PHYSICAL AGENTS. Objectives: To know the definition of physical agents To identify the physical agents as risk factors in the work and work environment.

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

Workplace- days of incapacity of work- a new worker- risk insurance

How can we protect ?

Worker

I. Reduces the PA at the source

Eg:- isolation - change the device

How we can protect ?

Worker

II. Reduce exposure time

Increase the distance

How can we protect ?

Worker

III. At the Worker LevelE.g.:- isolation (special cabin)- individual equipment protection

What is the Role of the OH Physician?

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

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/video/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?

I. Reduces the N at the source

E.g.:- isolation - change the device

Technical and organizational measures

Worker

III. At the worker levelE.g.:- isolation (special cabin)- individual equipment protection (ear plugs or ear muffs)

II. Reduce exposure time

Increase the distance

How can you protect from noise?

Medical measurements• Pre-employment examination• Periodical examinations

– Audiometric testing

• Risk assessment• Risk management

Ultrasounds and infrasoundUltrasounds > 20000 Hz= inaudible

Where to be found? (workplaces)• - industry (used in detecting defects,

cleaning of pieces etc)• medicine (ultrasounds, dental

scaling, therapy)• devices against thieves, pests etc

Infrasound 1-20 Hz= inaudible

Where to be found? (workplaces)• natural sources:

– 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

InfrasoundAcute 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 HzTarget 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 SyndromeNeurological 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 testVascular Doppler testInfrared thermograph testVibration perception test

Other investigations:- Bone X –ray- Biological

Bone X ray (lumbar vertebral column)RMN Biological investigations Gastric examinationRenal examination

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?

I. Reduce the V at the source

E.g.:- Design an

ergonomic tool to attenuate the V

- Change the device

Technical and organizational measures

Worker

III. At the worker levelE.g.:- individual protection equipment (special gloves)

II. Reduce exposure time

Avoid exposure to cold

Vibration damping system

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

Corpuscular :- Alpha particles- Beta particles- Neutrons

Electromagnetic fields Infrared (IR)Ultraviolet (UV)Visual radiation (V)Laser Microwave

Characteristics of radiation

Source Energy deposit

The first interaction Transport

Ionizing radiationHow 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 X-ray 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?

Radiosensitivity (RS)

High RS Medium RS Low RS

Bone marrowSpleenThymusLymphatic nodulesGonadsCrystallineLymphocytes

SkinMezodermic tissue of organs (e.g. liver, heart, lung etc)

MusclesBonesNervous system

Clinical Aspects

ACUTE CHRONIC

GENERAL• Radiation Acute Syndrome

(RAS)

LOCAL• Acute radio dermatitis• Eye impact• Infertility

GENERAL• Chronic radiation disease

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 radiationUltraviolet Visible Infrared

Source Natural: sunlight

Artificial: welding activities, cutting with plasma, laser with UV, incandescent metals, lamp with Hg vapours, etc

Natural: sunlight

Artificial: electric lamp, lamps with high intensity, flashes, laser, video terminals, etc

Natural: sunlight

Artificial: any object with temperature higher than 0 degrees absolute

Microwave radiation and radiofrequency waveSource: 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 linesLaser (Light Amplification by Stimulated Emission of Radiation)Source: cutting of metals, plastics, in communications, in medicine

Non-ionizing radiationWhat 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 radiationHow 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 non-ionizing radiation?

Technical and organizational measures

Worker

III. At the worker levelE.g.:- individual protection equipment (proper clothing, special eye protection)- protection cream

II. Reduce exposure time

Increase source distance

Use protective shields

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 Worker

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)

Against visual disorders:- ophthalmologic eyewash, vitamins, protection or correction glassesAgainst fatigue:- vitamins- antioxidantsAgainst 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

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, etcInside: workers in refrigerated warehouses, meat packaging and meat storage workers, etc.

What are the Health Effects to cold exposure?

• Local effects: FROSTBITE• General effects: HYPOTHERMIA

Heat production +

Heat retention

Treatment

EMERGENCIES

FIRST AID FIRST AID

INCREASE THE BODY TEMPERATURE GRADUALLY !!!

How can we prevent frostbite and hypothermia?

Worker

• Proper insulation (protective clothing) • Proper resting periods in a warm area• Balanced meals and adequate warm tea intake• NO alcohol !!!

Insulated Cabine

Technical measures

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?

Body heat (generated by

working)

Clothing requirements

Warm environment

Heat stress

Heat oedema Heat rashesHeat crampsHeat exhaustionHeat syncopeHeat 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?

I. Reduces the radiant from hot surfaces

Insulation of hot surfaces

Technical and organizational measures

Worker

III. Protection clothing Eyes protection

II. Reduce exposure time Increase the distance Shielding Ventilation Reducing the humidity

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

Hyperbarism Hypobarism- underwater activities- scuba divers (the pressure exceeds with at least 0.1 atmospheres the normal value)

- pilots - lift workers - workers in store-rooms with modern fire protection systems where the oxygen content of the air is reduced to 13 %

What are the Workplaces and Workers ?

Air pressureWhat are the Health Effects and Treatment?

Treatment : acute forms are medical emergencies and require Oxygen administration and modifying the pressure

Air pressureWhat are the Health Effects and Treatment?

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 HypobarismTechnical 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