): 27.5–44.7, total suspended solids (mg L−1): 34.1–61.7, dissolved oxygen (mg L−1): 3.07–6.53, biochemical oxygen demand (mg L−1): 0.13–2.77, total hardness (mg L−1): 28.3–60.0, and nitrate (mg L−1): 0.37–0.92. Only the turbidity values exceeded the permissible limit of 5 NTU. The concentration ranges (mg L−1) for the six metal ions determined were: Pb: 0.01–0.02, Cd: 0.01–0.03, Zn: 0.1–0.3, Cu: 0.03–0.07, Fe: 0.6–0.9, and Mn: 0.01–0.05. There were no significant variations in...

Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences, 2013

Dust samples were collected from 30 sites within Benin city, Nigeria, during the month of Decembe... more Dust samples were collected from 30 sites within Benin city, Nigeria, during the month of December, 2006-March 2007 and analysed for Cu, Cr, Ni, Cd and Pb using atomic absorption spectrophotometry. The samples were divided into 3 categories, including a control. Results showed that the dust samples contained significant levels of the metals studied compared to the control site. The mean values for Cu, Cr, Ni, Cd and Pb were 16.83 mg/kg, 55.40 mg/kg, 5.91 mg/kg, 3.17 mg/kg, and 182 mg/ kg, respectively, for the high traffic density. The mean concentrations of Cu, Cr, Ni, Cd and Pb were 11.98 mg/kg, 52.21 mg/kg, 6.89 mg/kg, 3.92 mg/kg and 167.34 mg/kg, respectively, for the medium traffic areas, while mean concentrations of Cu, Cr, Ni, Cd and Pb in the low traffic areas were 10.46 mg/kg, 58.7 mg/kg, 8.06 mg/kg, 3.49 mg/kg and 142.53 mg/kg, respectively. These values suggest that motor vehicles and electricity generating sets formed the major sources of these metals in the dust samples. The values of metals in the dust samples in these areas were compared with the results of investigations in other countries and these values at various zones of Benin city were found similar, which indicates that Benin city can be considered as one big urban centre with high population and traffic density.

Journal of Applied Sciences and Environmental Management, 2012

Sediment samples were collected from selected gutters and Lagos bar beach for the investigation o... more Sediment samples were collected from selected gutters and Lagos bar beach for the investigation of trace element concentrations. The metals investigated were chromium, lead, arsenic, selenium, cadmium and barium using the atomic absorption spectrophotometry. The results obtained further revealed elevated concentrations metals from both selected gutters and the Lagos bar beach. It was also observed that the Lagos bar beach is the receiving end of all the pollution loads arising from the channeled gutters. These elevated trace element concentrations obtained in sediment in this study were compared with other similar studies. The sediment contaminations by metals were traceable to industries and anthropogenic substances in Lagos metropolis. Keywords: Lagos bar beach, gutter sediments, trace elements, industries and anthropogenic substances J. Appl. Sci. Environ. Manage . Sept., 2012, Vol. 16 (3) 253 - 255

Archives of Environmental Contamination and Toxicology, 2021

This study provides data on the characteristic levels, spatial patterns, sources, and risk of n-a... more This study provides data on the characteristic levels, spatial patterns, sources, and risk of n-alkanes (AHs) [octane, n-C8, to tetracontane, n-C40] and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments from the Escravos River Basin (ERB), Nigeria. The n-alkane and PAH concentrations in sediments were quantified by chromatographic methods. The concentrations of AHs and PAHs in the ERB sediments varied from 95 to 3430 µg g−1 and from 0.75 to 213 µg g−1, respectively. Both the concentrations of AHs and PAHs in ERB sediments exceeded their respective guideline values. The carbon preference index and other AH markers provide evidence that the AHs in the ERB sediments originated from petroleum sources. Ecological risk assessment indicated that the ecological risk relating to an organism’s contact with PAHs in the ERB sediments was high. The possible carcinogenic risk arising from human exposure with PAHs in surface sediments through accidental oral ingestion and skin contact exceeded the safe level of 10–6, indicating a considerable probable cancer risk for fishermen and other inhabitants of the ERB. PAH isomer ratios and multivariate statistics suggested that the PAHs in sediments from the ERB originated from gas flaring inputs, discharges from oil drilling platforms, diesel engines, ships, and speed boats, and combustion of wood and other biomass.

International Journal of Recycling of Organic Waste in Agriculture, 2019

In the original publication of the article, the author’s name Reuben N. Okparanma was misspelled.

International Journal of Recycling of Organic Waste in Agriculture, 2019

Purpose This study sought to investigate the effects of organic amendments on the degradation of ... more Purpose This study sought to investigate the effects of organic amendments on the degradation of hydrocarbons and vegetative properties of Zea mays grown in crude oil-contaminated wetland soils of the Niger Delta, Nigeria. Methods Two soil types were investigated, namely, fadama soil (oxisol) and swamp forest soil (utisol). For each soil type, 48 treatment cells and 1 control containing 1 kg of soil each were spiked with crude oil at concentrations ranging from 50 to 200 g kg−1, representing 5–20% (m/m) contamination levels, respectively. Then, 5 days after the contamination, the soils were amended with cow dung (CD), poultry waste (PW), and palm oil waste (POW). The ratios of soil to organic amendments used were 1:1 and 2:1. The soils were tilled and irrigated regularly, and monitored for a total period of 112 days. The same conditions were used to investigate the vegetative properties of Z. mays in these oil-contaminated soils with organic amendments. Results The total organic car...

Polycyclic Aromatic Compounds, 2019

The present study presents the results for the determination of the concentrations of the 16 USEP... more The present study presents the results for the determination of the concentrations of the 16 USEPA polycyclic aromatic hydrocarbons (PAHs) in 30 samples of different types of vegetable oil (palm, groundnut, palm olein, soybean, cotton and castor seed oils) and shea butter in Nigeria. In addition, information is provided on the compositional patterns and sources of PAHs, as well as possible risks through consumption of contaminated products. Detection and quantification of the PAHs was carried out by means of gas chromatography-mass spectrometry (GC-MS). The PAH concentrations in the samples varied from 126 to 865 mg kg À1. The compositional patterns of the PAHs in the oil samples followed the order: 4R > 3R > 5R > 6R > 2R. The majority of the samples had individual PAH concentrations above the 2 mg kg À1 limit and all the samples surpassed the German Society for Fat Science limit of 25 mg kg À1 for the total PAHs. The estimated dietary intakes based on a 11.1 kg per capita consumption rate ranged from not detected to 133 ng BaP kg À1 bw day À1 , 3.0 to 154 ng PAH2 kg À1 bw day À1 , 11.7 to 178 ng PAH4 kg À1 bw day À1 and 13.2 to 234 ng PAH8 kg À1 bw day À1. The results indicate 5 to 669 chances in a million population of the risk of developing cancer. Source apportionment, as derived from PAH isomeric ratios, suggests that combustion processes, contamination by petroleum from transport trucks, as well as pyrolysis of fats, are the main sources of PAHs in these vegetable oils and shea butter.

Environmental Earth Sciences, 2018

The concentrations of eleven metals (Cd, Pb, Cr, Ni, Cu, Co, Ba, Mn, Zn, Fe and Al) were measured... more The concentrations of eleven metals (Cd, Pb, Cr, Ni, Cu, Co, Ba, Mn, Zn, Fe and Al) were measured in surficial sediments of the Forcados River and its estuary situated in the Niger Delta, Nigeria. The aim of the study was to provide information on the influence of seasonal changes on the distribution patterns and sources of these metals and the ecological risks associated with exposure to metals in the river sediment system. Samples from nine locations were collected monthly for a period of 6 months covering both the wet and dry seasons. The sediment samples were digested with aqua regia, and the metal concentrations in the digests were quantified by means of inductively coupled plasma-atomic emission spectrometry (ICP-AES). The concentration ranges of metals in the sediments were:

Toxicology and Environmental Health Sciences, 2016

The concentrations and compositional patterns of the United States Environmental Protection Agenc... more The concentrations and compositional patterns of the United States Environmental Protection Agency (US EPA) 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined in surface soils of an urban environment in the Niger Delta of Nigeria with a view to providing information on the sources, extent of contamination and human health risks of PAHs in these soils. The analyses were performed by means of gas chromatography-mass spectrometry (GC-MS) after extraction of the soils with hexane/dichloromethane and clean-up of the extracts. The concentration of ∑16 PAHs in the urban soils ranged from 188 to 684 μg kg-1 , while the ∑PAH 7c (carcinogenic PAHs) ranged from 28.5 and 571 μg kg-1. The estimated carcinogenic and mutagenic potency factors for these sites ranged from 2.34 to 197 and 9.66 to 195 μg kg-1 respectively. The composition of PAHs in these soils follows the order: 5-rings>4-rings>3-rings>6-rings>2-rings, and higher molecular weight PAHs accounted for a significant proportion of the ∑16 PAH concentration in this study. The results indicated that there is a high potential risk of cancer development as a result of exposure of PAHs via ingestion, dermal contact and inhalation. The diagnostic ratios indicate that the PAHs in these soils originated mainly from pyrogenic processes, such as combustion of petroleum, fossil fuels and biomass such as woods, charcoal straw and grasses. The results of this study provided information on the concentrations and compositional patterns of PAHs, which is useful in understanding the effects, sources, fate and transport of PAHs in soils, as well as environmental quality management and environmental forensic studies.

Toxicology and Environmental Health Sciences, 2016

The concentrations of the US EPA 16 priority polycyclic aromatic hydrocarbons (PAHs) were measure... more 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.

International Journal of Environmental Studies, 2016

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in nine popular smo... more The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in nine popular smoked fish species, (Clarias gariepinus, Parachana obscura, Heterotis niloticus, Pseudotolithus senegalensis, Gymnarchus niloticus, Ethmalosa fimbriata, Sardinella aurita, Scromber scrombus and Trachurus trachurus), in the Nigerian market by using gas chromatography-mass spectrometry after extraction by ultrasonication with hexane/dichloromethane. The mean concentrations of ∑16 PAHs in these species ranged from 52.4 μg kg−1 to 1230 μg kg−1. The estimated margins of exposure (MOE values) were less than 10,000 for C. gariepinus, G. niloticus and E. fimbriata indicating serious concern for the consumers’ health. The estimated excess cancer risk factors for these fish species investigated indicate that approximately 1 to 65 out of 106 equally exposed adults may suffer from cancer and cancer-related diseases during their lifetime through the ingestion of carcinogenic PAHs from smoked fish in their diet.

Environmental Forensics, 2015

ABSTRACT The spatial and seasonal changes in the distribution, composition, and concentrations of... more ABSTRACT The spatial and seasonal changes in the distribution, composition, and concentrations of aliphatic hydrocarbons were investigated in sediment cores of Ubeji, Ifie, and Egbokodo Creeks in the Niger Delta, Nigeria. A total of 222 sediment core samples were collected during the wet season (August 2010) and the dry season (January 2011). The samples were dried, soxhlet extracted, fractionated and analyzed for aliphatic hydrocarbons by using a gas chromatograph with flame ionization detector (GC-FID). The concentrations of aliphatic hydrocarbons ranged from 37 to 286,894 μg/kg (wet season) and from 30 to 11,773 μg/kg (dry season). The concentrations of n-alkanes for a number of stations in this study are comparable to sites with high anthropogenic activities in the Niger Delta. The carbon preference index (CPI) and the pristane/phytane ratios showed that the major source of hydrocarbon pollution in the sediment core was from petrogenic origin.

International Journal of Biological and Chemical Sciences, 2011

Analytical results are presented for the determination of Cd, Pb, Cu, Cr, Ni, Fe and Zn contents ... more Analytical results are presented for the determination of Cd, Pb, Cu, Cr, Ni, Fe and Zn contents in some species of fresh vegetables and spices (

Folia Malacologica, 2009

Zn; Cr was below the limit of detection. Concentrations of Pb, Fe, Ni, Cu, Co, Cd and Zn in the s... more Zn; Cr was below the limit of detection. Concentrations of Pb, Fe, Ni, Cu, Co, Cd and Zn in the snail tissue varied significantly (95% confidence limit) between the localities. No significant variation was observed in the concentrations of Cr and Mn. Pb and Cd concentration exceeded the statutory safety limits for these elements in meat. The results indicate a heavy metal pollution of the habitats.

Journal of Applied Sciences and Environmental Management, 2011

This paper present the results of nitrogen mineralization in hydromorphic (wetland) soils of the ... more 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. @JASEM

Soil and Sediment Contamination: An International Journal, 2009

This study assessed and modelled the accumulation of heavy metals in the seeds of Zea mays L. (ma... more This study assessed and modelled the accumulation of heavy metals in the seeds of Zea mays L. (maize) planted in a crude oil impacted soil. A total of thirteen soil samples were randomly collected. Five samples each were obtained from plot A (PA)and plot B (PB); the crude oil impacted plots. Three samples were obtained from plot C (PC); the control plot which was about 200 m away from the spill impacted area. All samples were analysed for Total Petroleum Hydrocarbon (TPH) and Heavy Metals [iron (Fe), lead (Pb), zinc (Zn), chromium (Cr) and vanadium (V)]. Maize was planted on each of the thirteen plots and the seeds upon harvest was analysed for heavy metals (Fe, Pb, Zn, Cr and V). The seed accumulation factors for each heavy metal was modelled using TPH as the independent variable. Aside the Zn regression model with R 2 value of 0.399, other models performed well with R 2 values of 0.994, 0.942, 0.974 and 0.964 for Fe, Pb, Cr and V respectively. TPH was able to model the seed parameters with relatively high model performance except for Zinc. This suggests that accumulation of some heavy metals in the seed of the Zea mays L. planted is dependent on TPH. These models can be useful in predicting accumulation of heavy metals in the seeds of Maize planted in a crude oil polluted soil.

International Journal of Environmental Science & Technology, 2006

This communication presents the results of preliminary investigation of the characteristic levels... more This communication presents the results of preliminary investigation of the characteristic levels of heavy metals in surface soils of an oilfield in the Niger Delta. The results indicate higher concentration of the following metals: Cd, Pb, Cu; Ni, Zn, Cr, Mn and Hg in soils around the gas plant than the pipeline areas. There is a significant temporal and spatial variation in the concentrations of the heavy metals. Samples collected during the wet season showed lower concentrations of heavy metals. The distribution pattern of heavy metals follows the following order Fe> Mn> Zn> V> Cr> Pb> Cu> Ni> Cd> Hg> As. The soils around the oilfield could be considered unpolluted since the concentrations of the metals fit into background levels and concentrations found in natural and agricultural soils. Since metal build up is a gradual process, farmland, fishing ponds and water bodies closer to these facilities will be at risk of heavy metal pollution over time.

Vet Arch, 2008

Results are presented for the levels of cadmium, chromium, copper, lead, iron, manganese and nick... more 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 ...