[Liver function of workers occupationally exposed to mixed organic solvents in a petrochemical industry]

A descriptive and cross sectional study was conducted to determine whether hepatic function changes in workers occupationally exposed to a mixture of organic solvents, were due to the exposure or confusing factors. A non random sample of 77 workers, operators and supervisors of the Olefin Plant I and II of a petrochemical industry in Maracaibo, Venezuela, was used. Their mean age was 29 +/- 7 years, and had at least one year of exposure to the solvents. This sample was compared with a group of employees of the administrative offices or control panel workers, with a mean age of 36 +/- 8 year and with similar anthropometric characteristics. Workers with a known history of liver disease, blood transfusions and diabetes mellitus were excluded of the study. In addition to a complete occupational disease medical history and a physical examination, serum samples were obtained to determine the activity of the aspartato aminotransferase (AST), alanin aminotransferase (ALT), gamma glutamiltransferase (GGT), alkaline phosphatase (AF), the concentration of the total bile acids (BAS), the surface antigen of hepatitis B(HbsAg) and the hepatitis A virus antibodies: AntiHAV-IgG and the AntiHAV-IgM. An urine sample was taken and analyzed by standard methodology to determine urinary phenols. The air concentrations of benzene, ethylbenzene, toluene and xylene were analyzed by gas chromathography. The serum activities of the liver enzymes, the concentration of bile acids and urinary phenols were not influenced by the exposure to the solvents. The increase of the activity of GGT was associated with obesity and alcohol consumption. The antibodies of the surface antigen of hepatitis A-IgM were normal in both groups and the antibodies for the antigen of hepatitis A-IgG presented a prevalence of 6% in the exposed group and 9% in the non exposed not being associated with liver abnormalities. The individual air concentrations of the solvents were below the environmentally permissible concentrations, except one sample of benzene (1, 14 ppm) that was over the allowed limit. The total maximum concentration of the mixture of organic solvents, resulting of the sum of fractions of each organic solvent, was within the allowed limits. In conclusion, obesity and alcohol consumption, and not the occupational factors, seem to be responsible for the alteration in GGT in workers of these Olefin Plants.