Exam 2 Flashcards
What are the basic body systems involved in routes of entry and how do chemicals enter these systems?
Skin: Absorbed through sweat glands and hair follicles
Inhalation: Nose and mouth, most harmful when particles get to the lungs.
Ingestion: Particles can also be ingested through eating and mucous.
Define toxicology.
The study of the adverse effects of chemicals on biological systems.
The study of how natural or synthetic poisons cause
undesirable effects on living organisms.
Define and compare/contrast the different concepts of re-dose.
Exposure Dose: Measurable, external to the worker Absorbed Dose: Not as easily measurable, depends on individual factors, variability among individuals Threshold Concept: The point at which the first measurable effect is noted. Nearly all exposed will show no measurable effect. Acute: Sudden onset, short duration Chronic: Delayed onset, long duration Lethal Dose (LD): Meaningful in animal toxicological studies. Dose that will cause death in a given percentage of the population (usually 50%, LD50) Lethal Concentration (LC): Meaningful in inhalation exposure situations ppm
By which means does the body eliminate or excrete chemicals, after absorption?
Blood and Lymph to Kidney, Bladder, then Urine.
Blood and Lymph to Lung Alevoli, then Expired Air.
Gastrointestinal Tract to Feces.
Extracellular Fluid to Secretory Structures then Secretions.
Define and identify all routes of entry into the human body
Skin: Sweat Gland, Hair Follicle, Sebaceous Gland, Erector Muscle, Fat Cells
Respiratory System: Nasal Passage, Oral cavity, Pharynx, Larynx, Trachea, Lung, Bronchi
What are the major categories of health effects and identify chemical hazards that cause these effects?
Allergens (Sensitizers): A wide variety of materials can cause skin, lung, eye, and mucous sensitivity.
Asphyxiants: Chemicals that interfere with the oxygenation of tissues. Examples include carbon monoxide, hydrogen cyanide, and hydrogen sulfide.
Carcinogens: Agents that cause cancer or increase the risk of cancer either by initiating or promoting cancerous cell growth. Examples include asbestos, cigarette smoke, and arsenic.
Irritants: A reversible inflammatory effect on tissue at the site of contact. Primary irritants exert little systemic toxic action. Secondary irritants may cause a local effect but their main hazard is a systemic effect. Examples include ammonia and nitrogen dioxide.
What are the various exposure limit terms?
OSHA PELs: Employers shall ensure that no employees are exposed to PEL concentrations. 8 hour TWA.
OSHA Action Limits: Levels at which employers must implement control measures.
OSHA STELs: Levels at which employers shall ensure that no employee is exposed as a 15-min TWA.
NIOSH RELs: TWA 10 hour concentration above which employees should not be exposed.
NIOSH Ceiling Limits: Concentration should not be exceeded at any time during the work shift.
NIOSH IDLH: Immediately dangerous to Life and Health.
ACGIH Excursion Limits: Since TLV-8 hr is an average of all exposures, the employee is sometimes exposed above the level. (3)(TLV-8hr) for up to 30 minutes. (5)(TLV-8hr) never to be exceeded!
What are the chemical properties of particles, vapors, gases and apply these properties to occupational settings?
Gases: State of matter, molecules unrestricted by cohesive forces. Example industrial gas.
Vapors: Volatile form of a substance normally solid or liquid, evaporation, solvents with low boiling points. Example spraying an oil mist.
Aerosols/Particulates: Liquid droplets or solid particles, fine enough to remain suspended in the air for a prolonged time. Example dusts from concrete grinding.
What are the Baker and NFPA Rating Scales?
NFPA: Health, Fire, Reactivity scale from 0-4
Baker: Heath, Flammability, Reactivity, Contact scale from 0 to 4
Define, compare/contrast instantaneous and integrated monitoring
Instantaneous: Short-time period (seconds or minutes), Immediate results, used for isolated short-term processes when peak levels are anticipated
Integrated: Integrates all the various concentrations to which a worker is exposed throughout a work shift, collection of a sample continuously over a prolonged period, lab analysis usually required
What is the hierarchy of controls?
Elimination Substitution Reduction Containment/Removal Alarm Systems Work Process Design PPE
What are the various approaches to controlling chemical health hazards and be prepared to provide examples of each?
Substitution: Replacing more toxic materials with less toxic materials. Glassware cleaners: Benzene, Acetone, Soap and Water
Process Change: Selecting a different means or method of performing work, in order to reduce or eliminate the hazard. Wet methods, Automation.
Isolation: Creating separation between worker and hazard. Isolation of process or worker.
What are the different parts of the Local Exhaust Ventilation system?
Hood, duct, air cleaner, fan, stack
What are the differences between General and Local Exhaust (industrial) ventilation systems, including the conditions required for appropriate use of each?
General Ventilation: contaminants are of relatively low toxicity, contaminants consist of gases, vapors, and small aerosols (< 25 microns), small quantities of air contaminants are being released into the work environment at fairly uniform rates, sufficient distance between worker and contaminant source
Local Exhaust: contaminant is relatively toxic at low concentrations, the worker is near the source, emission rate varies over time, sources are large and few, and in a fixed location
What are the different types of LEV hoods?
Slot (Flanged), Plain (Flanged), Booth, Canopy, Plain multiple slot opening (Flanged)
