الفهرس 
Manufacturing processes of plasticsOnly 14 pages are availabe for public view
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Abstract
This work was conducted in a plastic factory (Menoufia
governorate) to study respiratory and auditory disorders which may arise
among workers in that industry.
This study included an exposed group of plastic workers (180) who
accepted participating in the study and a control (unexposed) group (60)
from the worker’s relatives. Both groups were matched for age, sex,
residence, marital status, income and educational level.
The exposed group and controls were interviewed using a predesigned
questionnaire about respiratory and auditory manifestations. Also, they
were examined generally and locally for chest and ears. Spirometric
measurements as well as Audiometry were carried out for both exposed
group and controls aiming to assess pulmonary functions and hearing
thresholds.
Environmental studies were done by Tabbin Institute for
Metallurgical Studies Central Laboratory for the Studies Industrial
Pollution (TIMS/ CLISP) periodically via air sampling (using gas
analyzer from the respiratory zone of the workers), assessment of noise at
the level of workers ears (using sound level meter).
Most commonly used plastics polymers are: a) thermoplastic resins as
polyethylene, polyvinyl chloride (PVC), polypropylene (PP), polystyrene
(PS), styrene acrylonitrile (SAN), polycarbonate (PC), and acrylic, b)
thermoset resins as polyurethane, epoxy, phenolics and polyester.
Massive exposure to vinyl chloride may be responsible for
irritation of the respiratory tract congestion; oedema and haemorrhages of
the lungs have been observed in experimental animals.Impaired
Summary and Conclusion
11 5
pulmonary function with decreased alveolocapillary permeability, as
measured by single breath transfer for carbon monoxide (TLCO), was
observed in workers exposed both to vinyl chloride and polyvinyl
chloride dust. The incidence of lung cancers is increased in workers
exposed to vinyl chloride.
Occupational exposure to styrene is related to an increased risk of
hearing loss. Combined exposures to noise and styrene seem to be more
ototoxic than exposure to noise alone.
The following results were obtained:
- Polyvinyl chloride (PVC) and styrene levels were higher than that
recommended by the Egyptian Ministry of Trade and Industry, Law 4
Decree 1095/2011 and NIOSH (2002).
- Noise level was higher than the permissible exposure limits (PEL) by
Egyptian environmental Law 4 for the year 1994 and NIOSH (1998) in
some departments.
- The prevalence of chest manifestations e.g. cough, dyspnea, wheezes
and asthma were significantly higher among exposed group than controls
among exposed smokers than exposed non-smokers. .
- Regarding auditory manifestations, the exposed workers experienced a
significantly higher prevalence of hearing impairment and tinnitus than
controls.
- Concerning the mean values of spirometric measurements the FEV1%,
FEV1/FVC %, FEF25-75% and PEF% were significantly lower among
exposed group than controls. Exposed smokers experienced significant
lower mean values of the FVC%, FEV1%, FEV1/FVC % and FEF25-75%
than exposed non-smokers.
Summary and Conclusion
11 6
- Audiometric findings show different grades of decreased hearing
threshold. Noise induced hearing loss is bilateral with V-dip depression in
audiogram. This appears in some workers of exposed group not control
one.
- Within exposed group, the grinding department workers showed lower
spirometric measurements than other departments and this may be
attributed to the higher PVC and styrene level in this department.
- Within exposed group, the grinding department workers showed higher
prevalence of audiometric findings than other departments and this may
be attributed to the higher noise level in this department.
from above results, we can conclude that exposure to high level of
PVC, styrene and noise in plastic industry are blamed to increase the
frequency of chest manifestations, early spirometric changes and
occupationally induced hearing loss; respectively.