title: Current external and internal exposure to naphthalene of workers occupationally exposed to polycyclic aromatic hydrocarbons in different industries.
abstract: 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.
authors.affiliation: Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, University of Erlangen-Nuremberg, Schillerstrasse 25/29, 91054 Erlangen, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Preuss
authors.forename: Hans
authors.initials: H
authors.lastname: Drexler
authors.forename: Melanie
authors.initials: M
authors.lastname: Böttcher
authors.forename: Michael
authors.initials: M
authors.lastname: Wilhelm
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüning
authors.forename: Jürgen
authors.initials: J
authors.lastname: Angerer
mesh_terms: 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
chemical_list: D000395:Air Pollutants, Occupational; D002273:Carcinogens; D009281:Naphthalenes; D011084:Polycyclic Aromatic Hydrocarbons; C031721:naphthalene