1.OCCUPATIONALMEDICINEANDOCCUPATIONALDISEASES

2. OCCUPATIONAL MEDICINE Branch of medicine which isdevoted for the promotion andprotection of workers health. Early diagnosis and treatmentof diseases of occupationalorigin, and rehabilitation ofdisablement of workers. 3. Historical Background Paracelsus, 1493 1541. Bernardino Ramazzini, 1633 1714. Charles Turner Thackrah,1795 1833. Promulgation of Factory Act,1819. Appointment of CertifyingFactory Surgeon, 1884. 4. Occupational Health Hazards Physical agents : Heat, Light,Cold, Humidity, Air pressure,Vibrations, Noise, E.M.F., Injuriousforce, Dusts, Radiant energy. Chemical agents : Noxiousgasses, Aerosols, Corrosives,Solvents, Metals and Metal fumes,Insecticides and Herbicides. 5. Biological agents : Bacterias,Viruses, Fungi, Molds and otherbiological agents. Mechanical agents : badlymaintained machines, Lack ofprotective devices . Social factors : Job security andworking conditions, work relatedtensions and worries, familypressures. 6. Noise : Hearing impairment, hearingloss. Light : headache, loss ofconcentration and miners nystagmus. E.M.F.: Headache, sleep disturbances,risk of blood and brain cancer. Radiant energy :a) Cosmic radiation :-Cataract, skin cancer. b) U.V.radiation :- Skin and bone cancer. Injurious force : injuries andaccidents. 7. Ionising radiation : a) acute effects :-Radiation burns, acute radiationsyndrome.b) delayed effects :- Genetic mutations,cancers, teratogenesis. Dusts : organic and inorganic :-Respiratory diseases, Pneumoconioses. Chemical agents : Burns, Occupationaldermatoses and cancers. Biological agents : Various agentspecific diseases. Social factors : Nature of work andworking hours,Jealousy in promotions, poor housing,less pay, separation from family and lackof job satisfaction. 8. Noise Noise is often defined as unwantedsound, but this definition is quitesubjective. A better definition of noise is wrongsound, in the wrong place, and thewrong time, leading to healthhazard. Noise has become a veryimportant stress factor in theenvironment of man and the term NoisePollution has been accepted. Noise is also one of the most commonof all the occupational hazards. 9. Sources of noise they are manyand varied. These are automobiles, factories,industries woodcutters, textiles, primarymetals, petroleum and coal, chemicals,printing and publishing, aircraft etc. The domestic noises from the radios,TV sets, vacuum cleaners, elevators etc.add the quantum of noise in daily life. Properties noise has two importantproperties intensity or loudness, and- frequency. 10. INTENSITY Intensity or loudness dependsupon the amplitude of thevibrations, which initiated thenoise. The intensity of noise ismeasured in decibels (dB). Whenwe say that sound is 60 dB, itmeans that it is 60 dB more intensethan the smallest distinguishablenoise. Normal conversationproduces a noise of 60-65 dB. 11. Acceptable noise levels (dB/A)Acceptable noise levels (dB/A)Residential: Bed room 25Living room 40Commercial:Office 35-45 Conference 40-45 Restaurants 40-60Industrial: Workshop 40-60 Laboratory 40-50Educational: Class room 30-40 Library 35-40Hospitals: Wards 20-35 12. Sound levels of some noisesSource of noise Sound Level (dB/A)Wishper 10Speech, 2-3 people73Speech on radio 80Music on radio85Children shouting 79Children crying 80Vacuum cleaner76Piano 86Jet take off150 13. It has been observed that the humanear responds in a non-uniform way todifferent sound pressure levels, that is, itresponds not to the real loudness of asound, but to the perceived intensity. A weighting curve A has beenconstructed, which takes into account thesubjective effects of the sound. Soundpressure levels are therefore expressed indB (A). This is in decibels conforming tothe weighting curve A and reflects theperception of that sound emission by thenormal human ear. 14. Community noise levels160 Mechanical damage150140 Threshold of pain130120 Motor car horn110 Train passing station10090Recommended maximum (85 dB)80Printing-press70Heavy street traffic60Normal conversation5040Quiet library3020Whispering10 15. FREQUENCY The frequency is denoted inHertz (Hz). One Hz is equal to onewave per second. The human earcan hear frequencies from about20 to 20 000 Hz, but this range isreduced by age and othersubjective factors. The range offrequencies below 20 Hz are infra-audible, and those above 20 000Hz are ultra-sonic. 16. Measurement of noise The basic instruments used instudies on noise are: 1. Sound level meter, whichmeasures the intensity of sound in dB ordB (A) 2. Octave-band frequencyanalyzer, which measures the noise inoctave bands. The resulting plot showsthe sound spectrum and indicates thecharacteristics of the noise, whether itis mainly of high frequency, lowfrequency or of variable frequency. 17. 3. Integrating sound level meterand Noise dose meter or dosimeter(for measuring mainly of industrial noise).For measuring of non-steady noiseexposures, such as those that occur inintermittent or impulse noise, an integratedsound level meter is most convenient to use,which measure simultaneously theequivalent, peak and maximum sound levels.The noise dose meter or dosimeteris a form of integrating sound level meterthat can be worn in shirt pocket or attachedto the workers clothing. Data form thedosimeter may be computerized or printed 18. Measuring procedures inthe workplace There are two basic approaches tomeasuring noise in the workplace: The exposure of each worker, workertype or worker representative may bemeasured. The noise dosimeter is thepreferable instrument for this purpose. Noise levels may be measured in variousareas, creating a noise map for thedetermination of risk areas. In this case,a sound level meter would be used totake readings at regular points in acoordinate network. 19. Effects of noise exposureAuditory effects Auditory fatigue it appears in the 90 dBregion and greatest at 4000 Hz. Deafness or hearing loss this is the mostserious pathological effect. When this occursas a result of occupation in industries, it iscalled occupational hearing loss. Hearingloss may be temporary or permanent. Thetemporary one results from a specificexposure to noise and disability disappearsafter about 24 hours. Repeated or continuousexposure to noise above 85-90 dB may resultin a permanent hearing loss. 20. Non auditory effects Annoyance a primarypsychological aspect; neuroticpeople, especially workersoccupationally exposed to highnoise become often irritated andimpatient and disruptproduction, which also reducesthe efficiency of work witheconomic losses. 21. Non auditory effectsPhysiological changes anumber of temporary psychologicalchanges occur in the human body asa direct result of noise exposure.These are: a rise in blood pressure, arise in intracranial pressure, anincrease in heart rate and breathingand an increase in sweating, increasein catecholamines production,alteration in the functions ofgastrointestinal and endocrinesystems etc. General symptoms asfatigue, nausea, visual disturbancesmay also occur. 22. Control of noiseCareful planning of cities in planning cities, the followingmeasures should be taken to reducenoise: Division of the cities into zoneswith separation of areas concernedwith industry and transport andseparation of residential areas fromthe main streets by means of widegreen belts. House fronts should lienot less than 15 meters from the roadand the intervening space should bethickly planted with trees and bushes. 23. Control of vehicles heavyvehicles should not be routed into narrowstreets; traffic on residential streetsshould be reduced. Improving of the acousticinsulation of buildings from theacoustic standpoint, the bestarrangement is construction of detachedbuildings than a single large building.Installations that produce noise ordisturb the occupants within dwellingsshould be prohibited. Buildings should besound-proof where necessary. 24. Control of industrialnoise control of noise atsource is possible inindustries. The use ofwritten specifications todefine the requirements forequipment, its installation,and acceptance should be astandard practice. Once theequipment is installed andexcess noise identified,there are: 25. - Engineering controls available.Such are: replacement oradjustment of machines,lubrication of machine parts,reducing noise by using soundabsorptive materials on wallsand ceilings in work areas, byusing sound barriers along thetransmission path or completeenclosure of individual machines,isolation of the operator by providinga relatively soundproof booth. 26. - Personal hearing protection itis recommended for all workers whoare consistently exposed to noiselouder than 85 dB in the frequenciesabove 150 Hz, and is performed byuse of hearing-protective devices.Workers must be regularly rotatedfrom noisy areas to comparativelyquiet posts in factory. Periodicalaudiogram check-ups are alsoimportant for workers healthprevention. Workers have the right toclaim compensation if they havesuffered a hearing loss. 27. Vibration Vibration is oscillatory motion. Whole-body vibration occurs whenthe body is supported on a surfacewhich is vibrating (e.g., when sitting ona seat which vibrates, standing on avibrating floor or surface). Whole-bodyvibration occurs in all forms of transportand when working near some industrialmachinery buldozers, excavators,eorest machines, mine and quorryequipment, concrete productionproduction etc. 28. Hand-transmitted vibration isvibration that enters the bodythrough the hands. It is caused byvarious processes in industry,forestry, agriculture, mining, andconstruction where vibrating tools orworkpieces are grasped or pushed bythe hands or fingers.The main parameters of vibrationthe health effects depend on are: 29. MagnitudeOscillatory displacements of an objectinvolve a velocity in one direction and thena velocity on the opposite direction. Thischange of velocity means that the object isconstantly accelerating, first in onedirection and then in the oppositedirection. The magnitude of an oscillationcan be quantified by its displacement, itsvelocity or its acceleration. The units ofacceleration are meters per second(m/s2). 30. The magnitude ofvibration can be expressedas the distance between theextremities reached by themotion (the peak-to-peakvalue) or the distance fromsome central point to themaximum deviation (thepeak value), this is alsocalled amplitude. 31. FrequencyThe frequency of vibration, whichis expressed in cycles per second(Hz), affects the extent to whichvibration is transmitted to thebody (e.g. to the surface of a seator the handle of a vibratory tool),theextent towhichitistransmitted through the body(e.g. from the seat to the head),and the effect of vibration inthe body. 32. The relation between thedisplacement and the acceleration of amotion are dependent on the frequency ofoscillation; a displacement of one mmcorresponds to a very lowacceleration at low frequencies but avery high acceleration at highfrequencies. 33. The effects of whole-bodyvibration are usually greatest at therange from 0.5 to 100 Hz. For hand-transmitted vibration, frequenciesas high as 1000 Hz or more mayhave adverse health effects.Frequencies below about 0.5 Hz cancause motion sickness. 34. The frequency content ofvibration can be shown in spectra.For many types of vibration thespectra are complex, with somemotion occurring at allfrequencies. Nevertheless, thereare often peaks, which show thefrequencies at which most ofthe vibration occurs. 35. DirectionVibration may takeplace in three directions x-axis (fore-and-aft), y-axis(lateral) and z-axis(vertical).Vibration is usuallymeasured at the interfacebetween the body and thevibration. 36. Duration Human responses to vibration dependon the total duration of vibration exposure. Many occupational exposures areintermittent, vary in magnitude frommoment to moment or contain occasionalshocks. The severity of such complexmotion can be accumulated in a mannergiving appropriate weight to short periodsof high magnitude vibration or low periodsof low magnitude vibration. Differentmethods for calculating doses areused. 37. Measurement and evaluation of exposure Vibration measurements are made toprovide assistance for the development ofnew tools, to check these tools atpurchase, to verify maintenanceconditions, and to assess human exposureto vibration at workplace. Vibration-measuring equipmentgenerally consists of a transducer (usuallyan accelerometer), an amplifying deviceand amplitude indicator. 38. Whole-body vibrationshould be measured at theinterfaces between the bodyand the source of vibration. Forseated persons this involves theplacement of accelerometers onthe seat surface beneath theischial tuberosities of subject.Vibration is sometimesmeasured at the seat back or atfeet and hands. 39. The presence of otheradverse environmental factors,especially sitting posture,should be also be considered.It is assumed that for healtheffect estimation the totalexposure, rather than theaverage exposure, is important,and so a dose measure isappropriate. 40. Hand-transmittedvibration Vibration measurements should bemade on the tool handle or workpiececlose to the surface of the hand(s) wherethe vibration enters the body.In several (and the Bulgarian)standards hand-transmitted exposure isassesses in terms of four-hour and eight-hour energy-equivalent frequency-weighted acceleration calculated bymeans of equations. 41. Prevention The prevention of injuries or disorderscaused by vibration requires theimplementation of administrative, technicaland medical procedures. Appropriate adviceto manufacturers and users of vibrating toolsshould also be given.Administrative measures should includeadequate information and training to instructthe operators of vibrating machinery to adoptsafe and correct work practices. Sincecontinuous exposure is believed to increasevibration hazard, work schedules should bearranged to include rest periods. 42. HEALTH EFFECTS OFHAZARDS Heat : Heat cramps, Heatexhaustion, Heat stroke, Heatsyncope. Cold : Chill blains, Frost bite,Hypothermia. Humidity : Loss of body fluids,Dehydration. Vibrations : Injury and inflammationof bones, joints and soft tissues. Abnormal pressure : Pressure bends,Caissons disease, Air embolism. 43. Occupational Diseases Occupational lung diseases :Pneumoconiosis : Coalworkers pneumoconiosis,asbestosis, silicosis. Airway diseases : Bysinosis,Occupational asthma. Malignancies : Lung cancer. 44. Musculoskeletal injuries :i) Disorders of back, trunk, arm, leg. ii) Traumatically inducedReynauds phenomenn. Occupational Cancer (other than lung cancer) : Bladder, Blood, skin, liver, bones, brain and gonads. Severe traumatic injuries : Amputation, laceration, fractures, Eye loss, Death. Cardiovascular diseases : Hypertension, Coronary heart diseases. 45. Disorders of reproduction :Infertility, spontaneousabortions, Birth defects. Neurotoxic disorders :Peripheral neuropathy, C.N.S.disorders :- encepphalities,psychosis, personality changes. Noise induced hearing loss. Dermatologic condition :Dermatoses, Burns (thermal orchemical), Contusions,abrasions. 46. Psychological disorders : Alcoholism, substance abuse, Neuroses, personality disorders. Infectious diseases: i) Strange & exotic :- Brucellosis, sporotrichosis, anthraxii) Lyme disease. iii) Sexually transmitteddiseases. iv) HIV infection & AIDS . 47. Exposure Assessment at Work Place.1. Measurement of the level of hazard in REM (Relevant Exposure Medium).4. Measurement of Environmental factors I.e. temperature, humidity, & Air movement .3. Measurement of concentration of air borne contaminants ( Dust, Gases, Vapours & Particles .)4. Collection of Samples from other exposure media. 48. Exposure Assessment of Individual Worker1. Measurement of the concentration of harmful agents and their metabolites in biological samples of exposed worker ( Urine, Blood, Sputum & exhaled air).5. Assessment of intensity of biochemical & histological changes due to exposure.8. To carry out specialized investigation procedures ( biological Assays for responses to toxins , cytogenetic assays). 49. Health Hazards of Power plant workers 1) Temperature : Workers areexposed to high degree oftemperature at boiler rooms,turbine rooms and other workstations closer to boilers. 2) Health effects : heatexhaustion due to loss of bodyfluids due to excessivesweating. Signs andsymptoms :- Person feelsweakness , Low bodytemperature, rapid pulse , 50. 3) Heat cramps : Due to loss ofelectrolytes from the body. Signs and symptoms :- Painful cramps ofcalf muscles and abdominal muscles. 4) Heat stroke : Due to exposure toexcessive temperature. Signs and symptoms :- high bodytemperature i.e. 108 F 112F, increasedfrequency of urination, giddiness andloss of consciousness. 5) Prevention and control : Properventilation and air conditioning of workplace, Use of loose fitting clothes,provision of effervescent salt drinks toaffected workers, Physical fitness ofworkers. 51. Exposure to Noise : Exposure at boilerrooms , turbine rooms and other workstations. Type of noise :- a) steadywide band noise from continuouslyoperating motors and machines. b)Impact noise from steam let outs. Effects : social deafness :- person ishabituated for loud talking could notappreciate whisper, hearingimpairment, Occupational hearingloss, lack of concentration,annoyance, mental stress, hypertension and peptic ulcer. 52. Permissible level of noise forhumans : 60 to 85 decibels or 185Hertz . Prevention and control : a) pre-placement and periodic medicalexamination of exposed workers.Use of protective devices such asear muffs and ear plugs. Enclosingnoise producing machines, reductionof noise by fitting mufflers andsilencers to noisy machines. Soundproofing of work stations . 53. Coal and other Dusts Exposure at coal handling plant,tippling stations, boiler rooms. Respirable dust : dust particles of0.3 to 5 microns in size. Effects of dust inhalation :respiratory disorders likepneumoconiosis and progressivemassive fibrosis of lungs. Prevention and control : pre-placement and periodic medicalexamination of exposed workers. 54. Proper ventilation of working place. Good house keeping. Use of personal protective devicessuch as masks and respirators byexposed workers. Dust suppression measures likewet mopping of the floor, use ofaerosol sprays. 55. Health effects of Radiation Exposure at atomic power plants, nearNuclear Reactor, monitoring panels andother work stations. Permissible level of radiation for humans: Five rems /year. Effects of radiation : high degree ofexposure due to accidental leakage ofNuclear Reactor causing radiation burns,acute radiation syndrome, Cancer of theskin, blood and bones, still births,intrauterine foetal death, abortions,shortening of life span. 56. Prevention and Control Pre- placement and periodic medicalcheckup of workers. Shielding the source of radiation :the source of X-rays, gamma raysand particulate radiation should beenclosed in radio protective materialsuch as lead and concrete ofsuitable thickness. Distance from the source ofradiation : the controls should belocated as far as possible orremotely operated. 57. Electromagnetic Field in the Power Plant E.M.F. generates magnetic fluxdensity at work place and near overhead high tension power transmissionlines, electrical sub stations andpower generation plants. Safety limits : maximum field strengthshould not exceed 10 Kv /M. Recommended continuous exposurelimit : 5 gauss with a maximum of 50gauss for 2 hours. 58. Effects on HumanHealth Sleep disturbances. Headache. Increased susceptibility torespiratory infections. Increased risk of blood andbrain cancer. 59. Prevention and Control Insulation and shielding ofmachines. Barrier operation of machines. Continuous monitoring of E.M.F.level at work place. Periodic medical checkup ofexposed workers. 60. Hazards due to social factors Workers are affected by industrialpsychoses and neuroses. Tensions and worries arising out ofsocial environments in the industry i.e.poor intra and inter- personal relations ,poor housing conditions, separation fromfamily, job satisfaction and sicknessabsenteeism. Sickness absenteeism is related to lowproductivity and low workers morale . Level of absenteeism in the country : tothe tune of 8 10 days / head /year. 61. Prevention & Control2. Periodic Medical Examination of Workers.4. Provision of good housing facility & Recreational activities.6. Good intra & inter personal relations in the factory.8. Health Education & Addiction control programmes in the Factory.