Abstract for Poster 19

 

 

Dermal absorption of aromatic amines in workers in the rubber industry

G. Korinth*¹, T. Weiss², S. Penkert¹, J. Angerer¹, H. Drexler^1
1Institute and Out-Patient Clinic of Occupational, Social and Environmental Medicine, University Erlangen-Nuremberg, Erlangen, Germany
²Research Institute for Occupational Medicine of the Berufsgenossenschaften (BGFA), Institute of the Ruhr University of Bochum, Bochum, Germany

Background

For many chemicals the dermal absorption can be a relevant route of intake. The aim of the present study was to determine whether skin lesions as well as personal protective equipment have an impact on the internal exposure in workers exposed to aromatic amines in the rubber industry.  

Methods

51 (46 male, 5 female) workers (Age: 20-61, median: 37 years) of 3 plants were examined visually for lesions of the exposed skin of hands and forearms by one physician especially trained in this dermatological field in accordance with recently published studies or recommendations. The lesions considered included erythema, scaling and other pathological findings such as vesicles, fissures or callosities, categorised, immediately. The assessment of skin exposures was performed after clinical examination. Measurements of transepidermal water loss (TEWL) were carried out to objectify the individual status of the epidermal barrier. All workers were asked to report on the exposure conditions at the workplace, private and occupational risk factors for skin damage, history of skin diseases and the use of personal protective equipment by means of a standardised, self-administered questionnaire. Occupational exposure of workers to the aromatic amines aniline and o-toluidine was assessed by the relative internal exposure (RIE) index as described by Drexler et al. (1995):

 

RIE=	chemical concentration in urine (μg/l)
	chemical concentration in the air (μg/m3)

 

The cumulative internal exposure to aniline and o-toluidine was evaluated by the determination of the corresponding haemoglobin adducts. The influence of smoking on the internal exposure was determined by the urinary cotinine excretion of the workers.

Results

Considering the RIE index workers with damaged epidermal barrier (skin erythema) showed a higher internal exposure to aromatic amines as workers with healthy skin (Mean values: for aniline 4.6 vs. 4.0, for o-toluidine 2.3 vs. 1.6). These observations were significant (p<0.04) when the long-term exposure by means of haemoglobin adducts was taken into consideration. The clinical examinations were superior to the TEWL measurements. The wearing of respiratory masks and gloves reduced the internal exposure (p<0.03). However, a frequent washing of hands led to a higher incidence of erythema (p<0.02) and consequently to an increased internal exposure (p<0.015). The measurements of internal exposure demonstrated that hand washing seems to eliminate o-toluidine better from the skin as aniline. Skin barrier creams do not improve the skin status and enhanced the dermal absorption of aromatic amines (p<0.03). The use of skin care creams at the workplace was associated with a reduced internal exposure (p<0.03), probably due to regenerative effects.

Conclusions

The present study demonstrated in workers consistently a significant relationship between internal exposure and skin lesions. The internal exposure to aromatic amines can be enhanced by a damaged epidermal barrier, particularly by frequent hand washings, which lead to skin damages. The use of skin barrier creams enhanced the dermal absorption of aromatic amines, while skin care creams are able to improve the regenerative effects of the skin.

Reference

Drexler H, Göen T, Angerer J. Carbon disulphide. II. Investigations on the uptake of CS2 and the excretion of its metabolite 2-thiothiazolidine-4-carboxylic acid after occupational exposure. Int Arch Occup Environ Health 1995;67:5-10.

 

Content last modified: 22 May 2005