Physical hazards Dr Majid Golabadi

OCCUPATIONAL HEALTH HAZARDS Physical Chemical Biological Ergonomic Psychosocial

PHYSICAL HAZARDS Noise Temperature Vibration Radiation Atmospheric pressure

Temperature Heat Cold

Noise Hearing loss

Vibration Whole body Hand arm

Radiation Ionizing Alpha,ß, X,gama Non-ionizing EMF, Radiofrequency,Microwave Infrared (IR), Visible,Ultraviolet nr yfwsdaaf

Atmospheric pressure Compress Decompression (caisson )

Vibration

8-10 million workers in the USA exposed to occupational vibration. Of these 7 million: Whole Body Vibration. Others: Hand Arm Vibration.

Truck drivers & heavy equipment operators: Lumbar spinal disorders Hemorrhoids Hernia GI problems Urinary tract problems Result of extended sitting+ vibration

Resonance (amplification): Vibration of the same frequency. WBV: 5 Hz

WBV: <20 HZ Critical :3-5 Hz Discomfort:2-11 Hz Musculoskeletal, neurologic, circulatory, and digestive system disorders. Visual performance impairment: 10-25Hz

LBP,intervertebral disc damage, spinal degeneration, intervertebral osteochondrosis, calcification of discs. Reproductive effects: SAB, congenital malformation, menstrual changes.

Vibration sickness: GI problems, decreased visual acuity, labyrintine disorders, intense musculoskeletal pain.

Vibration induced white finger (HAVS)

Ranging from Hz Usually Hz Cumulative Trauma: at least 2000 hours and usually over 8000 hours. Hand Arm Vibration Syndrome(HAVS)

HAVS: Spasm of digital arteries (raynaud phenomenon): Damage of : Peripheral nerve Vascular tissue Subcutaneous tissue Bones joints

Pathology: Arterial muscle wall hypertrophy Demyelinating peripheral neuropathy Connective tissue deposition Micro vascular occlusion

Clinical findings:

symptoms: Tingling then numbness then white finger in cold. Intermittent blanching of tip of one finger. Progress to tip and base of all fingers. Progress to summer season.

Advanced cases: Degeneration of bone & cartilage resulting: Joint stiffness, restriction of motion, arthralgia. Manual dexterity may decrease. Clumsiness may increase.

Diagnosis: Exposure history & response to cold. Exclusion of idiopathic Raynaud disease & other causes of Raynaud phenomenon.

Other causes of Raynaud phenomenon: Trauma Frostbite Occlusive vascular disease Connective tissue disorders Neurogenic disorders Drug intoxication Vinyl chloride monomer

Prevention: Engineering Controls Wearing gloves Keep the hands warm Prevent long period of exposures Training Avoidance from: Vasoactive drugs & cigarette smoking

Pre-employment & periodic examination Work history with special emphasis on present or past use of vibrating tools during work or hobby activities Medical history: peripheral vascular, peripheral neural, musculoskeletal complaints Physical examination: with special attention to peripheral vascular, peripheral neural integrity, muscle force, grip strength Drugs,alcohol,smoke

Physical Examination peripheral neural status: Light tough Temperature, pain Two-point discrimination Depth perception peripheral vascular status Finger blood flow response to cold

Physical Examination Present of CTS, tennis elbow, or other work-related cumulative trauma disorder of the hand or arm Old injuries that could peripheral vascular or neural signs and symptoms Primary Raynaud disease

Treatment: Removal from exposure Massaging, shaking, placing in warm water For intractable episodes: Nifedipin 30-40mg/day Thymoxamine For more sever cases: Stanozolol PGE Biofeedback & surgical sympathectomy

The transfer of heat between skin and environment Convection Conduction Radiation Evaporation

Work in a hot environment  High ambient humidity impairs evaporative heat loss.  An obligatory rise in body temperature occurs in persons exposed to conditions of 100% humidity.  The magnitude of the risk to workers of an excessively warm environment can be predicted by examination of : -air temperature -wind velocity -amount of radiant heat -humidity

Threshold Limit Values for exposure to heat in occupational settings wet-bulb globe temperature (WBGT) Heat-index guidelines

WBGT index  The most widely used index of heat risk today is the wet bulb globe temperature (WBGT).  wet bulb temperature (WBT)  dry bulb temperature (DBT)  Black globe temperature (BGT) WBGT = WBT — DBT — BGT — 0.2 (outdoors) WBGT = WBT — BGT — 0.3 (indoors)

WBGT index

 The WBGT has been adopted as a guide to the modification of exertional activity during heat stress in the:  Military  Athletic organizations  Industry  well-acclimatized worker whose salt and fluid intake is adequate can wear the usual work uniform and perform the normal job while maintaining a rectal temperature below 38°C.

Acclimatization The scheduled and regulated exposure to heated environments of increasing intensity and duration allows the body to adjust to heat Beginning to sweat at lower body temperatures, Increasing the quantity of sweat produced, Reducing the salt content of sweat, Increasing the plasma volume, cardiac output, and stroke volume while the heart rate decreases.

Permissible Heat Exposure Limit Values work demands: lightmoderateheavy very heavy 100% work; (breaks incl.) not allowed 75% work; 25% rest not allowed 50% work; 50% rest % work; 75% rest Acclimatized Unacclimatized

medical disorders caused by excessive exposure to hot environments heat stroke, heat exhaustion, heat cramps, heat syncope, skin disorders

Indirect Heat-Related Health Effects: Reduced Work Performance Increased Accidents Reproductive Problems

Heat Stroke Life-threatening medical emergency Thermal regulatory failure Cerebral dysfunction with altered mental status Core (rectal) temperature approaches 41.1°C (106°F) Hyperventilation, respiratory alkalosis and compensatory metabolic acidosis Abnormal bleeding, renal failure, or arrhythmias

management Monitoring for hypovolemic and cardiogenic shock, Maintaining a patent air­way, providing oxygen Correcting fluid and electrolyte imbalances, Supporting vital processes. If hypovolemic shock is suspected, mL of 5% dextrose in 1% or 0.5% normal saline solution may be given intravenously without overloading the circulation. Fluid output should be monitored Monitored for complications, including renal failure (caused by dehydration and rhabdomyolysis), hepatic failure, or cardiac failure, respiratory distress, hypotension, electrolyte imbalance (hypokalemia), and coagulopathy.

prognosis Elevated creatine phosphokinase (CPK) Elevated liver enzymes, Metabolic acidosis are predictors of multiorgan dysfunction

Because hypersensitivity to heat continues in some patients for prolonged periods following heat stroke, they should be advised to avoid reexposure to heat for at least 4 weeks.

Heat Exhaustion Etiology: prolonged exposure to heat and insufficient salt and water intake can cause heat exhaustion, dehydration, and sodium depletion Symptoms and signs: weakness, nausea, fatigue, headache, con­fusion, a core (rectal) temperature exceeding 38°C (100.4°F), increased pulse rate, and moist skin, Hyperventilation and respiratory alkalosis

Heat Exhaustion Treatment Placing the patient in a cool and shaded environment and providing hydration (1-2 L over 2-4 hours) and salt replenishment—orally if the patient is able to swallow. Physiologic saline or isotonic glucose solution should be administered intravenously in more severe cases. At least 24 hours' rest is recommended.

Heat Cramps Etiology Result from dilutional hyponatremia caused by replacement of sweat losses with water alone Symptoms and signs: Slow and painful muscle contractions and severe muscle spasms that last from 1-3 minutes and involve the muscles employed in strenuous work. The temperature may be normal or slightly increased

Heat Cramps Treatment The patient should be moved to a cool environment and given a balanced salt solution or an oral saline solution. Salt tablets are not recommended. Rest for 1-3 days with continued salt supplementation in the diet may be necessary before returning to work.

Heat Syncope Etiology In heat syncope, sudden unconsciousness results from volume depletion and cutaneous vasodilatation with consequent systemic and cerebral hypotension. Episodes occur commonly following strenuous work for at least 2 hours. Symptoms and signs: The skin is cool and moist and the pulse weak. Systolic blood pressure is usually under 100 mmHg

Heat Syncope Treatment Recumbency, cooling, and rehydration. Preexisting medical conditions should be monitored and treated if necessary

Skin Disorders Caused by Heat Miliaria (heat rash) is caused by sweat retention resulting from obstruction of the sweat gland duct. Erythema abigne ("from fire") is characterized by the appearance of hyperkeratotic nodules following direct contact with heat that is insufficient to cause a burn. Intertrigo results from excessive sweating and often is seen in obese individuals. Skin in the body folds (e.g., the groin and axillas) is erythematous and macerated Heat urticaria (cholinergic urticaria) can be localized or generalized and is characterized by the presence of wheals with surrounding erythema ("hives").

Medical surveillance for hot environment

Medical screening Pre-employment Pre-employment Periodic Periodic RTW examination RTW examination

Pre-employment history Pre-employment history General (past medical,family, Drug) Social (alcohol, smoking, abuse) Occupational history Heat disease history

Limiting conditions Risk factors ( predisposing factors ) Risk factors ( predisposing factors ) Increased risk of heat disorders Heat-aggravated diseases: Heat-aggravated diseases: Multiple sclerosis Hypertension Cardiac diseases Some skin diseases; Dermatitis, acne, intertrigous diseases Dermatitis, acne, intertrigous diseases

Risk factors for individuals Increasing age over 40 Increasing age over 40 Overweight Overweight Very small body size Very small body size Poor nutrition Poor nutrition Poor physical condition Poor physical condition Lack of heat acclimatization Lack of heat acclimatization Dehydration Dehydration Diarrhea, vomiting Diarrhea, vomiting Infection Infection lack of sleep lack of sleep Pregnancy Pregnancy

Risk factors Systemic diseases: Cardiovascular disease Cardiovascular disease Hypertension Hypertension Hyperthyroidism Hyperthyroidism Diabetes mellitus Diabetes mellitus Neurological diseases Neurological diseases Anemia Anemia Skin disease Sunburn, skin rash Skin disease Sunburn, skin rash Liver, kidney, lung problem Liver, kidney, lung problem Previous heat illnesses Skin disease Previous heat illnesses Skin disease

Drugs Interference with thermoregulatrs mechanism: Lithium,fluoxetine  Limit cutaneous vasodilatation: Phenylephrine, adult cold  Heat production: thyroid hormone, amphetamines, TCAs  Decrease thirst: Haldol Decrease sweating: Antihistamines, anticholinergics Phenothiazines, Benztropine, cyclic antidepressant

Risk factors of the job Heavy work Heavy work Prolonged shifts Prolonged shifts Heavy clothing Heavy clothing Protective gear and respirators Protective gear and respirators Exposure to any toxic agent: Exposure to any toxic agent: CO CO (aggravated)

Physical Examination Cardiovascular Cardiovascular Respiratory Respiratory Neurological Neurological Skin Skin Musculoskeletal Musculoskeletal Psychological Psychological BMI BMI Weight Weight HR HR Blood pressure Blood pressure

Paraclinical tests CBC/diff CBC/diff Urinalysis Urinalysis FBS FBS BUN / Cr BUN / Cr LFT LFT EKG ( > 40 yrs) EKG ( > 40 yrs) Submaximal ETT ? Submaximal ETT ?

Radiation is defined by: Type Photon energy Wavelength Frequency

The Electromagnetic Spectrum:

Absorption of RF Direction Distance Frequency Type Body properties

Clinical finding Burning skin Headache Vertigo Nausa Eye symptom Cancer with ELF radiation(<200 Hz)

Injuries by IR Wavelength between 750 and 3million nm Examples of exposures: sun light, welding, glassmaking, drying and baking in consumer product

Injuries by IR Especially between nm Skin burn Eye symptom(cornea,iris,lens) Cataract (glassblowers, furnace workers)

Visible Radiatin

Injuries by Visible Radiatin Between IR and UV Wavelength between 400 and 750 nm Eye symptom(especially retina in nm “blue light”)

Ultraviolet Radiation - UV Sunlight contains 3 types of UV rays… Ultraviolet Radiation (UV) is simply one form of energy coming from the sun

UV radiation  UV-A: nm  UV-B: nm  UV-C: nm  Absorption by ozone and  oxygen in atmosphere is  wavelength dependent.  UV irradiance at surface:  UV-A: 94%  UV-B: 6%  UV-C: 0%

Injuries by UV  UVA  UVA—causes skin aging & wrinkles. UVA rays pass effortlessly through the ozone layer.  UVB  UVB—causes  sunburns,Photokeratoconjunctivities (especially270 nm),cataracts( nm), skin cancer. Melanoma may be associated with severe UVB sunburns. Most UVB rays are absorbed by the ozone layer.  UVC  UVC—these rays are the most dangerous. Fortunately, these rays are blocked by the ozone layer and don’t reach the earth.

Injuries by UV Erythema: DNA-damage: Erythemal UV irradiance at the surface: UV-A: 17% UV-B: 83%

Effects of UV Exposure Oklahoma State University Sunburn

Sunburn  Sunburn develops when the amount of UV exposure is greater than the protection your skin’s melanin can provide.

Effects of UV Exposure Oklahoma State University Eye Damage

 Spending long hours in the sun with no eye protection may increase your chance of developing cataracts.  UVB damage to the eyes is cumulative, so it is never too late to start protecting your eyes.

Effects of UV Exposure Oklahoma State University Skin Damage

 There are about 1.3 million new cases of skin cancer in the U.S. each year, resulting in about 9,800 deaths.  Melanoma is one type of skin cancer. It is the most common cancer among women between the ages of 25 and 29.

Examination History (occupational,…) Skin Attentive to patient reports of heating or other sensations Eye Ocular examination (particularly for shorter RF wavelengths,1 GHz and higher frequencies) Testis

Examination CBC,U/A CPK Pacemaker with surgically implanted metallic : Electromagnetic interference with implanted medical devices Persons with limited cardiovascular reserves who may work at an elevated workplace temperature may need additional medical surveillance.

Medical surveillance Detection and early prevention and treatment of any adverse exposure effects that might not have been anticipated in exposure guidelines. Collection of precise individual data on RF exposures and adequate medical records that can be used in future epidemiological studies. Report the occurrence of RF burns, implanted medical devices (e.g., copper IUD),