Current external and internal exposure to naphthalene of workers occupationally exposed to polycyclic aromatic hydrocarbons in different industries.
OBJECTIVE
External and internal exposure to naphthalene was examined in the most important industries that are typically concerned with polycyclic aromatic hydrocarbon (PAH)-induced diseases (cancer). Furthermore, a control collective from the general population was investigated.


METHODS
External naphthalene was determined by personal air sampling (n = 205). The internal exposure was examined by urinary metabolites 1-naphthol and 2-naphthol (n = 277).


RESULTS
Highest median concentrations of naphthalene in air were found in converter infeed (93.2 microg/m3) and coal-tar distillation (35.8 microg/m3). Moderate and low levels were determined in coking plants (14.5 microg/m3) and in the production of refractories (6.1 microg/m3) and graphite electrodes (0.7 microg/m3). Biological monitoring revealed concentrations of the sum of both metabolites [(1+2)-NOL] in smokers to be increased by 1.6-6.4 times compared with that in non-smokers at the same workplaces. Among non-smokers we found high median (1+2)-NOL levels in converter bricklayers (120.1 microg/l), in coal-tar distillation workers (56.0 microg/l) and in coking plant workers (29.5 microg/l). (1+2)-NOL concentrations around 10 microg/l were found in the production of refractories and graphite electrodes. There was a rough coherency between external and internal naphthalene exposure. In the controls, median (1+2)-NOL concentrations were 10.9 microg/l in non-smokers' urine and 40.3 microg/l in smokers' urine samples.


CONCLUSIONS
Actual conditions of occupational hygiene at the workplaces investigated in this comprehensive study are better than those that current limit values of 50,000 microg/m3 (TLV, TRK) seem to induce. It has become obvious that tobacco smoking is a crucial confounding factor in biological monitoring of naphthalene-exposed humans, making interpretation of occupationally increased naphthol excretions very difficult at low exposure levels.
Preuss
Ralf
R
Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, University of Erlangen-Nuremberg, Schillerstrasse 25/29, 91054 Erlangen, Germany.
Drexler
Hans
H
Böttcher
Melanie
M
Wilhelm
Michael
M
Brüning
Thomas
T
Angerer
Jürgen
J
D000328:Adult; D000395:Air Pollutants, Occupational; D002273:Carcinogens; D004784:Environmental Monitoring; D005858:Germany; D006801:Humans; D007221:Industry; D008297:Male; D008875:Middle Aged; D009281:Naphthalenes / Q000032:analysis / Q000652:urine*; D016273:Occupational Exposure / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons
D000395:Air Pollutants, Occupational; D002273:Carcinogens; D009281:Naphthalenes; D011084:Polycyclic Aromatic Hydrocarbons; C031721:naphthalene