Biological monitoring of carcinogenic, certain or suspicious, aromatic amines in samples of tanning workers and general population of ASL 11 Empoli

Azo dyes, used in the tanning industry in the past, contained derivatives of certain or suspected carcinogenic aromatic amines. Despite the limitations imposed by current legislation, we cannot exclude the possibility of workers’ exposure to aromatic amines for the possible in vivo metabolic transformation of azo dyes and/or the presence of traces of dangerous amines in commercial products. In order to test for exposure and absorption of hazardous aromatic amines, a biological monitoring of a group of 15 aromatic amines was performed in urinary samples of both tannery workers and not occupationally exposed population. The amines exceeding the LOD in at least 10% of the samples were: • in the general population: 2,4-diaminoanisole (27%), o-toluidine (23.8%), p-cresidine (21.6%), 3,3’-dimethoxybenzidine (17.8%), 2-anisidine (16.8%); 2,4-diaminotoluene (13.0%); benzidine (12.4%); • in the tannery workers: 2,4-diaminotoluene (40%), 2,4-diamminoanisole (39.4%), 4,4-diaminodiphenylmethane (14.2%), p-cresidine (13.3%); 3,3-dimethoxybenzidine (10.1%); with significant differences, in the tanners, for 2.4-diaminotoluene, 4,4-diaminodiphenylmethane, 2,4-diamminoanisole and 4-aminoazobenzene. The 4,4-oxydianiline has never been detected in both populations. Comparing the concentration mean values of each amine, a statistically significant difference between the two populations was found for 2,4-diamminoanisole, 2.4-diaminotoluene, benzidine and 4,4-diaminodiphenylmethane. Comparing the frequency of the LOD exceeding among the general population and the various workers classified according to the task being performed, a significant difference was found for 2,4-diamminoanisole, 2,4-diaminotoluene in the employees in the drying, drum dying, and finishing; the 4,4-diaminodiphenylmethane and the 4-aminoazobenzene only in the finishing. The difference between means values was significant for: 2,4-diamminoanisolo and 2,4-diaminotoluene in the employees in the drying and drum dying; 2-anisidine in the finishing, 4,4-diaminodiphenylmethane in drying and finishing; benzidine in drying. In sampling conducted in workers employed in the dye barrel in 2010 some samples exceeded the LOD for 2,4-diaminotoluene (13.46%), 3.3-dimethoxybenzidine (3.85%) and 4,4-diaminodiphenylmethane (3.85%), but the concentration mean values never were significantly different from the control population. The study shows that measured concentrations of amines are different depending on the job, and that some amines are present in the general population with values similar to those of workers. The reduction of all parameters in the employees in drum dying resulted in 2010 than in previous years can probably be explained by an overall improvement of working conditions and/or the reduction or even cessation of use of azo dyes made from derivatives of dangerous aromatic amines.