F. M. Adebiyi

Organic, Chemical and Elemental Characterization of Components of Nigerian Bituminous Sands Bitumen

Abstract Nigerian bitumen components (asphaltene, oil, and resins) were analyzed for functional groups of compound types present in them using infrared specrophotometry technique. These components were also subjected to trace metal analysis using the Buck Model 200 A atomic absorption spectrophotometer. Infrared peaks of alkenes, aldehydes, anhydrides, aromatics, and amides were shown in the bitumen components indicating that they were mixtures of paraffinic, aldehydric, anhydic, naphthenic, and heteroatomic containing compounds. Concentration of 8 metals (Zn, Cu, Ni, Pb, Co, V, Mn, and Fe) in the samples were studied to know the extent of possible catalytic poisoning and environmental degradation capacity, and more so the components in which these metals were more concentrated. The AAS result showed high concentration of Zn, Ni, V, and Fe in some components while other metals were not detected in the amount that were present in the bitumen components.

Characterization of Nigerian Oil Sands by TXRF Spectrometry

Abstract Total reflection X-ray fluorescence (TXRF) analytical technique was used to determine the elemental composition of Southwestern Nigeria oil sands. Twelve elements: K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, and Pb were detected and their concentrations, enrichment factors, and correlation determined. Very high enrichment factors were obtained for Cu, Zn, and As. The high enrichment factors for these metals showed that the concentrations of the metals were high enough to pose environmental degradation. Some metals detected (e.g., As, Zn, Ni, V) could act as catalytic poison, corroding the refining column during refining of oil sands and corroding the pipelines during transportation. The correlation matrix result showed that some of the trace metals detected have common sources or similar chemical properties. The accuracy and precision of the TXRF technique were assured by analyzing certified standard reference materials IAEA-Soil-7 (powder).

Air quality index pattern around petroleum production facilities

Purpose – The aim of this paper is to better understand the impact of petroleum production facilities on ambient air quality of host airshed.Design/methodology/approach – Field measurements were taken daily for four consecutive months around petroleum production facilities in the Niger Delta area, of Nigeria, one of the worlds important petroleum producing areas. Statistical analysis tool and air quality analytical tool known as the air quality index (AQI) were applied on the field data obtained.Findings – The mean measured daily concentrations of both carbon monoxide (CO) and nitrogen dioxide (NO2) between distances 50 and 500 m of petroleum flow stations were of the range 140 – 3400 μg/m3 and 23 – 1250 μg/m3 respectively. The AQI from measured CO concentrations in the study area ranged between 1 and 44, an indication of good AQI category with no known health effects but a need for cautionary statement. Similarly, over 97 percent of the measured concentrations of NO2 were below 0.60 ppm which implies th...

Air-borne SO2 Pollution Monitoring in the Upstream Petroleum Operation Areas of Niger-Delta, Nigeria

Abstract In the process of crude oil production, sulfur dioxide (SO2) gas is produced as a result of flaring and booming of crude oil associated gases. This paper presents the study carried out on the monitoring of SO2 emission from some oilfields in the crude oil producing areas of Niger-Delta region of Nigeria. Six locations were studied while monitoring involved morning and evening times for four months using a Testo 350 Flue Gas Analyzer. Comparison of the mean measurements with Nigerian FEPA tolerance limits indicate that SO2 values from 60 m away from the point sources for all the fields were comparatively higher than their maximum tolerance limits of 50 μg/m3 for long term exposure and SO2 values were also comparatively higher than the emission limit range (30–300 μg/m3) for SO2 from stationary sources. It is concluded that this breach of tolerance level may result in acid rain formation, which can be detrimental to the environment while the long-term effect can alter the ecology of the areas. It is recommended that the environmental matrix quality for soil, water, and air be carried out for these areas periodically.

Spectroscopic Characterization of Asphaltene Fraction of Nigerian Bitumen

This research article offers data on the spectroscopic elucidation of the asphaltene fraction of Nigerian bitumen in order to establish its features that might aid the developmental processes of the fossil fuel. Bitumen was extracted from the oil sands obtained from six locations where there were oil sand out-crops in Southwestern Nigeria using toluene via Soxhlet extraction and then deasphalted using n-pentane. The organic components of the precipitated asphaltenes were investigated using Fourier transform infrared spectrometry, while the elemental contents were determined using Inductively coupled plasma atomic emission spectroscopy and carbon/nitrogen analyzer. The results revealed that the average content (29.15 wt%) of Nigerian bitumen asphaltenes was less than that of Athabasca (40.10 wt%) but slightly higher than that of Cold Lake bitumen (24.40 wt%). The IR spectra of the asphaltenes indicated the presence of various organics and heteroatoms corroborating that asphaltenes composed of high molecular weight polycyclic constituents comprising of nitrogen, sulfur, and oxygen heteroatoms. The results indicated that the values of Cr, Cu, Fe, Mn, Ni, S, V, and Zn were comparatively higher in the asphaltenes than the parent bitumen due to the presence of comparatively high levels of porphyrins in the asphaltenes than the bitumen, while the concentrations of all the elements were higher in the Nigerian bitumen asphaltene than Nigerian crude oil asphaltene (except S and C). Cross plot analysis result between the asphaltenes and bitumen using their elemental mean concentrations as variables indicates that significant and positive correlation (R2 = 0.975) exists between them, indicating very strong interelement and geochemical relationships between them. The elements showed close clustering, indicating similar sources because the elements were known to associate with petroleum hydrocarbon formation. Also, apart from N, S, and C, other elements are transition metals with similar chemical affinity.

Contribution of Volatile Organic Compounds to Nigeria's Airshed by Petroleum Refineries

Abstract The emission factor approach was employed to predict the emission potential of volatile organic compounds (VOCs) from both operating and proposed petroleum refineries in Nigeria. The emission sources from the refineries (4 operating and 14 newly licensed) were classified as point and area with anticipated VOC release into the environment estimated. The overall contribution was also estimated using human population and land mass distribution. The no-control-measure option gave estimated VOCs from the existing 4 petroleum refineries located in the states of Delta, Kaduna, and Rivers as 147,212 ton/annum (if operated at full capacity), while the successful construction and commissioning of the approved 14 refineries located in the states of Akwa Ibom, Anambra, Cross River, Delta, Lagos, Ogun, Ondo, and Rivers can raise this by about 240%. Rivers State with the highest number of refineries has the highest emission distribution per head while Lagos State has the least; the southern part of the country was noted to be at great risk of VOC emission from petroleum refineries. Both technology and policy options are suggested to control the potential emissions.

Assessment of element accumulation from bitumen deposit by vegetation using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy technique

Vegetation samples from the bitumen deposit area of Southwestern Nigeria were analysed for element contents to assess their level of accumulation from a bitumen deposit area and to provide a framework for the establishment of relationships between the chemistry of the mineral deposit and the vegetation. The element concentrations of the samples were determined using the EDXRF spectrometry technique. Thirteen elements – K, Ca, Cr, Ti, V, Mn, Ni, Cu, Zn, Ga, Rb, Sr and Fe were detected. The results of the calculated concentration ratio (CR) showed that the vegetation samples have high uptake ability (CR > 0.9) from the soil for most of the elements determined. Strong and significant positive correlations exist between some elements, indicating a common source, chemical similarity and/or common natural background levels in the samples. Positive correlations were shown by the results of the cross-plot analysis of the vegetation/soil and vegetation/bitumen, suggesting inter-element correlations between components of the ecosystem and that ecosystem vegetation accumulated the elements via the soil as a result of contamination with the bitumen and also establishing relationships between the aforementioned components of the ecosystem and the bitumen deposit in the area.

A Measurement of Selected Polycyclic Aromatic Hydrocarbons in Petroleum Product Contaminated Soils Using a Gas Chromatograph

Oil contaminated soils around refined petroleum products depot and retailing stations were investigated for selected polycyclic aromatic hydrocarbons (PAHs) to determine their levels in the soils. Soil samples were collected using standard analytical procedures and the petroleum hydrocarbons extracted using standard method, while the PAHs (benzo[a]pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, and anthracene) contents of the extracted petroleum hydrocarbons were determined using SNR 8126 gas chromatograph equipped with a flame ionization detector (FID). The results indicated that benz[a]anthracene has the highest concentrations in both the oil depot contaminated soils (59.1 ± 3.3 mg/kg) and oil retailing station contaminated soils (20.8 ± 2.1 mg/kg). The results also showed that the oil depot contaminated soils were burdened with the analyzed PAHs than oil retailing station contaminated soils; this was confirmed by the results of t test analysis. Comparison of the values of the PAHs in the oil impacted soils with their background levels showed that their values in the two sets of oil impacted soils were excessive; this was corroborated with their high pollution (PI) and geoaccumulation (Igeo) index values, except chrysene, which moderately polluted the soils (low PI and Igeo values); this was clear indication of indiscriminate discharge of petroleum fuels and petrochemicals into the soils.

Chemical analysis of tobacco cigarette for organochlorine insecticides and heavy metal composition

The effects of cigarette smoking on smokers and the environment were investigated by analyzing some cigarette brands available to Nigerian smokers for the presence of some of the widely used organochlorine (OC) pesticides and heavy metals. OC pesticide residues were extracted from tobacco smoke, separated and identified using column chromatographic and thin layer chromatographic techniques respectively, while ashed and unashed commercial cigarettes were analyzed for heavy metals – Cr, Mn, Ni, Pb, Zn, Cd, Cu, and Co using atomic absorption spectrometry. TLC data indicated that dieldrin and p,p′-DDD were present in some of the cigarette brands. The results of heavy metal analysis showed that the levels of some toxic heavy metals and pollution index were higher in unashed cigarettes than corresponding ashes. Evidence suggests that significant amounts of these toxic metals are inhaled by the smoker and/or released into the environment in the process of cigarette smoking, thus confirming that cigarette smoking is harmful to the environment and human health.

The Impact of Bitumen Deposits on Groundwater Quality

Physico-chemical and elemental characteristics of groundwaters from a bitumen deposit area in Nigeria were determined with a view to assessing their levels of accumulation by the waters from the bitumen deposit and to provide a framework for the establishment of relationships between the chemistry of the mineral deposit and the groundwaters of the area. Physico-chemical parameters were measured using standard analytical procedures, while the elemental contents were determined by total reflection x-ray fluorescence spectroscopy technique. The results showed that the groundwaters have higher concentrations of elements (V, Cr, Mn, Cu, and Zn), which are known to be associated with hydrocarbon formation, than regular Nigerian groundwaters, apparently due to leaching of the elements from the bitumen deposit into the waters. Comparison of the analyzed parameters with their standard permissible values indicated that the waters were not potable. This was also corroborated by the values of their pollution index. Strong and significant positive correlations existed between some of the analyzed elements (K/Fe, K/Cu, Ca/Cr, V/Pb, Ni/Zn, Ni/Pb, Ca/Zn, V/Cr, V/Mn, V/Ni, V/Zn, Cr/Mn, Mn/Ni, and Ni/Cu), indicating a common source, chemical similarity, and/or common natural background levels in the waters. Elemental clustering results indicated that analyzed transition metals showed the closest inter-element clustering and were corroborated with their Pearson correlation matrices results, indicating chemical affinity and/or similar genetic origin. Strong positive correlations were shown by the results of the cross-plot analysis of the groundwater/oil sand water fraction and groundwater/bitumen suggesting inter-element correlations between them, and also establishing relationships between the groundwaters and the bitumen deposit in the area and that contamination of any components of the ecosystem would easily affect other ecosystems. These results could be used as a fingerprint for bitumen exploration elsewhere and also for similar mineral deposit settings, such as crude oil and coal deposits.