Hemoglobin Adducts of Acrylamide and Acrylonitrile in Laboratory Workers, Smokers and Nonsmokers

Abstract

Acrylamide is a chemical which is extensively used in research laboratories for the preparation of polyacrylamide gels for electrophoresis (PAGE). Blood samples were collected from laboratory personnel who were working with PAGE, from smokers, and from nonsmokers. Hemoglobin adducts of acrylamide, acrylonitrile, and ethylene oxide were determined using the modified Edman degradation procedure. Acrylamide adducts were detected in all persons. The PAGE workers (mean 54 pmol/g) had a significantly increased adduct level compared to nonsmoking controls (mean 31 pmol/g). The acrylamide adducts in smokers (mean 116 pmol/g) correlated with the number of cigarettes smoked per day. This confirms the presence of acrylamide in tobacco smoke and shows that it is an important source of acrylamide exposure. The increased level of acrylamide adducts in the PAGE workers corresponds to an uptake of acrylamide from about 3 cigarettes per day. It is not possible from this study to draw any conclusion as to which step in the working procedure is most critical for exposure. The PAGE workers are probably not at risk for neurotoxic damage to the peripheral nervous system. However, it needs to be investigated whether the exposure to acrylamide in PAGE workers represents a risk for genotoxic and reproductive effects. The high background of acrylamide adducts in nonsmoking controls was unexpected. The origin of this background is not known. Acrylonitrile adducts were below the detection limit (< 2 pmol/g) in nonsmoking controls. In the smokers (mean 106 pmol/g) this adduct correlated with cigarettes/day and with ethylene oxide adducts. Acrylonitrile adducts could be a better indicator of tobacco smoking than ethylene oxide adducts since the latter are showing a background of endogenous origin.

Differences in hemoglobin adduct levels of acrylamide in the general population with respect to dietary intake, smoking habits and gender

“…All previous data on the background level of the Hb adduct from AA [12][13][14][15][45][46], except for the study by Schettgen et al [47], came from the same laboratory as in the present study, using the same instruments and standards for quantification etc. In these published studies of altogether about 50 non-smoking individuals the adduct level varies between 0.02 and 0.07 nmol/g Hb.…”

“…The stored deep-frozen erythrocyte fractions for the selected subjects (n = 142) were prepared for analysis of Hb adducts according to the N-alkyl Edman method described earlier ( [43] with modifications and materials for AA analysis according to [12]). …”

“…In the study by Bergmark an average incremental AA-adduct level of about 0.006 nmol/g Hb per smoked cigarette and day was obtained [12]. This would indicate that continuous smoking of 5 cig/day, contributes to a level of the AA-adduct to N-termini in Hb of 0.030 nmol/g, i.e.…”

“…The observation of a regularly occurring background level (about 0.03 nmol per g globin) of adducts from AA to N-termini in Hb in non-smoking and occupationally unexposed control persons indicated the existence of another general exposure source [12,14]. The tracing of this unknown exposure source led to the demonstration of the formation of AA during cooking at elevated temperatures (cf.…”

“…Exposure to AA in work environments has been studied by measurements of stable reaction products (adducts) to hemoglobin (Hb), as a measure of internal dose [11][12][13][14][15]. In exposed workers dose-response relationships between Hb adducts and neurotoxic effects have been demonstrated [14,16].…”