الفهرس 
Human Health EffectsOnly 14 pages are availabe for public view
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Abstract
Benzene is a volatile, colorless, highly flammable liquid; it is one of the most widely used industrial chemical agents. It is an important pollutant compound, present in both occupational and general environment.
Benzene is readily absorbed by all routes of exposure, rapidly distributed throughout the body and metabolized to variety of intermediate compounds in several organs, including the liver and bone marrow. Inhalation exposure is probably the major route of human exposure to benzene, although oral and dermal exposures are also important.
The metabolism of benzene is required for its toxicity. The liver is the major site for the transformation of benzene, the bone marrow a minor site. The main route of excretion of unmetabolized benzene is exhalation and the main route of excretion of metabolized benzene is the urine.
Upon entering the blood stream after inhalation or dermal absorption benzene targets many organs and cells. It has the potential to cause central nervous system (CNS) dysfunction, hematotoxicity by decreasing each of the circulating formed elements of the blood i.e. erythrocytes (red blood cells), thrombocytes (platelets) and leukocytes (white blood cells), hepatotoxicity by increasing liver enzymes, nephrotoxicity and immunotoxicity. Common acute effects include epidermal, dermal and conjunctival irritation, headaches, drowsiness, impaired balance and confusions in addition to disturbing a balance between free radical production and antioxidant activities.
This work was done to evaluate the effect of exposure to benzene on clinical and certain biochemical parameters of the exposed workers aiming to asses the possible hepatic, renal dysfunctions, immunological and hematological disorders, some antioxidant enzymes and some biomarkers among workers occupationally exposed to benzene.
The study included 164 male and female workers; they were divided into two groups. 81 workers exposed to benzene, with a mean age of (37.5 ± 7.59) years and mean duration of exposure of (15.51 ± 6.29) years, and 83 non-exposed subjects with a mean age of (39.3 ± 5.41) years as a control group. Data were collected from the chosen workers themselves as regards age, duration of exposure, and type of work exposure, clinical examination of workers was carried out.
Blood samples were taken for the determination of complete blood picture, enzymes activity such as ALT, AST, γGT, ALP, simple immunoglobulins (IgG, IgA and IgM), in addition to kidney functions by estimating serum creatinine and blood urea. Also determination of some antioxidant enzymes (SOD and catalase), GSH and MDA. Urine samples were taken for the determination of creatinine in urine and some biomarkers such as trans, trans- muconic acid (t,t MA).
1- Clinical data showed that dry cough, wheezes, itching, general fatigue, headache, and confusion were the most common complaints among the exposed group.
2-The results showed that red blood cells, white blood cells and platelets count were significantly decreased among exposed workers as compared to the controls.
3-ALT, γGT and ALP activities were significantly higher in value, while AST was non significantly increase in the exposed group as compared with the healthy one.
4- Serum immunoglobulins IgG &IgA were significantly decreased, while IgM was significantly increased in the exposed group than the controls.
5- No significant change in the levels of both urea and creatinine.
6- Significant increase in the level of t,t-MA/creatinine in urine of the exposed workers especially in the smoking group than the controls was also observed.
7- Significant increase in the level of MDA of the exposed workers than the controls.
8- Antioxidant enzyme activities (SOD and catalase) also GSH were significantly decreased in the exposed group than the controls.
from this study, we recommend that workers must use protective equipment during their work and also periodical clinical and chemical examination should be done to detect early affected workers to be replaced to other more suitable workplaces. Health education of the exposed workers is mandatory as the workers should be informed about the different hazards of their jobs and they should be cautious to protect themselves.