DNA damage assessment and biological monitoring of occupational exposure to organic solvents, 2006

Introduction. Exposure to solvents is one of the highest potential risks for millions of workers in the world; they can generate substantial environmental pollution leading to outbreaks of public health problems. Objective. Blood levels were determined for metabolites of benzene, toluene and xylene, and polymorphisms for enzymes CYP2E1, GSTM1, GSTT1 were characterized. Damage to DNA was assessed by the comet assay for exposure to organic solvents. Materials and methods. A cross-sectional study was undertaken in 90 employees from 5 different companies. A survey form was administered; blood was sampled to detect the genetic polymorphisms and to apply the comet assay (single cell gel electrophoresis) to detect DNA fragmentation. The concentrations of phenol, ortho and meta methylhippuric acids were measured in urine. Statistical analyses explored the possible associations. Results. The percentage of workers directly exposed to solvents was 34.4%. In this group, the evidence indicated concentrations higher than the permitted limits: 3.3% for phenol, 6.6% for hippuric acid, 3.3% for ortho-methylhippuric acid and 36.7% for metamethylhippuric acid. In the Comet assay, the length of the comet's tail was greater than average (19.5 im) in exposed subjects, and the percentage of cells with mild damage (19.0%) (p=0.0007) was higher. The percentage of exposed individuals with absent genotypes for enzymes GSTT1 and GSTM1 was 46.7% and 56.8% respectively. Conclusion. Exposure biomarkers have become fundamental tools for the evaluation of risk associated with exposure to toxic agents.