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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
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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 • 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 Level • E.g.: • isolation (special cabin) • individual equipment protection
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
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 Non-auditory sleep disturbances general effects (cardiovascular, metabolic changes) behavioural effects Acute : • tinnitus • acoustic trauma Chronic: • hypoaccousia • Noise Induced Hearing Loss (NIHL)
The audiogram - records both ways of sound transmission: air and bone conduction Normal audiogram
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 Worker • Reduces the N at the source • E.g.: • isolation • change the device • III. At the worker level • E.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 infrasound Ultrasounds > 20000 Hz = inaudible 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 Where to be found? (workplaces) • - industry (used in detecting defects, cleaning of pieces etc) • medicine (ultrasounds, dental scaling, therapy) • devices against thieves, pests etc
What are the health effects of ultrasounds and infrasound? Ultrasounds 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 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
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.
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 Worker • Reduce the V at the source • E.g.: • Design an ergonomic tool to attenuate the V • Change the device II. Reduce exposure time Avoid exposure to cold Vibration damping system • 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
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.HTwherewT.= weighing tissue/organ factor andHT = 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:themedical 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).
Clinical Aspects ACUTE CHRONIC GENERAL Radiation Acute Syndrome (RAS) LOCAL Acute radio dermatitis Eye impact Infertility GENERAL Chronic radiation disease LOCAL Chronic radio dermatitis Skincancer
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 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.
