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Year : 2019  |  Volume : 7  |  Issue : 2  |  Page : 35-38

Influence of petroleum product exposure on serum micronutrient concentrations in automobile mechanics

Department of Chemical Pathology/Laboratory, College of Health Sciences, Ladoke Akintola University of Technology, Osogbo, Nigeria

Date of Submission16-Feb-2019
Date of Decision02-May-2019
Date of Acceptance02-Aug-2019
Date of Web Publication02-Jan-2020

Correspondence Address:
Dr. Ayobola A Iyanda
Department of Chemical Pathology/Laboratory, College of Health Sciences, Ladoke Akintola University of Technology, Osogbo
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/JIHS.JIHS_8_19

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Background Aim of the Study: Occupation-related pathological presentations have been recognized in automobile mechanics, several of which are oxidative stress-induced. Altered micronutrient levels can help in predicting the possibility of oxidative stress-related diseases. It is for this reason that micronutrient levels are being assessed in auto mechanics. Materials and Methods: Questionnaire was administered to obtain information on workers' safety assessment, lifestyle choices, and work experience. Estimation of micronutrient levels was carried out on sera of 80 adult males, 40 of whom were auto mechanics and the other 40 constituted the control group. Essential trace elements (Zn, Cu, Se, Mn, Co, Fe, Mo, and Cr) and vitamins (Vitamins A, B6, C, D, and E, thiamine, riboflavin, niacin, and folic acid) were determined using atomic absorption spectrometry and high-performance liquid chromatography, respectively. Student's t-test was utilized to establish a significant difference between test and control groups. P ≤ 0.05 was considered statistically significant. Results: Micronutrients with antioxidant attributes such as Zn, Cu, Mn, Se, Vitamin E, and ascorbic acid were significantly reduced compared with controls. Data obtained from an administered questionnaire showed that there were no conscious efforts or program to ensure the safety of the mechanics. Conclusions: Auto mechanics are prone to altered serum micronutrient levels.

Keywords: Automobile mechanics, trace elements, vitamins

How to cite this article:
Iyanda AA. Influence of petroleum product exposure on serum micronutrient concentrations in automobile mechanics. J Integr Health Sci 2019;7:35-8

How to cite this URL:
Iyanda AA. Influence of petroleum product exposure on serum micronutrient concentrations in automobile mechanics. J Integr Health Sci [serial online] 2019 [cited 2023 Mar 22];7:35-8. Available from: https://www.jihs.in/text.asp?2019/7/2/35/274541

  Introduction Top

Petrol sometimes called gasoline is a mixture of paraffins, naphthenes, olefins, and aromatics. Aromatic compounds of petrol are predominantly benzene, toluene, and xylene.[1],[2] Benzene is the most hazardous component of gasoline and has been classified as a human carcinogen by the American Conference of Governmental Industrial Hygienists.[3] Although toluene and xylene have not been classified as human carcinogens, exposure to them has been linked with neurological effects.[4],[5]

Occupation as a cause of exposure to agents that are deleterious to health is a problem with a worldwide appeal. While many developing countries have no laws that protect individuals in affected occupation, the developed countries that have had preventive measures in existence for more than 50 years are still encumbered with issues of toxic exposure to fuel. Bernardini et al.[6] reported of three cases of severe hematological diseases caused by an occupational exposure to benzene just over 10 years ago, in which contact was identified to have occurred from the use of ordinary automobile petrol as a solvent degreaser for metal parts.

One of the cases involved a 59-year-old blacksmith (suffering from acute myeloid leukemia [AML]) who had had contact with petrol for 36 years in the process of using it to degrease the forged metal parts before painting them. Another case was that of a 53-year-old mechanic with AML who had been exposed to petrol for 15 years while using it to degrease mechanical parts of tanker motors. The third case, on the other hand, was an 82-year-old car mechanic diagnosed with idiopathic myelofibrosis since the age of 75, who had used petrol to degrease mechanical car motor parts for 42 years. These three cases were found to be connected with the fact that the environmental hygiene measures necessary to limit inhalation or skin contact were not strictly adhered to. In fact medical history showed that in the case of the two mechanics, the petrol was siphoned by mouth, so there was substantial oral exposure to the 1%–5% benzene present in the petrol. The practice of siphoning petrol by mouth seems to be common also among automobile mechanics in many parts of the world.

Benzene is a known carcinogen, and unfortunately, many of the tests that are sensitive or specific to determine the early impact of these agents on DNA are not available in many health institutions in the developing world. However, since the metabolic processing of the components can induce oxidative stress, it is possible that such a practice (siphoning petrol by mouth) will be associated with an alteration in many of the micronutrients, especially those of them with antioxidant potential. The decrease in micronutrient levels can serve as a wake-up call to the mechanics of possible excessive exposure to fuel. Therefore, the aim of the study is to determine the serum levels of micronutrients in automobile mechanics.

  Materials and Methods Top

NQuestionnaire design and data collection

A brief questionnaire was designed to facilitate interviews of automobile mechanics so as to obtain the following information from them: sociodemographic status, workers' safety assessment, lifestyle choices, and work experience as well as work hours. Some of the day-to-day tasks or responsibilities of the auto mechanics recruited for the study included engine repair, oil changing, lubrication, and basic maintenance of fuel systems. Apprentices were not recruited because most of them had not spent up to 5 years in a mechanic workshop. The study was conducted according to revised Helsinki's Declaration. Prior to obtaining informed consent individually from each participant, adequate information was supplied to each participant to convey the aim and expected outcomes of the study. Only the individuals who were willing to participate were recruited for the study.


A random sampling of the recognized workshops in Ibadan was carried out, of which random sample of interested mechanics was obtained. The study population consisted of 40 auto mechanics and 40 nonmechanics which constituted test and control groups, respectively. Selection of controls included those who had not been exposed to gasoline (e.g., students) or had not been in occupation related to gasoline exposure (e.g., greengrocers, tailors, etc.) as well as those who were not living in residential areas in close proximity to where petrol-filling stations are situated. All auto mechanics were males who were 25 years and above. All participants were apparently healthy, not on micronutrient supplementation or any medication capable of altering micronutrient levels. All samples were obtained during regular work hours. 5 mL of venous blood was obtained from the antecubital vein of each participant and was immediately transferred into anticoagulant free bottles. The samples were centrifuged at 2500 g after which serum obtained from each participant was kept frozen at −20°C until the analyses were carried out.

Determination of serum micronutrient levels

Essential trace elements were assessed by atomic absorption spectrometry method, using Buck Scientific 205 Atomic Absorption acquired from Buck Scientific in East Norwalk, Connecticut (USA). The serum trace element measured included Zn, Cu, Se, Mn, Co, Fe, Mo, and Cr Serum levels of Vitamins A, B6, C, D, and E, thiamine, riboflavin, niacin, and folic acid were estimated by high-performance liquid chromatographic (HPLC) method. The HPLC equipment was supplied by Waters® Corporation Milford, Massachusetts, USA.

Statistical analysis

Statistical analysis was determined using SPSS version 15 (SPSS Inc., Chicago, IL, USA). Mean and standard deviation values of the data were determined, and Student's t-test was used to establish a significant difference between the test and control groups. P ≤ 0.05 was considered for statistical significance.

  Results Top

Of all the trace elements estimated, Zn, Cu, Mn, Se, Co, and Cr were significantly different in automobile mechanics compared with controls, with Cr being significantly increased and others (Zn, Cu, Mn, Se, and Co) significantly decreased (P < 0.05). Both iron and Mo were not significantly different (P > 0.05) as presented in [Table 1]. In [Table 2], Vitamins C and E were significantly reduced (P < 0.05) but Vitamin A was not significantly different (P > 0.05) in automobile mechanics compared with controls. All the results presented in [Table 3] show that the serum levels of riboflavin, folic acid, niacin, thiamine, pyridoxine, and Vitamin D were significantly lower (P < 0.05) in automobile mechanics than controls. Data obtained from the administered questionnaire showed that there were no conscious efforts or program to ensure the safety of the mechanics as there was no monitoring program to ensure noncontamination of the workshop environment; no periodic health assessment of the mechanics also took place. None of the participants was a smoker and all had not taken alcohol in the preceding 36 months. The average work hours were 8.
Table 1: Serum levels of trace elements in controls and auto-mechanics

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Table 2: Serum levels of antioxidant vitamins in controls and auto-mechanics

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Table 3: Serum levels of riboflavin, folic acid, niacin, thiamine, pyridoxine, and Vitamin D in controls and automobile mechanics

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  Discussion Top

While Vitamin A was not significantly different in auto mechanics compared with controls, L-ascorbic acid – a recognized antioxidant that also serves as a cofactor for enzymes such as hydroxylases and monooxygenases that take part in the formation of carnitine and neurotransmitter – was significantly decreased. The potential of ascorbic acid to prevent the oxidation of low-density lipoprotein primarily by scavenging the free radicals and other reactive oxygen species in the aqueous state as well as its role in accelerating wound repair and healing/regeneration process through stimulation of collagen synthesis has been recognized.[7],[8] All these functions may be adversely affected in the test participants since Vitamin C level was significantly lower in auto mechanics than controls.

Ascorbic acid shares the antioxidant property with other micronutrients such as Vitamin E, Zn, Cu, Se, and Mn,[9],[10] all of which were also significantly decreased in auto-mechanics compared with controls. This simply indicates that daily exposure to petroleum products can profoundly alter the status of the antioxidant micronutrient level. It can be postulated that this may raise the possibility of oxidative stress-related conditions in this occupational type. Unfortunately, since data were not collated on the types of oxidative stress-related ailments present in the test participants, the relationship between the altered Vitamin C status and associated pathological conditions could not be determined. Aside ascorbic acid, other vitamins such as riboflavin, niacin, pyridoxine, thiamin, Vitamin D, and folic acid were also significantly lower in auto mechanics. The fact that isolated micronutrient depletion was not encountered but a near comprehensive decreases were observed raises the level of concern the results of this kind should generate by regulatory bodies as well as those saddled with the responsibility of enforcing laws related to workers' safety.

Specific pathological conditions have been reported in mechanics. For example, Dioka et al.[11] revealed that exposure to petroleum products by mechanics resulted in significant increases in concentrations of some markers of hepatic and renal damage (e.g., uric acid, as well as significant increases in the activities of alanine aminotransferase and aspartate aminotransferase) when compared with unexposed individuals (nonmechanics). Furthermore, a study carried out by Kamal et al.[12] to investigate the levels of urinary biomarkers (1-OHPyr and α- and β-naphthols) of polycyclic aromatic hydrocarbons (PAHs) exposure and biomarkers of effect (i.e., blood parameters) in petroleum-refinery workers and auto-repair workers (mechanics) seems to support the results of the present study. Kamal et al.[12] reported that the test participants had elevated levels of white blood cell count compared with controls and the biomarker of oxidative DNA damage, i.e., 8-hydroxyguanine was significantly higher in mechanics. When the incremental lifetime cancer risk for mechanics was determined, moderate-to-low cancer risk from exposure to dust-bound PAHs was observed. Gasoline-induced acute myeloid leukemia has also been reported.[6] In each case, a possible role of micronutrients in those conditions was not determined, but since many disorders have been linked with oxidative stress, the impact of micronutrient depletion cannot be discounted.

Although the utilization of protective gears such as masks and overall has been advocated to limit the degree of exposure to vapor, Nganje et al.[13] have reported that the level of concentrations of PAHs in surface soils was increased in many petroleum product-related work places (e.g., petrol stations, mechanic workshops, and airport fuel dump) with higher levels detected in mechanic workshop compared with petrol stations. This high soil contamination of mechanic workshops has been adduced to occur from a variety of causes, for example, motor vehicle exhaust, gasoline spillage, and direct contact with used engine. Although Nganje et al.[13] are of the opinion that in such workshops, it is very likely that the major source of soil contamination is originating from petroleum product spillage. Many infectious and noninfectious diseases abound in many developing countries, whether this kind of insult is a contributing factor to disease burden (especially among the mechanics), may need to be determined.

The fact that several disorders are linked with this occupation warrant the need for regular monitoring of mechanics for possible exposure to petroleum products above the tolerable levels. Regular monitoring will no doubt serves as precautionary and preventive steps in predicting the possibility of these disorders, many of which are known to have long latency. Since altered micronutrient status can predate these clinical manifestations, the assessment of serum levels of these vitamins and elements can be employed as screening markers for the harmful effects of gasoline exposure. This will no doubt be effective in predicting excessive gasoline exposure among many rural automobile mechanics that may not have access to tertiary health institution, whereby more specific tests of oxidative stress can be carried out.

  Conclusions Top

The study suggests that there was absence of any program that catered for the safety of the mechanics. In addition, the significant decreases in the levels of Zn, Cu, Se, Mn, as well as Vitamins C and E that interact with other biomolecules to exert antioxidant properties connote that there is the possibility of abnormal physiologic processes in the body.

Limitations of the study

The study is limited by the small sample size and the fact that the selection of the participants took place within a single city (Ibadan) which may affect the usefulness of the result obtained, in making inference about the study population (Nigerian automobile mechanics). Data on the actual duration of work experience (years) as well as specific ailments among the auto mechanics were not collected and therefore could not be correlated with age.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Keretetse GS, Laubscher PJ, Du Plessis JL, Pretorius PJ, Van Der Westhuizen FH, Van Deventer E, et al. DNA damage and repair detected by the comet assay in lymphocytes of African petrol attendants: A pilot study. Ann Occup Hyg 2008;52:653-62.  Back to cited text no. 1
Periago JF, Zambudio A, Prado C. Evaluation of environmental levels of aromatic hydrocarbons in gasoline service stations by gas chromatography. J Chromatogr A 1997;778:263-8.  Back to cited text no. 2
American Conference of Governmental Industrial Hygienists. Threshold Limiting Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists; 2008.  Back to cited text no. 3
Agency for Toxic Substances and Disease Registry. Toxicological Profile for Xylene. Atlanta, Department of Health and Human Services, Public Health Service. GA, U.S: Agency for Toxic Substances and Disease Registry; 2006.  Back to cited text no. 4
Agency for Toxic Substances and Disease Registry. Toxicological Profile for Toluene. Atlanta, Department of Health and Human Services, Public Health Service. GA, U.S: Agency for Toxic Substances and Disease Registry; 2007.  Back to cited text no. 5
Bernardini P, Giannandrea F, Voso MT, Sica S. Myeloproliferative disorders due to the use of gasoline as a solvent: Report of three cases. Med Lav 2005;96:119-25.  Back to cited text no. 6
Frei B, England L, Ames BN. Ascorbate is an outstanding antioxidant in human blood plasma. Proc Natl Acad Sci U S A 1989;86:6377-81.  Back to cited text no. 7
Maggini S, Wenzlaff S, Hornig D. Essential role of Vitamin C and zinc in child immunity and health. J Int Med Res 2010;38:386-414.  Back to cited text no. 8
Shenkin M, Baines G, Fel T, Lyon DG. Vitamins and trace elements. In: Burtis CA, Ashwood ER, Bruns DE, editors. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Missouri: Saunders; 2006. p. 1075-164.  Back to cited text no. 9
Iyanda AA. Evaluation of serum micro-nutrient concentrations in kerosene-exposed female Wistar rats- A sub-chronic study. Am J Pharm Health Res 2014;02:82-90.  Back to cited text no. 10
Dioka CE, Orisakwe OE, Adeniyi FA, Meludu SC. Liver and renal function tests in artisans occupationally exposed to lead in mechanic village in Nnewi, Nigeria. Int J Environ Res Public Health 2004;1:21-5.  Back to cited text no. 11
Kamal A, Cincinelli A, Martellini T, Palchetti I, Bettazzi F, Malik RN, et al. Health and carcinogenic risk evaluation for cohorts exposed to PAHs in petrochemical workplaces in Rawalpindi city (Pakistan). Int J Environ Health Res 2016;26:37-57.  Back to cited text no. 12
Nganje TN, Edet AE, Ekwere SJ. Distribution of PAHs in surface soils from petroleum handling facilities in Calabar. Environ Monit Assess 2007;130:27-34.  Back to cited text no. 13


  [Table 1], [Table 2], [Table 3]


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