Hazards Flashcards
Explain hazards
The resulting harm in hazards involve what?
A hazard can be described as existing or potential source of harm. It is actually;
–Attribute or nature of anything that can cause harm.
–A set of physical circumstances that could lead to harm
–an inherent harm property of anything which will manifest if condition & circumstance permit.
–Resulting health harm is referred to as health hazard
•Note therefore that hazard is defined differently but what is important is to know these shades of meaning and identify which is being used at any given time.
The harm vary in severity-some hazard cause death, serious illness or disability, others are minor like cuts and bruises.
•The harm may also involves damage to property , loss of production or the environment.
State and give three examples each of six classes of hazards
State and explain the classification of hazards based on the temporal relation between expose and effect of the hazard
Classification of Hazards
•Mechanical hazards include machine parts, transport and transport ways, floors, working stands and platforms, ladders, roof supports and other means of access and poor house- keeping
• Physical hazards include noise and vibrations, Electricity , non-ionizing radiations such as the sun, extreme temperatures, humidity, and air velocity and air cleanliness. Illumination and color design come from natural and artificial lighting.
•Chemical hazards are caused by chemicals (dust, gases and vapors) toxic materials, waste, fire and explosions. Examples are explosives,toxicants,oxidants,mutagens,carcinogens,teratogens(find their hazard signs)
Classification of Hazards
•Biological hazards are bacteria, viruses and fungi
•Ergonomic h hazards include lifting of heavy load, unsuitable tools and control, and wrong working postures.
•Psychosocial hazards include long working hours, monotonous work, and working alone, working under pressure to meet set production target, and bullying at work. Exampke is sexual harassment at work
Other Classifications
–This classification based on the temporal relation b/n expose and effect of the hazard
–Obvious Hazard
•Cause immediate damage to health
•Electricity, fire, lifting and handling loads, sharp edges
–Hidden hazards;
•long term damage to health
•Noise, dust, stress, shift work staffing levels, long working hours
What is a risk and state the levels of risk rating
Risk:
–is the likelihood/probability that a defined harm will be realised under specific condition or circumstance of use/work.
–The probability that under certain circumstances, the hazard will be expressed.
–The frequency with which individual is expected to sustain a given level of harm from a hazard
–Simply put risk describe how likely and severe is the harm from the hazard
•Risk can be rated as high, medium or low
LEVELS OF RISK RATING
•Qualitative: Judgement is used, difficult to prioritize
•Semi-quantitative: decide which area of the risk matrix represents intolerable risk
•Quantitative: use a target for intolerability of risk if fatal accident can cause exposure to hazard
Risk is the function of what two determinants?
Severity of health harm under determinants of risk is based on what criteria?
Explain probability of occurrence as a determinant of risk
DETERMINANTS OF RISK
•Risk is function of the
–Severity of the health harm associated with hazard
–Expected Frequency or probability of harm occurrence
DETERMINANTS OF RISK
•Severity of health harm is based on the ff criteria
–Prognosis of the condition
–Incapacitation or disability associated
–Stigma associated with the condition
–Lost of work days/medical absence
–cost of treatment
DETERMINANTS OF RISK
•Probability of occurrence
–Existing likelihood: past incidence or prevalence of health harm, fault tree analysis
–Potential Likelihood:
•Levels of control against hazard in place
•Computer simulations
How are hazards evaluated and state the levels of hazard assessment or evaluation
Evaluation of hazards
•Measurements
–Air sampling, noise meters, light meters, thermal stress meters, accelerometers (vibration)
•Calculation of dose
–Level and duration of exposure
•Keep records
Or
Levels:
Hazard identification
Dose-response assessment
Exposure assessment or concentration
Risk characterization (if it’s toxic or not,if it’s an ergonomic risk or other types of risk
State the Potential health effects of biological hazards ,chemical hazards,ergonomic hazards,psychosocial hazards
Potential health effects of hazard
The effect of biological hazards are:
•Infections
•Parasitic infestation and
•allergies
The effects of chemical hazards
•Allergies
•cancers
Ergonomic predispose workers to musculo-skeletal injuries often affecting the back.
Psychosocial hazards-stress, depression etc
Explain occupational toxicology
Occupational Toxicology
•Workplace exposure to chemicals
•You or someone you know has probably experienced an episode of toxicology
–Injury or death due to:
•Smoke inhalation
•Confined space incident
•Ingestion or absorption of a chemical
Explain the dose response relationships
What is a dose
What is a response
What is threshold dose
Know the graphs and the variables at each part of the graph
The longer the exposure,the higher the effects of the dose
Concentration and duration are factors affecting dosage
True or false
The Dose-Response Relationship
•A time of exposure (dose) to a chemical, drug, or toxic substance, will cause an effect (response) on the exposed organism
•If the amount or intensity of the dose increases, there will be a proportional increase in the response
Dose: The amount of a substance administered (or absorbed), usually expressed in milligrams of substance per kilogram of the exposed organism (mg/kg)
•Response: The effect(s) of a substance; may be positive or negative
Threshold dose is the minimum conc or dose of a chemical at which response to the drug occurs
What is chronic exposure
Acute exposure
Acute response
Chronic response
Acute and Chronic Terminology: Exposure as well as Response
•Acute exposure: short time / high concentration
•Chronic exposure: long-term, low concentration
•Acute response: rash, watering eyes, cough from brief exposure to ammonia
•Chronic response: emphysema from years of cigarette smoking
What are the possible response levels to a drug (define no response,threshold dose,NOAEL,LOAEL,above threshold dose)
Possible Response Levels
•No response: at low dosage levels there may be no response at all
•Threshold dose: the lowest level of dosage at which a response is manifested
–NOAEL: no observed adverse effect level. This is the max dose of the drug at which there’ll be no effect
–LOAEL: Lowest observed effect level. This is the minimum dose of the drug at which we’ll have an effect . So it may be a high dose you’ve taken but out of all the doses ,the one that causes the effect first is the LOAEL. So 1000mg is a high dose but at 1001mg you get an effect and at 1002 mg you get an effect so the LOAEL is 1001mg
•Above threshold dose: response can be positive up to a point and then could become toxic to the organism
•Different people or organisms will exhibit a variety of responses
State the indicators of relative toxicity
What is toxicity
Indicators of Relative Toxicity
•Toxicity: ability of a substance to cause harm or have an adverse affect
•How much harm?
•What aspect of the population?
–LD, lethal dose
–LC, lethal concentration
–ED, effective dose
–EC, effective concentration
What is LD50
How do you use LD50 to get the relative toxicity between two substances?
Where is LD50 determined ?
LD50 – a measure of relative toxicity
•Most common toxicity notation
•Determined in the lab and based on an acute exposure to adult test animal
•Lethal dose that produces death in 50% of the exposed population
•LD50, 35 mg/kg, oral, rat
–35 mg of dose per kg of rat’s body weight, when administered orally, produces death in 50% of exposed population
•Comparing the LD50 between two substances gives the relative toxicity between the two substances
What is the LD50value for alcohol ,botulinum toxin,dioxin,hemicholinium,nicotine,morphine,sodium chloride
BT and hemocholinium cause encephalopathy true or false
LD50 Relative Toxicity
Agent
LD50 (mg/kg)
Ethyl Alcohol
10,000
Sodium chloride
4,000
Morphine sulfate
900
Strychnine sulfate
2
Nicotine
1
Hemicholinium-3
0.2
Dioxin (TCDD)
0.001
Botulinum toxin
0.00001
What is given to alcoholics to replace their lost vitamins
What are the stages of encephalopathy
vitamin B1 –to alcohol users to prevent a type of brain damage called Wernicke encephalopathy. It’s vitamin B1, or thiamine, a substance that plays a key role in converting the foods we eat into energy.
West Haven classification system, as follows [26] :
Grade 0 - Minimal hepatic encephalopathy (also known as CHE [27] and previously known subclinical hepatic encephalopathy); lack of detectable changes in personality or behavior; minimal changes in memory, concentration, intellectual function, and coordination; asterixis is absent.
Grade 1 - Trivial lack of awareness; shortened attention span; impaired addition or subtraction; hypersomnia, insomnia, or inversion of sleep pattern; euphoria, depression, or irritability; mild confusion; slowing of ability to perform mental tasks
Grade 2 - Lethargy or apathy; disorientation; inappropriate behavior; slurred speech; obvious asterixis; drowsiness, lethargy, gross deficits in ability to perform mental tasks, obvious personality changes, inappropriate behavior, and intermittent disorientation, usually regarding time
Grade 3 - Somnolent but can be aroused; unable to perform mental tasks; disorientation about time and place; marked confusion; amnesia; occasional fits of rage; present but incomprehensible speech
Grade 4 - Coma with or without response to painful stimuli
Or
Changes in behavior with minimal change in level of consciousness+1
Gross disorientation, drowsiness, possibly asterixis, inappropriate behavior+2
Marked confusion, incoherent speech, sleeping most of the time but arousable to vocal stimuli+3
Comatose, unresponsive to pain; decorticate or decerebrate posturing 4
What are the clinical signs of botulinum toxicity ,morphine toxicity ,alcohol,
Cyanide effects
BT:
nausea, vomiting, dysphagia, diplopia, dilated/fixed pupils, and an extremely dry mouth unrelieved by drinking fluids.
Morphine:
Bluish fingernails and lips.
Coma.
Constipation.
Difficulty breathing, shallow breathing, slow and labored breathing, no breathing.
Drowsiness.
Pinpoint pupils.
Muscle and skin damage (discoloration, blisters, ulcers) from being immobile while in a coma.
Nausea, vomiting.
Alcohol toxicity:
slurred speech, ataxia, and impaired judgment is common
Cyanide
Dizziness
Headache
Nausea and vomiting
Rapid breathing
Rapid heart rate
Restlessness
Weakness
Low blood pressure
Slow heart rate
Respiratory failure
