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Year : 2018  |  Volume : 21  |  Issue : 3  |  Page : 276-279

Are roadside petrol dispensers at risk of oxidative stress? a study from gombe, North East Nigeria

1 Department of Chemical Pathology, Gombe State University, Gombe, Nigeria
2 Department of Chemical Pathology, University College Hospital, Ibadan, Nigeria
3 Department of Chemical Pathology, Ahmadu Bello University, Zaria, Nigeria
4 Department of Community Medicine, College of Medical Sciences, Gombe State University, Gombe, Nigeria

Date of Acceptance12-Jan-2018
Date of Web Publication09-Mar-2018

Correspondence Address:
Dr. S Adamu
Department of Chemical Pathology, Gombe State University, Gombe
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/njcp.njcp_186_17

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Background: Gasoline is one of the most frequently utilized chemicals whose use is on the increase. Exposure to the volatile constituents of gasoline generates free radicals leading to oxidative stress. This is associated with nucleic acid, lipids, and protein damages leading to chronic diseases including cancers. Occupational exposure to this product is of public health concern, especially in the developing countries where the awareness and enforcement of safety measures are not adequate. Materials and Methods: Plasma level of total antioxidant status (TAS) was compared between 90 roadside dispensers of gasoline and 90 age- and sex-matched controls. TAS was measured using standard colorimetric method. Results: The mean age of the exposed and control groups is 29.03 ± 3.7 and 29.24 ± 3.5 years, respectively. The mean plasma TAS level of the exposed (0.60 ± 0.33 mmol/L) was significantly (P < 0.001) lower than that of the controls (1.29 ± 0.25 mmol/L). Conclusion: Our data have demonstrated higher level of oxidative stress in roadside dispensers of gasoline compared to the controls. This is an indication that roadside gasoline dispensers are probably at greater risk of developing chronic diseases associated with increased oxidative stress. Antioxidant supplementation may be of benefit to the roadside gasoline dispensers. Legislation on roadside gasoline dispensing should be enforced to reduce the incidence of long-term complications from repeated exposures.

Keywords: Chemical exposure, gasoline, Gombe, occupational exposure, oxidative stress

How to cite this article:
Adamu S, Akinosun O M, Abbiyesuku F M, O Kuti M A, El-Bashir JM, Abubakar J D. Are roadside petrol dispensers at risk of oxidative stress? a study from gombe, North East Nigeria. Niger J Clin Pract 2018;21:276-9

How to cite this URL:
Adamu S, Akinosun O M, Abbiyesuku F M, O Kuti M A, El-Bashir JM, Abubakar J D. Are roadside petrol dispensers at risk of oxidative stress? a study from gombe, North East Nigeria. Niger J Clin Pract [serial online] 2018 [cited 2022 Nov 29];21:276-9. Available from:

   Introduction Top

Gasoline is a petrochemical that is commonly used for fueling automobiles and some power generating machines. It is very volatile, with many organic and inorganic constituents. Activation of some volatile constituents of gasoline leads to continuous production of reactive oxygen species (ROS) and consumption of antioxidants.[1] The imbalance between the rate of production and manifestation of ROS and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage is known as oxidative stress.[2],[3] The ROS produced may lead to injury and diseases by causing damage to DNA, RNA, and proteins by chemical reactions such as oxidation, nitration, and halogenations leading to genetic modification and alterations in the functions of important lipids, enzymes, and other proteins.[1] Chronic exposure to gasoline has been found to be associated with oxidative stress and many diseases, especially cancers.[4]

Occupational exposure to toxic chemicals is a major public health concern worldwide. Gasoline is one of the most frequently utilized chemicals, and the frequency is increasing due to rapid development in technology.[5] Researchers have found a great deal of hematological alteration, increased risk of malignancies, and other chronic diseases among humans and rats exposed to gasoline vapors.[1],[6] The risk is greatest in the developing countries, including Nigeria, where there are limited facilities to reduce overexposure and the toxic effects of the chemicals. Knowledge on the safe handling and transportation of chemicals is also very limited.

Roadside dispensers of gasoline, which are common sights in Nigeria, most especially in the Northern parts, often use their mouths to create a vacuum pressure to dispense the product through pipes from one container to another. This may lead to high levels of exposure to gasoline vapors leading to oxidative stress.[7] In Nigeria, there is a paucity of literature on the antioxidant/oxidative stress in roadside dispensers of gasoline.

Therefore, the aim of the study is to assess the levels of the oxidative stress among roadside dispensers of gasoline. This will help in generating data to be used in the prevention and timely intervention of chronic gasoline toxicity, especially in roadside dispensers of gasoline.

   Materials and Methods Top


This study was conducted in Gombe State in Northeast Nigeria. The individuals in the study are roadside petrol dispensers and controls. The chemical analysis was conducted in the Department of Chemical Pathology, University College Hospital, Ibadan. The hospital is the premier teaching hospital in Nigeria and serves as a major referral center in Nigeria.


This is a cohort study approved by both the Gombe State Ethical Committee domiciled at the Federal Teaching Hospital, Gombe and the joint Ethical Review Committee of the University of Ibadan/University College Hospital, Ibadan, recruiting ninety otherwise healthy known roadside dispensers of gasoline in Gombe state using multistage sampling method.

Inclusion criteria

Only apparently healthy, full-time roadside dispensers of gasoline that are 1 year and above in the trade were included in the study.

Exclusion criteria

People who have other conditions that can cause oxidative stress were excluded. These include those working in painting, welding, battery, and automechanic industries,[8] and petrol station attendants were also excluded from the study. Patients who have other acute or chronic illness such as diabetes, chronic renal failure, and hypertension were excluded from the study. Cigarette smokers and patients taking multivitamins supplements and antiretroviral treatment were also excluded from the study.[4],[9]

Selection of controls

Age- and sex-matched controls were selected from the general population in the same environment using nonprobability convenient method.

Anthropometric measurements

Height: This was measured to the nearest centimeter against a flat, vertical surface with the individuals standing upright. A sliding headpiece was brought to the vertex of the individual's head, and the reading at this level was taken.

Weight: This was taken with salter bathroom scale placed on a flat surface. The reading was recorded to the nearest 0.5 kg. Body mass index (BMI) was then calculated using the formula

Their waist and hip circumferences were measured to the nearest 0.5 cm. Waist-to-hip ratio was then calculated by dividing waist circumference by the hip circumference. Blood pressure was measured using standard procedures.

Sample collection and laboratory procedures

Random plasma glucose was done using a glucometer to screen (exclude) participants with hyperglycemia. The questionnaires were administered to participants who were asked to fast for sample collection the next morning.

5 ml of fasting venous blood was collected from each of the 180 participants into a heparinized plastic tube. Plasma was separated by centrifugation and frozen within an hour of collection till the time of analysis.

Total antioxidant status estimation

Total antioxidant status (TAS) was estimated in this study using prepared reagents. The method was as described by Koracevic et al., 2001.[8]

Statistical analysis

The data were analyzed on a microcomputer using SPSS version 20.00 for windows (IBM statistics, USA). The mean (X) and standard deviation for height (HT), weight (WT), BMI, waist circumference, hip circumference, waist-to-hip ratio, and TAS of the gasoline exposed and the nonexposed were computed for comparison.

Student t-test was used to determine significant difference between means of the two groups. Pearson correlation coefficient was used to establish correlation between TAS and the duration of exposure to gasoline. The level of significance was fixed at the 5% probability level.

   Results Top

Descriptive statistics

There were 90 (50%) cases (roadside gasoline dispensers) and 90 (50%) controls among the respondents. Among the controls, 11 were teachers, 9 (10%) were farmers, 17 (18.9%) were students, and 20 (22.2%) were other occupations [Table 1]. About 103 (57,2%) of the respondents were Fulani by tribe while 46 (25.6%) were Hausas. Bolewa, Tera, and others make the remaining 30 (16.7%) [Table 2].
Table 1: Occupational distribution of the control group

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Table 2: Distribution by tribe of the participants

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The mean age, BMI, systolic blood pressure, and diastolic blood pressure are 29.1 ± 3.6 years, 23.26 ± 3.14Kg/M2, 130 ± 13.6 mmHg, and 77 ± 5.62 mmHg, respectively [Table 3]. The mean number of year spent by the cases hawking gasoline is 6.4 ± 2.4 years and the average number of hours per day spent on the petrol trade is 7.99 ± 0.71 h.
Table 3: Mean and standard deviation of some variables

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All continuous variables were normally distributed and parametric analysis was used. There was no significant mean difference in terms of age and other anthropometric characteristics between the exposed and nonexposed. This is to remove their confounding effects on the outcome of the study.

Total antioxidants status

The mean plasma TAS was significantly lower in the exposed group (0.60 ± 0.33 mmol/L) than the nonexposed (1.29 ± 0.25) (P< 0.01). There was statistically significant but weak correlation (r = 0.14) between the duration of exposure and TAS (P< 0.05).

   Discussion Top

The objective of this study was to evaluate the risk of oxidative stress in roadside dispensers of gasoline. Gasoline contains some volatile constituents, which, when inhaled, will lead to continuous production of ROS and consumption of antioxidants. Since oxidative stress is an imbalance between the rate of production of ROS and their removal by antioxidants, oxidative stress can be assessed by either assessing the increase in production of ROS and its oxidizing effects on proteins, lipids, and nucleic acids or by decreased levels of antioxidants.[1],[4],[9],[10] This study therefore compared the plasma levels of TAS between the gasoline exposed population and nonexposed and also determined the effect of the exposure period on the TAS.

Remarkably, there is significantly lower level of antioxidants among the roadside gasoline dispensers compared to the control group. This indicates higher level of oxidative stress among the gasoline exposed than the controls.

Measurement of TAS has been shown to be a better marker of oxidative stress than the individual antioxidants[11],[12] because it combines the synergistic effects of all the antioxidants in the system in addition to reduction of cost, time, and errors involved in measuring the individual oxidants and antioxidants. In this study, we found significantly lower levels (<50%) of TAS among the roadside dispensers of gasoline compared to the control population suggesting very high level of oxidative stress among them. This finding of higher oxidative stress among those roadside gasoline dispensers supports earlier reports of oxidative stress among people exposed to gasoline,[13],[14] although most of them measured the antioxidant enzymes, antioxidant vitamins, and trace metals rather than the TAS. Another thing worthy of note is that many studies[15],[16],[17],[18] showed <40% reduction in TAS in their cases compared to >50% reduction among the exposed group in this study. There is also an average of 0.3 mmol/L lower values of TAS in both exposed and nonexposed reported in this study compared to those reported in studies in other parts of Nigeria.[15],[16],[18] This disparity could be due to age, nutritional, and environmental differences between their participants and the participants in this study. More so, most of the studies were carried out in a more elderly group in the South while this study was carried out in a relatively younger population in the North.

   Conclusion Top

This study has demonstrated higher level of oxidative stress in roadside dispensers of gasoline compared to the controls. This is an indication that roadside gasoline dispensers are probably at greater risk of developing chronic diseases associated with increased oxidative stress. A study to demonstrate the effect of antioxidant supplementation on the TAS among gasoline-exposed population will be of benefit. Meanwhile, legislation on roadside gasoline dispensing should be enforced to reduce the incidence of long-term complications from exposure.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Uzma N, Kumar BS, Hazari MA. Exposure to benzene induces oxidative stress, alters the immune response and expression of p53 in gasoline filling workers. Am J Ind Med 2010;53:1264-70.  Back to cited text no. 1
Sies H. Oxidative stress: Oxidants and antioxidants. Exp Physiol 1997;82:291-5.  Back to cited text no. 2
Halliwell B. Biochemistry of oxidative stress. Biochem Soc Trans 2007;35:1147-50.  Back to cited text no. 3
Uzma N, Salar BM, Kumar BS, Aziz N, David MA, Reddy VD,et al. Impact of organic solvents and environmental pollutants on the physiological function in petrol filling workers. Int J Environ Res Public Health 2008;5:139-46.  Back to cited text no. 4
Navasumrit P, Chanvaivit S, Intarasunanont P, Arayasiri M, Lauhareungpanya N, Parnlob V,et al. Environmental and occupational exposure to benzene in Thailand. Chem Biol Interact 2005;153-154:75-83.  Back to cited text no. 5
Adamu S, Akinosun OM, Abbiyesuku FM, Kuti MA, El-Bashir JM, Oluwatoyin GO,et al. Are roadside petrol dispensers at risk of renal dysfunction? A study from Gombe, North East Nigeria. Borno Med J 2015;12:16-22.  Back to cited text no. 6
Adamu S, Akinosun MO, Abbiyesuku FM, Kuti MA, El-Bashir JM, Marafa B. Evaluation of antioxidant vitamins among roadside gasoline dispensers in Gombe, Nigeria. J Environ Occup Sci 2015;4:145-9.  Back to cited text no. 7
Koracevic DG, Koracevic V, Ojordjevic S, Andrejevic C. Method for measument antioxidant activity in human fluid. J Clin Pathol 2001;54:356-61.  Back to cited text no. 8
Sies H. Strategies of antioxidant defense. Eur J Biochem 1993;215:213-9.  Back to cited text no. 9
Myatt L, Cui Z. Oxidative stress in the placenta. Histochem Cell Biol 2004;122:369-82.  Back to cited text no. 10
Ghiselli A, Serafini M, Natella F, Scaccini C. Total antioxidant capacity as a tool to assess redox status: Critical view and experimental data. Free Radic Biol Med 2000;29:1106-14.  Back to cited text no. 11
Fasola F, Adedapo K, Anetor J, Kuti M. Total antioxidants status and some hematological values in sickle cell disease patients in steady state. J Natl Med Assoc 2007;99:891-4.  Back to cited text no. 12
Rekhadevi PV, Rahman MF, Mahboob M, Grover P. Genotoxicity in filling station attendants exposed to petroleum hydrocarbons. Ann Occup Hyg 2010;54:944-54.  Back to cited text no. 13
Bayraktar NM, Karagözler AA, Bayraktar M, Titretir S, Gözükara EM. Investigation of the blood biochemical status of gas station workers. Toxicol Environ Chem 2006;88:587-94.  Back to cited text no. 14
Odum EP, Ejilemele AA, Wakwe VC. Antioxidant status of type 2 diabetic patients in Port Harcourt, Nigeria. Niger J Clin Pract 2012;15:55-8.  Back to cited text no. 15
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Ajala MO, Ogunro PS, Odun A. Effect of hemodialysis on total antioxidant status of chronic renal failure patients in government hospitals in Lagos Nigeria. Niger J Clin Pract 2011;14:154-8.  Back to cited text no. 16
[PUBMED]  [Full text]  
Ogunro PS, Balogun WO, Fadero FF, Idogun ES, Oninla SO, Elemile PO,et al. Plasma lipid peroxidation and totalantioxidant status among dyslipidaemic and hypertensive Nigerians with high risk of coronary heart disease. West Afr J Med 2009;28:87-91.  Back to cited text no. 17
Akinosun OM, Bolajoko EB. Total antioxidant status in type 2 diabetic patients: Experience at University College Hospital (UCH) Ibadan, Nigeria. Niger J Clin Pract 2007;10:126-9.  Back to cited text no. 18


  [Table 1], [Table 2], [Table 3]


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