PHYSICAL AGENTS
Objectives:
• To know the definition of physical agents
• To identify the physical agents as risk factors in the work
and work environment
• To explain the main effects of physical hazards on health
• To know, roughly, the threshold values of physical hazards
• To recognize the main occupational diseases because of
physical hazards exposure and to know when to refer the
patient to an occupational physician
• To explain the specific role, tasks and responsibilities of the
occupational health services and occupational physician at
the workplaces with physical hazards exposure (prevention,
treatment)
Which are the physical agents?
•
•
•
•
•
•
Noise
Vibrations
Radiations
Temperature
Lighting
Pressure
• The 5th European Working Conditions Survey
shows that the physical hazards have
remained a problem for the European workers
in the last few years.
Which are the main
characteristics?
• We cannot see
• We cannot touch
• We can feel them by the neuro-sensorial
organs (except radiation)
• We can measure them in the occupational
workplace/environment
• We cannot measure them in the human body
(except ionizing radiation)
Which are the effects?
Worker
- occupational diseases
- occupational related
diseases
- accident of work
Source
• Time of exposure
• Level of exposure
Workplace
- days of incapacity of work
- a new worker
- risk insurance
How can we protect ?
Source
I. Reduces the PA at
the source
Eg:
- isolation
- change the device
Worker
How we can protect ?
Worker
Source
II. Reduce
exposure time
Increase the
distance
How can we protect ?
Source
Worker
III. At the Worker Level
E.g.:
- isolation (special
cabin)
- individual equipment
protection
What is the Role of the OH
Physician?
Identifies the
physical hazards
Prevention
Screening at
pre-employment
Monitoring health
OH physician
Periodical
examination
Treatment
First aid
specific/supportive
Noise
• What is noise?
– a group of unwanted or/and wanted sounds which
produce an unpleasant hearing sensation,
sometimes
disturbing,
which
impede
communication
– an annoying sound
• The perception depends on the listener and the
circumstances (e.g. rock music can be pleasant for a
person, but uncomfortable in a surgery room).
What is occupational noise?
• a complex of sounds, of variable intensities
and pitches, having different characteristics,
rhythmic
or
rhythmless,
produced
continuously or discontinuously by machines,
tools, devices, means of transportation, the
human voice, etc, during the performance of
the professional activity
Characteristics of sounds
Frequency
= the peach of sound
Hertz
High pitches>3000 Hz
Intensity =
Loudness =
the level of the sound
or the sound pressure
the subjective human
response to sound
dB
Low pitches<500 Hz
E.g. the woman’s voice
and the man’s voice
500 and 2000 Hz are
the most important
for understanding
speech
3000 Hz and 4000 Hz are the
first to be affected by noise
“0” dB does not mean the lack
of any sound, but a sound level
where the sound pressure is
equal to that of the reference
level which corresponds to 0.02
mPa.
E.g. if the noise produced by a
machinery is 97 dB (A), when
doubling the source of noise (if we
have 2 identical machineries), the
noise will increase by 3 dB, it will
not be doubled!
dependent on sound
pressure and, then, on
frequency
What is the Threshold Limit Value?
• The Threshold Limit Value (TLV) depends on the work
specificity (International Standard, ISO 1999-1990).
• The Law establishing this is the Directive 2003/10/EC
of the European Parliament and of the European
Council.
• This directive is to be transposed into the national
legislation of all Member States.
• In the European countries the maximum admitted
values (Leq - weekly equivalent acoustic level) at the
workplace with normal neural-sensorial solicitation
are between 85 and 90 dB (A).
What are the Health Effects?
http://www.hse.gov.uk/noise/vid
eo/hearingvideo.htm
What are the Health Effects?
Auditory
Acute :
• tinnitus
• acoustic trauma
Chronic:
• hypoaccousia
• Noise Induced
Hearing Loss (NIHL)
Non-auditory
• sleep disturbances
• general effects
(cardiovascular, metabolic
changes)
• behavioural effects
The audiogram - records both ways of sound
transmission: air and bone conduction
Normal audiogram
NIHL
Treatment
1. Ceasing the exposure to noise and other
toxic substances (Hg, SC2, toluene,
Gentamycin, Kanamycin etc)
2. Medication: antioxidants, vitamins
3. Hearing aids in severe cases
How can we protect from noise?
Technical and organizational measures
Source
I. Reduces the N at
the source
E.g.:
- isolation
- change the device
Worker
II. Reduce
exposure time
Increase the
distance
III. At the worker level
E.g.:
- isolation (special cabin)
- individual equipment
protection (ear plugs or
ear muffs)
How can you protect from noise?
Medical measurements
• Pre-employment examination
• Periodical examinations
– Audiometric testing
• Risk assessment
• Risk management
Ultrasounds and infrasound
Ultrasounds > 20000 Hz
Infrasound 1-20 Hz
= inaudible
= inaudible
Where to be found? (workplaces) Where to be found? (workplaces)
• - industry (used in detecting defects, • natural sources:
cleaning of pieces etc)
• medicine (ultrasounds, dental
scaling, therapy)
• devices against thieves, pests etc
– geological (earthquakes,
landslides, avalanches) or
– meteorological events (storms,
tornadoes)
• artificial sources:
– industrial machines
– ventilation systems, air
conditioning
– aircraft
– rail traffic
What are the health effects of ultrasounds and
infrasound?
Ultrasounds
Acute effects: 18-30 kHz
• headache, fatigue at the
end of the day, sleepiness
during day time, the feeling
of pressure inside the ear,
walking
disturbances,
numbness, and sensitivity
disturbances.
Chronic effects:
• vascular
disturbances,
increase of the central and
skin
temperatures,
hyperglycemia, increased
number of eosinophiles
Infrasound
Acute exposure:
• to intensities high enough
to be heard, it can
determine a decrease in
vigilance
Chronic exposure:
• to normal levels present in
the environment, there is
not enough evidence
How do we protect from ultrasounds and
infrasound?
• By respecting the technical prophylactic
measurements concerning noise exposure
• In case of ultrasounds, wearing rubber cotton
gloves may be of help
Vibration
• Vibrations are the mechanical oscillations of an object
reported to an equilibrium point.
• Vibrations enter the body through the organ in contact with
the vibrating equipment. There are two situations:
– the hand-arm vibration exposure, when a worker operates
hand-held equipment such as a chain saw or jackhammer,
the vibrations affect the hands and the arms;
– the whole body vibration exposure, when a worker sits on
a vibrating seat or stands on a vibrating floor, the
vibrations exposure affect almost the entire body.
How do you measure vibrations?
• The measurement of vibrations is made with a
special device similar to the sonometer and
the established parameter according to legal
standards is the acceleration
• http://www.occup-med.com/content/3/1/13
• Legal framework: European Directive
2002/44/ CE
What are the workplaces with vibrations?
• Mining, constructions, forestry work, car
driving (tractor, excavator, and bulldozer),
helicopter, etc.
• Sources of vibrations: pneumatic tools, chain
saw and other vibrating tools.
What are the health effects?
Hand-arm vibration
exposure
Whole body vibration
exposure
20-500 HZ
< 20 Hz
Target organs:
- blood vessels of the fingers
- sensitive nerves of the hand
- bone-muscle-articulation
- structures of the hand-arm system
Target organs:
- organs of the abdominal cavity
- circulatory system
- vertebral column
- nervous system
What are the health effects?
Hand-arm vibration
exposure
Whole body vibration
exposure
Vascular changes:
- Vibration – Induced White Finger (VWF)
- Hand – Arm Vibration Syndrome (HAVS)
- Carpal Tunnel Syndrome
Neurological changes:
- night numbness, tactile sensitivity
decrease, alteration of the superficial
thermal pain sensitivity
Osteo-musculo-skeletal disorders:
-cysts at the carpal bones
-Osteoarthritis of the metacarpal- trapeze
bone articulation
-Kienbock disease (aseptic necrosis of the
semilunar bone)
-Dupuytren disease (retraction of the
superficial palmar aponevrosis)
Motion sickness: (0,1-2 HZ)
Gastro-intestinal disorders: (4-8 Hz)
Circulatory disorders: (4-8 Hz)
Visual disorders: (5-20 Hz)
Osteo-musculo-skeletal disorders:
- especially back pain with disc or
arthrosis modifications
Laboratory investigations
Hand-arm vibration
exposure
Whole body vibration
exposure
Cold provocation test
Vascular Doppler test
Infrared thermograph test
Vibration perception test
Bone X ray (lumbar vertebral column)
RMN
Biological investigations
Gastric examination
Renal examination
Other investigations:
- Bone X –ray
- Biological
Treatment
• Cessation to vibrations exposure
• Symptomatic treatment
Medical prevention
• Pre-employment examination
• Periodical medical examination
• Increased caution for people with
cardiovascular diseases and musculo-skeletal
disorders
How can we protect from
vibrations?
Technical and organizational measures
Source
I. Reduce the V at the II. Reduce exposure time
source
E.g.:
Avoid exposure to cold
- Design an
ergonomic tool to
Vibration damping
attenuate the V
system
- Change the device
Worker
III. At the worker level
E.g.:
- individual protection
equipment (special gloves)
Radiation
What do we know about radiation?
• Radiation is a complex process through which
the energy emitted by a source is transmitted
through different media and then absorbed by
a support.
• According to the ionizing capacity of the
matter, we have ionizing and non-ionizing
radiation.
Visible Light
Enough energy
to produce
ionization
Classification according to the
ionizing capacity of the matter
Ionizing radiation
Non-ionizing radiation
Electromagnetic:
- X rays
- Gamma rays
Electromagnetic fields
Infrared (IR)
Ultraviolet (UV)
Visual radiation (V)
Laser
Microwave
Corpuscular :
- Alpha particles
- Beta particles
- Neutrons
Characteristics of radiation
Source
Energy
deposit
Transport
The first interaction
Ionizing radiation
How can we measure radiation?
The radiation dose is the most important measure from the
medical point of view. The radiation dose can be expressed as:
• Absorbed dose (D) - the amount of energy absorbed per unit
weight of the organ or tissue;
- measured in Gray (Gy).
• Equivalent dose (H) - Absorbed dose in Gy multiplied by a
weighing radiation factor (WR) which expresses the biological
effectiveness of radiation;
- measured in Sievert (Sv).
The equivalent dose takes into consideration the radiation type, because
the equal doses of all types of ionizing radiation are not equally harmful.
Effective dose (E) E = T wT.HT where wT.= weighing tissue/organ factor
and HT = equivalent dose in tissue/organ
What are the limits of exposure to
radiation?
• The Threshold Limit Values (TLVs) published by the ACGIH
(American Conference of Governmental Industrial Hygienists)
are:
– 20 mSv - average annual dose for radiation workers, over
an average of five years
– 1 mSv - annual dose limit recommended for general public
(ICRP - International Commission on Radiological
Protection)
• The risk of radiation-induced diseases depends on the total
radiation dose that a person receives over the time.
• Legal framework: there are specific standards for each
type of radiation.
Where we can find ionizing radiation?
Sources of radiation:
• natural (85%): cosmic, the natural radioactivity of the earth,
the natural radioactivity of the air (Radon), the natural
radioactivity of the water, vegetation, and food;
• artificial (15%): medical, occupational, and from other
sources such as: industrial, nuclear research, nuclear accident
(Chernobyl, Fukushima).
Workplaces: the medical sector (X-ray examinations ~
1mSv/year, nuclear medicine ~ 1-2mSv/year), research
(operating accelerators ~ 4-5mSv/year), industry (industrial Xray examination, radioisotopes production, manufacturing of
luminescent products), nuclear industry, natural sources
(Radon in the uranium mining activity, the cosmic radiation
during plane flights).
What are the Health Effects?
TYPES OF
EFFECTS
CELL DEATH
CELL
TRANSFORMATION
DETERMINISTIC
STHOCASTIC
Somatic
Somatic and hereditary
Clinically attributable in individual
exposure
Epidemiological attributable in large
population
E.g. acute radiation disease, burns
E.g. cancer, mutations
Existence of a threshold
(under this, no observable
effects)
Severity increased by dosage
No threshold
Probability of the effect
increases by dosage
BOTH
ANTENATAL
Somatic and hereditary
Expressed in the foetus,
newborn or descendants
Radiosensitivity (RS)
High RS
Medium RS
Low RS
Bone marrow
Spleen
Thymus
Lymphatic
nodules
Gonads
Crystalline
Lymphocytes
Skin
Mezodermic
tissue of organs
(e.g. liver, heart,
lung etc)
Muscles
Bones
Nervous system
Clinical Aspects
ACUTE
CHRONIC
GENERAL
• Radiation Acute Syndrome
(RAS)
GENERAL
• Chronic radiation disease
LOCAL
• Acute radio dermatitis
• Eye impact
• Infertility
LOCAL
• Chronic radio dermatitis
• Skin cancer
Treatment
In case of over-exposure:
• Identify the affected people, select, isolate and
monitor them
• Proper protection of the personnel involved in the
rescue and in the research !!!
• Reconstruct the accident through physical and
biological measurements and clinical data
• Symptomatic treatment (antivomitives, sedative
drugs, etc)
In local exposure the prognosis is better.
How can we protect from ionizing
radiation ?
•
•
•
•
•
•
Technical and organizational measures
Increase the distance from the source
Reduce exposure time
Protect exposed people
Fundamental concepts of radioprotection:
Justification
Optimization
Dosage limitation
How can we protect from ionizing
radiation ?
Medical measures
- blood count !!!
- nucleoli test
- ophthalmological examination
- psychological test
Non-ionizing radiation
• Non-ionizing radiation: electro-magnetic
fields, infrared, ultraviolet (UV), visual
radiation, laser, microwave
• How do we measure non-ionizing radiation?
Measure unit: frequency – Hz (cycle/second),
wavelength – λ (m)
Non-ionizing radiation
Source
Ultraviolet
Visible
Infrared
Natural: sunlight
Natural: sunlight
Natural: sunlight
Artificial: welding
activities, cutting with
plasma, laser with UV,
incandescent metals,
lamp with Hg vapours,
etc
Artificial: electric
lamp, lamps with
high intensity,
flashes, laser,
video terminals,
etc
Artificial: any
object with
temperature
higher than 0
degrees absolute
Microwave radiation and radiofrequency wave
Source: in radio communications, industry (heating), drying, hardening of
metal, food sterilization, display screen, in medicine (diathermy)
Very low frequency radiation (<200Hz, especially 50-60 Hz) include
the frequencies used for the high voltage electric lines and the domestic
electric lines
Laser (Light Amplification by Stimulated Emission of
Radiation)
Source: cutting of metals, plastics, in communications, in medicine
Non-ionizing radiation
What are the Health Effects?
• Two types:
- thermal effect
- non-thermal effect (genetic, phototoxic, and photo-allergic)
• Main affected organs: - eyes (Laser exposure)
- skin
• Clinical effects of exposure to very low frequency are very
controversial. Research has focused on possible carcinogenic,
reproductive, and neurological effects. Other suggested health
effects include cardiovascular, brain, behaviour, hormonal and
immune system changes.
Non-ionizing radiation
Treatment:
• Restriction or cessation to the exposure
• Specific treatment of the eye and skin lesions
Non-ionizing radiation
How can we protect from non-ionizing
radiation?
• Medical measures
People having mechanical or cardiac implants
are not allowed on/ around electromagnetic
fields !!!
• We can not employ people with:
– eye conditions
– central nervous system condition
– cardio-vascular condition
– skin diseases
How can we protect from nonionizing radiation?
Technical and organizational measures
Worker
Source
II. Reduce exposure time
Increase source
distance
Use protective shields
III. At the worker level
E.g.:
- individual protection
equipment (proper
clothing, special eye
protection)
- protection cream
Lighting
• What do you know about lighting?
• Light is a key element for our capacity to see
and it is necessary to appreciate the form, the
colour and the perspective of the objects that
surround us.
• Light or visible light is electromagnetic
radiation that is visible to the human eye, and
is responsible for the sense of sight.
• Good lighting implies:
– uniform illumination
– optimal luminance
– no glare
– adequate contrast conditions and use of correct
colours as detail and background
– absence of stroboscopic effect or intermittent
light
How do we measure lighting?
• The device for measuring lighting is the lux meter.
• The measuring unit for lighting is “lux”
(luminance) i.e. the luminous flux per unit area at
any point, on a surface exposed to incident light.
• Legal framework: according to the European
legislation
• A good lighting level is necessary to be sufficient
(at least equal with the specific values)
What are the sources and workplaces?
• Sources: natural: the sunlight,
artificial: lighting by incandescence,
fluorescence, high-pressure sodium or mercury lamp,
low-pressure sodium or tungsten lamp, mixed
lighting (i.e. natural and artificial).
• The sunlight is composed of: 40% visible radiation, 59%
infrared visible radiation, 1% ultraviolet visible radiation.
• Workplaces: agriculture, constructions, sailing
activities, foundries, office work.
• Professions: workers in outdoor activities in summer
and winter, inside activities with visual solicitation
(jeweler, watchmaker, etc).
What are the Health Effects?
Poor lighting may affect the workers'
Health
• Visual trouble (visual
fatigue, tearing, and other
visual problems)
• Fatigue
• Headache
• Musculoskeletal disorders
Performance
• Errors
• Accidents
Treatment
Workplace
Solving the technical problems
of inadequate lighting:
- type of light
- position
- distances
- organization of work
- 10 minutes breaks every 1 hour
(e.g. fine, very fine, computer
work)
Worker
Against visual disorders:
- ophthalmologic eyewash,
vitamins, protection or
correction glasses
Against fatigue:
- vitamins
- antioxidants
Against MSD:
- physiotherapy
- swimming
- NSAID
It is recommended to use natural lighting!
How can we prevent the effects of poor
lighting?
Technical measures
• For good lighting it is necessary to have an
ergonomic organization of the workplace and
to take into consideration:
– the precision required for the performed tasks
– the amount of work
– the mobility of the worker
– the characteristics of the workplace (windows,
type of lighting and the season)
How can we prevent the effects of
poor lighting?
Medical measures
• Monitoring the visual capacity of employees
before employment and after that, through
periodical examination (usually, a screening
examination per year).
Microclimate (cold and warm climate)
• The microclimate is characterized by:
- temperature (dry)
- relative humidity
- air current speed
- surface temperature
- caloric radiation
• Very cold and very hot temperatures could be
dangerous to health.
Temperature action and worker
reaction
Cold/warm
environment
• Temperature
• Air movement
• Humidity
Worker
• Proper insulation (protective
clothing)
• Physical activity
• Controlled exposure to cold or
warm
How do we measure temperature?
• Measuring device: globe thermometer
• Measuring unit: temperature in degrees
Celsius or Fahrenheit
• Legal framework: according to the European
legislation
Cold exposure
• What are the workers exposed to cold?
Outside: road builders, construction workers,
police officers, fire fighters, emergency
response workers, military personnel,
transport workers, bus and truck drivers,
fishermen, hunters and trappers, etc
Inside: workers in refrigerated warehouses,
meat packaging and meat storage workers,
etc.
What are the Health Effects to cold
exposure?
Heat
Heat production
Loss
+
Heat retention
• Local effects: FROSTBITE
• General effects: HYPOTHERMIA
Treatment
FROSTBITE
EMERGENCIES
HYPOTHERMIA
FIRST
AID
FIRST
AID
INCREASE THE BODY TEMPERATURE GRADUALLY !!!
How can we prevent frostbite and
hypothermia?
Technical measures
Cold
Worker
environment
Insulated
Cabine
• Proper insulation (protective
clothing)
• Proper resting periods in a
warm area
• Balanced meals and adequate
warm tea intake
• NO alcohol !!!
How can we prevent frostbite and
hypothermia?
Medical measures:
• pre-employment
• periodical medical examinations
• People presenting the following conditions
are not allowed to work in cold environments:
•
•
•
•
cardiovascular diseases
Reynaud’s syndrome
otitis, sinusitis
nephropathy
Heat environment
• What are the workplaces with warm/hot
exposure?
Outdoor occupations, such as: constructions, road
repairing, open-pit mining and agriculture - summer
sunshine being the main source of heat.
Inside occupations, such as: foundries, steel mills,
bakeries, smelters, glass factories, and furnaces extremely hot or molten material being the main source
of heat; in laundries, restaurant kitchens, and canneries,
high humidity adds to the heat burden.
Heat environment
• What is acclimatization?
• The temporary adaptation of the body to work in heat
conditions and to which a person is exposed over time.
• Complete heat acclimatization generally takes 6 to 7
days, but some individuals may need longer.
• When a person gets acclimatized, the central
temperature decreases with up to 1 degree Celsius and
the cardiac frequency decreases with 10-14
beats/minute, compared to a non-acclimatized person in
the same conditions.
• This is a consequence of the increased sweating process
and a good vaso-motor control.
How does warmth act? What are the
Health Effects?
Warm
environment
Heat stress
Body heat
(generated by
working)
Clothing
requirements
Heat oedema
Heat rashes
Heat cramps
Heat exhaustion
Heat syncope
Heat stroke and hyperpyrexia
Treatment
• Removal from the heated environment
• Resting in a cool area
• ± consumption of cool salted drinks
• Heat stroke and hyperpyrexia require
immediate first aid and medical survey !!!
How can we protect from heat
exposure?
Technical and organizational measures
Worker
Source
I. Reduces the radiant
from hot surfaces
Insulation of hot
surfaces
II. Reduce exposure
time
Increase the
distance
Shielding
Ventilation
Reducing the humidity
III. Protection clothing
Eyes protection
How can we protect from heat
exposure?
Medical measures:
• Acclimatization !!!
• a decrease in heat tolerance occurs even after a long
weekend. This is the reason for which it is often not
advisable for anyone to work under very hot
conditions on the first day of the week.
• Also, the new employees should acclimatize before
assuming a full workload.
• People with cardiovascular diseases are not allowed
to work in heat conditions.
Air pressure
• The activities performed in conditions of
abnormal pressure are grouped into two
categories:
• activities performed in hyperbarism
(atmosphere compression or decompression)
• activities performed in hypobarism (pressure
below that of the ground level atmospheric
pressure)
Air pressure
What are the Workplaces and
Workers ?
Hyperbarism
- underwater activities
- scuba divers (the pressure
exceeds with at least 0.1
atmospheres the normal
value)
Hypobarism
- pilots
- lift workers
- workers in store-rooms with
modern fire protection
systems where the oxygen
content of the air is reduced
to 13 %
Air pressure
What are the Health Effects and Treatment?
HYPERBARISM
• the trauma of the ears and the sinuses during
compression period
• the toxic effect of nitrogen and CO2 while
working in increased pressure
• caisson disease during decompression period
Treatment : acute forms are medical emergencies and require
Oxygen administration and modifying the pressure
Air pressure
What are the Health Effects and Treatment?
Hypobarism
• the decompression disease at high altitude
(pilots, aircraft personnel)
• the altitude hypoxia (pilots, aircraft personnel)
• the lift workers disease
• the high altitude disease
The effects that occur depend on: how quick the transfer from
normal pressure to decreased pressure is, how trained the
person is and whether he adapts to the pressure.
Treatment: returning to the level of the ground;
specific treatment according to the condition of the
patient.
How can we prevent the effects of exposure to
hyperbarism and hypobarism?
Hyperbarism
Hypobarism
Technical measures:
- by assuring good quality and good
temperature of compressed air
- by respecting the decompression
protocol
- by reducing the work time ~ deep
- availability of a special room for
relaxing and clothing
Technical measures:
- by pressurizing the planes
- by climbing in stages
Medical measures:
- pre-employment examination
- periodical examinations
- adaptive control
Medical measures:
- pre-employment examination
- periodical examinations
- adaptive control