Abstract
Exposure to 2,4-difluoroaniline (DFA) was monitored by GC-MS of DFA adducts bound to hemoglobin (Hb). In two studies, involving 20 and 16 workers potentially exposed to low concentrations of DFA, median concentrations of 10 (range 1-83) and 20 (range 4-322) pmole/g Hb were found, respectively. For better interpretation of these results, the in vivo binding of DFA to Hb was investigated. DFA was administered orally at doses of 0, 0.078, 0.775, 7.75, and 77.5 mumole/kg/day, to 10 male and 10 female Fischer 344 rats for 10 consecutive days (2 rats/sex/dose group). A linear relation between dose and adduct concentration was observed. At the two lowest doses (0.078 and 0.775 mumole/kg/day) no methemoglobinemia was observed, but adducts could easily be measured. At these doses, the mean adduct levels were in the same range as found in the human studies. As yet, no occupational exposure limit for DFA has been established. The German biological tolerance value (BAT-value) for aniline was set at 7.2 nmole/g Hb. This BAT-value is based on the relation between methemoglobinemia and adduct formation. The amount of Hb binding by aniline and DFA was found to be similar in the rat. Assuming that this is also the case in humans, the BAT-value for aniline may tentatively be used for DFA as well. In both studies of occupationally exposed workers, the adduct levels were well below this BAT-value.
Full text
PDF


Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bryant M. S., Skipper P. L., Tannenbaum S. R., Maclure M. Hemoglobin adducts of 4-aminobiphenyl in smokers and nonsmokers. Cancer Res. 1987 Jan 15;47(2):602–608. [PubMed] [Google Scholar]
- Eadsforth C. V., Logan C. J., Morrison B. J., Warburton P. A. 2,4-Difluoroaniline and 4-fluoroaniline exposure: monitoring by methaemoglobin and urine analyses. Int Arch Occup Environ Health. 1984;54(3):223–232. doi: 10.1007/BF00379051. [DOI] [PubMed] [Google Scholar]
- Farmer P. B., Bailey E. Protein-carcinogen adducts in human dosimetry. Arch Toxicol Suppl. 1989;13:83–90. doi: 10.1007/978-3-642-74117-3_8. [DOI] [PubMed] [Google Scholar]
- Lewalter J., Korallus U. Blood protein conjugates and acetylation of aromatic amines. New findings on biological monitoring. Int Arch Occup Environ Health. 1985;56(3):179–196. doi: 10.1007/BF00396596. [DOI] [PubMed] [Google Scholar]
- Neumann H. G. Biomonitoring of aromatic amines and alkylating agents by measuring hemoglobin adducts. Int Arch Occup Environ Health. 1988;60(3):151–155. doi: 10.1007/BF00378690. [DOI] [PubMed] [Google Scholar]
- Sabbioni G. Hemoglobin binding of monocyclic aromatic amines: molecular dosimetry and quantitative structure activity relationships for the N-oxidation. Chem Biol Interact. 1992 Jan;81(1-2):91–117. doi: 10.1016/0009-2797(92)90029-k. [DOI] [PubMed] [Google Scholar]
- Sabbioni G., Neumann H. G. Biomonitoring of arylamines: hemoglobin adducts of urea and carbamate pesticides. Carcinogenesis. 1990 Jan;11(1):111–115. doi: 10.1093/carcin/11.1.111. [DOI] [PubMed] [Google Scholar]
- Stillwell W. G., Bryant M. S., Wishnok J. S. GC/MS analysis of biologically important aromatic amines. Application to human dosimetry. Biomed Environ Mass Spectrom. 1987 May;14(5):221–227. doi: 10.1002/bms.1200140505. [DOI] [PubMed] [Google Scholar]