RESUMO
Methyl tertiary Butyl Ether [MTBE] has been used as a gasoline additive, since at least 20 years, in many countries. It is usually used to increase octane levels and more recently to reduce the levels of carbon monoxide emissions. The present work aimed at investigating the possible health hazards due to occupational exposure to methyl tertiary ethyl ether [MTBE]. Forty-five workers exposed to MTBE during their work; 17 of them from the Cairo Petroleum Refinery Company and 28 from several gasoline stations [n= 28], chosen on a stratified random sample basis. All workers included in the present work were interviewed, they were informed about the nature of the study, and subsequently consented to have additional blood withdrawn for blood count, biochemical [hepato-renal function tests], as well as chromosomal study of their peripheral blood lymphocytes. Clinical examination was done, stressing the condition of the chest, heart, liver, kidneys and skin. About 46% of the studied workers had chest, ear, nose and throat, as well as other manifestations. Haematological, hepatic and renal function test results were elicited among the tested group. However, on performing the haematological and biochemical investigation, pre- and post- exposure, statistically insignificant differences were elicited, except for RBCs [less on post- exposure] and creatinine [more on post- exposure]. In addition, the group belonging to the refinery were more affected in their haematological, biochemical and chromosomal aberrations' parameters, than their colleagues at the gasoline pumping stations, and the differences were statistically significant in relation to haemoglobin, SGOT, SGPT, and blood urea levels. Mild to moderate chromosomal abnormalities affected 44% of the examined workers, in forms of: gaps, breaks, deletions, isogaps, isobreaks, centromere separation, dicentrics, and polyploidy. Workers employed in measuring the MTBE levels at the refinery company, i.e. measurers, were more affected in their haematological, biochemical and chromosomal aberrations' parameters, than their colleagues, and the differences were statistically significant in relation to haemoglobin, SGOT, and total number of chromosomal aberrations. Different symptoms were more complained of among the measurers than among the others. The study revealed many adverse effects, which strongly suggest the relation with either acute or chronic consequences of the new gasoline additive MTBE. The onset of such manifestation was observed by the complained workers following the start of addition of MTBE, about 2 years ago. The study also revealed mild to moderate chromosomal aberrations among 44% of the exposed workers. Occupational health surveillance system should be followed on periodic basis. Testing for the quality and function of blood, hepatic, renal, cytogenetic systems are among the primary targets of the proposed system. First aid measures are to be provided in workplaces where possible exposure to MTBE exists. Addition of the Threshold Limit Value for MTBE to the Egyptian legislative decree concerned with limit values for chemicals, as well as adding the probable health consequences due to MTBE occupational exposure to the Egyptian list for occupational illness. Continuous monitoring of MTBE in workplace environment, as well as their related metabolites [in biological samples], should be a routine procedure