IMPACT OF COMBUSTION ENGINE EMISSION ON HEME OXYGENASE-1, HAEMATOLOGICAL, SPIROMETRIC AND IMMUNE INDICES OF OCCUPATIONALLY EXPOSED SUBJECTS IN BENIN CITY.

ABSTRACT

Traffic and generator-related air pollution has been inextricably described as primary sources of exposure to combustive fumes in urban areas and this has been associated with a wide range of hazards to human beings. This study was conducted to determine the impact of combustion engine emission on heme oxygenase-1, haematological, spirometric and immune indices of occupationally exposed subjects in Benin City. The purpose was to relate combustion engine emission to the health status of occupationally exposed individuals in a specific work by analyzing some diagnostic markers. Blood samples were collected from 300 occupationally exposed subjects divided into 100 each of Commercial Bus Drivers Fumes Exposure Subjects (CBDFES), Diesel Generator Fumes Exposed Mechanics (DGFEM) and Premium Motor Spirit Fumes Exposed Mechanics (PMSFEM) as well as 100 Non-Occupationally Exposed Controls (NOEC). About 9ml of blood was collected into appropriate container for analysis of haematology profile, benzene and lead. Also, leucocyte functional assays such as chemotaxis, respiratory burst, phagocytic index and CD4 cell count as well as high sensitivity C-reactive protein (hs-CRP), prothrombin time (PT)/activated partial thromboplastin time (aPTT)/plasma fibrinogen concentration (PFC), protein C/S, spirometry, carbon monoxide level and human heme oxygenase-1 (HO-1) were determined using appropriate laboratory methods. The results were expressed as mean±standard error of mean (x̅±SEM). The levels of carbon monoxide, benzene and lead were significantly higher in all the exposed groups compared with NOEC (P<0.05, respectively) while white blood cell total count was higher in PMSFES than NOEC and other subjects. The differential lymphocytes showed higher values in CBDFES and DGFEM groups while basophils and monocytes exhibited significant increases in PMSFEM and DGFEM exposed subjects (P<0.05, respectively). The leucocyte function parameters showed significant increases in chemotaxis and phagocytic indices while haemostatic indices recorded a decreased xix platelet count, prolonged PT (in all groups) coupled with an increase in protein S especially in the CBDFES (P<0.05, respectively). The lung functional indices showed a significant decrease only in PEF25% among the DGFEM and PMSFEM groups. Conclusively, exposure to petrochemical fumes through CEEs have been found to increase carbon monoxide and benzene in all subjects while blood lead level increased only in CBDFES. The lowering of platelet count with prolonged PT aPTT could induce bleeding tendencies in the subjects. Also, the increased values in hs-CRP as well as PFC with concomitant decreases in neutrophil-lymphocyte and platelet-lymphocyte ratios indicated an active inflammatory process elicited by exposure to high carbon monoxide, benzene and lead. It is recommended that simple white cell ratios could be used as sensitive inflammatory markers while greener technology and the use of electric automobiles should be encouraged to save our environment as well as enhance our well-beings.