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

Atmospheric pressure Compress Decompression (caisson )

Radiation Non-ionizing Ionizing

Radiation is defined by: Type Photon energy Wavelength Frequency

The Electromagnetic Spectrum:

Non-Ionizing Radiation

EXTREMELY LOW FREQUENCY (ELF) The generation, transport, and use of electricity are associated invariably with ELF fields. ELF radiation was classified by IARC as ‘possibly carcinogenic to humans’ (Group 2B), based on the childhood leukemia association

RADIOFREQUENCY (RF) A major difference between RF and ELF exposures is RF thermal effects. erythema and a heating sensation acutely followed by hypertension and psychiatric symptoms lasting several months Microwave-induced cataracts Additional non-thermal effects of RF – behavioral alterations, changes in immune cells, and adverse reproductive outcomes.

Infrared Radiation (IR) All objects with temperature above absolute zero emit IR radiation.

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 750-2000 nm Skin burn Eye symptom(cornea,iris,lens) Cataract (glassblowers, furnace workers)

Biologic systems exposed to IR experience a corresponding rise in the temperature of the absorbing tissue. excessive ocular exposure to IR-A may lead to damage to the lens (cataracts),choroid and retina. IR-B can damage the cornea, conjunctiva and aqueous humor.

Visible Radiatin

Injuries by Visible Radiatin Between IR and UV Wavelength between 400 and 750 nm Eye symptom(especially retina in 440-500 nm “blue light”) Chronic exposure to excessively bright light may lead to premature degeneration of the cones responsible for color vision

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

UV radiation • UV-A: 320-400 nm • UV-B: 280-320 nm • UV-C: 200-280 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—causes skin aging & wrinkles. UVA rays pass effortlessly through the ozone layer. UVB—causes sunburns, Photokeratoconjunctivities, cataracts, skin cancer. Melanoma may be associated with severe UVB sunburns. Most UVB rays are absorbed by the ozone layer. UVC—these rays are the most dangerous. Fortunately, these rays are blocked by the ozone layer and don’t reach the earth.

Effects of UV Exposure Eye Damage Oklahoma State University

Eye Damage Spending long hours in the sun with no eye protection may increase 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 Skin Damage Oklahoma State University

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

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.

Ionizing Radiation

Definition and types Two types: Ability to disrupt atoms or molecules and produce ions, free radicals and biochemical lesions. Two types: Electromagnetic (X-ray, Gamma ray) Particulate (neutron, Alfa particle, Beta particle …)

X-Rays and Gamma Rays Gamma and X radiation differ by source: gamma rays comes from the nucleus and X-rays come from the electron orbits they penetrate very deeply Xrays are similar to gamma but with a longer wavelength A person exposed to X-rays or gamma rays does not become radioactive This black and white photograph shows graphite meltdown that resulted in release of gamma rays.

Penetration Abilities of Different Types of Radiation Alpha Particles Stopped by a sheet of paper Beta Particles Stopped by a layer of clothing or less than an inch of a substance (e.g. plastic) Radiation Source Gamma Rays Gamma Rays Stopped by inches to feet of concrete or less than an inch of lead Alpha particles. Alpha particles do not penetrate the dead layer of skin and can be stopped by a thin layer of paper or clothing. If an alpha emitting radioactive material gets inside the body through inhalation, ingestion, or through a wound, the emitted alpha particles can cause ionization that results in damage to tissue. Beta particles. Depending on its energy, beta radiation can travel from inches to many feet in air and is only moderately penetrating in other materials. Some beta radiation can penetrate human skin to the layer where new skin cells are produced. If high enough quantities of beta emitting contaminants are allowed to remain on the skin for a prolonged period of time, they may cause skin injury. Beta emitting contaminants may be harmful if deposited internally. Protective clothing (e.g., universal precautions) typically provides sufficient protection against most external beta radiation. Gamma rays and x-rays (photons). Gamma rays and x-rays are able to travel many feet in air and many inches in human tissue. They readily penetrate most materials. Thick layers of dense materials are needed to shield against gamma radiation. Protective clothing provides little shielding from gamma and x radiation, but will prevent contamination of the skin with the gamma emitting radioactive material. Neutrons. Neutrons also penetrate most materials. They are able to travel many feet in concrete and thousands of feet in air. Thick layers of materials with lots of hydrogen in them (like water or concrete) are needed to shield against neutron radiation. Protective clothing provides no shielding from neutron radiation. Neutrons are not likely to be encountered except in the initial seconds of a nuclear criticality event. Neutrons Stopped by a few feet of concrete

Occupational exposure Aircrew Dental worker Radiologist Reactor worker Electron microscopist Industrial radiographer Plasma torch operators High-voltage TV repairman Underground Uranium miner Atomic power plant worker

Radiation Effects Mutation Chromosome aberrations Cytotoxic effects Effects on tissues and organs Cancer

Acute Expoture Prodromal stage Latent period, Stage of manifest illness, Recovery

Acute Radiation Syndrome Spectrum of Disease

Hematopoietic ARS Dose: 2-10 Sv Illness: 2-3 weeks after prodromal Signs and symptoms: Leukopenia, Thrombocytopenia, Anemia

Intestinal ARS Dose: 10-20 Sv Illness: 2-3 days after prodromal Signs and symptoms: abdominal pain, fever, diarrhea, dehydration

Pulmonary ARS Dose: 6-10 Sv Illness: 1-3 months after prodromal Signs and symptoms: Acute pneumonitis, pulmonary fibrosis, cor pulmonale

Cerebral ARS Dose: more than 50 Sv Illness: X minutes to X hours after prodromal Signs and symptoms: confusion, ataxia, convulsion, coma, death

Skin Reproductive system Eye

Delayed effects of radiation Radiodermatitis Endarteritis obliterans Intestinal stenosis Pulmonary fibrosis Cataract Cancer

Cancers due to irradiation Leukemia (exc. CLL) Breast cancer Thyroid tumors (Papillary adenoma and carcinoma) Bone tumors Liver carcinoma Lung cancer

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)

Hand Arm Vibration Syndrome(HAVS) Ranging from 5-1500 Hz Usually 125-300 Hz Cumulative Trauma: at least 2000 hours and usually over 8000 hours.

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