This document discusses occupational health and toxicology. It defines occupational health as promoting worker well-being in all occupations. Occupational safety aims to control workplace hazards and their impact. The document outlines several occupational diseases caused by exposure to substances like asbestos, silica, coal dust, heavy metals and industrial chemicals. It describes symptoms, exposure sources and prevention methods for conditions like pneumoconiosis, asbestosis, silicosis, and poisonings from lead, nickel, manganese, chromium, carbon monoxide and ammonia. The objectives of occupational health services are to prevent diseases and injuries, adapt work environments, and promote worker efficiency and wellness.

1. Occupational Health &
Toxicology

2. • Occupational health is defined as “The highest degree of
physical, mental and social well-being of workers in all
occupations.”
Definition:
Occupational safety and health (OSH) is commonly defined as
the science of the anticipation, recognition, evaluation and control
of hazards arising in or from the workplace that could damage
the health and wellbeing of workers, taking into account the
possible impact on the surrounding populations and the
environment

4. OBJECTIVES OF OCCUPATIONAL
HEALTH:
• To maintain and promote the physical, mental and social well being of the
workers.
• To prevent occupational diseases and injuries.
• To adapt the work place and work environment to the needs of the workers i.e
application of ergonomics principle.
• To reduce industrial accidents.
• To achieve maximum human efficiency and machine efficiency.
• To reduce sick absenteeism.
• It should be preventive rather than curative.

5. Advantages of Occupational health
• Investigates and assesses load factors and hazards and gives expert assistance
for eliminating them
• Gives information and advice
• Estimates employees’ working ability and monitors their health condition
• Prevents occupational diseases and other work-related illnesses
• Reduces absenteeism due to sickness
• By its knowledge and skills supports action for maintaining working ability in the
development of individuals, working environment and working community

6. THE UNDERTAKINGS FOR THE NEED OF
OCCUPATIONAL HEALTH SERVICES:
1. Any undertakings, which employ more than the prescribed number.
2. Public sector undertakings
3. Atomic energy unit, explosive production unit, mining unit, and asbestos
production unit etc.,
4. A unit where workers are exposed to health hazards from toxic substances.

7. FUNCTIONS OF OCCUPATIONAL HEALTH SERVICE
1.Pre-employment medical examination.
2.First Aid and emergency service.
3.Supervision of the work environment for the control of dangerous substances in
the work environment.
4.Special periodic medical examination particularly for the workers in dangerous
operations.
5.Health education for on specific hazards and risks in the work environment.
6.Special examination and surveillance of health of women and children

8. 7. Advising the employer or management for improving working conditions, and
placement of hazards.
8. Monitoring of working environment for assessment and control of hazards.
9. Supervision over sanitation, hygiene and canteen facilities.
10. Maintenance of medical records for medical check-up and follow-up for
maintaining health standards and also for evaluation.
11.To carry out other parallel activities such as nutrition programme, family
planning, social services recreation etc., Concerning the health and welfare of the
workers.

9. THE FACTORS FOR EFFECTIVENESS OF
OCCUPATIONAL HEALTH SERVICES:
1. The nature of industry; small, medium or large and its
location.
2. Existing infrastructure of health services.
3. Trained manpower.
4. Workers involvement and employers commitment.
5. Surveillance of the working environment by means of
epidemiological studies and testing.

11. 1. INDUSTRIAL HYGIENE AND
TOXICOLOGY UNIT
• Air Quality Monitoring
• Air-borne particulate sampling
• Ambient noise measurement and control
• Ventilation testing
• Lighting evaluation
• Biological Monitoring of workers exposed to lead, Manganese, Chromium
and Nickel

12. 2. OCCUPATIONAL PHYSIOLOGY UNIT
• Evaluation of occupational work capacity
• Diagnosis of exercise induced cardio-pulmonary stress
• Disability Evaluation
• Evaluation of fitness for highly demanding jobs

13. 3. OCCUPATIONAL PSYCHOLOGY UNIT
• Stress Management
• Job enrichment
• Executive skill development
• Organizational development
• Safety awareness system development
• Absenteeism control
• Job satisfaction
• Mental health survey and human relation

14. 4. WORK PHYSIOLOGY &
ERGONOMICS UNIT
• Development of exercise program
• Study of vibration exposure
• Categorization of work load
• Determination of energy expenditure
• design ergonomics (machinery, equipment)
• Evaluation of occupational work capacity
• Ergonomics analysis of work systems
• Work station design
• Development of pre employment job fitness tests

15. OCCUPATIONAL DISEASES

16. Occupational diseases
•Occupational disease, any illness associated with a particular occupation or industry
•Diseases result from a variety of Biological, physical, chemical and physiological factors
that are present in the work environment.
•The control of occupational health hazards decreases work related diseases and
accidents
•It improves the health of the workforce, leading to decreased absenteeism and
increased worker efficiency.

17. MAJOR OCCUPATIONAL DISEASES
1. Pneumoconiosis
2. Asbestosis
3. Silicosis
4. Siderosis
5. Anthracosis
6. Aluminosis
7. Anthrax

18. 1. PNEUMOCONIOSIS
• It is an occupational lung disease and a restrictive lung disease caused by
the inhalation of dust, often in mines and from agriculture
• Symptoms: difficulty breathing and cough ,causes fibrosis
• Reason: inhalation of dust particle such as coal dust, asbestos and silica.
• In 2013, it resulted 260000 deaths globally
• Not curable

19. • The reaction of the lung to dusts depends on many factors such as size,
shape, solubility and reactivity
• Size 5 to 10 micrometer unlikely to reach lungs
• Size below 0.5 micrometer move in to and out of alveoli
• Size 1 to 5 micrometer are more dangerous
• Depending upon type of dust , disease is given different names.( Asbestosis,
silicosis, aluminosis)

20. • Coalworker's pneumoconiosis (also known as miner's lung, black
lung or anthracosis) — coal, carbon
• Aluminosis — Aluminium
• Asbestosis — asbestos
• Silicosis (also known as "grinder's disease" or Potter's rot, or
when related to silica inhaled from the ash of an erupting
volcano, Pneumonoultramicroscopicsilicovolcanoconiosis) —
crystalline silica dust

21. • Bauxite fibrosis — bauxite
• Berylliosis — beryllium
• Siderosis — iron
• Byssinosis — cotton
• Silicosiderosis — mixed dust containing silica and iron

22. 2. ASBESTOSIS
• Asbestos compounds are naturally of occurring metallic silicates which have
crystallized into long thin particle
• These inhaled particle are caught in the lung and they are carcinogenic after a
long latent period
• Exposure sites: Asbestos cement products, processing of asbestos fibre,
asbestos materials, insulation work of boilers, furnaces, changing of brake
linings, shipyards, construction works

23. • Symptoms: gradually increasing shortness of breath with chest tightness
• In non smokers there is no cough unless the disease is advanced.
• Leads to lung cancer

24. 3. SILICOSIS
• Disease resulting from the inhalation of silicon dioxide
• High exposures can occur in mining, Quarrying and tunneling of granite or rock
with a high quartz content
• Other industries include sandblasting, pottery making, brick works, foundry
works.

25. • Acute Silicosis
• High levels of exposure can produce immediate alveolar damage
due to death of alveolar cells as well as macrophages.
• Acute alveolitis with leakage of protein fluid may present within
weeks of the start of exposure and is followed by fibrotic
obliteration of the alveoli.
• Initial symptoms are of dry cough and shortness of breath
• Chronic Active Silicosis
• The disease is usually advanced before it becomes symptomatic.
• Shortness of breath is usually the presenting symptom by which
time the X-ray changes are widespread.

26. Chronic Inactive Silicosis :
• This condition may occur in workers only occasionally exposed to
silica dust or to workers exposed to mildly contaminated dust.
• The disease may only present after a long period of exposure.
Properties of silica
• The particles must be of respirable size (0.2 to 10 micron) to reach the distal
airspaces of lungs
• Particles of size 0.2 to 2 micron are the most dangerous

27. • High levels of exposure can produce immediate alveolar damage due to
death of alveolar cells as well as macrophages
• Initial symptoms: dry cough and shortness of breath
• Fall in gas transfer leads to cyanosis(bluish skin, eye, lips and nails)
• Condition is often fatal sometimes with in few months
• No effective treatment.

28. 4. SIDEROSIS
• Siderosis is the deposition of excess iron in body tissue
• Repeated inhalation of fine iron or rust dust that happens usually over a
number of years
• Exposure site: welding, grinding, foundry works, paint manufacture, iron
ore mining, Fine iron dust
• Welders disease
• Word sider means iron in Greek

29. • Symptoms: persistent breathlessness, coughing and decreased lung
function.
• Ocular siderosis: eye disease due to eye exposure to iron dust
• Leads to eye discoloration, cataract and eye blindness.
• Not curable. Damage is permanent. Symptoms can be treated.

30. 5. ANTHRACOSIS(COAL WORKERS’
PNEUMOCONIOSIS)
• Also known as Black Lung Disease/Black Lung
• It is caused by log term exposure to coal dust
• leads to inflammation, fibrosis(greater than 1 cm diameter) & in worse
case necrosis(Cells death due to lower blood circulation)
• Lungs may appear black and lungs function decreases
• Common in coal miners & other who work with coal

32. 6. ALUMINOSIS
• Disease caused by the inhalation of fumes dust of aluminum metal and
its compounds
• Exposure site: production of aluminum, aircraft industry
• Symptoms: shortness of breath, chest pain, coughing, general weakness,
loss of appetite, stomache pain, nausea, tearing pain trough out body,
dermatitis.
• Test: X-Ray
• Treatment: exclude contact with aluminum, Oxygen therapy, breathing
exercise, take anti TB drugs

33. 7. ANTHRAX
• Infection caused by the bacterium Bacillus anthracis
• It can occur in 4 forms: skin, lungs, intestinal & injection
• Symptoms begin between 1 day & 2 months after the infection.
• Skin form: small blister with surrounding swelling that often turns in to a
painless ulcer with black center
• Inhalation form: fever, chest pain & shortness of breath
• Intestinal form: diarrhea with blood content & abdominal pain
• Injection form: fever and an abscess at the site of drug injection

34. • Anthrax is spread by contact with bacterium spores
• contact is by breathing, eating or through an area of broken skin
• Risk factors: people who work with animals and animal products,
travelers, postal workers & military people
• Diagnosis can be confirmed based o finding antibodies or the toxin in the
blood
• Prevention : anthrax vaccination & antibodies
• 20 – 80 % die without treatment
• More than 2000 cases per year

35. POISONING BY LEAD
• Cause: exposure of lead
• Uncommon in developed countries
• Sites: lead extraction from its ore, recycling of scrap lead(car batteries),
manufacturing of batteries, paint, colours, rubber product, glass, lead
compounds
• Symptoms: abdominal pain, colic, constipation, pallor, muscle weakness
• Treatment: avoiding further exposure, heavy metal toxicity medication

36. POISONING BY NICKEL
• Cause: exposure of Nickel
• Metal commonly used to make coins, magnets, jewelry, stainless steel,
electronics and industrial machines.
• Familiar nickel plating
• Nickel stored in body fat
• Carcinogenic metal
• Leads to lung cancer, heart diseases neurological deficits, developmental
deficits in childhood, high blood pressure

37. POISONING BY MANGANESE
• Cause: exposure of Manganese
• Hard white metal- mainly used in the production of toughened steel
• Compounds of manganese are also used in dry cell batteries, paints,
varnishes, inks, matches, fireworks, fertilisers and drugs
• Permanganate compounds are used in ceramics and glass industries
• Mainly absorbed via lungs (poorly via guts)
• It is bound to red cells in the blood

38. • Irritants to skin, eyes and mucous membrane
• Inhalation produces inflammatory reaction in lungs and leads to
pneumonia
• Cause Parkinson like syndrome
• Symptoms are tiredness, fatigue, apathy, headache, weakness of the legs,
joint pains, irritability, excessive salvation, organic psychosis, disturbances
of speech
• Treatment: avoid exposure, L-dopa treatment
• Patient with urine manganese level more than 50 microgram/liter should
be recommended for suspension for further exposure

39. POISONING BY CHROMIUM
• Chromium is used in three basic industries: metallurgical, chemical,
and refractory (heat-resistant applications)
• In the metallurgical industry: chromium is an important component of
stainless steels and various metal alloys
• In the chemical industry, chromium is used primarily in paint
pigments, chrome plating, leather tanning, and wood treatment.
• Refractory uses: magnesite-chrome firebrick for metallurgical furnace
linings and granular chromite for various other heat-resistant
applications.

40. ● The health effect of chromium are at least partially related to the
valance state of the metal at the time of exposure
● Chromium exist in a series of oxidation state from - 2 valance to + 6
● The most important stable states are 0, + 3 and + 6
● +3 is an essential dietary mineral in low doses whereas certain
compounds of +6 are Carcinogenic
● Excretion of chromium occurs via Urine, biliary excretion and through
hair, nails, milk and sweat.
● The target organ off inhaled chromium is the lung.
● The kidney liver skin and immune system may also be affected

41. ● They are Skin irritant and corrosive
● Chrome holes( Ulcer) seen in nail root, knuckle, finger web, back of the
hand, and forearms.
● Chromium +6 is respiratory track irritants
● May cause chronic tracheobronchitis, chronic pharyngitis and respiratory
Cancer

42. CARBON MONOXIDE(CO) POISONING
● CO- Coloureless odoureless and tasteless gas
● Carbon monoxide poisoning typically occurs from breathing in too much
carbon monoxide
● Symptoms are often described as “flu-like” , “Cherry red skin” and
commonly include headache, dizziness, weakness, vomiting, chest pain
and confusion
● Large exposure can result in loss of consiousness or even death
● CO is not toxic to all forms of life.
● Its harmful effects are due to binding with hemoglobin
● So it has no effect on photosynthesis plant
● It is easily absorbed through lungs

43. ● Different people or population may have different CO tolerance level
● Exposure at 100 ppm or more than is dangerous to human life
● Based on OSHA limits long term exposure levels to be less than 50 ppm
average over an 8 hour period
● Exposure may lead to a significantly shorter life span due to heart
problem
● Acute poisoning: headache, nausea, fatigue, fast heart rate, low blood
pressure and cardiac arrhythmia.
● Chronic poisoning: persistent headache, depression, confusion, memory
loss, hearing loss, vomiting

44. ● Prevention: remains a public health issue
● Avoid exposure
● Public education on the safe operation on appliances, heaters, fireplaces,
and internal combustion engines
● Installation of carbon monoxide detectors
● CO is Coloureless odoureless and tasteless gas, hence it cannot be
detected by visual cues or smell

45. AMMONIA POISONING
● Ammonia is a colorless, highly irritating gas with a pungent, suffocating
odor.
● It is lighter than air and flammable,
● It is easily compressed and forms a clear, colorless liquid under pressure.
● Dissolves readily in water to form ammonium hydroxide - an alkaline
solution.
● Exposure to ammonia is very irritating to the eyes.
● Possible injuries to the eye include conjunctivitis, lacrimation, photophobia,
corneal irritation and temporary blindness.
● Ammonia has a greater tendency to penetrate and damage the iris

46. ● Concentrated ammonia may produce necrosis and deep penetrating burns.
● Inhalation of even diluted ammonia is irritating to the upper respiratory
tract.
● Ammonia can cause bronchospasm, laryngitis, tracheitis, wheezing,
dyspnea and chest pain.
● Nausea and vomiting occur frequently following ingestion of ammonia
solutions.
● Swelling of the lips, mouth and larynx have occurred.
● Oral and esophageal burns may occur if the ingestion is of the
concentrated form.
● Seizures may occur if there is extensive absorption.

47. DUST POISONING
● These are solid particles generated by handling, crushing, grinding,
rapid impact, detonation, and decrepitation (breaking apart by heating)
of organic or inorganic materials, such as rock, ore, metal, coal, wood,
and grain.
● Dust is an airborne solid particles that range in size from 0.1–25 µm in
diameter
● Dust more than 5 µm in size usually do not remain airborne long
enough to present an inhalation problem.
● Dust sources: when a dusty material is handled
● Mechanical action of the grinding or shaking device supplies energy to
disperse the dust.

48. ● Evaluating dust exposures properly requires knowledge of the chemical
composition, particle size, dust concentration in air, how it is dispersed
● Dust particles penetrate to the alveoli or inner recess of the lungs and are
hazardous
● A person with normal eyesight can detect dust particles as small as 50
µm in diameter.
● Smaller airborne particles can be detected individually by the naked eye
only when strong light is reflected from them.
● Particles of the dust of respirable size (less than 10 µm) cannot be seen
without the aid of a microscope

49. INDUSTRIAL TOXICOLOGY
● Industrial toxicology is the investigation of the toxicity of chemicals
found at the workplace
● It study the adverse effects of agents that may be encountered by
workers during the course of their employment.
● Occupational toxicologists assess the hazards and risks to health
posed by chemicals
● To evaluate the risks of adverse health effects from chemicals, one
must be aware of the routes of entry into the body, duration of
exposure, the toxicity of the chemical, exposure limits, and odour
threshold of the chemical.

50. ROUTES OF ENTRY
● Hazardous agents are enter in to human body via skin, lungs, nose,
mouth and the digestive, urinary, and genital tracts.
● The most common routes of entry are:
(a) Through the lungs (inhalation)
(b) Through the skin (absorption)
(c) Through the mouth (ingestion)

51. (A) THROUGH THE LUNGS (INHALATION)
● More hazardous agents get into your body by inhalation than by any
other route.
● Body's respiratory system has very effective mechanisms for filtering out
normal pollutants from the air you breathe. Filtering systems in the nose
and mouth (for example, the hairs in the nose, the mucus in the mouth
and lungs) prevent large foreign particles
● Small dust particles are difficult to eliminate & they can cause serious
local respiratory problems
● High concentrations of dust, toxic vapours, cigarette smoke, etc. the
filtering mechanisms can become overloaded and damaged. Once they
are damaged, various bacteria, viruses, etc. are more likely to grow in the
lungs, causing infections such as pneumonia. Workers in dusty
occupations are more susceptible to tuberculosis, bronchitis and other
respiratory diseases.

52. ● Some chemicals have damaging effects on the lungs, while others will
potentially damaging target organs.
● Target organs are those parts of the body that particular chemicals always
affect. (Eg. lead affects the central nervous system
● Other target organs for different chemicals are heart, lungs, kidneys and
liver.
● Your body has several built-in mechanisms which can act as warning
signals when hazards are present:
• smell
• sneezing
• coughing
• a runny nose
● These also will help you to remove a hazardous agent from your
respiratory system.

53. (B) THROUGH THE SKIN (ABSORPTION)
● Your skin is a major route of entry for hazardous agents in the workplace.
● Diseases can develop when chemicals and other materials come into
contact with your skin.
● Skin is an important protective cover for the body, but it cannot always
protect you against workplace hazards.
● Chemicals can be absorbed (taken in) directly into the body through the
healthy skin.
● Once they are in the body, chemicals can be absorbed into the
bloodstream and transported to target organs.
● There are many materials or conditions found in the workplace that can
cause occupational skin diseases and injuries.

54. ● Chemicals are a major source of occupational skin diseases
● Some chemicals can damage your skin, making it red, blistered, itchy or
flaky. This condition is called dermatitis.
● Some of the many chemicals that cause dermatitis are:
○ strong acids (such as sulphuric acid);
○ strong alkalis (such as caustic soda);
○ all forms of mineral oil, including diesel, lubricating and fuel oils, solvents,
thinners, turpentine and petroleum products;
○ Tars and other coal tar products

55. ● Contact dermatitis - a type of allergic reaction, just like asthma or hay
fever.
● A worker may be allergic to a particular chemical and, once he or she
becomes sensitized to that chemical, every time he or she comes into
contact with it, dermatitis will result.
● Contact dermatitis never occurs on the first exposure to a new chemical.
it takes time to develop. However, once it develops, even exposure to a
small amount can cause a severe skin reaction.
● Chemicals that cause contact dermatitis are:
Formaldehyde, nickel compounds, epoxy resins and catalysts used in
the plastics industry, germicidal agents used in soap and other
cleaners,

56. (C) THROUGH THE MOUTH (INGESTION)
● Hazardous agents can also get into the body by ingestion.
● Ingestion happens when a hazardous agent is swallowed.
● Some ingested agents pass into the digestive system where they can be
destroyed or neutralized by the acid in the stomach.
● However, some can be absorbed very quickly into the bloodstream
through the walls of the stomach and small intestines.
● Once in the bloodstream, they can travel to different target organs (such
as the kidneys and liver) where they can have damaging effects.

57. ● Workers can swallow hazardous agents by accident if they do not wash
their hands before eating, drinking or smoking at work, or if they keep
their food, drink and cigarettes in a contaminated (dirty) area.
● Eliminating hazardous chemical and biological agents is the best way to
prevent ingestion.
● Other important methods of prevention are personal hygiene (cleanliness)
and ensuring that workers have access to washing facilities, food storage
and eating areas that are away from their work areas.
● It is also important that workers are educated about the importance of
personal hygiene, and storing and eating food away from work areas.

58. ● Vomiting and diarrhoea are ways in which the body tries to remove
certain toxic substances from the digestive system.
● However, these response mechanisms cannot remove all ingested
hazardous agents from the body.
● Vomiting and diarrhoea can be signals of ingestion of chemical and
biological agents and must be investigated.

59. EFFECTS OF TOXIC SUBSTANCES
● It is important to understand the body's reaction to toxic materials.
● Toxic substances can cause four types of effects on the body:
❑ Local
❑ Systemic
❑ acute
❑ chronic

60. 1. LOCAL EFFECTS
● Some hazardous agent have only a localized effect on one part of the
body.
● Acid burn on the skin
● Ammonia, chlorine, welding fumes and exhaust fumes can cause local
irritation to the lungs when they are inhaled.

61. 2. SYSTEMIC EFFECTS
● Systemic effects are problems caused inside the body once a hazardous
agent has entered.
● When the substance is absorbed into the bloodstream, and in the
organs that either store the toxic material (such as the bones and the
brain), neutralize it (such as the liver), or remove it from the body (such
as the kidney and bladder).
● A typical systemic effect in the blood is anaemia (a shortage of red blood
cells) which can be caused by a number of chemicals, including lead,
beryllium, cadmium, mercury compounds and benzene.
● Benzene can damage the cells that form blood, leading to leukaemia.

62. ● The liver can be damaged by toxic substances because it tries to break
down many of them once they have entered the body.
● Some chemicals known to damage the liver are: benzene, DDT, dioxane,
phenol and trichloroethylene.
● The kidneys and bladder also can be affected by many toxic substances
because they are major routes of exit out of the body.

63. 3. ACUTE EFFECTS
● Exposure to many occupational hazards causes the body to produce an
immediate obvious response, called an acute effect.
● Acute effects often disappear soon after the exposure stops and are
often reversible.
● An example of an acute effect is nausea, headache or vomiting a worker
might experience after using a solvent to clean auto parts.
● Acute effects can be localized to one part of the body (such as a skin
reaction from a chemical), but they can also be systemic (if, for example,
that chemical also gets absorbed into the bloodstream, there can be
effects on target organs).

64. 4. CHRONIC EFFECTS
● Chronic effects, which usually appear a long time after the exposure
occurred and persist over time.
● It usually only appears after a long time because of the disease's latency
period (time between the exposure and the first sign of disease).
● Chronic conditions, such as many occupational cancers, may take 20 or
30 years to develop.
● Some chronic conditions develop after just a short exposure, whereas
other chronic conditions only develop after repeated contact with a
substance or work process.
● Like acute effects, chronic effects can be local effect and systemic
● Prevention is the only cure. With chronic diseases it is difficult

65. THRESHOLD LIMIT VALUE - TLV
The TLV is the upper limit of a toxin concentration to which an
average healthy person may be repeatedly exposed on an all-
day, everyday basis without suffering adverse health effects.
TLV is Typically used for workplace exposure determinations.
• Gaseous substances in air, are usually express in:
parts per million (ppm).
• Fumes or mists in air, are expressed in:
milligrams per cubic meter (mg/m3).
TLV values are set by the American Conference of Governmental
Industrial Hygienist (ACGIH).

66. TLV – TWA
“TLV-TWA The TWA concentration for a conventional
8-hour workday and a 40-hour work week, to which it is
believed that nearly all workers may be repeatedly
exposed, day after day, for a working lifetime without
adverse effect.”
TWA (8-hr) = C1T1 + C2T2 +…..CnTn
8

67. CALCULATE 8-HOUR TWA
Working period mg/m3 Duration of sampling (h)
0800 - 1030 0.32 2.5
1045 - 1245 0.07 2
1330 0.2 2
1545 – 1715 0.1 1.5
Assume exposure is zero in rest breaks 1030–1045, 1245–1330 & 1530–1545
8-hr TWA = (0.32 x 2.5) + (0.07 x 2) + (0.2 x 2) + (0.1 x 1.5) + (0 x 1.25)
8
= 0.8 + 0.14 + 0.4 + 0.15 + 0
8
= 0.19 mg/m3

68. TLV – STEL
TLV-STEL is a 15 minute TWA exposure that
should not be exceeded at any time during a
workday, even if the TWA is within TLV- TWA

69. TLV – STEL (CONT)
Can be exposed continuously for a short period without
suffering from:
• Irritation
• Chronic or irreversible toxic effects
• Dose-rate dependent toxic effects or
• Narcosis sufficient to increase likelihood of accident,
impaired self rescue, or reduced work efficiency

70. TLV – STEL (CONT)
• Exposures above TLV-TWA up to TWA-STEL
< 15 minutes
≤ 4 times a day
60 minutes between successive exposures

71. TLV - C
TLV-C the concentration that should not be exceeded
during any part of the working exposure
• If instantaneous measurements are not available, sampling should be conducted
for the minimum period of time to detect exposures at or above ceiling value

72. (Continued)
INTRODUCTION TO TOXICOLOGY
Poison: “All substances are poisons; there is none which is
not a poison. The right dose differentiates a poison and a
remedy.”
Toxicant: A toxicant can be a chemical or physical agent,
including dusts, fibers, noises and radiation.
Toxicity: Toxicity is the a property of the toxicant
describing its effects on biological organisms.
Toxicology: The qualitative and quantitative study of the
adverse effects of toxicants on biological organisms.

73. IMMEDIATELY DANGEROUS TO
LIFE AND HEALTH - IDLH
An IDLH level represents a maximum concentration of any
toxic, corrosive or asphyxiant substance that poses an
immediate threat to life or would cause irreversible or
delayed adverse health effects or would interfere with an
individual’s ability to escape from a hazardous atmosphere.
IDLH levels are typically published by OSHA and NIOSH.
In practice, when the concentration of a toxic substance in a
given area is known, IDLH levels may be used for
determining which type of breathing apparatus is needed
when entering the area.

74. MUTAGENS, TERATOGENS AND CARCINOGENS
● Gen means birth or origin, as in the book of Genesis
● "Muta" means change
● "terato" means monster
● "carcino" means crab
● All three "gens"-are physical or chemical agents that cause or originate
malformations
● Mutagens cause changes (mutations) in the genetic material of cells
● Teratogens cause irreversible, deleterious structural malformations in
fetuses
● Carcinogens cause cancerous tumors

75. 1. MUTAGENS
● Potential to Cause Mutation in the Genetic Code
● Mutagen- substance or agent that causes an increase in the rate of change
in genes
● Mutations (changes)- passed along as the cell reproduces, sometimes
leading to defective cells or cancer.
● Examples of mutagens: certain biological and chemical agents as well
exposure to ultraviolet light or ionizing radiation.
● Mutagenesis is the formation of mutations.
● Mutations are harmful and have little or no effect on the body's function.
● Mutagens can be identified using the Ames test and other biochemical
testing methods.

76. ● Do not confuse a mutagen with a carcinogen (a substance that causes cancer).
● Mutagens may cause cancer, but not always.
● Do not confuse a mutagen with a teratogen (a substance that causes change
or harm to a foetus or embryo).
● Avoid working with mutagens whenever possible.
● If you must work with a mutagen be sure to wear personal protective
equipment (PPE) and utilize workplace controls such as a fume cupboard to
minimize your exposure.
● Ethidium bromide is a known mutagen
● Agents Shown to Cause Potential Mutagenic Effects
- Hydrogen Peroxide (a Bleaching Agent), Ethyleneimine (an Alkylating Agent)
Ethylene Oxide (Hospital Sterilant), Hydrazine (Used in Rocket Fuel), Ionizing
Radiation Exposure, Benzene

77. 2. TERATOGENS (LATIN - “THE STUDY OF MONSTERS”)
● It is the Study of Congenital Malformations, the causes of malformations
are
● A teratogen is an agent that can cause malformations of an embryo or unborn child
(foetus).
● This can be a chemical substance, a virus or ionizing radiation.
● Embryotoxin, an agent that causes poisoning effects on a developing foetus.
● Both embryotoxins and teratogens are reproductive toxins, substances which cause
damage to a pregnant women's reproductive and/or endocrine system and/or a
developing foetus.
● Pregnant women should avoid all contact with teratogens, particularly during the first
three months of pregnancy
- Heredity
- Maternal Diseases Like German Measles
- Maternal Viral Infections During Pregnancy
- Maternal Malnutrition
- Physical Injury
- Ionizing Radiation Exposure
- Chemical Exposure

78. ● Many drugs can also have an adverse effect on developing foetus (eg.thalidomide)
● This drug was used to control morning sickness but was withdrawn from the market
● There are few examples of transplacental carcinogens, substances which can cause
foetuses exposed during pregnancy to eventually develop cancer.
● The best-known example is DES, diethylstilbestrol
● Always minimize the use and release of teratogens (or believed teratogens) in the
workplace.
● Women who are of child-bearing age should pay particular attention to teratogenic
materials
● Cause severe damage during the first 3 months of pregnancy when many pregnancies
are not yet known.
● Many teratogens cause effects at very low exposure levels.
● The chemicals having potential teratogenic effects are;
● Agents having conclusive teratogenic effects are
- Quinine, Boric Acid, Insecticides, Pesticides, Chloroform,
Carbon Tetrachloride, Benzene, Xylene, Propylene Glycol
- Anesthetic Gases, Organic Mercury Compounds, Ionizing Radiation
German Measles, Thalidomide

79. 3. CARCINOGENS
● A carcinogen is a substance that causes cancer (or is believed to cause
cancer).
● A carcinogenic material is one that is known to cause cancer.
● The process of forming cancer cells from normal cells or carcinomas is
called carcinogenesis.
● A known human carcinogen means there is sufficient evidence of a cause
and effect relationship between exposure to the material and cancer in
humans.
● Such determination requires evidence from epidemiology, clinical, or
tissue/cell studies involving humans who were exposed to the substance
in question.
● Obviously, it is unethical to deliberately test potential carcinogens on
humans, so "proving" something to be a carcinogen in humans is a
difficult, demanding and lengthy task.

80. • Carcinogenicity
A carcinogen is an agent capable of inducing benign or malignant
neoplasms
A1 - Confirmed human carcinogen
A2 - Suspected human carcinogen
A3 - Confirmed animal carcinogen with unknown
relevance to humans
A4 - Not classifiable as a human carcinogen
A5 - Not suspected as a human carcinogen
• Some Confirmed or Suspected Human Carcinogens
- Acrylimide - Beryllium - Nickel Sulfide
- Acrylonitrile - Calcium Chromate - Tetranitromethane
- 4-Aminodiphenyl - Chromium (Vi) - O-Tolidine
- Arsenic - Ethylene Dichloride - Vinyl Bromide
- Benzine - Ethylene Oxide - Xylidine
- Benzidine - Lead Chromate - Zinc Chromates

81. TOXICOLOGY

82. “ALL SUBSTANCE ARE POISONS”; THERE
IS NONE, WHICH IS NOT A POISON.
THE DOSE DIFFERENTIATES A POISON
AND A REMEDY.

83. SOURCES OF TOXIN:
• Environment
• Food/Feed/Water
• Drugs

84. ENVIRONMENT
 Air Pollution
Carbone monoxide
 Nitrogen oxides
 Smoke
 Poor Ventilation
 Ammonia, Hydrogen Sulfide
 Volatile
Compounds
 Chlorine, Hydrocarbon fuels
 Volatile
Compounds
 Chlorine, Hydrocarbon fuels

85. TOXICITY
• Toxicity is the degree to which a substance can damage an organism.
• Toxicity can refer to the effect on a whole organism, such as an animal,
bacterium, or plant
• as well as the effect on a substructure of the organism, such as a cell
(cytotoxicity) or an organ such as the liver (hepatotoxicity).
• T
oxicity is the capacity of a chemical compound to produce injury.

86. SOME POSSIBLE OUTCOMES OF TOXICANT:
- Death after a short period of time- Acute toxicity
- Cancer / mutation in DNA
- Skin / eye irritation
- Fertility problems
- Carcinogenicity / mutagenicity
- Reproduction effects
- Sudden heart failure and death

89. TYPES OF TOXICITY
Acute toxicity
Sub-acute toxicity
Sub-chronic toxicity
Chronic toxicity

90. CONDITIONS OF STRONG POISONING
1. High temperature
2. Deep or rapid breathing
3. Long working hours
4.Combination of two or more poisonous
substance

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Degreeof
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LD50
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>
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92. Median Lethal Concentration
(LC50)
LC50: Concentration of a toxicant
(mg/m3) in air to kill 50% of the
animals exposed for the specific
length of time.

93. Maximum allowable concentration (MAC) of toxic chemicals
It is the maximum concentration of toxic chemicals that healthy
male adults can breath for 8 hours a day over a period of years
without any harmful effects on his health
The lower the MAC value, the more poisonous is the
substance.

94. O
dourperceptionlim
it(Thresholdofs
m
ell)
Theconcentration of the substancein the air at whichthe smell of the substance
becomes noticeableiscalledodourperceptionlimit.It isnotdirectlyrelatedtoM
A
C
value.Somepoisons suchasC0hasnosmellatall.M
A
Cvalueoftoxicsubstances
maybehigheror lower thanthe odourperception limit of those substances. It is
obvious thatthe smell isnot only the condition ofatoxichazard.
MAC/odourperceptionlimitofsomechemicals:
Chemical MAC value (ppm) Odour perception
limit (ppm)
Ammonia 25 5
Benzene 10 100
Carbon
tetrachloride
10 70
T
oluene 100 50

95. HUMAN HEALTH AND HEAVY METAL EXPOSURE
• Metals, a major category of globally-distributed pollutants,
are natural elements that have been extracted from the
earth and harnessed for human industry and products for
millennia.
• Metals are notable for their wide environmental dispersion
from such activity; their tendency to accumulate in select
tissues of the human body; and their overall potential to be
toxic even at relatively minor levels of exposure.

96. Adverse health effects of metals are illustrated in following table:
Name of Metal Adverse Health Effects Metal Exposure
Arsenic, As Skin pigmentation, Hyper keratosis,
Nasal congestion, Abdominal pain,
Cancer- Skin, Lungs, Lump glands
Drinking water, inorganic arsenic
compounds formerly used in pesticide
sprays, Wood preservatives, arsenic
containing fossil fuels, leaching of mine
tailing, smelter runoff, paints and
Microelectronics industry.
Lead, Pb Hypertension, Anemia, Hemoglobin
Synthesis, Convulsion, Coma, Renal
failure, Death.
Combustion leaded gasoline,
Drinking water (lead pipe, lead solder.)
Solder used in food can, paint, ceramic
ware etc. Pigments, glaze solder,
automobile batteries, cable sheathing,
weights.
Cadmium, Cd Kidney damage, Painful bone, Joint
disease (Rice contaminated),Cancer-
Liver, Prostate
Contaminated in river by tannery
wastage. Smelting plants, Pigments,
metal plating, Cigarette, and some
plastic and batteries.
Chromium Dermatitis, Nasal cavity, Ulcers on
the hands and arms, Inflammation of
larynx, Liver and Bronchitis,
Lung cancer.
Contaminated in river by tannery
wastage, Dyeing, Paints industry.
Mercury Kidney damage, memory loss,
insomnia, timidity and delirium.
Manufacture of fluorescent lamps,
Dental amalgams, Building industries,
Chemical and metal processing