Affiliations: Research Lab Supervisor, Urban Environmental
Engineering and Management Program, School of Environment, Resources and
Development, Asian Institute of Technology, G.P.O. Box 4, Klong Luang,
Pathumthani 12120. Thailand
Abstract: This study was conducted to assess the occupational exposure and its
health impact on the chromium alloy workers. Environmental and biological
monitoring, noise and audiometry measurements were done to evaluate the
exposure levels in the factory. A total of 112 non-smoking workers were
monitored from July 2001 to August 2002. The results showed that most of the
chromium and lead exposures in the factory were below the ACGIH-TWA of 50
μg/m^3 for chromium (VI) and OSHA-PEL of 50
μg/m^3 for lead. The highest chromium (7.25 ± 0.16
μg/m^3) and lead (14.50 ± 0.29
μg/m^3) concentrations were measured in the vibro room.
The results indicated that elevated concentrations of chromium and lead were
found in both blood and urine samples especially in those areas which were
characterized by poor ventilation. The metal contents in blood and urine
samples were significantly correlated with airborne metal concentrations in the
factory. The result demonstrated that blood and urinary levels among workers
were associated with increasing age and duration of exposure. The background
noise level of the factory ranged from 67.6 to 89.2 dBA and was frequently
higher than the threshold limit value for noise (90 dBA). According to the
audiometric test, the exposed workers showed signs of noise-induced hearing
loss. Noise at work continued to be an important factor to hearing loss among
exposed workers. In our statistical analysis, a significant hearing loss was
established on age effect and year of exposure among the workforce.
Keywords: chromium and lead exposure, electroplating, environmental and biological monitoring, audiometry measurement