Dr. S.K. Haldar's Lectures on Industrial Health for AFIH Students - Occup. Health Hazards- Physical...

7/30/2019 Dr. S.K. Haldar's Lectures on Industrial Health for AFIH Students - Occup. Health Hazards- Physical Agents

1/28

4/12/2012 Dr. Haldar

Occupational Health Hazards & Its Control

Industrial Health

Industrial Hygiene

Industrial PsychologyIndustrial Physiology

Institutional Training

In Plant Training

Occupational Study :- National & Consultation

Occupational Health Audit:- Safety & Health Audit

Health Audit:- Pre-requisite for Thermal Power Plant

Occupational Health Survey:- From Competent Authority and from Outside Authority

Bernardo Ramazini:- An Italian Scientist labelled as Father of Occupational Health.

Occupational Health

OH

OD/H OE

Occupational Diseases/Hazards Occupational Environment

Occupational Environment is defined as :- External Condition & Influences prevailed at the place of

work which has direct & indirect effect on health of working population.

Occupational Health is the promotion & maintenance of highest degree of Physical, Mental & Social

well being of workers in all occupations. It is a division of General Medicine & is devoted to prevention

of Occupational Diseases & Injuries & Promotion of Health of people at work.

Principles of Occupational Health:- 1) Prevention

2) Promotion:- Training of people

3) Protection

4) Adaptation

5) Cure & Rehabilitation

6) Primary Health Care

1) Prevention:- Prevention of accidents, heat stress, NIHS etc.

2) Promotion:- Primacy:- Detailed training of job hazard.

Frequency:- Periodical Training.

Resency:- Lay Mans gap is big, they may forget. Thus feeding of information

Through posters, Exhibits etc. is required.

3) Protection:- Personal Protective Devises (PPE)

4) Adaption:- Acclimatization, cope up adjustment

5) Cure & Rehabilitation

6) Primary Health Care

Occupational Disease:- Disease which arises out of or in course of occupation. It is difficult todiagnose, has long incubation period, in early stage show no signs & Symptoms. In advance stage it

becomes a burden on the person, family, company and on nation.


2/28

Etiological Fractions of OD:- Skin Diseases:- 45%, maximum

Musculo-skeletal:- 33%

Nervous:- 30%

Respiratory Diseases:- 25%

Cardiovascular:- 20%

Mental:- 5%

Cancer:- 4%, least of total cancers in the world

Interaction in Occupational Environment:-

Workers Vs Physical AgentsChemical Agents

Biological Agents:- e.g. Mosquito bite

Workers Vs Machines

Workers Vs Workers

Types of Hazards:-

1)Physical 2)Chemical 3)Biological 4)Mechanical:- Accidents, Injuries & 5)Psychological

1) Physical Agents:- 1) Heat :- erethema abegnie(?):- brownish discolouration

2) Cold:- Ice forming freezing, Non ice forming freezing. Used for generalized

shipment preservation. Causes Local:- Frost bite;- Superficial (only skin effect,Deep:- Internal tissues involved, Thawing, immersion feet / Trench feet

3) Noise

4)Vibrations:-Hand drum vibrations (8 Hz/sec White Fingers, Renolds

Phenomenon

5) Ionizing Radiation(Penetrate tissues & deposits its energy (Alpha, Bata &

Gamma)

6)Non Ionizing Radiation:- UV rays, Infra Red Rays (Immediate-sickness,

Delayed :- Somatic- carcinoma, Leukaemia, Genetic:- Chromosomal Point

Mutation) , Micro Wave, Laser

7)Electricity:- Voltage, Path through body, duration, resistance at the point of

entry &8)Light.

0

5

10

15

20

25

30

35

40

45

50


3/28

9) Barometric Pressure:- High, Low. Barotraumas- Kolar Gold mines

Compression Barotrauma affects ears, eyes, joints. Barometric Pressure at sea

level is 100 KPa. At pressure 7,000 KPa symptoms starts.

Decompression Syndrome:- air embolism due to Nitrogen bubbles during

decompression. V = P X T

10) Ultrasonographic (USG):_ Long term exposure causes disintegration of

tissues, which mainly affects RBCs leading to Anaemia11) Electromagnetic Field (EMF):- Unit of EMF is Tesla:- Permitted 1uT. Causes

Cancer, Reproductive problems:- Males:- Brain Tumour

Females:- Foetal Developmental abnormalities, Miscarriages, abortions,

Psychological:- Suicidal Tendency

No effect on heart but causes disturbances t pace maker.

12) Moisture

13) Colour:- Ceiling white, Red is freshening

14) Fire:- Emit about 400 toxins, Chemical Asphyxiants (CO, H2S, HCN), CO2 is

simple Asphyxiant:- stimulates respiratory centre causing increasing depth &

rate of respiration, thus more amount of toxic gases are inhaled. Thus indirectly

helping toxicity of other asphyxiants.Welding:- Flash / Arc Eye:- due to UV rays- Redness, watering, foreign body

sensation, diplopia- 48 Hours of rest needed.

15) Barotrauma:- Barometric Pressure High or low

Model Rule (A + B) / 2 = anteroom (?)

Metal Fumes Fever:- While welding fumes of metals like Zn, Cadmium, Aluminium (metal fumes

containing Al & Cadmium):- Flu like symptoms lasting for few hours, sometimes breathlessness &

asthma.

Mill Fever:- Exposure to cotton, flax or hump:- Fever, non productive cough, malaise, sneezing, whichlasts for few hours, due to endotoxins from Gr.-ve bacteria contaminating cotton.

Bagasosis:- Acute Monday fever due to delayed hypersensitivity (Pl. Check)


4/28

2) Chemical Agents:-

Dust Gases Metals & their Fumes Solvents Chemicals

Organic inorganic Acid

Sugarcane Silica AlkalisHay Coal Organic

Asbestos

Irritants Asphyxiants Drugs Like

(Heart of Total Hazards)

Primary Secondary Anaesthetic Solvents Hydrocarbon

Affecting Secondary Ether Chloroform

Site of to absorption Benzene

Absorption gives Systemic Toluene

effectsOR Simple Chemical

Water Water CO2 CO

Soluble Insoluble Methane, H2S

(Readily) ( Slightly Hydrogen HCN

Soluble) Aniline

Dust:- Silica, Nascent:- Chalk Dust

Asphyxiants:- Does not allow body to utilize Oxygen

Cement:- Dermatitis, Burns & Ulcers

Oil:- Contact Dermatitis, Oil AcneAsbestos:- Crocidolite Asbestos is Banned. Asbestos fibres with hemosidrin form asbestos bodies which

are retained in the alveoli.

Why Blue Asbestos is dangerous:-1) It is brittle, so cause more dust leading more amount inhalation.

2) Cannot produce asbestos bodies. There is no clearance.

3) edges are very sharp cause much irritation.

4) Causes Mesothelioma of Pleura, Lung & GIT Cancer

Silicosis:- Many times causes Mixed dust fibrosis. Silica + Iron in steel, iron mines.

Coal miners lung

Stannosis:- Tin dust

Lead:- Inorganic Lead:- Foot drop, wrist drop

Organic Lead:- Leaded Petrol, Tetra ethyl lead, anti-knocking agentPhenol Lead: Cause leucoderma, Bindi

Chromium:- Chrome Ulcers, holes

Chromium, Nickel, Cadmium, Arsenic cause Nasal Septal Perforation (Pl Check)

Smoking & Occu. Disease:- Additive effect all irritant gases

Synergistic:- Smoking + Asbestos

Potentiating:- Smoking + Cotton

Reducing:- Zinc, Cadmium

Coke:- When Coal is burnt produces ash. If coal is burnt without Oxygen produces coke. Coke is used

in ink industry, to produce gramophone records.

Silica:- SiO2 3 types 1) Quartz 2) Tidimi @ 800 C 3) Crystabolite @ 1200 C

Boiler lining cleaning, Sand blastingDispersion Module:- SO2, Ammonia, LPG, CS2


5/28

Chemical Interaction & Its effect on Human Body

Additive Synergistic Potentiating Reducing

All irritant Gases Smoking+ Asbestos Smoking + Cotton Zinc, Cadmium

3) Biological:- Bacteria, Viruses, Protozoa( rat, cat, dog, snake bite),

Anthrax:- Cutaneous, PulmonaryLigionella

4) Mechanical:- Accidents, Injuries

Environmental Human

Physical Physiological Psychological

Heat Colour Blind Age Accident Proneness

Noise Deaf Sex Over Enthusiastic

Experience

Orientation

Timing

Shift

5) Ergonomics:-Computer operators


6/28

5) Psychological:-

Behavioural Psycho- somatic

Neurosis High BP

Fear Sleeplessness

Alcoholism Peptic Ulcer

Drug Addiction

Sustained Trauma Disorder (STD) / Cumulative Trauma Disorder (CTD)

Work related Musculo-skeletal disorders

Exercise Program:- Fitness gain

Nutrition at work

Preventive Measures:- Medical

Safety

Statutory / Legislative

Administrative:- acclimatization

Medical Examination :- Pre-employment, periodic, Pre-placement, Pre-retirement & Special

Notification:- 29 (+5) notifiable diseases, compensable by Workmans Compensation Act

If the disease is misdiagnosed by the doctor penalty is Rs. 1,000.

1) OHS Principles2) First Aid Boxes:- Factory Act chapter IV a added after Bhopal Gas Disaster.3) FA Centre4) Hospital

OHS IN India:- Supervision

Maintenance

Health Education & Counselling

Donabedian Model

UK, US Model

Repeat audit on regular basis in order to ensure Set Standards

That the standards are maintained

Measure / Observe Current Practices

Impose changes in order to meet Corporate current procedures &

or improvements

This is a common model for Occupational Health Audit.


7/28

5/12/2012

Physical Hazards

1) HEAT

Flow chart of Heat Hazards

Heat Loss by all means Woker

(Radiation, Convection, Conduction, Evaporation) entering into factory

Increased Body Heat

Shifting of heat to periphery (higher to lower)

Heat Stress

Loss of Heat (Evaporation)

Heat Strain

(after working for sometime)

Sweating Vasodilatation (VD)

Heat Stress:- The amount of heat that is to be eliminated from human body in thermal equilibrium &

measured as metabolic Heat load & Heat Loss or Gain through the process of Convection, Conduction,

Radiation & Evaporation.

Heat Equilibrium M+ (R+C+K) E = S

M = Metabolic Heat Load, R = Radiation, C = Convection, K = Conduction, E = Evaporation,

S = Stored Heat / Heat Stress

Thus equation becomes:- M + (R+C+K) E = + S As per heat gain or loss

Heat Strain Physiological or Pathological changes of body due to heat stress.

Vasodilatation causes sweating. Upto this level heat is compensated. Loss of heat is from body surface,

thus the internal heat is shifted to periphery. This is the cut off point called as Prescribing Zone.

Vasodilatation

Sweating

Fluid Depletion (heat exhaustion) Loss by Evaporation

Salt Loss causing Heat Cramps Mainly Calf & Abd. Muscles Heat Hyperpyrexia

Vasodilation (Pulling blood to lower part of the body) Complete Stoppage of Sweating

Less Blood to Brain Heat Stroke

(Temperature Regulating Centre

Heat Syncope Paralysed 40% Mortality)

(Thermo Regulatory centre is not paralysed)

Indirect effects :- More accidents, errors, fatigue, sleepless nights, decrease productivity.

Measurement of Heat Stress:- Heat stress can be measured by two departments 1) MedicalDepartment 2) Hygiene Department

Hygiene Department measures Ambient Temperature.


8/28

Medical department:- Usually a worker has 3 breaks. Take the resting pulse weight, & oral

temperature. After working for maximum hours take the measurements again.

Give minutes of rest, then take pulse for one full minute ( 0.5 to 1.5 min.). This is P1. Now give rest

for one minute ( 1.5 to 2.5min.). Now take the pulse again. This is P3.

In Heat Stress:- 1) Oral Temp. Is more than 37.5C

2) P1 is more than 1103) P1 P3 is less than 10

This all should be done at work place, called as Work Place Health Monitoring.

Cooling measure is the immediate treatment. In this case rectal temp should not go below 102 F.

Preventive measures:- Well ventilated rest room, Drinking water, Salt water. All measures should be at

source.

Acclimatization:- This is 1 to 2 week program. Actual workers duty is at 100 F carry 100 Kg. Of load.

On day 1:- Built a set up- Start with 50 F & 50 Kg Weight and increase by 10 % every day. Thus on last

day of the week he will have full load. From next week continue with full load.

In acclimatization sweating is same but retention of salt is more and excretion of salt in urine is less.

This is due to Renin Angiotensin - Aldosteron Mechanism. Thus here excretion of salt is mainly

through sweat.In Heat Stress Comfort Zone (Worker can work comfortably) depends upon 1) CET (Corrected Effective

Temperature and 2) P4SR (Predicted 4hour sweat rate)

1) Corrected Effective Temperature :- This is a combined effect of 1) Ambient Temp. 2) AirMovement (Internal Air Movement should touch the skin of the worker) 3) Moisture 4) Radiant

Heat. These all should be added to correct the effective temp.

2) P4SR Predicted 4 hour sweat rate:- 1 to 3 lit. S a comfort zone.Corrected Effective Temperature

Zone Corrected Effective Temperature in Farenheight

Pleasant & Cool 69F

Comfortable & Cool 69F 76FComfortable 77F 80F

Hot & Uncomfortable 81F 82F

Extremely Hot 83F 85F

Intolerably Hot 86F+

P4SR:-

Zone Sweat Rate

Comfortable 1 3 Lit.

Just Tolerable 3 4.5 Lit.

Intolerable More than 4.5 Lit.

Model Rule for permissible limit of heat (Permissible Heat Exposure Threshold Limit Values)

Work & Rest Regiment Light Work Moderate Work Heavy Work

Continuous 30 C 26.7 C 25 C

75% Work + 25% rest in each hour 30.6 C 28 C 25.9 C

50% Work + 50% rest in each hour 31.4 C 29.4 C 27.9 C

25% Work + 75% rest in each hour 32.2 C 31.1 C 30 C

Heat causes Marjolins ulcers on face due to sun burn or heat. It is pre cancerous condition. It also

causes Keloid.


9/28

7/12/2012

2) NOISENational Programs on Occupational health are two:- 1) Hearing Conservation Programs 2) Vision

Conversation Program

Definition :- According to ANSI (American National Standard Institute) any unwanted sound is Noise.

Noise is conducted By 1) Air Air Conduction (AC) and 2) Bone Bony Conduction (BC)

Sound Wave hits the tympanic Membrane, which then vibrates. In the middle ear there are three

ossicles Malleus, Incus and Stapes, situated between Tympanic Membrane & Round Window. The

wave motion is converted into mechanical motion and passes through these ossicles passes to inner ear

into perilymph. It vibrates the perilymph. In the inner ear are situated cochlear hair cells. Movements

of their cilia produce action potential. The electric current passes through nerve cells to brain, where it

is interpreted.

Types of Noise:- a) Continuous

b) Impulse / Hammering

c) Interrupted:- i) Subjective ii) Objective

Units of Noise:- 1) Intensity or loudness dB measured by Noise Level Meter or Sound Level Meter

2) Frequency or Sharpness Hz

dB has 3 scales A-Mimicking ear, B & C

Permissible Limit as per Factory Act 1948

Hours of

Exposure

dB

Model Rule (India) As per OSHA Rule As per ACGIH

16 Hrs. - 85 80

8 Hrs. 90 90 85

6 Hrs. 92 90 -

4 Hrs. 95 90 90

3 Hrs. 97 90 -

2 Hrs. 100 90 95

1 Hr. 105 90 100 Hr. 110 90 -

Hr. 115 90 -

1 dB :- When a dry leaf falls on earth, the colliding noise is 1 dB.

Hammering or Impulse sound:-

Sound in dB No of impulses in 24 hours

140 100

135 315

130 1,000

125 3,160

120 10,000Deafness:- Types:-1) Conductive

2) Perceptive or sensory neural

3) Mixed


10/28

Audiometric Chart

Normal Conductive Deafness

(Bone Conduction)

E-----E-----E----E-----E-----E-----E-----E

O----O----O----O----O-----O----O----O

(Air Conduction)

E-----E-----E----E-----E-----E-----E-----E

(Bone Conduction)

O----O----O----O----O-----O----O----O

(Air Conduction)

Both Abnormal Zones

Perceptive(Sensory Neural) Mixed

(Bone Conduction)E-----E-----E----E-----E-----E-----E-----E

O----O----O----O----O-----O----O----O

(Air Conduction)

E-----E-----E----E-----E-----E-----E-----E

(Bone Conduction)

O----O----O----O----O-----O----O----O

(Air Conduction)

Minimal Gap Long Gap

Audiometric Room:- Should be small and preferably AC. If it is AC room measure the noise in the room.

It should be below 25 dB.

Keep the frequency dB fixed and go on increasing the intensity Hz.

Threshold of Perception = Minimal sound required to be audible to a particular person at that

frequency.

In audiometry we measure AC & BC of each ear. We can measure Air Conduction upto 8,000 Hz and

Bone Conduction upto 4,000 Hz. Normal AC & BC are upto 25dB. Bone Conduction is disturbed only

when there is profound problem. AC & BC of each ear are denoted as follows:-AC Right ear :- 0----0----0-----0-----0 AC Left ear :- x----x----x-----x-----x

BC Right ear :- E----E-----E-----E-----E BC Left ear :- ]----]-----]-----]-----]


11/28

First start from 100 dB then gradually go on reducing. Yes No Yes is the 50% response and that is the

threshold. Destruction of hair cells of cochlea causes sensory neural deafness.

Health Effects / Hazards:- 1) Auditory 2) Non auditory

Auditory:-Conductive as well as Perceptive 1) If it is a blast / loud hammering noise, the tympanic

membrane may rupture causing Conductive deafness.

2) Occupational :- NITTS (Noise Induced Temporary Threshold Shift) or NIHL (Noise Induced

Hearing Loss). NITTS is due to fatigue of Hair cells (Cochlear cells). In such case give complete rest for48 hours and then do audiometry again, if still there is hearing loss then it is permanent hearing loss

Characteristics if NIHS:- (Painless, Progressive, Permanent, Precedes NITTS, Preventable,

1) Gradual2) Painless3) Bilateral4) Irreversible5) Precedes NITTS6) In early stage normal conversation is not disturbed7) When exposure increases, invades upper & lower frequencies ranges8) Always starts at 4,000 Hz9) Sensory neural type of deafness10) Depends upon individual susceptibility11) Not amenable to treatment12) It can be measured

It starts at 4,000 hz

4,000 Hz

Why at 4,000 Hz ?

Mechanical theory of Tanndof:- The initial segment (first turn) of cochlea is responsible for 4,000 Hz of

frequency. The sound hit the first turn first where the first damage occurs.

Bone conduction:- We can measure bone conduction upto 4,000 Hz only.

Recent concept of Fence Value:- High & Low fence value

High:- above 91.4 to 100% hearing loss

Low:- upto 25% hearing lossHow to calculate this fence value ?

For example:-

25 dB


12/28

--Hz Threshold of Perception--

500 1000 2000 3000

Right Ear 40 35 40 45 =160/4=40

Left Ear 50 45 50 35 =180/4=45

Now we calculate % hearing loss:- Lower level Upto 25 is normal, thus

Right ear:- 40(value from above table) 25 (normal) = 22

1dB loss = 1.5 % hearing loss

So% hearing loss in right ear =22 X 1.5 = 22.5 % hearing loss

% hearing loss in Left ear from above table = 45 25 = 20 X 1.5 = 30 % hearing loss

How to calculate Hearing Handicapped ?

Better ear = 22 X 5 = 110

Poorer Ear = 30 X 1 = 30

Combined together 110 + 30 = 140 /6= 23% handicapped

Better ear multiplied by 5 and Poorer ear is multiplied by 1

This multiplication by 5 & 1 is a research work done by AAOO (American Agency of Ophthalmology and

Otorhinolaryngeology).

Calculation of hearing impairment

From audiogram calculate the average of the thresholds of hearing for frequencies of500,1000,2000,4000 and 6000 Hz.

Deduct 25 db. Multiply it by 1.5 We will get the percentage of hearing impairment for that ear.

Percentage handicap

The percentage handicap of an individual is calculated using this formula : [Better ear % x 5] + [worse ear % ]

6

Old age Deafness is also Sensory Neural Deafness:- For compensation purpose age factor is not

considered.

For every of age after 40 yrs of age there is 0.5 dB of loss. So Age above 40 multiply by 0.5 dB for every

year.

(pl. Check following equation)

e.g age is 50 yrs. Age Factor - Industrial Factor

50yrs. - 40yrs. = 10yrs. X 5 multiplication factor=50 - 5 (0.5dB X 10yrs.) =45%


13/28

Peculiarity of Noise:- NIHS is not detected in early stage without audiometry. At the range of 500 to

2,000 Hz normal conversation is heard. Thus in early stage hearing loss cannot be perceived by the

patient. So signs & symptoms cannot be detected.

500Hz 2,000Hz 4,000 Hz

This range of normal conversation 500 to 2,000 is not disturbed, so normal conversation will not be

disturbed. When the patient complaints shortness of hearing means it is advanced hearing loss.

Personal Protective Equipment (PPE):-

Ear Plug:- Maximum reduction possible is 15dB

Ear Muff: Maximum reduction possible is 20dB

Now if first ear plug is worn and over that ear muff is worn, then ear plug reduction will be 5 and earmuff will be 15. This is only for air conduction and not for bone conduction. In that case Hearing

Protective Helmet can be used, this reduces the exposure by 30dB

Property of Frequency:-1) Normal ear range is 20 to 20,000 Hz.

2)It takes progressively less intensity to be audible, upto 4,000Hz.

x120dB

x100dB

25 dB


14/28

4,000 Hz

3) From 1,000 to 4,000 Hz the response is fairly constant

4) From 4,000 to 20,000 Hz a greater intensity is required for sound to be audible.

5) Threshold of Pain:- at the intensity more than 140 dB we feel pain. So Threshold of pain is 140dB.

Level of Intensity:- 1) Soft whispering Voice;- 30 dB

2) Soft Conversation:- 70dB3) Large chipping hammer:- 120dB

4) Turbo Jet Engine :- 160dB

B) Non auditory Effects of Noise:- 1) Pupils dilates, Voluntary & Involuntary muscles contract. BP

Increases, Blood Sugar increases lasts for only few seconds

2)Noise stimulates adrenal glands & induces catacholeaminesle& Circulatory disturbances.

3) May cause nausea, Vertigo, increased heart rate, increased pulse rate.

4) Causes more accidents more errors, less productivity

5)Socially undesirable

6) increased Physical & Psychological stress.

7) Sickness & absentism8) Tendency to speak loudly

9) Pulmonary functions decreases because of loss of surfactants. Thus increased infections.

How to differentiate old age deafness (Presbycusis) and Industrial noise induced deafness ?

1) Usually in old age dB loss is not beyond 65 to 75. In NIHL no age factor.2) At age of 70 yrs. 5,000 Hz is mostly affected. 1,000 to 2,000 Hz does not become significant

until late in life.

3) 4,000 to 6,000 Hz affect is the early effect of age.

25dB

30dB 1KHZ

35dB 2KHZ

40dB 3KHZ

60dB 4KHZ

70dB 5KHZ

100dB

Age 70 Yrs.

Here at the age of 70 years as the frequency increases more & more loss of hearing is seen.

Hearing Conversation Program:-

Aims:- 1) To prevent NIHL

2) To reduce claim for compensation

It has 3 components:- 1) First Phase:- Physical Evaluation of Noise Exposure2) Medical evaluation of hearing

3) Control of noise exposure. Noise slowing, mapping of area by SLM (? Sound Level Meter).


15/28

It is a team approach. Leader of the team is Medical Officer.

Function Members involved

Identification of noise source Industrial Hygienist, Plant Supervisor, Workers

Reduction of noise exposure level Plant Engineer, Industrial Hygienist, Audiologist,

Supervisors & Workers

Hearing Measurements Ottologist, Aodiologist & Workers

Need Audiometers, Noise meters & Protective measures.

Grades of hearing:-

Grade Threshold of perception Hz.

500Hz 1,000Hz 2,000Hz

Ability to understand speech

Non Significant Below 25db No difficulty

Slight 25-40dB Difficulty with faint speech

Mild 40-55dB Frequent difficulty with friends speech

Moderate 55-70dB Frequent difficulty with loud speech

Severe 70-90dB Can hear only shouted speech

Profound 90dB + Very limited hearing

Fallacies of Personal Protective Equipment:-1) Gap between plug & Skin may be more

2) Quality is not upto the mark

3) Material itself vibrates

4) Bone Conduction cannot be obstructed

When two machines together are making noise

Difference between two machines Addition

0 to2 3 will be added

3 to 4 2

5 to9 1

Above 9 0

e.g . Two machines of 85 dB are working at a time, then 85 + 3 = 88 is the cumulative effect.

When to conduct audiometry test ?

After completion of 8 hours of duty conduct first test. Here suppose you find threshold of perception is

40dB. Normal is 25 dB. Now here difference is 15. Give rest of 48 hours and then do audiometry again

at the beginning f the shift. Now suppose you get threshold of perception 30 dB.

Normal is 25. NITTS is 10 and NIPTS is 5. This loss of 5 will be permanent.

Treatment of NIHS:- Cochlear implant

Control Measures:- - Engineering

- Administrative

- Legislative

Sound absorbing material:- - Thermocoal, Wool, Glass wool, Anti eco panels

SLM:- Where persons ear is getting contact

Ear plugs:- Rolled, Pulled, insert

Ear Muffs

Helmets


16/28

-1001020304050607080

90100110

Hearing

(db)

Frequency (Hz)

2540

40-55 dB

55-70 dB

70-90 dB

90 dB +


17/28

Management

Medical treatment: There is evidence that hearing loss can be minimized by taking mega

doses ofMagnesiumstarting early after exposure to loud noise . A Magnesium high diet also seems to be helpful as an NIHL preventive . You can get magnesium from many foods. Foods rich in magnesium

include whole grains, nuts, and green vegetables.Green leafy vegetables

are particularly good sources of magnesium.

Rich sources of magnesium include tofu, legumes, whole grains, greenleafy vegetables, wheat bran, Brazil nuts, soybean flour, almonds,

cashews, blackstrap molasses, pumpkin and squash seeds, pine nuts, and

black walnuts.

Folate may prevent hearing loss in men Increased intakes of folate andfolic acid may reduce the risk of hearing loss in men by 20 per cent.

AdultAdolescent and adult males: 270 - 400 mg daily

Adolescent and adult females: 280 - 300 mg daily

Pregnant females: 320 mg daily

Breastfeeding females: 340 - 335 mg daily

Antioxidants such as vitamins C and E, and beta-carotene were notassociated with any benefits.
http://health.ezinemark.com/magnesium-folate-prevents-hearing-loss-16bd61ec27b.htmlhttp://health.ezinemark.com/magnesium-folate-prevents-hearing-loss-16bd61ec27b.htmlhttp://health.ezinemark.com/magnesium-folate-prevents-hearing-loss-16bd61ec27b.htmlhttp://health.ezinemark.com/magnesium-folate-prevents-hearing-loss-16bd61ec27b.html


18/28

OCCUPATIONAL DEAFNESS

Defects in Audiogram


19/28


20/28

1/1/2013 3)VIBRATIONClassification of Vibration Disorders

Vascular Component

Stage Grade Description

0 - No attacks

1v Mild Occasional attacks affecting only tips of one or more fingers2v Moderate Occasional attacks affecting distal, middle phalanges (rarely proximal) of

one or more fingers

3v Severe Frequent attacks affecting all phalanges of most of the fingers

4v Very Severe As in stage III with tropic skin changes at finger tips

Sensorineural Component

Stage Grade Description

0 SN Exposure to vibration but no symptoms

1 SN Intermittent numbness with or without tingling

2 SN Intermittent or persistent numbness with decreased sensory perception

3 SN Decreased tactile discrimination or loss of manipulative dexterity

Preventive measures of vibration disorders

1) Training of potential hazards of vibrations.

2) Need to service their tools regularly.

3) To grip the tools as per rules. Non slippy, light grip

4) Use of PPE like Attenuated Gloves (antivibration gloves). Due to these gloves there will be no injury,

hands will remain warm & vibrations are reduced.

Raynauds Phenominon:-

To develop Raynauds Phenomenon 3 factors are responsible:-

1) Cold Weather 2) Vibration & 3) SmokingCold weather factor :- Previously this was considered as disease of cold countries. Now-a-days it was

found in our country also.

Mechanism:- 1) Stimulation of sympathetic nervous system with circulatory disturbances

2) Thickening of medial coat of digital artery ( Muscle hypertrophy), thereby occluding

the lumen

3) In later stages results in cyanosis (Acrocynosis)

4) Finally tropic changes to the finger tips.

Smoking & Occupational Diseases:-

Chronic cough, Chronic Bronchitis, COPD, CO toxicity, Cyanide Toxicity, Lead, Cadmium, Benzene

ToxicitySynergistic effect:- Lung Carcinoma in Asbestosis, Vigenosis

Asbestosis, Bysinosis Synergistic Effect of Ca lung

Raynauds Phenomenon:- Precursor of Cancer:- Leuplekia, Lung cancer itself, High B.P., Atheroma:-

Nicotine, CO causes atherosclerosis, Foetal Development Abnormalities, Foetal Toxicity, Abortions

Kidney Damage.

Prevention:- Teach Skills, Attenuated Gloves (Keeps hands worm & moist, prevent injuries, reduces

vibrations)

Periodic Medical surveillance

Source of vibrationReduce transmission of vibration

Rubber padding, rubber matting over vibrating platform


21/28

Reduce Exposure

Administrative measures

Whole body vibration (WBV):- 0.1 to 20 Hz frequency can cause WBV

Affects eyes, vestibular apparatus (Motion sickness 0,1 to 0,63 Hz), adrenal cortex, thyroid

Hand Arm Vibration Syndrome (HAVS):- 50 to 300 Hz

Vascular;- blanching, , cyanosis, trophic changes

Sensorineural:- numbness, tinglingMusculosketal:- Carpo-metacarpal pain, arthritis, wrist pain, arthralgia,

4) COLDSubnormal atmospheric temperature. 1) Generalized effects 2) Local Effects

Generalized effects:- i) Coldness 2) Shivering 3) Weakness 4) Desire to sleep 5) Coma 6) Death

Local Effects:- Depends upon Freezing Temperature of Non Freezing Temperature

Freezing Temperature:- 1) Frost Nip

2) Frost Bite

Superficial Deep Fluids from fingers solidifies & then

Superficial Deeper tissues involved Again when temp, of atmosphere

skin is involved causes gangrene Increases it liquefies seen in cold

Usually no gangrene storage workers.

Freeze Thaw refreeze causes tissue injury

treatment of choice is amputation

While working worker gets sudden death due to release of K from the cells.

NFT( Trench Foot, immersion foot, Flenders foot, Shelters limb):- Occurs by standing in cold water:-

Preventive Measures:-

Room B :-

Temp. is subnormal

Anti Room C

Temp = A+B

2

Room A

Normal Temp.

Take hour rest in the Anti room before the duty and hr rest after the duty.

5) IONIZING RADIATION

The radiation which can penetrate the tissue & deposits its energy within is called as ionizing radiation.Examples are Alapha, Beta, Gamma rays, cosmic rays, X-Ray

Hazards

Immediate Delayed

Burns

Ionising Sickness / Syndrome Somatic Genetic

Nausea, vomiting 1) Carcinogenic 1) Chromosomal Mutation e.g Sterility

2) Leukaemia 2) Point Mutation:- here gene is

3) Foetal developmental involved.

Abnormalities

4) Shortening of life expectancy

Most dangerous ionizing radiation is Alpha though its penetration power is less How & Why ?


22/28

H = DQ

H = Dose equivalent measured in Sievert D = Absorbed dose Q= Quality factor

Quality factor in case of Alpha is 20. For X-Ray it is 1

Penetration Power

Radiation Penetration abilityAir Tissues Lead

Alpha 4 cms. 0.05 mm 0

Beta 6 to 300 cms 0.06 to 4 mm 0.005 to 0.3 mm

Gamma 400 meters 50 cms. 40 mm

X-Ray 120 to 240 meters 15 to 30 cms 0.3 mm

Electromagnetic :- X-Ray & Gamma Corpuscular:- Alpha & Beta

Units of IR H is measured in sievert. 1 Sievert = 100 Rem

D (Dose) is measured in Greys. 1Rad = 0.01 Grey.

Permissible Exposure Limits:-

Radiation should not exceed to 5 Rad in a year (Old concept).

Newer:- ICRP (international Commission on Radiological Protection):- 235 Rems of whole body radiation

for a person occupationally exposed from 18 to 65 years of age

Units of Radiation:-

A Activity of a radioactive material is number of nuclear disintegration per unit of time. It is

measured in Bq (Becquerel). 1 Bq = 1 disintegration / second

Formarly it was also known as Ci (Curie)

B- Potency of radiation is measured by a) Roentgen:- Unit of Exposure (Old)

Newer International System unit is C/Kg ( C is Coulomb)

1 R = 2.58 X 10 CKg = 1 Rotgen

Rad is replaced by Gray:- 1 Rad =0.01GyAbsorbed Dose:- old is Rem which is replaced by Sievert 1Sievert = 100 Rem

Only in case of X-ray Rem = Rad

6) NON IONISING RADIATIONThey cannot penetrate tissues. Their wave lengths are characteristics. So classified according to their

wave lengths.

UV VIBGYOR IR 1 nm = 10meter

UV = 100nm (nano meter) to 400 nm 1 m = 10

Visible light = 400nm to 760 nm 1 mm = 10

Infra Red = 760 nm to 1 mm

Effects of Ionizing Radiation depends Upon:- 1) Type of Ionizing Radiation 2) Quality of IR

3) Dose of IR 4) Dose Rate of IR 5) Tissue Distribution of IR

Dose related Effects:- A uniform Whole Body Irrediation with 1 to 10 Gy. It is also known as Low

Linear Energy causes:- 1) Pancytopenia leading to Infections & Bleeding usually 2-4 weeks after

Exposure

2) In Human Bone Marrow the total no of Nucleated Cells are reduced at

Day 1 of exposure by a) 10-20% Reduction after 1-2Gy Exposure

b) 25-30% Reduction after 3-4Gy Exposure

c) 50-60% Reduction after 5-7Gy Exposure

d) 80-85% Reduction after 8-10Gy Exposure

Types of Leukemias found :- 1) Acute Myloid Leukemia 2) Acute Lymphoblastic Leukemia


23/28

Micro wave = 1 mm to 1 meter

The effects are mainly on skin & eyes.

1) Cornea:- Less than 300nm can be absorbed2) Lens:- 300 to 400 nm can penetrate and reach inside3) Retina:- More than 400 nm can reach upto retina

UV Rays:- 3 types UV(C) = 100 to 280 nm

UV(B) = 280 to 315 nm

UV(A) = 315 to 400 nm

UV(C) can be absorbed in upper atmosphere.

UV(B):- Sources- Welding, solar

Acute effects:- Arc Eye

Chronic effects:- Sources:- Snowy region (High Altitude), Welders

Effects:- 1) Chronic Blephro conjunctivitis with loss of elasticity of conjunctiva

2) Band degeneration of cornea

UV(A):- Mainly absorbed in lens, little can reach upto retina

Effects:- Acute:- Eye:- 1) Induces cataract formation2) Severe conjunctival & Corneal lesions e.g. Ptyrigium, Recurrent

corneal lesions

Skin:- Tanning without superficial burning of skin.

Chronic:- Eyes:- Increased concentration of chromatophores in the lens. Thus yellowish

discolouration of lens. In later stage it will protect the eye from UV(A)

Infra Red:-

Blue colour to some extent deposits its energy into eye.

So long term exposure to blue light is to be avoided

IR(A) 1.4 m

IR(B):- 1.4 m to 3 mIR(C):- 3 m to 1 mm.

When glass is melted IR & Radiation will affect the eye.

IR(A):- Usually not visible to the eye but we can see a red glow.

Sources:- 1) Molten glass or metals at temp, above 1,500C

2) Funnaces

3) Heating & Dryibg appliances

4) Sun Rays

Effects:- It affects lens, retina & choroid lining, leading to retinal oedema

Pigmentation of retina

Cataract formation due to protein denaturisation.

Diagnosis:- Not by ophthalmoscope. Need Fluorescent AngiographyIR (B) & (C):- Source:- Sunrays, Furnaces, laser

Effect:- Cataract formation. Protein degeneration mainly occurs in glass.

Microwave:- Sources:- Radar, Ovens, Satellite communication towers, Insect control, Surgical

Diathermy

Effects:- Cataract formation

Laser:- (Light Amplification of Stimulated Emission R........)

Types:- 1) Columnated:- Parallel light rays

2) Monochromatic:- Only one wavelength

3) Coherent:- Phase wiseAlso 1) Continuous wave

2) Pulsed:- a) Continuous b) Short Duration:- Q switched


24/28

Sources:-1) Engineering Process:- Drilling, cutting, welding

2)Holography

3) Communication

4) Civil engineering measurement

5) Medical application;- A) Ophthalmologyi) for diagnosis:- i)to detect opaque ocular media like

cataract, vitreous haemorrhage.

ii) Scanning Laser Ophthalmoscopy forimages of retina

For Treatment:- of Glaucoma, Diabetic retinopathy

B) Dermatology;-1) To produce burn in dermatitis

2) To burn benign vascular tumours

3) To improve cosmetic appearance.

Hazards of Laser:- Retinal burn, Skin Burn, Fire hazards

Laser safety as per British Standard no. 4083 (1983)

Class I :- no hazard

Class II:- Not hazardous within a blink reflex

Class III:- Viewing directly is hazardous

Class IV:- High Risk Laser skin & fire hazard

7) BAROMETRIC PRESSURE

It is pressure of atmosphere at sea level. Normal atmospheric pressure at sea level is 100KPa.

High Baro-pressure:- When barometric pressure is more than 7,000KPa barometric pressure effect

will start. The effect also depends upon the media e.g. Air at the bottom of mines; Water- e.g. divers.

The depth increases pressure.

High Barometric Pressure Effects

Compression Barotrauma Decompression illness (Cassions Disease)

Compression Barotrauma:- 1) Middle ear barotraumas:- Characterised by pain in affected ear

radiated down to the neck.

2) Sudden relief of this pain may be due to rupture of tympanic membrane. This rupture will be

towards the middle ear, as the pressure is from outer ear side.

If the ear muffs are used then the rupture will be towards outer ear, due to the pressure

transferred from eustachian tube to the middle ear.

3) Alternobaric Vertigo:- Due to inequality in pressure between right & left middle ear, which is

transient.

4) Inner ear barotrauma:- This is due to transmission of increased CSF pressure through

perilymph. This may cause rupture of oval or round windows, and fistula formation, leading to

persistent vertigo, & total or partial sensoryneural hearing loss. Treatment of choice in this case

is immediate operative repair.

5) Sinus, eyes & teeth:- Pain in sinuses, conjunctival oedema or haemorrhage, teeth ache

6) Ear & Skin infections mainly due to Pseudomonous species.

Decompression Illness:- Any return from raised to normal atmosphere pressure may be associated with

some clinical manifestations. Some of them can be serious.

There are two clinical types:- 1) Expansion of gas & 2) Evolution of bubbles in the body mainly due to

Nitrogen gas, and also to some extent Helium.

Microbubbles are formed due to high pressure below. If ascent is slow they are eliminated by

exhalation. If the decent is rapid then these gases are retained in tissues & organs, which can be

potentially fetal.

Health Hazards:- 1) Cutaneous decompression illness (Skin Bends):-


25/28

i) Itching of skin around ears, face, neck, arms & upper trunk, due to cutaneous

absorption of nitrogen.

ii) A blotchy red or purple rash, mainly over upper trunk, may be due to

superficial vasodilatation & stasis called as Cutis Marmorata.

iii) Pu De Orange usually seen in limbs, as well as oedema of face & trunk due to

lymphatic blockage by bubbles. Scar like depressions are formed on the

skin.iv) Sensation of insects crauling on the skin.

2) Musculoskeletal pain. Bends (Bubbles within the joints, mainly affect shoulder. It is

called as bends because pain is relieved on bending the joint) :- Pain

in knees, shoulders & other synovial joints

characterized by redness, oedema & limitation of movements.

3) Constitutional manifestations:- Malaise, anorexia, fatigue etc.

4) Cardiopulmonary decompression illness:-

5) Pulmonary Barotrauma:- Chest pain, crepetitions in suprascapular region,

Pneumothorax causing breathlessness. Chokes (Substernal pain, cough &

Dyspnoea, pain increasing on breathing) due to build of venous gas emboli, passing to

the lungs through Pulmonaryartery. The gas bubbles accumulates in Pulmonary capillaries.

& associated vasoactive products of surface activity in the pulmonary circulation.

6) Neurological Decompression illness:- i) Loss of consciousness due to gas emboli

ii) Hemi, mono, paraplegia

iii) Vertigo

iv)Spiciness:- detachment from reality

v)visual disturbances

vi) Behavioural changes

vii) Psychosis

viii) Da Staggers:- Associated with nausea, vomiting,&/or ipsilateral deafness

ix) Onset of tingling or wooliness in the feet.

x) Diminished sense of vibration (imp)

xi) Impairment of sphincteric tone--> Retension of urine

xii)Urinary & fecal incontinence.

7) latency:- Loss of consciousness on arriving the surface due to relative rapid assent.

Characterised by the conditions associated with arterial gas emboli.

Long Term Effects:- 1)Hearing loss

2) Pulmonary Changes:- i) Occupational narrowing of small airways leading to

20% reduction of FVC

ii) Diminished gas transfer capacity3) Neurological:- CNS changes

4) Dysbaric Osteonecrosis:- Severe joint pain (imp)

Treatment:- 1) End the drive

2) If conscious & co-operative lay on the back and give O2

3) If not responsive but breathing, then lay on the side, head supported and O2

4) If not breathing then CPR, treatment of shock

5) Serious cases:- transfer to recompression chamber by low altitude flight & give

hyperbaric O2

Prevention:- 1) Deep dives then shallow

2) Asent rate not more than 18 meters or 60Ft. Per minute. Five minute os safety shock

while coming up. Interval between two dives 16hours. 24 hrs before or after diverefrain from flying.


26/28

Low Barometric Pressure

Effects are acute & chronic

Acute:- Found in Jet pilots, person staying at high altitude, mountaineers

1) High altitude Pulmonary Oedema, characterised by progressive dyspnoea, tachypnoea,

cyanosis. Treatment is immediate descent & oxygen inhalation2) High altitude Pulmonary Oedema:- Slurred speech, frontal headache with neck stiffness,

temporary loss of peripheral vision, impaired co-ordination & ataxic gait.

Treatment is immediate descent & oxygen inhalation

3) Acute Mountain Sickness:- Headache, nausea, lethargy, impaired memory. Treatment is

acetazolmide prior to assent.

4) Migraine Headache:- Nausea, numbness & loss of peripheral vision but no headache.

Treatment is immediate descent & antiemetics.

5) Bronchopneumonia

6) Perforation of ear drum from inside.

Chronic:-1) Bronchial Asthma

2) Mitral valve prolapsed3) Paroxysmal Supraventricular Tachycardia

4) Paroxysmal Atrial Tachycardia

5) Essential Hypertension

6) High Altitude Haemoglobinopathy (imp)

7) Risk of spleenic & Renal Infarction.

8) Insomnia

8) ELECTRO MAGNETIC FIELD (EMF)In India electricity is on 50 cycles/sec, in US it is 60 cycles/sec. It should be as minimum as possible.

Very very low intensity of EMF unit is Tesla.

Exposure sites;- very low:-TV, Computers, Cell Phones,

People living below high tension wires, Cell Phone Towers, Radars

As per ACGAH maximum permissible level is 1 mT

Effects:- 1) Health:- 1) Carcinogenic:- Mainly reproductive organs are affected

2) Effective on Reproductive System:-

If Male :- 1) his offsprings suffer from brain tumour

2)Foetal developmental abnormalities

Females:-Her offsprings suffer from 1)foetal developmental

Abnormalities

2) Miscarriages, abortions

3) CNS:- Psychosis, suicidal tendency e.g. military person working in Radar

4) Effects on pace maker but no effect on CVS

9) ELECTRICITYSeverity of Electric Current depends upon 1) Type & Voltage of electric current

2) Duration of the flow within the body

3) Resistance at the point of entry

4) Path through which it is passing into the body

Most dangerous is AC. AC flow of 60 cycles/sec will produce tingling sensations (tingling is a threshold

of perception) at 1-2 mA. While if it is DC it need 5 mA current to produce tingling sensation.

Health Effects;- 1) Immediate life threatening effect is Cardiac or Respiratory Arrest, requires

immediate CPR2) Electrical burns:- Burn at the point of entry of the current & at exit and in between.

So we cannot measure the degree of burns in this case.


27/28

3) AC of 60 Hz at 110 to 220 V travelling across the chest for less than 1 second is

capable of inducing ventricular fibrillation at current as low as 60 to 80 mA.

4) Electrical current can burn the tissue at the point of entry as well at exit & in

between. Thus there is more tissue damage than it is apparent.

5) Current flows along the path of blood vessels & muscles may cause thrombosis &

necrosis of the tissues at sites remote from apparent injuries.

6) There may be severe muscle contractions leading to fractures of bones.7) Oliguria due to destruction of muscles & production of myoglobin in the kidneys.

Treatment:- First Aid & Hospitalization

10) LIGHTLight

Dimness Brightness

Illumination is measured by Lux Meter.

Dimness:- Dim Light:- Chronic effects are mainly seen in miners working in dim light for so many years,

leads to Miners Nystagmus.

Brightness:- Effects are Acute & Chronic. Glare Index is 12

Acute:- 1) Glare;- Search light directly falling on the eyes. Also reflected light. At high altitude

falling sunrays on snow causes reflection.

Symptoms:- Watering, lacrimation, Pain, Redness in eyes, foreign body sensation,

Diplopea

Chronic:- Fatigue of eye muscles, annoyance, watering

Acute & chronic both effects are reversible.

11) ULTRASOUND

Very safe. If person is working for very long time USG disintegrates the cellular structure. The target is

RBCs, causing anaemia.

12) MOISTURE

65% humidity is pleasant. Increase or decrease in humidity is not desirable. If steam is generated, it

causes lung disorders. Dryness is also not desirable.

13) COLOUR

Red & White stimulates.

In industries several colours are used to 1) Improve their Quality of workmanship 2) To reduce no of

rejections 3) To reduce accidents 4) To reduce absenteeism 5) To raise house keeping 6) To improve

moral of workers.

Adverse effects of colour are mainly due its psychological effects.

Colour Psychological Effects

Red & White Stimulating

Yellow Freshening

Orange Tension producing

Light Green & Blue Relaxed feelingPurple Depressing


28/28

Apparent size of the object:- In green & blue coloured machines the surface recedes, so they

look smaller.

Red & Yellow:- Objects come forward

Temperature feeling:- Red & Yellow:- warm feeling

Blue & green;- Cool Feeling

Dr. S.K. Haldar's Lectures on Industrial Health for AFIH Students - Occup. Health Hazards- Physical...

Documents

Transcript of Dr. S.K. Haldar's Lectures on Industrial Health for AFIH Students - Occup. Health Hazards- Physical...