enviroment human health

1. OCCUPATIONAL HAZARDS
AND PRINCIPLES OF
CONTROL
DR. SHADMAN NASREEN

2. OBJECTIVES:
■ Identify the occupational health hazards associated with
workplace
■ Recognize the effect of exposure to hazardous
substances
■ Explain the etiology and clinical features of occupational
diseases
■ Understand the responsibilities of doctor providing
occupational health services
■ Learn the significance of using appropriate preventive
measures and work practice controls to prevent the
occupational diseases

3. CONTENTS:
■ Hazards
– Physical hazards
– Chemical hazards
– Biological hazards
– Psychosocial hazards
■ Pneumoconiosis
■ Plumbism
■ Sickness absenteeism
■ General control of occupational hazard
■ Legislation on occupational health in Pakistan

5. DISEASES DUE TO PHYSICAL
AGENTS:
COLD
Chillblains Trench Foot Frost Bite

6. DISEASES DUE TO PHYSICAL
AGENTS:
PHSICAL
AGENTS
DISEASES
Heat
Heat hyperpyrexia, heat exhaustion, heat syncope,
heat cramps, burns and local effects e.g., prickly
heat
Light Occupational cataract, Miner’s nystagmus
Pressure Caisson disease, air embolism, blast (explosion)
Noise Occupational deafness
Vibration
Motion sickness, blurred vision, Raynaud’s
phenomenon, permanent disability
Radiation Cancer, Leukemia, aplastic anemia, pancytopenia
Chemical Factors Injuries, accidents

7. Irritant Gases or Fumes:
GAS/FUME
S
SOURCES ACUTE EFFECTS CHRONIC
EFFECTS
Ammonia Fertilizers,
explosives,
refrigeration, oil
refining, plastic
production
Pain in eye, mouth &
throat, oedema of mucous
membrane, conjunctivitis,
pulmonary oedema
Airway
obstruction
Chlorine Alkali, bleaches
and
disinfectants
Chest pain, cough,
pulmonary oedema
Occasionall
y Airway
obstruction

8. GAS/FUM
ES
SOURCES ACUTE EFFECTS CHRONIC
EFFECTS
Nitrogen
oxides
Silo filling, arc
welding,
combustion of
nitrogen containing
materials
Pulmonary oedema,
obliteration of bronchiole
in severe cases
Permanent
lung
damage if
continuous
exposure
Ozone Argon-shielded
welding
Cough, chest tightness,
pulmonary edema
None
Phosgene Chemical industry,
WW1 gas
Pulmonary oedema Chronic
bronchitis
Sulphur
dioxide
Paper production,
oil refining,
atmospheric
Pain in eye, mouth &
throat, oedema of
mucous membrane,
Chronic
bronchitis

9. GAS/FUM
ES
SOURCES ACUTE EFFECTS CHRONIC
EFFECTS
Mercury
vapour
Chemical and
metal industries
Cough and chest pain,
acute pneumonia
Rarely
pulmonary
fibrosis
Osmium Chemical &
metal industries
lab.
Tracheitis, bronchitis,
conjuctivitis
None
Vanadium
pentoxide
Ash and soot
from fuel oil
Nasal irritation, chest pain,
cough
Bronchitis,
bronchopne
umonia
Zinc
chloride
Manufacture of
dry cells,
galvanizing
Tracheobronchitis None

10. DISEASES DUE TO CHEMICAL
AGENTS:
■ Metals and their compounds: Toxic hazards from lead,
mercury, cadmium, manganese, beryllium, arsenic,
chromium etc.
■ Chemicals : Acids, alkalies, pesticides
■ Solvents : Carbon bisulphide, benzene, trichloroethylene,
chloroform, etc.
Grain dust

11. DISEASES DUE TO CHEMICAL
AGENTS:1.DUSTS (Pneumoconiosis)
Inorganic dusts:
a. Coal dust ____ Anthracosis
b. Silica ____ Silicosis
c. Asbestos ____ Asbestosis, cancer lung
d. Iron ____ Siderosis
Organic (vegetable) dust:
a. Cane fibre _____ Bagassosis
b. Cotton dust _____ Byssinosis
c. Tobacco _____ Tobacossis
d. Hay or _____ Farmer’s lung
grain dust

12. Occupational Dermatosis:
■ Contact dermatitis : Epoxy resins, rubber chemicals,
chrome, nickel, cobalt, formaldehyde, antibiotics, local
anesthetics
■ Eczema

13. OCCUPATIONAL
CANCERS
AGENT CANCER
Asbestos Mesothelioma
Arsenic Skin, Lung, Liver
Benzene Leukemia
Benzidine Urinary bladder
Beryllium Lung
Cadmium Lung
Chromium Nasal sinus, Lung
Ethylene oxide Leukemia
Ionizing radiation Skin, Thyroid, Lung
Nickel Nasal sinus, Lung
Polycyclic aromatic hydrocarbons Skin, Scrotum, Lung
Radon Lung
Silica Lung
Vinyl chloride Liver

14. Effect of Radiation:

15. DISEASES DUE TO
BIOLOGICAL AGENTS
DISEASES DUE TO
PSYCHOLOGICAL
ORIGIN
■ Industrial neurosis
■ Hypertension
■ Peptic ulcer etc.
■ Brucellosis
■ Leptospirosis
■ Anthrax
■ Actinomycosis
■ Hydatidosis
■ Psittacosis
■ Tetanus
■ Encephalitis
■ Fungal infections etc.

16. PNEUMOCONIOSIS:
■ “A disease of the lungs due to inhalation of dust,
characterized by inflammation, coughing, and fibrosis”
■ Particles 0.5 – 3 micron are dangerous
■ Ventilatory function by “Peak flow meter” and
“Spirogram”
■ Following indices can be measured:
■ Forced expiratory volume in 1 sec (FEV1)
■ Forced mid expiratory flow rates (FMF)
■ Forced vital capacity (FVC)
■ FEV-FVC ratio

17. SILICOSIS:
■ Cause : inhalation of silica or silicon dioxide (SiO2)
■ Industries involved : Mining industry (coal, mica, gold,
silver, lead, zinc, manganese and other metals), pottery
and ceramic industry, sand blasting, metal grinding,
building and construction work, rock mining, iron and
steel industry and several others
■ Incubation period : few months - 6 years
■ Pathogenesis: particles ingested by phagocytes
accumulate and block lymph channels
■ Characterized by dense nodular fibrosis

18. ■ Sign and Symptoms :
Irritant cough, dyspnea on
exertion and pain in chest, in
more advanced cases TLC of
lung becomes impaired
(rarely shows tubercle bacilli)

19. ANTHRACOSIS:
■ A type of coal workers' pneumoconiosis due to inhalation
of coal dust not containing silica.
■ 2 phases
– 1st is called “simple pneumoconiosis” little ventilatory
impairment
– 2nd characterized by massive pulmonary fibrosis
■ Sign & Symptoms : chronic cough, sputum production
in case of pulmonary fibrosis --- dyspnea, respiratory
failure

20. ■ Chest X-Ray: Small irregular opacities (prominent in upper lobes
mostly)
Large masses often surrounded by lucent regions
■ Differential Diagnosis: (PFT showing lung restriction in absence of
pulmonary fibrosis or systematic symptoms)
Sarcoidosis, Fibrosing alveolitis
PREVENTION:
1. Proper ventilation
2. Improved work practices (wetting coal face before mining it and
wetting dust before removing it from mine shaft)
3. Affected workers should be removed from further exposure
4. Respiratory support (supplemental oxygen), bronchodilator therapy

21. BYSSINOSIS
■ Cause: Inhalation of cotton fibre
■ In textile industry
■ SIGN & SYMPTOMS : chronic cough, progressive
dyspnea, chronic bronchitis, emphysema

22. BAGASSOSIS
■ CAUSE:
– Inhalation of bagasse
– Occurs due to inhalation of spores of thermophilic
actenomycete named Thermoactinomyces sacchari
■ SIGN & SYMPTOMS:
Breathlessness, cough, hemoptysis and fever.
Impairment of
pulmonary function. If left untreated, diffuse fibrosis,
emphysema and bronchiectasis

23. ■ Skiagram : Mottling in lung and shadows
PREVENTION:
■ Dust control (wet process, enclosed apparatus,
exhaust ventilation etc.)
■ Personal protection (mask or respirator with
mechanical filters or with oxygen or air supply)
■ Medical control (periodical medical checkups)
■ Bagasse control : by keeping the moisture
content above 20% and spraying the bagasse
with 2% propionic acid which is a fungicide

24. ASBESTOSIS:
■ Lung disease that develops by inhaling asbestos fibers and
they cause scarring in lungs
■ Is a natural mineral, used in asbestos cement, fire proof
textiles, roof lining, brake lining, gaskets and several other
items
■ PATHOLOGY: Deposited in alveoli causing pulmonary fibrosis
leading to respiratory insufficiency and death
■ SIGN & SYMPTOMS: Dyspnea in advanced cases clubbing of
finger, cardiac distress and cyanosis
■ Greater risk of lung cancer (bronchial cancer, mesothelioma)

25. ■ Fibrosis is diffuse in character
and basal in location while in
silicosis fibrosis is nodular and
present in upper part of lung
■ Sputum shows “asbestos
bodies:
“Ground-glass
appearance”

26. Preventive measures:
■ Use of safe type of asbestos (chrysolite, amosite)
■ Substitution of other insulants (glass fibre, mineral
wool, calcium silicate, plastic foam etc.)
■ Dust control
■ Periodic examination of workers, biological monitoring
(clinical, X-ray, lung function)
■ Continuing research

27. FARMER’S LUNG:
■ Due to inhalation of mouldy hay or grain dust
■ Cause : Thermophilic actinomycetes of which
Micropolyspora faeni is the main cause of farmer’s
lung
■ Pulmonary fibrosis, inevitable pulmonary damage and
corpulmonale
Pulmonary Fibrosis

28. PLUMBISM (LEAD POISONING)
SOURCES OF LEAD:
■ Manufacturing storage batteries, glass manufacturing, ship building,
printing & potteries, rubber industry etc.
■ Non-occupational sources------gasoline, drinking water, chewing lead
paints on widow sills or toys in case of children
MODE OF ABSORPTION :
■ Inhalation
■ Ingestion
■ Through skin

29. CLINICAL FEATURES:
■ Inorganic Lead ----- Anorexia, abdominal colic, anemia,
blue line on gums, basophilic stippling of RBC,
constipation, wrist drop and foot drop
■ Organic Lead ------- insomnia, Persistent headache,
mental confusion, delirium etc. (CNS symptoms)
LABORATORY TESTS:
a. Coproporphyrin in urine
b. Amino levulinic acid in urine
c. Measurement of lead in blood & urine
d. Basophic stippling of Red Blood Cells

30. PREVENTIVE MEASURES
■ Substitution: by less toxic material
■ Isolation: harmful conc. of dust & fumes should be
enclosed and segregated
■ Personal Protection: by respirators
■ Good Housekeeping: essential where lead dust are
present. Floors, bench, machines should be kept clean by
wet sweeping
■ Working Atmosphere: in working place its conc. should
be kept below 2 mg/10 cu metres of air

31. ■ Periodic Examination of Workers: lab determination of urinary lead, blood lead, red cell count,
haemoglobin estimation and coproporphyrin test of urine should be done periodically
■ Personal Hygiene: hand washing before eating, adequate washing facilities in industry, prohibition
on taking food on work place
■ Health Education: high risk and personal protection.
■ MANAGEMENT:
Saline purge (will remove unabsorbed lead from gut)
■ Penicillamine (has been reported to be effective)
■ Ca-EDTA is a chelating agent and promotes lead excretion in urine

32. MANAGEMENT:
■ Saline purge (will remove unabsorbed lead from gut)
■ Penicillamine (has been reported to be effective)
■ Ca-EDTA is a chelating agent and promotes lead
excretion in urine

33. SICKNESS ABSENTEEISM
■ Term used to refer to unscheduled employee
absences from the work place
Prevention:
■ Good factory management and practices
■ Adequate preplacement examination
■ Good human relations
■ Application of ergonomics

34. LEGISLATION ON OCCUPATIONAL
HEALTH IN PAKISTAN
■ Factories Act 1934: Chief inspector of Factories is
authorized to declare any process as hazardous
■ Dock Labourers Act 1934
■ Mines Act 1923
■ Workman Compensation Act 1923
■ Provincial Employees Social Security Act 1965
■ Boilers and Pressure Vessels Ordinance 2002
All depends on inspector industries to enforce these
laws