PCC 201 Exam 1 Questions and Solutions

PCC 201 Exam 1 Questions and Solutions What is the difference between a toxin and a toxicant? A toxicant is a substance that causes adverse effects in a plant, animal, or human by impairing vital metabolic functions. A toxin is a type of toxicant that is produced by a living organism. acute toxicity adverse effect seen soon after a one-time exposure to a chemical Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:04 / 0:15 Full screen Brainpower Read More chronic toxicity results from long term exposure to a lower dose of a chemical or an adverse effect that happens long after an exposure has ended local effects when exposed to a substance, the effects are experience at the point of contact with the skin, eyes, lungs, or GI tract systemic effects effects that are experienced on the whole after being absorbed into the body What is meant by the value LD50? LD50 is the dose killing 50% of the animals exposed to it additive chemicals in mixture exert effects in a similar manner, the chemicals do not interact, but the effect is added synergism combined effect is much greater, could be exponential antagonism one chemical interferes with the action of another, it acts as an antidote Explain what happens to a chemical after it enters the body. (ADME) o Absorption - absorbed into the bloodstream o Distribution - distributed throughout the body o Metabolism - metabolized by the body tissues and organs into different chemicals o Excretion - exerted from the body What are the four main routes of entry or exposure to chemicals. injection, inhalation, ingestion, skin absorption What are two factors affecting toxicity? Gender, age, nutrition Explain the relationship between risk, hazard, and exposure. Hazard + Exposure = Risk risk the chance of harmful effects to human health or to ecological systems resulting from exposure to an environmental stressor hazard a situation that poses a level of threat to life, health, property, or environment risk assessment provides information on potential health or ecological risks risk management the action taken based on the consideration of that and other information factors affecting risk management scientific, economic, social, political, legal Discuss the 4 Step Risk Assessment Process used by the EPA. 1) Hazard Identification - to identify the types of adverse health effects that can be caused by exposure to some agent in question, and to characterize the quality and weight of evidence supporting this identification 2) Dose-Response Relationship - to document the relationship between dose and toxic effect 3) Exposure Assessment - to calculate a numerical estimate of exposure or dose 4) Risk Characterization - to summarize and integrate information from the preceding steps of the risk assessment to synthesize an overall conclusion about risk List the three factors in an epidemiological study. host, environment, agent What difficulties are there in conducting epidemiological studies? confounding factors, exposure, community studies What is a safety or uncertainty factor? The highest dose that animals tolerate without showing ill effects, or the no observed adverse effect level (NOAEL) times 10 Give at least four examples of each of the following: administrative controls, engineering controls and personal protection. o Administrative Controls: rules, policies, resource allocation, training o Engineering Controls: design of facilities, processes, ventilation, fire alarms Personal Protection: safety glasses, aprons, gloves, breathing apparatus Discuss the benefits and problems with administrative controls (regulations) designed to minimize hazards in the environment. o May bring difficult risk/ benefit questions to a decisive point of closure o May take years/ decades of review/ discussion/ risk assessment o May be tightened/relaxed over time List at list four "dilemmas" of regulation. Doesn't ensure compliance, Unexpected or undesired responses, Sometimes unfair for specific industries or geographic locations, Limited resources Define Emergency Planning and Community Right to Know Act (EPCRA), when it was signed into law, following what event(s), and describe how it impacts companies and citizens today. o 1986 o Emergency planning - requires local governments to prepare for emergency fire, spills, gas leaks o Discloses information on public threats from toxic materials o Created the Toxics Release Inventory What is Right to Know (RTK), what two realms does it work in, and when did the movement begin and when was the legislation signed into law? o Citizens have the right to know about chemicals to which they are exposed o Two Realms: workplace, community o Movement started in the 1960's o Legislation enacted in mid-1980's o After Rachel Carson and 1984 Bhopal Incident Be able to correctly label each portion of the NFPA diamond with the category name and color (no need to list each of the 0-4 ratings). Also be familiar with the symbols used in the white section. o Left: Blue, 2, Health Hazard o Top: Red, 4, Flammability o Right: Yellow, 3, Instability o Bottom: White, W, Special Hazards What is the TRI and what is one major issue that people have with it? o Toxics Release Inventory: requires businesses to make public each year their emissions of any of about 600 chemicals o Problems: - Doesn't require the reduction of emissions, only reporting - Only tells the hazard of the emission but not the risk Provide a general description of the differences in vapor and liquid protection for the EPA Levels of chemical protective ensembles. Vapor is fully encapsulating Since the EPA provides only guidelines for chemical protective clothing, what does the NFPA provide in its standards that helps first responders and manufacturers? Different levels of classes with specific details about safety for first responders What are the different types of respiratory protection? o Self-Contained Breathing Apparatus (SCBA) o Air-Purifying Respirator (APR) o Powered Air-Purifying Respirator (PAPR)