The higher concentration of traces of aromatic hydrocarbons prevailing in the refinery atmosphere causes severe occupational health hazard to refinery workers. In this study, the biochemical role of genetic polymorphism in modulating urinary excretion of benzene metabolite as phenol level has been investigated in 90 workers exposed to benzene in the petroleum refinery plants of Korea. Glutathione S-transferase (GST) subfamily as GSTM1, GSTT1 and GSTP1 and NAD(P)H: quinone oxidoreductase 1 (NQO1) gene polymorphisms were determined by polymerase chain reaction (PCR)-based methods. The mean concentration of volatile benzene in the refinery environment was 0.042 mg/m3 (SD, 0.069) and that of urinary phenol was 7.42 mg/g creatinine (SD, 11.3). The airborne benzene concentration was significantly related to the concentration of phenol in urine (r = 0.640, p⁄0.01).
However, all the genotypes of GST subfamily and NQO1 except small sample size of genotypes in GSTM1 and GSTT1 none of them were higher than that of present genotype. Also, it was higher in the GSTP1*1/*1 than in the GSTP1*1/*2.
The various biological (i.e. age and liver function parameters) or lifestyle factors (i.e. medication, smoking, alcohol and coffee intake), also taken into account as potential confounders, did not influence the correlations found.
These results suggested that GST subfamily and NQO1 genotypes might play an important role in the metabolism of benzene.