Formaldehyde and tobacco smoke as alkylating agents: the formation of N-Methylenvaline in pathologists and in plastic laminate workers

Objective. Aim of this study was to investigate the relationships between the concentration of formaldehyde in air and the alkylation of hemoglobin to form a terminal N-methylenvaline residue in three occupationally exposed groups: a) technicians of pathology wards, b) workers of the plastic laminates industry, c) a control group. All subjects recruited in this study were also tested on their smoking habits. Methods. Formaldehyde adsorbed on passive air samplers was quantified by HPLC with UV detection (360 nm), cotinine was quantified by GC-MS. Terminal hemoglobin N-methylenvaline was determined by treating globine under reducing conditions with pentafluorophenyl isothiocyanate to yield a derivative, subsequently detected by GC-MS. One-way analysis of variance was performed to compare among the three groups the biomarkers considered in this study. Results. For air-FA and N-methylenvaline a difference between the three groups was detected (p < 0.0001) and a significant higher concentration in the two professionally exposed groups was proved. Mean values for FA (µg/m3): group a) 188.6, group b) 210.1, group c) 41.4; mean values for N-methylenvaline (nmol/gr of globin): group a) 377.9, group b) 342.8, group c) 144.8. Conversely, the comparison between the two professionally exposed groups, a) vs b), does not show any significant difference highlighting similar exposition to FA and, consequently, similar biological response. Tobacco smoke proves to have a minor impact on the formation of N-methylenvaline molecular adduct. Conclusions. A positive correlation was demonstrated between professional exposition to air-formaldehyde and hemoglobin alkylation to form N-methylenvaline molecular adduct in two occupationally exposed groups of subjects considered in the present study. In comparison with occupational exposition, tobacco smoke proved to have a minor impact on the formation of N-methylenvaline molecular adduct.