Occupational Hygiene Flashcards
According to him, the dose makes the poison
Paracelsus
Introduced because of Percival Potts work on scrotal cancer in chimney sweeps
The British Chimney Sweeps Act
Not-for-profit organization which sets standards or professional competence for occupational hygienists and hygiene techs in Canada
Canadian Registration Board of Occupational Hygienists (CBROH)
No-for-profit organization that established and published Threshold Limit Value (TLV)
American Conference of Governmental Industrial Hygienists (ACGIH)
Most common route of toxic chemical entry
Inhalation
3 ways that doses are expressed
The quantity administered per unit body weight, quantity per skin surface area, & quantity per unit vol of air breathed
2 variables involved in air contaminants
The concentration of the substance and the duration of exposure
Lethal Dose (LD50)
The total amount of a substance applied to skin, injected in the muscle, or given by mouth over a stated period of time which will kill 50% of a group of test animals
A high LD50 means it’s _______ _______ than a compound with a low LD50.
less toxic
Lethal Concentration (LC50)
The concentration of an airborne substance that will kill 50% of a group of test animals when absorbed by INHALATION in a stated length of time.
Category of chemicals with the highest toxicity according to GHS
Category one
Toxicity
The ability of a substance to produce an unwanted effect when the chemical has reached a sufficient concentration at a certain site in the body
Degree of toxicity depends on:
Dose, route of entry, route of absorption, individual differences
Degree of hazard depends on toxicity including:
Chemical and physical properties of the substance, how much is being used, conditions and manner of use, control measures in place, & duration of exposure
Gases that are liquified by extremely low temperatures
Cryogenic liquids
Most significant health hazard in the welding process
Generation of toxic metal fumes and gases
Disease caused by Tin fumes
Stannosis
Disease caused by Iron fumes
Siderosis
Disease caused by Titanium fumes
Fibrosis
Disease caused by carbon
Anthracosis
Caused by UV radiation from welding
Arc eye/welder’s eye/arc flash
Fever chills, flu-like symptoms from exposure to welding fumes that contain zinc oxide and/or magnesium
Metal fume fever
Caused by the impairment of organ of corti
Noise-induced hearing loss
3 small bones in the middle ear that helps in the hearing process
Malleus, incus, stapes
Definition of sound
A slight, rapid variation in atmospheric pressure, caused by longitudinal vibration(sound waves)
Characteristics of a sound wave
Frequency (perceived pitch), wavelength, and velocity
The speed of sound is always _______ the product of the frequency and the wavelength
equal to
Sound power per unit area at a given point, measured in W/m2
Sound intensity
An increase of 3 dB represents a __________ of the sound intensity
doubling
For every doubling of the distance, the sound intensity will be __________ by 6 dB
reduced
The weakest sound a healthy human ear can detect has an amplitude of _______
20 micropascal (uPa)
Noise exposure limits are expressed in ____
dBA
Formula for noised dose exposed to different weighted sound levels
D = (C1/T1)+ (C2/T2)+(Cn/Tn) = 1
Noise from 2 sound sources
0-1 dB difference, add 3dB to greater source
2-4 dB difference, add 2dB
5-9 dB difference, add 1dB
10 dB+ difference, add 0 dB
SPL _________by ___ dB for every doubling of distance
decreases, 6
Controls for noise exposure can be used in 3 parts. What are they?
source, path, receiver
Type of Sound Level Meter (SLM) that is sufficient for industrial field evaluations
Type 2
This is similar to dosimeter and it determines equivalent sound levels over a measurement period
ISLM
Noise measuring instrument that is best for personal noise exposure
dosimeter
Components of hearing conservation program
Monitoring, Audiometric testing, hearing protectors, training, record keeping
Observable health conditions such as reddening of skin due to high exposure to radiation
Deterministic effects
Not immediately observable health effects such as cancer or genetic damage
Stochastic effects
Ionizing radiation that can be stopped by a sheet of paper. Considered to be only internal radiation hazards
Alpha particles
Ionizing radiation that can be stopped by 1/2 inch of aluminum
Beta particles
A secondary x-ray radiation produced when beta particles are slowed down or stopped
Bremsstrahlung radiation
Best shields for neutrons
Concrete, Polyethylene, boron
Ionizing radiation that requires thick lead for shielding
Gamma rays
Max effective dose of radiation in 1-yr & 5-yr period by an adult worker
1 year = .05 Sv or 5 rems or 50mSv
5 year = 100 mSv
The total radiation dose accumulated during the 50 years following the intake
Committed dose
Sum of weighted equivalent radiation dose in all the organs and tissues of the body
Effective dose
A small badge that can be worn as a clip and contains a small piece of photographic film that is sensitive to radiation
Film badges
A radiation detector containing small chips of lithium fluoride that will store ionizing radiation and will release this energy when heated
Thermal Luminescence Detectors (TLD)
Radiation detectors that are direct reading, allow for immediate results
Pocket dosimeters
Opening the shutter allows the radiation to pass through the material and to be measured by a detector mounted opposite the source
Fixed gauges
Method using portable gauge that involves placing a source rod in a tube that is inserted beneath the soil surface through a punched access hole
Direct transmission
Equation for body’s heat balance
S=M+R+C+K-E
Rate of heat storage = Metabolism rate + Radiation gain or loss + Convective heat gain/loss + Conductive heat gain/loss - Evaporative heat loss
Acclimatization generally takes how many days
6-7 days
Fingers will become white and stiff with intermittent blanching, tingling, and reddening
Reynaud’s disorder
Hypothermia
Body temperature of 35C and below
Laboratory procedures intended for processing clinical Anthrax specimens should be managed where?
Biosafety Level 2
If aerosol is produced, Level 3
A rare but serious lung disease caused by Hantavirus
Hantavirus Pulmonary Syndrome (HPS)
Biosafety level for high risk of life threatening disease
Biosafety Level 3
Class of biosafety cabinets that provides protection by means of non-recirculated inward airflow away from the operator
Class 1
Extremely high exposure to this can lead to a condition known as organic dust toxic syndrome
Mycotoxins
Types of Class 2 BSCs
Type A - inward airflow velocity of 75-100 fpm, exhaust air usually discharged to the work environment
Type B - 100fpm, HARD-DUCTED to the outside atmosphere
Affects agricultural workers causing “farmers lung”
Aspergillus versicolor
Airborne concentrations of substances and represent conditions under w/c it is believed that nearly all workers may be repeatedly exposed day after day without adverse health effect
Threshold Limit Values (TLVs)
The time-weighted average concentration for a conventional 8-hr workday and a 40-hr work week to w/c it is believed that nearly all workers may be repeatedly exposed day after day for a working lifetime without adverse effects
TLV-TWA
How high can concentration go above the TLV-TWA?
Levels may exceed 3 times the TLV-TWA for no more than 30 mins during a workday but never exceed 5 times
What is TLV-Short Term Exposure Limit (STEL)?
The concentration to w/c worker can be exposed continuously for a short period of time (15 min) without without adverse effects. Should not occur > 4x/day, with at least 60 mins between exposure.
A concentration that should not be exceeded during any part of the work exposure.
TLV-C (Ceiling)
Biological Exposure Indices (BEI’s)
Represents warning levels of biological response to the chemical, or warning levels of the chemical or its metabolic product(s) in the tissue, fluids, or exhaled air of exposed workers, regardless of whether the chemical was inhaled, ingested or absorbed via the skin.
A level at which action is required for some specific substances and noise exposure
Action limit
3 groups of calibrators/standard meters for air sampling
Volume, flow rate, & velocity meters
2 most common primary standards of air sample calibrator
soap bubble and frictionless piston meter
Short duration samples usually less than 5 minutes. Used to evaluate peak or ceiling concentrations
Grab samples
Used to determine a worker’s TWA or STEL exposure to a particular substance by collecting one or more personal samples during a particular task
Integrated air sampling